Dissertations / Theses: 'Chitosan nanoparticle'

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Zarate-Triviño, D. G., Acosta E. M. Valenzuela, E. Prokhorov, G. Luna-Bárcenas, Padilla C. Rodríguez, and Molina M. A. Franco. "Chitosan-Gold Nanoparticle Composites for Biomedical Application." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35404.

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The aim of this work is to synthesize chitosan-gold nanoparticles films by direct chemical reduction of HAuCl4 in a chitosan solution and to investigate the influence of gold nanoparticles concentration on the structure of films, conductivity and healing effect on mice skin after surgery. Results obtained have shown that new chitosan-gold nanoparticle-collagen bionananocomposites demonstrated better healing effect on the mice skin after surgery than control performed on commercial TheraFormTM material. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35404

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Saner, Brandon. "Physiochemical and Antibacterial Properties of Quaternized Chitosan Nanoparticle-Surfactant Mixtures." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1525440791263562.

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Patel, Nimitt G. "Fabrication and characterization of gold nanoparticle reinforced Chitosan nanocomposites for biomedical applications." Thesis, Clarkson University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3636199.

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Chitosan is a naturally derived polymer, which represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Polymeric materials can be regarded as promising candidates for next generation devices due to their low energy payback time. These devices can be fabricated by high-throughput processing methodologies, such as spin coating, inkjet printing, gravure and flexographic printing onto flexible substrates. However, the extensive applications of polymeric films are still limited because of disadvantages such as poor electromechanical properties, high brittleness with a low strain at break, and sensitivity to water. For certain critical applications the need for modification of physical, mechanical and electrical properties of the polymer is essential. When blends of polymer films with other materials are used, as is commonly the case, device performance directly depends on the nanoscale morphology and phase separation of the blend components. To prepare nanocomposite thin films with the desired functional properties, both the film composition and microstructure have to be thoroughly characterized and controlled.

Chitosan reinforced bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through a solution casting method. Gold nanoparticles (∼ 32 nm diameter) were synthesized via a citrate reduction method from chloroauric acid and incorporated in the prepared Chitosan solution. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed by SEM images. Synthesis outcomes and prepared nanocomposites were characterized using TEM, SAED, SEM, EDX, XRD, UV-Vis, particle size analysis, zeta potential and FT-IR for their physical, morphological and structural properties. Nanoscale mechanical properties of the nanocomposite films were characterized at room temperature, human body temperatures and higher temperatures using instrumented indentation techniques. The obtained films were confirmed to be biocompatible by their ability to support the growth and proliferation of human tissue cells in vitro. Statistical analysis on mechanical properties and biocompatibility results, were conducted. Results revealed significant enhancement on both the mechanical properties and cell adherence and proliferation. The results will enhance our understanding of the effect of nanostructures reinforcement on these important functional polymeric thin films for potential biomedical applications.

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Han, Yi. "Development and Evaluation of Mucoadhesive Chitosan Nanoparticle-based Salmonella Vaccine for Oral Delivery in Broiler Birds." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587571015936815.

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Picone, Carolina Siqueira Franco 1983. "Formação de nanopartículas por associação de biopolímeros e surfactantes = Formation of nanoparticles by biopolymer - surfactant association." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254194.

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Orientador: Rosiane Lopes da Cunha
Texto em português e inglês
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-20T12:57:32Z (GMT). No. of bitstreams: 1 Picone_CarolinaSiqueiraFranco_D.pdf: 4074904 bytes, checksum: 1a2779daa118fabb35ba241a8f6bf16f (MD5) Previous issue date: 2012
Resumo: As nano partículas possuem grande potencial para a liberação controlada de bioativos, porém ainda são pouco exploradas na área de alimentos. Neste trabalho foi estudada a formação de nanopartículas a partir da autoagregação de surfactantes, associação surfactante-polissacarídeo e complexação eletrostática entre diferentes polissacarídeos, no caso, quitosana e gelana. A compreensão das interações moleculares responsáveis pela formação das partículas e o conhecimento das variáveis que afetam sua formação permitem predizer e controlar suas propriedades. Tais interações dependem fortemente das características de cada macromolécula, como flexibilidade, estado conformacional e densidade de cargas que são diretamente afetadas pelas condições físico-químicas do meio como pH, força iônica e temperatura. Por isso, este trabalho foi dividido em três etapas. (I) Inicialmente foi avaliado o comportamento em solução dos polissacarídeos utilizados posteriormente para a formação de complexos. Os efeitos do pH e da temperatura nas características reológicas e no estado conformacional de soluções puras de gelana e quitosana foram estudados. A agregação da gelana foi mais sensível às alterações do meio que a quitosana. (II) Na segunda etapa, nanopartículas foram formadas por autoassociação de polissorbatos na presença de quitosana. A influência do comprimento da cauda hidrofóbica do surfactante e do pH do meio nas propriedades das partículas foi estudada por espalhamento de luz, reologia, condutivimetria e microscopia de luz polarizada. O tamanho e estrutura das partículas formadas pelo surfactante de menor cadeia hidrofóbica foram mais favoráveis à associação com a quitosana. O pH do meio (3,0 ou 6,7) não influenciou de maneira significativa as características das partículas. O efeito da concentração de quitosana na estrutura e tamanho de partículas foi analisado. Maiores concentrações levaram a viscosidades mais elevadas, impedindo a agregação das micelas e formando partículas menores. (III) No terceiro estudo, nanopartículas foram obtidas pela complexação eletrostática de gelana e quitosana. Os efeitos da razão de concentração de cada polissacarídeo, do tempo de estocagem a 25 °C e da presença de um surfactante nãoiônico (polissorbato) no tamanho, carga e quantidade de partículas formadas foram avaliados. Devido à menor densidade de carga e flexibilidade da gelana, maior quantidade deste polissacarídeo foi necessária para obtenção de partículas neutras. De forma geral, as partículas apresentaram aumento de tamanho ao longo das primeiras 100 horas após o preparo e não foram observadas mudanças significativas das propriedades das partículas devido à adição de surfactante. O método de preparo das amostras também foi estudado. Partículas preparadas pela mistura das soluções de polissacarídeos em dois passos foram consideravelmente maiores que as preparadas pela mistura em uma única etapa. Este trabalho confirmou a possibilidade de formação de nanopartículas promissoras para a encapsulação de bioativos em alimentos a partir da associação de biopolímeros e surfactantes, cujas propriedades poderiam ser moduladas em função da composição e condições de processo
Abstract: Nanoparticles are promising vehicles for bioactive delivery, but their potential has not been fully explored by the food industry. This work studied the formation of nanoparticles by self-assembly of surfactants, polysaccharide-surfactant association, and electrostatic complexes formed by different polysaccharides, especially chitosan and gellan gum. The knowledge of molecular interactions and the variables that affect particle formation allows predicting and controlling the properties of nanoparticles. These interactions depend on the characteristics of each macromolecule such as conformation, charge density and flexibility, which are affected by the physicol-chemical properties of the solution, such as pH, ionic strength and temperature. This work was divided in three parts: (I) Firstly it was studied the behaviour of each polysaccharide alone. The influence of the pH and temperature on the rheological properties and structural conformation of the pure gellan and chitosan samples was determined. Gellan aggregation was more strongly affected by such variables than chitosan. (II) In the second part, nanoparticles were obtained by polysorbate-chitosan association. The effect of the length of surfactant tail and the solution pH on the particle properties was studied by dynamic light scattering, rheological and conductivity measurements and polarizing microscopy. The size and structure of nanoparticles composed by the shorter surfactant were more appropriated to chitosan assembly. The pH (6.7 or 3.0) did not affect significantly the particle properties. The effects of chitosan concentration on particle structure and size were studied. Greater chitosan concentration led to smaller particles due to the increase in viscosity values which prevented micelles aggregation. (III) In the third study nanoparticles were produced by electrostatic complexation of chitosan and gellan gum. Particle size, charge density, stability and complexes number were evaluated as a function of polysaccharide concentration, chitosan:gellan ratio and the presence of a non-ionic surfactant. Due to the stiffness and low charge density of gellan gum, a greater amount of such polysaccharide was necessary to obtain neutral particles. Overall particles showed an increase in size during 100 hours of storage at 25 °C, but no significant changes on particle properties were observed due to surfactant addition. The methodology of particle preparation was also evaluated. Particles prepared by 2 mixing steps were markedly larger than those prepared by mixing polysaccharides in a single step (all together). This work showed that it is possible to produce nanoparticles with promising application on bioactive delivery by biopolymer-surfactant association, since their properties could be modulated as a function of composition and process conditions
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos

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Rayasam, Revanth. "Oral delivery of insulin for diabetes therapy : the design, fabrication and characterisation of a modified-chitosan based nanoparticle system." Thesis, Kingston University, 2017. http://eprints.kingston.ac.uk/41955/.

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A number of innovative techniques were developed for the extra-vascular delivery of insulin, of which oral delivery of insulin being one of the most active fields of study in pharmaceutics. Interest in this domain is due to two factors: the therapeutic potential of the approach and lack of delivery systems which demonstrate promising results for clinical implementation. Oral delivery of insulin is of a particular challenge due to highly evolved and complex barriers presented by the gastrointestinal tract (GIT). Long-term s.c. injections are invasive and are associated with major drawbacks such as pain, weight gain, hypoglycaemia, hyperinsulinemia, leading to low patient compliance and adherence. The present work aims to develop novel insulin-loaded chitosan (CS) and pegylated chitosan (CS-O-mPEG) based nanoparticles (NPs) and investigate them for potential colonic delivery. PEG-Chitosan was chemically conjugated using low molecular weight chitosan and mPEG-2000. Insulin loaded pegylated chitosan (CS-O-mPEG) NPs were prepared via the iontropic gelation technique by cross-linking with tripolyphosphate (TPP). The characteristics of the NPs i.e. particle morphology, particle size and zeta potential was evaluated. The effect of pH and the polymer:TPP wieght ratios on NP characteristics was also evaluated. An HPLC analytical method to quantify insulin was developed and validated. In vitro release and entrapment studies of the nanoparticles were conducted using the Franz diffusion cells. Prepared nanoparticle formulations were assessed for biocompatibility using the MTT (Tetrazolim dye) assay and permeability studies on the Caco-2 and MDCK monolayers. Successful CS-O-mPEG conjugation was confirmed by FTIR and 1H NMR spectroscopy. SEM revealed the spherical nature of CS and CS-O-mPEG NPs. A mean diameter ranging from 50 - 250 nm was recorded for the NPs. Characterisation of NPs for zeta potential was carried out for both the CS and CS-O-mPEG formulations. Particle size measurements for the NPs revealed size ranges between 110-250 nm, in accordance to the hydradynamic diameter measured by DLS. RP- HPLC analytical method was developed and validated according to ICH guidelines to quantify Insulin. The data showed presence of well-defined single insulin peak, being successfully recovered at retention time between 7.5 - 9 minutes. CS-O-mPEG NPs demonstrated maximum release in simulated intestinal fluids (SIF). There was some encouraging data obtained in regard to the biocompatibility studies for the prepared Insulin loaded NP formulations using MTT assay. Permeability studies were also conducted for the prepared NP formulations on Caco-2 and MDCK monolayers, revealing better permeation of insulin through the CS-O-mPEG NPs. Insulin-loaded NPs of CS and CS-O-mPEG were successfully formulated. CS-O-mPEG NPs demonstrated superior in vitro characteristics over the conventional CS NPs in terms of aqueous solubility, particle size, entrapment efficiency and drug release profile, In addition, permeation studies revealed that CS-O-mPEG NPs enabled a significantly higher insulin transfer across Caco-2 and MDCK cell monolayer models compared to the CS NPs making the former a promising candidate for oral delivery of insulin.

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Malli, Sophia. "Formulations multifonctionnelles pour le traitement des infections parasitaires cutanéo-muqueuses." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS043.

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Ce projet vise à proposer des nouveaux candidats médicaments pour lutter contre les infections parasitaires cutanéo-muqueuses qui représentent un problème de santé majeur. C’est notamment le cas de la Trichomonose urogénitale et la leishmaniose cutanée.Malheureusement, l’administration systémique de première intention par le métronidazole (MTZ) pour traiter la trichomonose urogéntitale occasionne des problèmes de résistances et des effets secondaires indésirables. Ainsi, nous avons développé de nouvelles stratégies thérapeutiques en ciblant à la fois les mécanismes pharmacologiques et physiques de l’infection par Trichomonas vaginalis. Après avoir réussi à augmenter la solubilité apparente du MTZ dans l’eau en utilisant une beta-cyclodextrine méthylée, nous l’avons formulé dans un hydrogel thermosensible et mucoadhésif composé de pluronic® F127 et d’un biopolymère cationique et mucoadhésif, le chitosane. Cette formulation est spécifiquement adaptée à une application topique tout en offrant un contrôle de la libération du MTZ et une réduction de son passage systémique à travers la muqueuse vaginale. La viscosité élevée de l’hydrogel à température corporelle nous a conduit à étudier son effet sur la mobilité du protozoaire Trichomonas vaginalis. Il s’agit d’une stratégie physique d’immobilisation du parasite en parallèle à la chimiothérapie par le MTZ. Le suivi des trajectoires des parasites par vidéo-microscopie a montré la capacité de l’hydrogel seul ou en association avec le chitosane à immobiliser complètement T. vaginalis et à inhiber son attachement à la muqueuse. Ces évaluations ont été réalisées chez la souris. Cependant, le chitosane seul n’a pas permis d’immobilier les parasites et n’a pas montré une activité anti-T. vaginalis propre. Dans ce contexte, nous nous sommes inspirés des travaux antérieurs menés par notre équipe sur le développement de formulations à base de chitosane, et plus particulièrement des nanoparticules (NPs) composées de poly(isobutylcyanoacrylates) recouvertes de chitosane. Ces NPs ont une activité trichomonacide propre, même sans rajouter des substances actives, alors que des NPs sans chitosane étaient inactives. Nous avons étudié le mécanisme d’action et nous avons montré une meilleure internalisation des NPs lorsqu’elles étaient recouvertes de chitosane. Ces NPs ont provoqué des altérations morphologiques drastiques de la membrane du parasite. Cette activité pourrait être due en partie à l’interaction électrostatique entre la surface de T. vaginalis chargée négativement et les NPs recouvertes de chitosane cationique.Dans le but d’élargir le champ des applications de ces NPs à d’autres parasites, nous nous sommes intéressés à l’évaluation de leur effet anti-leishmanien vis-à-vis de Leishmania major. En effet, le chitosane connu pour ces propriétés cicatrisantes nous a paru particulièrement adapté pour cette pathologie. Nous avons ainsi montré in vitro et in vivo que les NPs recouvertes de chitosane avaient une activité anti-L. major propre, sans ajouter de substances actives. Dans un deuxième temps, nous avons décidé de nous orienter vers des particules de formes allongées et d’évaluer leur activité anti-leishmanienne. Ces particules appelées « plaquettes » sont constituées d’assemblages de chitosane hydrophobisé avec l’acide oléique et l’alpha-cyclodextrine dans l’eau. Cette stratégie nous a paru intéressante pour améliorer l’interaction des plaquettes avec la membrane de L. major, vue que ces parasites sont également de morphologie non-sphérique. Les résultats histologiques et immunohistochimiques des lésions cutanées ont montré une diminution significative du granulome inflammatoire et une réduction de la charge parasitaire par rapport à l'amphotéricine B seule utilisée comme référence.En conclusion, au cours de cette thèse, plusieurs formulations ont été développées et ont montré des efficacités biologiques en agissant sur des mécanismes pharmacologiques et/ou physiques des parasites
This project aims at developing new therapeutic strategies against parasitic muco-cutaneous infections such as urogenital trichomonosis and cutaneous leishmaniasis which still represents a major health problem worldwide.Unfortunately, metronidazole (MTZ) is a first-line systemic treatment for urogenital trichomoniasis that causes resistance and side effects. We have thus developed new strategies by acting on both the pharmacological and the physical mechanisms of Trichomonas vaginalis infection. After a successfull increase of the apparent solubility of MTZ in water using a methylated -cyclodextrin, we formulated it in a thermosensitive and mucoadhesive hydrogel composed of pluronic® F127 and a cationic and mucoadhesive biopolymer, chitosan. This formulation is specifically adapted for topical application providing a control of MTZ release and reduction of its systemic passage through the vaginal mucosa.Then, the ability of the high viscosity hydrogel to immobilize T. vaginalis was investigated by video-microscopy. Monitoring the trajectories of each parasite by multiple particle tracking showed the ability of the hydrogel alone or in combination with chitosan to completely immobilize T. vaginalis and to inhibit parasite attachment to the mucosa. These evaluations were performed on mice experimental model. However, chitosan alone did not allow parasite immobilization and did not show any anti-T. vaginalis activity. In this context, we were inspired by previous works conducted by our team on the development of formulations based on chitosan, and more particularly nanoparticles (NPs) composed of poly(isobutylcyanoacrylates) coated with chitosan. These NPs have their own trichomonacidal activity, even without adding active substances, while NPs without chitosan were inactive. Investigated of the mechanism of the activity showed better internalization of NPs when coated with chitosan. These NPs caused drastic morphological alterations on the parasite membrane. This activity could be due to the electrostatic interaction between negatively charged T. vaginalis surface and cationic chitosan coated NPs.In order to broaden the applications of these NPs to other parasites, we were interested in evaluating the anti-L. major activity of NPs coated or not with chitosan. Indeed, chitosan known for its healing properties could be particularly adapted for this pathology. We thus showed in vitro and in vivo that NPs coated with chitosan had intrinsic anti-L. major activity without adding any drug. In a second step, we decided to design chitosan elongated particles and to evaluate their anti-leishmanial activity. These particles called "platelets" are composed of chitosan hydrophobically-modified with oleic acid and cyclodextrin in water. This strategy could be interesting to improve the interaction of platelets with the L. major membrane, as these parasites had also non-spherical morphology. The histological and immunohistochemical results of skin lesions showed a significant decrease in inflammatory granuloma and a reduction in parasitic load compared with amphotericin B alone, used as a reference.In conclusion, during this thesis, several formulations were developed and showed biological activities by acting on pharmacological and/or physical mechanisms of the parasites

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Bissonnette, Caroline. "Biodegradable Polylactide-co-Glycolide-Chitosan Janus Nanoparticles for the Local Delivery of Multifaceted Drug Therapy for Oral Squamous Cell Carcinoma Chemoprevention." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1590751959128008.

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Yoshida, Jony Takao. "Nanopartículas de quitosana como veículo de vacinação contra a hepatite B via nasal." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/9/9134/tde-15032013-163603/.

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A imunização por via nasal pode representar uma alternativa as imunizações intramusculares, pois a aplicação por essa rota não é invasiva e há fácil acesso da vacina à mucosa. Além disso, a mucosa nasal apresenta diversas características que podem favorecer a imunização, por exemplo, há uma grande área superficial altamente vascularizado disponível para a absorção dos antígenos. Outra característica fundamental é a capacidade da mucosa de responder a antígenos, através das células imunocompetentes presentes, como as células M e dendríticas. Apesar disso, outros métodos podem ser empregados para melhorar absorção e disponibilidade dos antígenos pela mucosa, como a utilização de polímeros biodegradáveis. Entre estes, a quitosana é um biopolímero, derivado da desacetilação da quitina, que tem como principal característica, a possibilidade de estrutura-los em nanopartículas. Outra característica importante é sua propriedade catiônica a qual possibilita a sua ligação a proteínas e também à mucosa, que provoca maiores taxas de retenção de antígenos pela mucosa. Assim, neste trabalho, foi avaliado a imunogenicidade da inoculação do antígeno de superfície da hepatite B (HBsAg), via mucosa nasal em camundongos, os quais produziram anticorpos IgG contra HBsAg, apresentaram aumento da secreção de IgA pela mucosa nasal, e também ao avaliar a resposta de citocinas em células RAW 264.7, houve secreção de TNF-α .
The nasal vaccination is not invasive since its do not require needles for your application and your administration for is easy, thus the immunization via nasal route could be an alternative to intramuscular immunizations. Furthermore, the nasal mucosa has several characteristics like highly vascularized surface area available for absorption of antigen that could elicited the mucosal immune response caused by the competents cell available on the mucosal tissue. Nevertheless, other methods can be employed to improve absorption and availability of antigens to the mucosa, such as the use of nanoparticles of chitosan. Chitosan is a biopolymer product of deacetylation reaction of chitin, that has as main characteristic, the moldability, which enables the production of nanoparticles and its cationic property which allows its binding to proteins and also to the mucosa, which would lead to higher rates of absorption of antigens through the nasal mucosa. Thus, this work investigated the immunogenicity of the administration nanoparticles of chitosan with the surface anti-gen of hepatitis B (HBsAg) via the nasal mucosa in mice, which show levels of IgA in nasal lavages and serum IgG, as well as cytokines such as TNF-α released by RAW 264.7 cells of mice.

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Cover, Natasha Faith. "A Novel Device and Nanoparticle-Based Approach for Improving Diagnosis and Treatment of pelvic Inflammatory Disease." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4020.

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Pelvic Inflammatory Disease (PID) is one of the most common causes of morbidity in women. PID is a polymicrobial infection of the female reproductive tract, and is associated with pelvic pain, abnormal uterine bleeding, and tubal damage that can lead to ectopic pregnancies and infertility. It is curable but the effects of PID can be permanent if not properly diagnosed and treated. PID presents as a spectrum of disease and is often missed at early stages; even acute PID can be difficult to diagnose, as there is no single conclusive diagnostic test. Currently, PID is identified and treated syndromically because pelvic pain is the only consistent clinical finding. The Center for Disease Control and Prevention (CDC) recommends doxycycline, a broad-spectrum antibiotic, for treatment but doxycycline can cause gastrointestinal irritation and local inflammation leading to an incomplete treatment. Most cases of PID are polymicrobial infections of the tubes and endometrium, which are not accessible to culture due to the difficulty of procuring samples above the naturally contaminated vagina and distal cervix. Given the difficulty of properly diagnosing PID and the limitations and side effects of the current treatments, there is an urgent need for new approaches for improving the accuracy for diagnosis and treatment of PID. We propose a new and practical approach to collect sterile specimen samples from the endometrium for more accurate PID diagnosis, and to treat the reproductive tract locally using doxycycline-loaded nanoparticles. The proposed research presents a novel sterile uterine sampler cover (SUSC) device that can safely and effectively collect uncontaminated specimen samples from the uterus, and also deliver nano-encapsulated drugs directly to the site of infection. The analysis of uncontaminated endometrium samples is expected to provide an understanding of uterine flora in symptomatic and asymptomatic women, and will lead to the identification of infective microbes in symptomatic women for pathogen-specific treatment. The use of nano-encapsulated doxycycline will enable localized drug delivery to lower drug dosage and minimize side effects for the patient. The doxycycline-loaded nanoparticles are characterized and evaluated based on their drug release properties, size distribution, and tissue response in vitro. This research will lead towards a more effective approach for the diagnosis and treatment of PID while freeing women from prolonged systemic treatments and their adverse effects. Moreover, this research will increase our understanding of the uterine biome under various hormonal and pathologic conditions, in symptomatic and asymptomatic women.

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Neto, Elias Antonio Berni. "Desenvolvimento de nanobiocompósitos contendo nanopartículas de prata para aplicações bactericidas." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-14062010-162736/.

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Neste trabalho de mestrado foram desenvolvidos nanobiocompósitos contendo quitosana (QS) e nanopartículas de prata (AgNPs) para aplicação em matrizes poliméricas com propriedades bactericidas. O trabalho foi conduzido em 4 etapas, sendo: i) a primeira referente ao estudo e escolha do melhor modo de estabilização dos colóides de prata em solução, sendo escolhido o modo de estabilização estérica com a quitosana (QS); ii) a segunda parte está relacionada com um estudo detalhado da interação entre a QS e as nanopartículas de prata (AgNPs) além da otimização da relação QS:AgNPs no nanocompósito para se obter maior ação bactericida; iii) foi também proposta uma rota de síntese na qual não se utiliza-se o Boro Hidreto de Sódio (NaBH4) como redutor, composto altamente reativo, sendo utilizados o citrato de sódio e QS conjuntamente como redutores; iv) inserção do nanocompósito QS:AgNPs em uma matriz de polivinil álcool (PVA). Foram utilizadas as técnicas de espectroscopia UV-vis e FT IR, DLS, Potencial Zeta, MET, DR-X, ensaios microbiológicos de MIC, OD595 e teste de halo de inibição, TGA, DSC e ensaios mecânicos. Concluímos que o uso da QS como agente estabilizante em comparação ao PVA é a mais indicada, devido ao maior número de grupos funcionais interagindo com as nanopartículas de prata. O poder de ação bactericida do nanocompósito QS:AgNPs pode ser aumentado numa certa relação entre ambos, a saber 4:1 em massa. A síntese utilizando citrato de sódio e QS como redutores mostrou a possibilidade da obtenção de nanopartículas de prata pequenas, com tamanho de 2 - 5 nm com estrutura esférica ou maiores. com tamanho de 300 nm, apresentando estruturas dendríticas, dependendo apenas do tempo de reação e concentração de citrato de sódio. A última etapa revelou a possibilidade da inserção do nanocompósito no polímero PVA sem perda significativa das características térmicas e mecânicas do polímero.
The work reported here was aimed at developing chitosan/AgNPs based nanobiocomposits for bactericidal applications. The studies were divided into four main steps, viz.,: i) optimization of the silver colloids stabilition process, in which the use of chitosan resulted in the best stability, ii) a detailed investigation on the interactions between chitosan and AgNPs, as well as the optimization of the chitosan :AgNPs ratio to promote the best bactericidal effect, iii) development of a new synthetic route without using NaBH4, in a search for an environmentally-friendly route, and iv) incorporation of the chitosan:AgNps nanobiocomposites in a PVA matrix for application as smart food packaging. The nanobiocomposites were characterizaed via UV-vis and FT IR spectroscopies, DLS, Zeta potential, TEM and DR-X. Biological essays had also been carried out, as well as tensilestress and thermo analyses (DSC and TGA). The best bactericidal effect was observed for a nanobiocompostie comprising chitosan:AgNPs at a ratio of 4:1 (wt/wt). The synthetic route employing sodium citrate as reducing agent resulted in AgNPs with average diameters of 2 5 nm, as well as bigger nanoparticles with diameters of ca. 300 nm, depending on the reaction time and citrate concentration. The incorporation of the chitosan:AgNPs composites in the PVA matrix resulted in the formation of a bactericidal composite with good mechanical and thermal properties, suitable for applications as smart food packing.

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Dhakal, Santosh. "Development and Evaluation of Nanoparticle-based Intranasal Inactivated Influenza Virus Vaccine Candidates in Pigs." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1529829066502348.

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Mannix, Oonagh. "Etude de complexes de nanoparticules et polysaccharides par diffusion de rayons X aux petits angles." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV068.

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Les propriétés macroscopiques et la stabilité d’une suspension colloïdale sont déterminées par sa microstructure et le comportement dynamique du système, qui résultent des interactions entre particules. Les systèmes colloïdales sont souvent métastables ; les corrélations entre particules ont donc une dépendance temporelle, affectant la microstructure ainsi que les propriétés macroscopique du système. Les systèmes colloïdaux peuvent être hiérarchiques : de petites particules colloïdales peuvent être utilisées comme blocs pour construire de plus grandes structures ; il faut donc examiner un tel système sur plusieurs échelles, pour caractériser les propriétés des structures de différentes tailles. Cette thèse exploite la technique de diffusion des rayons-x aux petits angles (DXPA), et aux très voire ultras petits angles (DXTPA, DXUPA), et la spectroscopie de corrélation de photons-x (XPCS) pour étudier la complexation colloïdale sur plusieurs échelles de temps et de dimensions. En examinant l’échelle spatiale de l’ordre de nanomètre au micromètre et l’échelle temporelle de quelques millisecondes à plusieurs mois le mécanisme de formation et l’évolution structurale des complexes peut être élucidé. Afin de relever les mécanismes d’une pertinence générale les matériaux employés dans ce travail sont de qualité technique. Cette étude porte tout particulièrement sur la complexation des nanoparticules de silice avec le chitosan, un polysaccharide cationique d’origine biologique. Premièrement, une modèle fractal est employé d’une nouvelle façon pour décrire les courbes de diffusion des suspensions de nanoparticules de silice polydisperse. Deuxièmement, les divergences importantes, qui ne sont pas facilement expliquées, entre la diffusion aux petits angles de chitosan par les neutrons et les rayons-x ainsi que par la diffusion statique de la lumière sont révélées. Après avoir caractérisé les matériaux de base, le mécanisme de complexation entre nanoparticules et polysaccharide de charges opposés est étudié par des mesures DXPA cinétiques à l’aide d’un mélangeur rapide pour accéder aux temps courts. Les mesures statiques DXPA et DXUPA sont analysées pour élucider la structure des complexes dans le contexte d’un diagramme d’état. Finalement, la force ionique de la solution est fortement abaissée par dialyse, et le comportement subséquent du système est examiné. Étonnamment, aux temps courts, les dispersions dialysées ne x semblent pas significativement différentes des dispersions à forte force ionique ; aux temps longs, le comportement des échantillons dialysés diffère de celui des dispersions d’origine. Dans le système dialysé des cristallites de silice colloïdale sont observés. Ces résultats ainsi qu’une analyse de la dépendance du système en fonction de la température mettent en évidence la microstructure de ce type de complexation colloïdal
The macroscopic properties and long-term stability of a colloidal suspension are controlled by its microstructure. Inter-particle interactions determine the microstructure and dynamics of the system. Colloidal systems are often metastable and so the inter-particle correlations can change with time (and so change the microstructure, and macroscopic properties of the system). As smaller colloidal particles can be used to form larger structures with different properties it is necessary to examine a system across various size scales.In this PhD thesis a combination of small and ultra-small angle x-ray scattering (U)SAXS and x-ray photon correlation spectroscopy (XPCS) techniques are used to investigate colloidal complexation across both time and space. Spatial scales from nanometers (si{nanometre}) to microns (si{micrometre}) and time scales from milliseconds (si{millisecond}) to months were examined to elucidate the formation pathway and structural evolution of the complexes. To uncover general mechanisms of broad relevance this work uses technical-grade, non-ideal materials. The study is on the complexation of silica nanoparticles and chitosan, a bio-sourced, cationic polysaccharide.First, a new description for scattering data of polydisperse silica nanoparticles using a fractal model is employed. An investigation into the small-angle scattering of chitosan by neutrons and x-rays, and static light scattering reveals significant differences that are not readily explained. The investigation of nanoparticle and polysaccharide complexes uses kinetic SAXS measurements to study the formation pathways of the complexes, with rapid mixing experiments to access shorter times (stopped-flow apparatus). Combined USAXS and SAXS data are analysed to provide information on the complex structure within a state diagram. Salt was removed from the system using dialysis, and the subsequent behaviour of the system was investigated. It was found that the behaviour of the dialysed system differed to the behaviour of the non-dialysed system over long timescales. In the dialysed system the growth of crystallites of colloidal silica was observed. These results, along with an investigation into the temperature dependency of the system lead to some understanding of the microstructure of this type of colloidal complex

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Huang, Yan. "Micro- and Nanogel Formation through the Ionic Crosslinking of Polyelectrolytes." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1417781855.

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Pibre-Weber, Caroline. "Caractérisation et comparaison des propriétés immunostimulantes de nanoparticules biodégradables de poly(acide lactique) et de chitosane après adsorption de TLR ligands ou d’antigènes du VIH1." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10333/document.

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Les vecteurs nanoparticulaires comme systèmes de relargage contrôlé pour des applications vaccinales font l’objet d’intenses recherches, notamment dans le domaine du VIH1. Une approche novatrice consiste à co-administrer des molécules immuno-stimulatrices avec les antigènes d’intérêt, afin d’amplifier le recrutement et l’activation des cellules dendritiques (DCs). Un tel vecteur vaccinal stimulerait l’intensité de la réponse immunitaire et une immunité au niveau des muqueuses vaginales et anales pourrait être obtenue après vaccination. Des nanoparticules de poly(acide lactique) (NP-PLA) ou de chitosane/sulfate de dextrane (NP-CSD) ont été utilisées comme véhicules et adjuvants de protéines du VIH1, gp140 et p24. Le poly(I:C), ligand de TLR3 est la molécule immuno-stimulatrice retenue pour ses propriétés adjuvantes. Les NP-PLA et NP-CSD présentent un potentiel équivalent pour l’adsorption de protéines. Par contre, si les NP-CSD permettent l'adsorption du poly(I:C) (95%), elle est moins reproductible sur les NP-PLA. Pour chaque formulation, la capacité à induire in vitro la maturation des DCs a été évaluée en suivant les marqueurs CD25, CD80, CD83, par cytométrie en flux. L’adsorption de poly(I:C) sur les NP-PLA ou les NP-CSD amplifie les capacités de maturation de ces nanoparticules, un effet synergique étant observé avec les NP-CSD. Nos travaux montrent que la co-adsorption d’un TLR ligand, avec des antigènes protéiques du VIH sur des nanoparticules biodégradables, est possible et confère à la formulation vaccinale un effet immuno-stimulant in vitro. In vivo, les formulations vaccinales contenant du poly(I:C) induisent de très forts taux d’anticorps sériques chez la souris
Use of nanoparticulate vectors in vaccination as controlled release systems based on biodegradable polymers has been widely studied, particularly for HIV vaccine research. An innovative approach is to co-administer antigens of interest with immuno-stimulatory molecules to amplify the recruitment and activation of dendritic cells (DCs). Such a vaccine candidate could boost the intensity of the immune response, and mucosal immunity in vaginal and anal secretions could be obtained after vaccination.We used nanoparticles of poly(lactic acid) (NP-PLA) or chitosan / dextran sulfate (NP-CSD), as vehicles and adjuvants for HIV-1 proteins, gp140 and p24. Poly (I:C), TLR3 ligand molecule, is the immuno-stimulatory molecule chosen for its adjuvant properties. The NP-PLA and NP-CSD have shown their great potential as carriers of proteins. By cons, if NP-CSD allows the adsorption of poly(I:C) with a yield of 95%, the adsorption is less reproducible on NP-PLA. For each formulation, the ability to induce in vitro maturation of DCs was evaluated by following the marker CD25, CD80, CD83, by flow cytometry. Adsorption of poly(I:C) on the NP-PLA or the NP-CSD amplifies the maturation abilities of particles and has a synergistic effect with the NP-CSD.Our work shows that co-adsorption of a TLR ligand with HIV protein antigens onto biodegradable nanoparticles is possible and gives an immuno-stimulant effect to the vaccine formulation in vitro. In vivo, vaccine formulations containing poly(I:C) induce very high levels of serum antibodies in mice

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Giacalone, Giovanna. "Implant chargé en nanoparticules pour la libération contrôlée et le ciblage lymphatique de nucléotides et d’analogues nucléotidiques." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA114845.

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Les nucléotides naturels et les analogues nucléotidiques présentent des activités pharmacologiques importantes : par exemple, le nucléotide adénosine triphosphate (ATP) présente un intérêt pour le traitement de l'ischémie ou de plaques d'athérosclérose. L'utilisation clinique de ces molécules est cependant limitée en raison de la présence d'un groupe triphosphate, qui est sujet à l'hydrolyse in vivo, et responsable de la forte hydrophilie des molécules, ce qui limite fortement leur capture par les cellules cibles et l'accès à leurs cibles pharmacologiques intracellulaires. Pour surmonter ces limitations et permettre l'administration de nucléotides et d’analogues nucléotidiques, l'utilisation de systèmes de drug delivery comme les nanoparticules pourrait assurer la protection et l'administration ciblée des molécules actives. Cependant, les nanoparticules conçues pour l’administration intraveineuse ne sont pas toujours adaptées au traitement de certaines maladies chroniques. C’est pour cela qu’un implant sous-cutané avec des caractéristiques de libération prolongée peut représenter une alternative valable, tout en étant peu invasif et capable d’atteindre les tissus lymphatiques, cible importante de plusieurs thérapies.Le premier chapitre de cette thèse porte sur la formulation de nanoparticules pour encapsuler l’ATP ou la zidovudine triphosphate (AZT-TP), grâce à la présence du chitosane (CS). Ces nanoparticules sont formées par interactions ioniques entre les charges positives du chitosane et les charges négatives des groupes triphosphates de l’ATP ou de l’AZT-TP. Dans ce travail, les nanoparticules sont caractérisées et leur délivrance cellulaire de l’ATP et de l’AZT-TP est démontrée sur une lignée cellulaire de macrophages. Dans un deuxième temps, la stabilité de ces systèmes a été améliorée afin d'obtenir un meilleur comportement en conditions physiologiques. Cette amélioration de la stabilité a été obtenue par la complexation du fer(III) au chitosane (CS-Fe). Cette stratégie a été appliquée aux nanoparticules de tripolyphosphate (TPP) et d’ATP. Les nanoparticules ont été ensuite testées sur deux lignées de cellules macrophagiques, montrant une internalisation améliorée de l’ATP par rapport aux nanoparticules précédentes. Enfin, les nanoparticules à base de CS-Fe et ATP ont été dispersées dans une solution de PLGA, dans le but de mettre au point un implant à formation in situ. Une fois en contact avec les fluides physiologiques, la suspension prend la forme d’un dépôt solide. Des études de libération in vitro montrent la capacité des systèmes de retenir les nanoparticules à l’intérieur de la matrice et de les libérer de façon progressive pendant 5 jours. Après administration sous-cutanée chez la souris, les implants de PLGA contenant les nanoparticules ont retenu l’ATP au lieu de l’injection jusqu’à 50 heures, comparé à quelques heures pour l’ATP libre et les nanoparticules libres, montrant ainsi leur pertinence comme systèmes pour la libération prolongée de nucléotides
Natural nucleotides and nucleotide analogs display important pharmacological activities: for example the nucleotide adenosine triphosphate (ATP) could be an interesting molecule for the treatment of ischemia or atherosclerotic plaques. The clinical use of these molecules is however limited due to the presence of a triphosphate group, which is prone to hydrolysis in vivo, and responsible for the high hydrophilicity of the molecules, thereby strongly limiting their uptake by targeted cells and access to their intracellular pharmacological targets. To overcome these limitations and enable the administration of nucleotides and nucleotide analogs, the use of drug delivery systems such as nanoparticles may enable the protection and the targeted delivery of these drugs. Nanoparticles designed for intravenous injections are however not always convenient, e.g. in the case of chronic diseases. Therefore, a subcutaneous implant with sustained release features might represent a valid alternative, which is less invasive and can reach lymphatic tissues (important targets of many therapies). The first chapter of this thesis presents the formulation of nanoparticles to encapsulate ATP as well as zidovudine triphosphate (AZT-TP), thanks to the presence of chitosan (CS). These nanoparticles are formed through ionic interactions between the positive charges of chitosan and the negative charges of the triphosphate groups of ATP or AZT-TP. In this work, nanoparticles are characterized and their cellular delivery of ATP and AZT-TP inside a macrophage cell line is demonstrated. In a second time, the stability of these systems has been improved in order to obtain a better behavior in physiological conditions. This improved stability has been achieved through the complexation of chitosan to iron(III) (CS-Fe). This strategy has been applied to TPP and ATP nanoparticles. These nanoparticles have been tested on two macrophages cell lines showing an improved internalization compared to the previous ones. Finally, CS-Fe/ATP nanoparticles have been dispersed in a PLGA solution in order to develop an in situ forming implant. Once in contact with physiological fluids, the suspension turns into a solid depot. In vitro release studies show the ability of the systems to retain nanoparticles inside the matrix and to gradually release them over 5 days. After subcutaneous administration to mice, PLGA implants containing nanoparticles were able to retain ATP at the injection site for up to 50 hours, as compared to few hours of free ATP or free nanoparticles, showing therefore their relevance as sustained release systems of nucleotides

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Blanchard, Kévin. "Développement de nouveaux systèmes de délivrance de vaccins à base de polysaccharides." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1184.

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La vaccination, particulièrement chez les espèces animales, demeure toujours un outil efficace de préventions des maladies infectieuses. Les adjuvants sont des composants généralement indispensables dans la formulation des vaccins de par leurs rôles de vecteurs de l'antigène ainsi que de stimulateurs du système immunitaire. En effet, les antigènes seuls, pour la plupart, ne permette pas d'induire une protection satisfaisantes. Les propriétés uniques du chitosane, polymère naturel biocompatible et biodégradable, offrent un matériau de choix pour l'élaboration de nouvelles générations d'adjuvant tel que des nanoparticules ou des hydrogels.Les travaux de cette thèse ont portés sur l'élaboration d'adjuvants à base de chitosane chez l'animal. La préparation de solutions visqueuses de chitosane (0, 2 = Cp = 0,75 % (w/v)) en association avec différents types d'antigènes à savoir une souche atténuée de bactéries vivantes atténuées, de virus vivants atténués ou inactivités ainsi qu'une protéine recombinante purifié ont permis d'obtenir une réponse immunitaire chez les différentes espèces animales étudiées. Par ailleurs, le chitosane, par l'inspection des animaux durant les essais ainsi que post-mortem, a démontré une bonne innocuité ainsi qu'une résorbabilité satisfaisante. Dans le cadre du développement d'un système de relargage retardé d'antigènes, nous avons débuté l'élaboration d'un système permettant de prélever et d'injecter, via un système classique seringue/aiguille, une solution visqueuse gélifiante en conditions physiologiques (150 mM, 37°C). La diffusion plus lente d'un antigène associé à ce matériau a pour objectif d'améliorer la protection des animaux en stimulant de manière prolongée les différents acteurs du système immunitaire
Vaccination, especially in animal species, remains already an efficient tool in the prevention of infectious diseases. The carrier and immunostimulant properties of adjuvant allow increasing the action of antigen which, alone, is not enough capable to induce a long and strong immune response in host. The unique properties of chitosan, a biocompatible and biodegradable natural polymer, offer a choice material to elaborate new generations of adjuvant such as nanoparticles or hydrogels.This PhD works was focus on the development of chitosan-based adjuvant for animal species. The preparation of chitosan-based viscous solutions, with a polymer concentration from 0.2 to 0.75 % (w/v) mixed with different kind of antigens such as live attenuated bacteria, live attenuated or inactivated virus and a recombinant protein allowed obtaining an immune response in the studied animals. Moreover, the observation of animals during the protocol or in post-mortem inspections indicated a satisfying safety and resorbability. In vitro experiments were also conducted developing a syringeable and injectable in situ gelling chitosan-based hydrogel containing a model protein, destined to standard injection system. The slow release of antigen in the host should interact with the immune system longer increasing the final protection against diseases

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DODERO, ANDREA. "Electrospun Nanofibers as a Green Approach for the Development of Advanced Biomedical, Pharmaceutical, and Filter Materials." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1046151.

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The present Thesis focuses on the fabrication of polysaccharide – based nanofibrous mats via electrospinning technique primarily for, but not limited to, the development of wound healing patches with enhanced tissue regeneration capabilities. Specifically, this project arose to overcome the lack of methodologies concerning the proficient electrospinning of polysaccharides due to their poor processability, the requirement of hazardous and/or toxic solvents, and nanofiber inadequate stability in aqueous environments. To tackle this task, this Thesis proposes the use of poly(ethylene oxide), a biocompatible and water – soluble synthetic polymer able to increase the polysaccharide – based formulation spinnability, along with a simple washing – physical crosslinking treatment to fabricate pure polysaccharide nanofibers with boosted water resistance and marked biocompatibility. In the first Chapters, after a general discussion concerning the technological relevance and versatility of electrospinning technique together with its main applications, this Thesis concentrates on briefly presenting the properties of polysaccharide materials and their advantages with respect to synthetic polymers, as well as the experimental methodologies and characterization approaches used to achieve the investigated purpose. Then, either alginate or chitosan polysaccharides are employed for the fabrication of nanofibrous mats, whose physical – chemical properties, drug delivery capabilities, and biological responses are fully characterized. As a matter of fact, the developed systems effectively display a significant capacity to promote cell adhesion and proliferation along with proper mechanical, water – related, and drug release features, hence representing promising materials to be used in several biomedical and pharmaceutical products. Finally, the preparation of a multilayer nanofibrous patch comprised of an external hydrophobic stratum and an internal bioactive one is explored and discussed. To this end, combining a polyurethane nanofibrous layer with an alginate nanofibrous layer enriched with ZnO nanoparticles allows the fabrication of potential wound healing patches endowed with superior support and protective performances. These results are an important first step in making straightforward the electrospinning of polysaccharide materials granting the possibility to easily prepare nanofibrous meshes with potential uses in various application fields, with particular relevance in the biomedical and pharmaceutical industries where the bioactivity of these materials with respect to synthetic polymers plays a topical role.

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Hansson, Annasara. "Développement et évaluation in vitro d’un dérivé de chitosan fonctionnalisé avec des peptides RGD pour la cicatrisation." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10182/document.

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L’objectif du travail présenté dans cette thèse était de développer des nanoparticulesfonctionnelles ayant la capacité d’induire l’adhésion et la migration de kératinocyteshumains normaux. L’utilisation de systèmes particulaires pour favoriser l’adhésion etla migration cellulaire dans les processus de cicatrisation constitue une nouvelleapproche de l’ingéniérie tissulaire. Dans cette optique, un dérivé hydrosoluble du chitosan rendu fonctionnel par l’ajoutde peptides RGD a été développé. Les nanoparticules furent développées parcoacervation complexe entre le dérivé cationique du chitosan et le sulfate dechondroïtine anionique. La capacité du système particulaire à induire unchangement cellulaire phénotypique a été évaluée in vitro.Lors de l’évaluation de ce nouveau polymère, le succès de la synthèse a été montrépar l’absence de cytotoxicité et par la préservation de son activité biologique médiéepar les séquences RGD. Aussi bien les polymères que les nanoparticules ont induitl’adhésion et la mobilité de fibroblastes dermiques humains, confirmant le conceptde nanoparticules bio-actives. Cependant, concernant l’étude des interactions entreles nanoparticules et les kératinocytes, aucune conclusion n’a pu être tirée etd’autres travaux sont nécessaires. Pour résumer, un système particulaire bio-actif a été développé. Le choix despeptides RGD pour induire la migration des kératinocytes doit être réévalué, etl’utilisation de concentrations plus importantes, de mélange de peptides d’adhésionou l’utilisation de peptides d’adhésion différents doit être envisagée pour laréalisation d’études ultérieures
The aim of the work presented in this thesis, was to develop functionalizednanoparticles with the ability to induce adhesion and migration in normal humankeratinocytes. Using particulate systems to promote and support cell adhesion andmigration in epidermal restoration is a novel approach of tissue engineering.In this view, a water-soluble chitosan derivative functionalized with RGD peptideswas developed. Nanoparticles were formed through complex coacervation betweenthe cationic chitosan derivative and the anionic chondroitin sulfate. The particulatesystem was evaluated in vitro for its ability to change phenotype in cells.In the evaluation of the novel hybrid polymer, the successful synthesis wasconfirmed by the absence of cytotoxicity and a preserved bioactivity specific to theRGD-moieties. Both the polymer and the particles formed thereof induced celladhesion and spreading in human dermal fibroblasts, proving the concept ofbioactive nanoparticles. However, when investigating the interaction between thenanoparticles and keratinocytes, no clear conclusion could be drawn and furtherassays are required. To summarize, a bioactive particulate system was developed. The choice of RGDpeptides to induce migration in keratinocytes needs to be re-evaluated and higherconcentrations, mixtures of adhesion peptides or other adhesion peptides might beconsidered for further investigations

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Hajjali, Hassan. "Assemblage nanoparticules lipidiques solides-polysaccharide : étude des propriétés physico-chimiques pour la vectorisation d’un polyphénol." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0210/document.

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Ce travail porte sur la conception d'un système lipo-polysaccharidique sous forme d'un assemblage de taille micrométrique entre des nanoparticules lipidiques solides (SLNs) et un biopolymère. Le but est de formuler un vecteur pouvant : transporter un principe actif hydrophobe, résister aux conditions gastriques, et permettre un relargage contrôlé en conditions spécifiques. Le choix de la molécule active s'est porté sur un polyphénol, la curcumine, pour ses activités anti-oxydantes et anti-inflammatoires. Etant hydrophobe, la curcumine a été encapsulée dans des nanoparticules de beurre de karité qui est un lipide d'origine naturelle et solide à température ambiante. Les systèmes lipidiques ne résistant pas aux conditions gastriques, les nanoparticules ont été incluses dans une matrice de chitosane sous forme d'un assemblage micrométrique contrôlé par des interactions électrostatiques. Ce polymère naturel, chargé positivement grâce à la présence de groupements amines, résiste aux attaque des enzymes gastriques et présente des interactions spécifiques avec la muqueuse intestinale et notamment les mucines permettant ainsi un ciblage vers l'intestin et le côlon. La première partie de cette étude est focalisée sur le système beurre de karité-curcumine en absence de chitosane. L'effet du polyphénol sur la cristallisation du lipide a tout d'abord été étudié. L'influence de la composition du mélange ternaire (beurre de karité, tensioactif, eau) sur les propriétés des nanoparticules formées a ensuite été étudiée en utilisant la méthodologie des plans de mélanges. Cela a permis de contrôler la taille des SLNs formulées et de mettre ensuite en évidence l'influence de la taille des particules sur le taux d'encapsulation de la curcumine. La seconde partie est axée sur l'assemblage entre les nanoparticules et le chitosane. Des particules micrométriques ont ainsi été obtenues par interactions électrostatiques entre les SLNs encapsulant la curcumine et stabilisées par des phospholipides et le chitosane
This work deals with the design of a lipo-polysaccharidic system as a micrometric assembly between solid lipid nanoparticles (SLNs) and a biopolymer. The aim is to formulate a vector can: carry a hydrophobic active molecule, resist to gastric conditions, and allow a controlled release in specific conditions. Choosing the active molecule is carried on a polyphenol, curcumin, for its antioxidant and anti-inflammatory activities. Being hydrophobic, curcumin was encapsulated in shea butter nanoparticles, which is a natural lipid and solid at room temperature. Lipid nanocarriers are not resistant to gastric conditions; the nanoparticles have been included in a chitosan matrix in the form of a micrometric assembly controlled by electrostatic interactions. This natural polymer, positively charged due to the presence of amine groups, is resistant to attack by gastric enzymes and has specific interaction with the intestinal mucosa and in particular the mucin which can be useful as a carrier for curcumin in colon targeted drug delivery. The first part of this study focused on shea butter–curcumin system with the absence of chitosan. The effect of polyphenols on the lipid crystallization was studied. The influence of the composition of the ternary mixture (shea butter, surfactant, water) on the properties of the nanoparticles was then investigated by using the response surface methodology. This helped to control the size of SLNs and then to show the influence of particle size on the encapsulation efficiency of curcumin. The second part focuses on the assembling between the nanoparticles and chitosan. Micrometric particles were obtained through electrostatic interactions between SLNs encapsulated curcumin and chitosan

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Vo, Nguyen Dang Khoa. "Synthèse et propriétés de nanoparticules d’or par chimie sous rayonnement utilisant des polysaccharides naturels comme agents stabilisants." Thesis, Reims, 2013. http://www.theses.fr/2013REIMS021/document.

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L'objectif est la mise au point d'une méthodologie de synthèse des nanoparticules d'or en présence du chitosane sous rayonnement permettant l'obtention d'objet de taille homogène et contrôlée. Dans ce but, nous mettrons l'accent sur l'étude des interactions entre les ions Au(III) et le chitosane en solution avant irradiation. En effet, la coordination entre des unités de glucosamine et l'ion Au(III) favorise la réduction de Au(III) en Au(0) et la formation de nanoparticules d'or. Cela est démontré clairement par l'étude de l'influence du pH sur la formation de nanoparticule lors du vieillissement des solutions d'HAuCl4 en présence de chitosane. Ce phénomène a été avance pour expliquer tout au moins partiellement, le mécanisme de la réduction des ions Au(III) en présence du chitosane sous rayonnement. Il s'agissait de définir si le mécanisme de réduction des ions Au(III) en ions Au(0) suivait un processus classique tels qu'il a été décrit dans les travaux de Belloni et de Henglein, ou si la présence de chitosane influe sur ce processus. L'élaboration des nanoparticules d'or en présence du chitosane utilisé comme agent stabilisant a été réalisée sous irradiation par faisceau d'électrons ou par rayonnement gamma. L'influence des paramètres de synthèse (rapport du [GLA]/[Au(III)], conditionnement des échantillons, effet de la dose d'irradiation, effet du débit de dose, rôle d'un piégeur de radicaux ou d'électrons solvatés) a ensuite été évaluée sur les propriétés caractéristiques des solutions de nanoparticules d'or (taille, charge, résonance plasmon de surface). L'activité catalytique des nanoparticules synthétisées a été testée vis-à-vis de la réaction de réduction du 4-nitrophénol en 4-aminophénol par NaBH4.Mots-clés : or, nanoparticules, chitosane, coordination, irradiation, faisceau d'électrons, rayonnement gamma, 4-nitrophénol
The goal of this work is to develop a methodology for the synthesis of gold nanoparticles in the presence of chitosan under radiation to obtain a homogeneous object and controlled size. To reach this purpose, we will focus on the study of interactions between the ions Au(III) and chitosan in solution before irradiation. Indeed, the coordination between units of glucosamine and Au(III) promotes the reduction of Au(III) to Au(0) and the formation of gold nanoparticles. This is clearly demonstrated by the influence of pH on the formation of nanoparticles upon aging of HAuCl4 solutions in the presence of chitosan. This formulation has been used to explain the mechanism of reduction of Au(III) in the presence of chitosan in radiation. It was to define whether the reduction mechanism of ion Au(III) ions Au(0) followed a conventional process such as those described by the work of Belloni and Henglein, or if the presence of chitosan affects this process. The development of gold nanoparticles in the presence of chitosan used as a stabilizing agent was produced by the electron beam and gamma radiation. The influence of the synthesis parameters (report [GLA]/[Au (III)], sample conditioning, effect of irradiation dose, dose rate effect, role of a radical scavenger) on the characteristic gold nanoparticles was then evaluated (size, charge, surface plasmon resonance). The catalytic activity of these nanoparticles was tested towards the reduction reaction of 4-nitrophenol to 4-aminophenol by NaBH4.Keywords: gold, nanoparticles, chitosan, coordination, irradiation, electron beam, gamma radiation, 4-nitrophenol

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Muhsin, Mohammad Didare Alam. "Preparation and in vitro evaluation of a polymer based controlled release dry powder inhaler formulation for pulmonary delivery." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/71806/1/Mohammad%20Didare%20Alam_Muhsin_Thesis.pdf.

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This thesis described the synthesis of an L-leucine conjugate of the biodegradable polymer, chitosan and its potential application for the development of controlled release nanoparticulate dry powder inhaler (DPI) formulations. The study demonstrated that the physicochemical properties of conjugated chitosan nanoparticles had favourable effects on the dispersibility and controlled release profile of a model drug. The toxicity profile of the nanoparticulate formulation revealed promising outcome for its use in pulmonary delivery. The chitosan conjugate produced in this project would be useful for the application of polymer nanoparticulate systems for efficient lung delivery of drugs.

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Hsueh, Chang-Jung. "Development of Electrochemical Biosensors for Potential Liver Disease Detections of ALT & AST and Application of Ionic Liquid into Biosensing-Modified Electrodes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1364989187.

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Hijazi, Nibal. "Développement de composites nanostructurés à base de biopolyesters et de nanoparticules de chitosane générées par des procédés assistés par CO2 supercritique." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2014. http://www.theses.fr/2014EMAC0016/document.

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Dans une logique d’éco-conception et de développement durable, de nombreux travaux ont pour objectif l’étude de polymères biosourcés. Parmi les recherches menées à ce jour, une piste d’étude consiste à les structurer aux échelles micro et nanoscopiques tout en valorisant certaines de leurs propriétés spécifiques, l’objectif étant la création de matériaux à propriétés fonctionnelles originales et performantes. Dans ce contexte, une attention particulière a été portée sur l’utilisation du dioxyde de carbone supercritique (CO2-sc). En effet, sa capacité à se solubiliser en grande quantité dans de nombreux polymères et donc d’en modifier les propriétés (viscosité, tension interfaciale, …) peut permettre une amélioration des matériaux composites fabriqués. Ce projet s’intéresse plus particulièrement à l’élaboration d’assemblages de biopolymères nanostructurés et revêt deux enjeux principaux : (1) la synthèse de nanoparticules de biopolymères (dans notre cas, du chitosane), (2) l’élaboration d’assemblages de biopolymères nanostructurés. La première étape a consisté à concevoir et développer de nouveaux procédés de génération de nanoparticules de chitosane par des procédés utilisant le CO2-sc soit comme antisolvant soit comme agent de dissolution et d'atomisation. Pour la deuxième étape, des films composites à base de poly (acide lactique) PLA et de poly (hydroxybutyrate-co-valérate) PHBV ont été préparés par la voie hot-melt par extrusion bi-vis. Des analyses thermiques, moléculaires et structurales, morphologiques et de granulométrie ont permis de caractériser les films biocomposites ainsi produits
In a logic of eco-design and sustainable development, many works aim to study the bio-sourced polymers. Among these studies, a promising concept consists in structuring materials at micro and nanoscales while enhancing some of their properties, the objective being the creation of original materials with improved functional properties and performance. In this context, particular attention has been paid to the use of supercritical carbon dioxide (sc-CO2). Its ability to dissolve into many polymers in large quantities and thus to change their properties (viscosity, interfacial tension, ...), can improve both the composite material and its manufacturing process. This project focuses on the development of nanostructured biopolymers and addresses two main issues: (1) the synthesis of biopolymer nanoparticles (in this case, chitosan), and (2) the development of nanostructured biopolymers. The first step consisted in designing and developing new processing methods to generate biopolymer nanoparticles, using sc-CO2 as antisolvent agent or as dissolving and atomizing agent. For the second step, poly (lactic acid) PLA and poly (hydroxybutyric-co-hydroxyvaleric acid) PHBV based composite films were prepared by a hot-melt process by twin-screw extrusion of the nanoparticles and the matrix. Thermal, molecular and structural analysis, as well as morphological and particle size distribution studies allowed a good characterization of the biocomposite films

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Rusu, Viorel Marin. "Composite materials made of chitosan and nanosized apatite : preparation and physicochemical characterization." Phd thesis, Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2005/231/.

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Taking inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite were investigated. A new preparation approach based on a co-precipitation method has been developed. In its earlier stage of formation, the composite occurs as hydrogel as suspended in aqueous alkaline solution. In order to get solid composites various drying procedures including freeze-drying technique, air-drying at room temperature and at moderate temperatures, between 50oC and 100oC were used. Physicochemical studies showed that the composites exhibit different properties with respect to their structure and composition. IR and Raman spectroscopy probed the presence of both chitosan and hydroxyapatite in the composites. Hydroxyapatite as dispersed in the chitosan matrix was found to be in the nanosize range (15-50 nm) and occurs in a bimodal distribution with respect to its crystallite length. Two types of distribution domains of hydroxyapatite crystallites in the composite matrix such as cluster-like (200-400 nm) and scattered-like domains were identified by the transmission electron microscopy (TEM), X-ray diffraction (XRD) and by confocal scanning laser microscopy (CSLM) measurements. Relaxation NMR experiments on composite hydrogels showed the presence of two types of water sites in their gel networks, such as free and bound water. Mechanical tests showed that the mechanical properties of composites are one order of magnitude less than those of compact bone but comparable to those of porous bone. The enzymatic degradation rates of composites showed slow degradation processes. The yields of degradation were estimated to be less than 10% by loss of mass, after incubation with lysozyme, for a period of 50 days. Since the composite materials were found biocompatible by the in vivo tests, the simple mode of their fabrication and their properties recommend them as potential candidates for the non-load bearing bone substitute materials.
Inspiriert von Natur, bei der Kompositmaterialien aus Polymermatrices und anorganischen Füllstoffen z.B. in Knochen, Krustentieren und Eierschalen vorzufinden sind, wurde die Herstellungsmöglichkeit von Kompositmaterial aus Chitosan und Hydroxyapatitdispersionen untersucht. Basierend auf einem Kopräzipitationsverfahren wurde eine neue Herstellungsmethode entwickelt, die als flexibler Zugang zu einem Spektrum von Komposittypen führt. In den frühen Phasen der Kompositbildung entsteht ein in der wässrigen alkalischen Lösung suspendiertes Hydrogel, das durch Filtration und Zentrifugation isoliert werden kann. IR und Ramanspektroskopie klären das Vorhandensein von Chitosan und Hydroxyapatit im Kompositmaterial. Hydroxyapatit ist als Nanopartikel der Größe von 15-50 nm in bimodaler Verteilung in der Chitosanmatrix dispersiert, und in durch Transmissionselektronenmikroskopie (TEM), X-Ray Diffraction (XRD) und Konfokaler Laserscanmikroskopie (CSLM) nachweisbaren 200-400 nm großen Clustern assembliert. NMR-Relaxationsmessungen an Hydrogelkompositmaterial decken die Existenz zweier Klassen vorkommenden Wassers im Netzwerk auf, gebundenes und freies Wasser. Mechanische Tests zeigen, dass die mechanische Festigkeit etwa eine Größenordnung unter der von massivem Knochen liegt, der Festigkeit von porösem Knochen aber gleichkommt. Enzymatische Abbauraten des Kompostimaterials sind als langsam einzuschätzen. Eine 50-tägige Einwirkzeit von Lysozym führte zu einem Abbau von 10 % der Kompositmasse. Die sich durch in vivo Tests herausstellende Biokompatibilität, die einfachen Herstellungsmöglichkeiten und die physikochemischen Eigenschaften empfehlen dieses Material als vielversprechenden Kandidaten für Knochenersatzmaterial in mäßig belasteten Bereichen.

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Ibrahim, Amir I. O. "Nanoparticles as advanced treatment modalities to disinfect the root canal system." University of the Western Cape, 2019. http://hdl.handle.net/11394/6624.

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Philosophiae Doctor - PhD
Persistent root canal pathogens are one of the main causes of endodontic treatment failure. These pathogens are usually isolated in areas within the root canals that are inaccessible to mechanical instrumentation, chemical irrigants and medicaments resulting in incomplete sterilization of the root canal system. Furthermore, the development of resistant microbial species renders it difficult to disinfect the root canal system using commonly available root canal irrigants and intra-canal medicaments. Intra-canal medicaments are antimicrobial agents that are placed inside the root canal system in order to eliminate the remaining microorganisms that persist after mechanical instrumentation and irrigation. However, their antimicrobial efficacy is effective only against some of the root canal pathogens. Furthermore, the presence of tissue inhibitory factors such as dentine powder and serum albumine within the root canal system inhibits their antimicrobial activity. The use of nanoparticles as antimicrobial agents has recently attracted considerable attention especially in the medical field as a result of their unique antibacterial properties. These properties include their ability to use multiple mechanisms to eradicate microbial cells and their low potentiality to produce microbial resistance. Polymeric nanoparticles such as chitosan nanoparticles (Ch-Np) gained significant interest as a result of their biocompatible and antimicrobial properties. In medicine, several vehicles were designed to carry these antibacterial nanoparticles. Zeolites (Ze) are microporous crystalline hydrated sodium aluminosilicate material that is utilized in the chemical sciences as a carrier for various nanoparticles.

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MELONI, MARIA CRISTINA. "Preparazione e caratterizzazione di due sistemi carrier: beads a base di chitosano e chitosano/alginato; nanoparticelle di N-trimetilchitosano." Doctoral thesis, Università degli Studi di Cagliari, 2012. http://hdl.handle.net/11584/266151.

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Chitosan is a very attractive polysaccharide and it is known to be a favorable pharmaceutical material because of its low toxicity, biodegradability, biocompatibility, mucoadhesivity and natural origin. Therefore it forms an ideal hydrophilic carrier system. In this study we described the preparation and characterization of two carrier systems, chitosan and chitosan – alginate beads, and N-Trimethyl Chitosan (TMC) chloride nanoparticles. We realized spherical beads using different polymeric dispersions, chitosan, alginate and chitosan - alginate mixture, to investigate their effect on the phytoterapic anti- inflammatory agent delivery. The main purpose of the present in vitro study is to have some information about their stability in the gastrointestinal tract and to formulate a drug delivery system for the oral administration of this phytoterapic agent. Alginate beads were prepared by ionotropic gelation in presence of CaCl2 and BaCl2 solutions; chitosan beads were prepared by using a TPP (tripolyphosphate) solution as an ionic cross-linking agent and acetone as a coacervating agent; beads of chitosan - alginate mixture were prepared according to the two combined procedures reported above. The swelling degradation behaviour of the bead samples and drug release were investigated using four different medium solutions (PBS pH 7.4, HCl 0.1N pH 1, buffer pH 5). TMC with different degrees of quaternization were synthesized and characterized by 1 H- NMR spectroscopy, XRD and viscosity. Trimethyl Chitosan chloride nanoparticles (TMC-NPs) were prepared according to the ionotropic gelation process of TMC with TPP. The aim of this study is to characterized TMC-NPs (particle size -Z-average mean-, PDI and zeta potential) and evaluate their potential for brain delivery.

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Roux, Rémi. "Élaboration d'assemblages colloïdaux à partir de nanoparticules de poly(acide lactique) et de chitosane." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10088/document.

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Les assemblages colloïdaux représentent une nouvelle piste très prometteuse dans le domaine de l'ingénierie tissulaire. Idéalement, ce type d'assemblage permet l'obtention de matériaux injectables et gélifiants sur le site lésionnel, favorisant par la suite le développement de néo-tissus viables. Ce travail porte sur la formation de tels assemblages à base de chitosane et de poly(acide lactique) (PLA). Deux types d'assemblages ont été conçus et étudiés dans ce travail. Dans une première approche, le mélange de particules anioniques de poly (acide lactique) (PLA) avec du chitosane en solution faiblement acide conduit à la formation de « gels composites », résultant des interactions colloïde-polymère. Des analyses rhéologiques et de diffusion des rayons X aux petits angles ont permit de mettre en évidence le mode de formation et l'influence de plusieurs paramètres sur les propriétés finales de ces gels. Notamment, ils présentent des propriétés rhéofluidifiantes et un caractère réversible, c'est-à-dire que le gel peut se reformer après déstructuration mécanique. Le second type d'assemblage résulte du mélange de particules anioniques de PLA et de nanogels cationiques de chitosane, conduisant à la formation de « gels colloïdaux », par interactions colloïde-colloïde. L'influence de plusieurs facteurs sur la formation et les propriétés de ces gels a également été étudiée par mesures rhéologiques. Notre étude s'est notamment orientée sur la caractérisation et la stabilité des hydrogels physiques de chitosane sous forme colloïdale, ainsi que sur l'optimisation de leur cohésion
Colloidal assemblies may be a promising pathway to obtain injectable scaffolds favoring the development of neo-tissue in regenerative medicine. This work investigates the formation of such assemblies composed of chitosan, soluble or in suspension (nano-hydrogel), and poly(lactic acid) (PLA) nanoparticles. Two types of assemblies are studied. As a first approach, mixing negatively charged PLA particles and chitosan solution leads to the formation of “composite gels”, based on colloidpolymer interactions. Rheological and Small Angle X-Ray Scattering measurements highlighted the formation process and the influence of various parameters on final properties of these gels, which features shear-thinning and reversibility behavior, that is, the capacity to gel again after yielding. PLA nanoparticles could also be mixed with cationic chitosan nanoparticles, which are crosslinker free nano-hydrogels, leading to the formation of “colloidal gels”, based on colloid-colloid interactions. Influence of various parameters on gel synthesis and properties are investigated through rheological measurements. The study also focuses on the characterization and control of the morphological and cohesion properties of chitosan nanogel

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MARCI, LUISA. "Studio di formulazione e caratterizzazione di nanoparticelle a base di trimetil chitosano e sodio alginato per il rilascio mirato di farmaci." Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266711.

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The purpose of this study was to develop positively charged nanoparticles (NPs) based on trimethyl chitosan (TMC) and sodium alginate (SA) as drug delivery systems able to interact with the sialic residues of the mucous membranes. The TMC has been synthesised in our laboratory slightly modifying literature procedure, and characterised by 1H-NMR spectroscopy. NPs were prepared with the ionotropic gelation method, using sodium tripolyphosphate (TPP) as cross-linking agent. Ten different nanoparticle formulations were developed by varying the concentration of one component, while keeping constant the other two, or by varying the ratio between the components. The aim of this formulation study was to determine the effect of both polymers and cross-linker concentrations and their ratios on nanoparticle dimensional parameters, such as mean size, size distribution, and surface charge. Overall results of the formulation study indicated that samples prepared with 2 mg/mL TMC concentration and different SA concentrations, namely 1 or 2 mg/mL, showed the best dimensional features, while the optimum concentration of cross-linking agent was 1 mg/mL. Moreover, nanoparticles showed a positive charge surface, suitable to interact with mucous membranes. Preliminary morphological examination of NPs was performed by scanning electron microscopy (SEM), and the interactions between polymers were examined by FTIR and 1H-NMR spectroscopy. The formulations which show best results in terms of size, size distribution, and surface charge have been used for the encapsulation of two model drugs for nose to brain drug delivery, progesterone (PG-NPs) and levodopa (LD-NPs), at different concentrations. Indeed, recent developments have proved the possibility of using the nasal pathway for direct transport of drugs from nose to brain. Both PG-NPs and LD-NPs have positive zeta potential (~ + 30 mV) and particle size dependent on the drug concentration. Encapsulation efficiency (EE%) has been calculated for both series, and the obtained data demonstrated that the average EE% values are ranging around 85-90% for PG-NPs and less than 20% for LD-NPs. Therefore, the studied drug delivery system seems to be more suitable for the encapsulation of lipophilic drugs (as PG) than hydrophilic drugs (as LD). We deeper characterised PG-NPs, in terms of stability and drug release profile. We found out that the release of the drug is constant and prolonged and that NPs are almost stable in solution for a 30-day period. In conclusion, this study reports on the preliminary results on TMC/SA NPs that could represent a promising strategy for nose to brain drug delivery. Further studies are required to confirm the potentiality of these systems, as cytotoxicity and ex-vivo permeation studies, and to evaluate their efficacy in vivo.

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Rotar, O. V., and V. I. Rotar. "Application of Chitosan / Cyclodextrin Nanoparticles for Tissue Glutathione Delivery." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35422.

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The aim of this study was to investigate an ability of chitosan nanoparticles for tissue delivery of the peptide glutathione. Formulations composed of chitosan or chitosan plus cyclodextrin-beta comlex were prepared. Reduced glutathione was loaded and delivered to mucosal layer of small intestine after ischemia-reperfusion injury more efficiently in chitosan/cyclodextrin-beta nanoparticles. From the data obtained, we believe that chitosan / cyclodextrin nanoparticles can be used for the oral administration of glutathione and other small peptides. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35422

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Vieira, Raquel Nadine Cadete. "Coating of magnetite nanoparticles with chitosan for magnetic hyperthermia." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21895.

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Mestrado em Materiais e Dispositivos Biomédicos
O cancro é uma das doenças com maior ocorrência na população mundial e com uma elevada taxa de mortalidade. Os principais problemas na luta contra o cancro prendem-se com a dificuldade de diagnóstico precoce, a citotoxicidade associada aos fármacos anticancerígenos usados em quimioterapia convencional e a falta de tratamentos mais eficazes. Com o advento da nanotecnologia, tem havido um crescente interesse na aplicação de nanopartículas e nanoestruturas, nas mais diversas áreas da ciência, nomeadamente em aplicações biomédicas. Neste contexto em particular, as nanopartículas magnéticas apresentam propriedades interessantes, por exemplo, em sistemas de libertação controlada de fármaco e em hipertermia. A sua aplicação em áreas relacionadas com a saúde, como o tratamento de cancro por hipertermia magnética, passa necessariamente por uma boa caracterização das suas propriedades e pela correta avaliação das suas capacidades de libertação de energia sob a forma de calor por indução magnética. Nesse sentido, este trabalho teve como objetivo a síntese de nanopartículas de magnetite devido a sua compatibilidade com o organismo humano e propriedades magnéticas. No entanto, devido ao seu elevado grau de agregação assim como facilidade de oxidação em meios aquosos existe uma necessidade de revestir estas partículas. Para tal, foi utilizado um biopolímero: a quitosana. A ligação do revestimento da quitosana ao núcleo do óxido de ferro foi realizada através de dois tipos de ancoragem: através da dopamina, conhecida pela sua grande afinidade aos grupos aminas e através do ácido cafeico, por apresentar uma similaridade estrutural à dopamina. Para a caracterização estrutural e morfológica das partículas recorreu-se à difração de raios-X (DRX), à espetroscopia de infravermelhos com transformada de Fourier (FTIR), à dispersão dinâmica da luz (DLS), ao Potencial Zeta e à microscopia eletrónica de transmissão (TEM). As propriedades magnéticas foram medidas por magnetometria de SQUID (Superconducting Quantum Interferance Device). Por fim foi avaliada a capacidade das partículas sintetizadas para aplicação em hipertermia magnética.
Cancer is a disease with high incidence in the world population and equally with a high mortality rate. The main problems in the fight against cancer are linked to the difficulty of early diagnosis, the cytotoxicity associated with anticancer drugs used in conventional chemotherapy and the lack of more effective treatments. With the advent of nanotechnology, there has been increasing interest in the application of nanoparticles and nanostructures, in several areas of science, such as biomedicine. In this context, the magnetic nanoparticles have interesting properties in controlled drug release systems and hyperthermia. Its application in areas related to health, such as the treatment of cancer by magnetic hyperthermia, necessarily requires a good characterization of their properties and the correct assessment of their ability to release energy in the form of heat by magnetic induction. Therefore, this study aimed the synthesis of nanoparticles of magnetite due to their biocompatibility and magnetic properties. However, due to their high degree of aggregation as well as facile oxidation in aqueous media there is a need to coat these particles. For this purpose, a biopolymer was used: chitosan. The binding of the coat to the core of the iron oxide was accomplishment through two types of anchorages molecules: dopamine, knowing for their great affinity with amine groups and through caffeic acid due to structural similarity to dopamine. The structural and morphological characterization was performed using X-ray diffraction (DRX), Fourier transformed infrared spectroscopy (FTIR), dynamic light scattering (DLS), Zeta Potential; thermalgravimetric analysis and transmission electron microscopy (TEM). The magnetic properties were studied using a Superconducting Quantum Interference Device (SQUID) magnetometer. Finally, we evaluated the ability of some of the synthesized NPs for use in magnetic hyperthermia.

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Wang, Hui. "Development of nicotine loaded chitosan nanoparticles for lung delivery." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/108006/1/Hui_Wang_Thesis.pdf.

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This research offers a specific strategy for the management of a global health problem associated with smoking addiction. Novel controlled release nicotine-loaded chitosan nanoparticles have been developed as a potential therapy. In vitro and in vivo evaluation of these nanoparticles indicate that they are suitable as dry powder inhaler formulations for pulmonary delivery. Results from a mouse model should translate to humans to provide a safe and effective approach to treat smoking dependence.

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Miladi, Karim. "Élaboration de nanoparticules contenant l’alendronate de sodium pour une application en ostéoporose." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10231/document.

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L'ostéoporose est la maladie métabolique la plus fréquente qui touche l'os. Plusieurs substances actives sont utilisées pour le traitement pharmacologique de cette maladie. Cependant, ce sont les bisphosphonates et surtout l'alendronate de sodium, qui sont prescrits en première intention. L'alendronate de sodium est, en effet, très efficace mais présente une faible absorption quand il est administré par la voie orale. Sa solubilité dans l'eau est de 20 mg/ml. Il présente en outre une faible biodisponibilité (de 0,6 à 0,7%). Cette substance active est aussi à l'origine d'effets indésirables d'irritation au niveau de l'oesophage, l'estomac et l'intestin. Ces effets sont dus à un contact local des cristaux de la substance active avec la muqueuse. L'approche d'encapsulation des substances actives dans des particules polymériques a permis d'obtenir plusieurs bénéfices thérapeutiques comme l'amélioration de la biodisponibilité et la diminution des effets indésirables. Dans la première partie de notre étude, on a réalisé l'encapsulation de l'alendronate dans des nanoparticules à base de poly-epsilon-caprolactone en utilisant la nanoprécipitation et l'émulsion double. Les nanoparticules obtenues ont une forme sphérique et une taille comprise entre 200 et 450 nm. Le meilleur pourcentage d'encapsulation a été de 34% et il a été obtenu avec la technique d'émulsion double. Ceci confirme que cette méthode est plus adaptée à l'encapsulation des molécules hydrophiles. Le profil de libération in vitro a montré deux phases : une première phase de libération relativement rapide et une deuxième phase beaucoup plus lente. L'analyse par modélisation mathématique a montré que la libération in vitro de l'alendronate se fait par diffusion et relâchement des chaines polymériques
Osteoporosis is the most frequent metabolic disease that affects bone. Many actives have been used as pharmacological treatment of this disease. However, bisphosphonates, especially, alendronate sodium, are indicated as first line regimen. Alendronate is highly efficient but presents low absorption after oral administration. Its solubility in water is 20 mg/ml. It has also poor bioavailability (0.6-0.7%). In addition, this active could lead to many side effects, which are mainly related to the esophagus, the stomach and the intestine. Such effects are linked to a local contact of drug crystals with the mucosa. Encapsulation of active molecules allowed the obtaining of many advantages over conventional pharmaceutical forms such as, bioavailability and tolerance enhancement. In the first part of our study, we managed to encapsulate alendronate sodium in poly-epsilon-caprolactone nanoparticles via two techniques: nanoprecipitation and double emulsion. Obtained nanoparticles presented a spherical form. Their size ranged between 200 and 450 nm. The highest encapsulation efficiency value was 34% and was obtained via double emulsion technique. This confirms that double emulsion is more suitable for hydrophilic drugs encapsulation. In vitro release profile showed two phases: first phase of burst release and a second more prolonged phase. Mathematical modeling showed that alendronate in vitro release occurs by drug diffusion and polymer chain relaxation. In the second experimental part, we managed to find a more interesting alternative. In fact, we opted for the use of chitosan which is a natural hydrophilic polymer. One of the obtained advantages is the avoidance of organic solvents use. In addition, this approach allowed the enhancement of encapsulation efficiency as this value increased to 70%. The used technique is ionic gelation. It is a simple encapsulation technique that is based on the transformation of a dissolved polymer to a gel-like state

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34

Halladay, Jeff. "Chitosan nanoparticles for mucosal and intramuscular delivery of DNA vaccines." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17267.

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Gruškienė, Rūta. "Cationized and poly(ethylene glycol) modified chitosan derivatives and nanoparticles." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100702_105158-57314.

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The main aim of this work was to synthesize water-soluble chitosan – methoxy poly(ethylene glycol) (MPEG) graft copolymers and cationized chitosan derivatives of various structure and desirable graft density, and to study their properties. Novel chitosan-MPEG derivatives with different degree of substitution of chitosan were prepared for the first time by “click” chemistry. Several new schemes of the synthesis of chitosan-MPEG and additionally cationized chitosan derivatives were suggested based on protection of amino functionality by using chitosan-dodecyl sulphate complexes. Additional cationization of chitosan through its hydroxyl groups in alkaline medium enabled to prepare chitosan derivatives with very high charge density. A method of enzymatic hydrolysis of the cationized chitosans was proposed which allowed a tenfold decrease of the molecular weight of chitosan derivatives. Modification of chitosan by tartaric, citric or adipic acid yielded chitosan nanoparticles. Further modification of chitosan nanoparticles by dithiobenzendicarboxylate resulted in RAFT macroinitiators used as precursors of functionalized nanoparticles.
Pagrindinis šio darbo tikslas buvo susintetinti vandenyje tirpius norimos struktūros bei pakeitimo laipsnio skiepytuosius chitozano – polietilenglikolio (MPEG) kopolimerus bei katijonizuotus chitozano darinius ir ištirti jų savybes. Įvairaus pakeitimo laipsnio chitozano-MPEG skiepytieji kopolimerai susintetinti vykdant „klik“ chemijos reakcijas. Pasiūlyti nauji chitozano-MPEG bei papildomai katijonizuoto chitozano sintezės būdai, chitozano aminogrupių apsaugai naudojant chitozano kompleksus su dodecilsulfatu. Dalinai katijonizuoto chitozano darinius papildomai katijonizuojant šarminėje terpėje, gauti chitozano dariniai, turintys labai didelį krūvio tankį. Pasiūlytas katijonizuoto chitozano fermentinės hidrolizės metodas, kurį naudojant chitozano darinio molekulinę masę lengvai galima sumažinti dešimtimis kartų. Chitozaną modifikuojant vyno, citrinų arba adipo rūgštimis, susintetintos nanodalelės. Prie chitozano nanodalelių prijungus (4-cianpentano rūgšties)-4-ditiobenzenkarboksilatą, susintetintas makroiniciatorius gyvybingajai radikalinei polimerizacijai RAFT metodu.

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Prasanna, Maruthi. "Preparation and characterization of antigen loaded chitosan nanoparticles for immunization." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT1037.

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Les vaccins anti-pneumocoques existants sont basés sur des polysaccharides capsulaires de sérotypes sélectionnés et n'offrent qu’une protection incomplète contre les infections dues à ce pathogène, tout en favorisant un phénomène dit de remplacement sérotypiques. Les stratégies préventives actuelles impliquent le développement de vaccins basés sur des protéines pneumococcales communes. Dans cette étude, nous avons développé un glycoconjugué semi-synthétique (GC) en liant de manière covalente l'adhésine de surface du pneumocoque A (PsaA) avec un mime synthétique du polysaccharide capsulaire de Streptococcus pneumoniae sérotype 14 (Pn14TS). Des études d'immunisation chez la souris ont montré que le GC était capable d'induire des anticorps de type IgGs contre ses composants protéiques et sucres. Les GC-CNP ont été préparés en utilisant une méthode de gélification ionique simple, conduisant à des nanoparticules de taille 150 nm et un potentiel zêta de 30 mV. Les GC-CNPs ont montré une efficacité d'encapsulation de 70%, une stabilité colloïdale dans le liquide muqueux nasal simulé et ont pu contrôler la libération d'antigène plus de 24h. Ces nanoparticules ont montré de faibles niveaux de toxicité et ont pu induire une régulation positive des marqueurs de costimulation et d'activation des lymphocytes T. Les études d'immunisation chez la souris révèlent que, lors de l'immunisation S.C., les GC-CNP induisent une réponse IgG anti-PsaA et anti-sucre 100 fois et 10 fois plus élevées, que le GC nu. En résumé, l'étude démontre que le nanosystème à base de glycoconjugué semi-synthétique augmentait la réponse immunitaire
Existing pneumococcal vaccines are based on capsular polysaccharides from selected serotypes and provide no complete protection against pneumonia, and the major concern is serotype replacement. Current preventive strategies involve the development of vaccines based on common pneumococcal proteins. In this study, we have developed a semisynthetic glycoconjugate (GC) by covalently linking the pneumococcal surface adhesin A (PsaA) with a synthetic mimic of the capsular polysaccharide from Streptococcus pneumoniae serotype 14 (Pn14TS). Preliminary immunization studies in mice have shown that the GC was able to induce IgG antibodies against both of its protein and tetrasaccharide components. The GC-CNPs were prepared using a simple ionic gelation method, resulting in nanoparticles with 150 nm size and zeta potential of 30 mV. The GC-CNPs showed 70% encapsulation efficiency, colloidal stability in simulated nasal mucosal fluid and were able to control the antigen release more than 24h. These nanoparticles displayed low levels of toxicity and were able to induce the upregulation of costimulatory markers and T cell activation. Finally, the immunization studies in the mice reveal that, on S.C immunization the GC-CNPs displayed a 100-fold and 10-fold higher anti-PsaA IgG and anti-CP (capsular polysaccharide) IgG response respectively over the mice immunized with GC. In summary, the study demonstrates the semisynthetic glycoconjugate based nanosystem as a potential pneumococcal vaccine

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Wong, Chun Yuen Jerry. "Evaluation of Chitosan-Based Nanoparticles in Oral Delivery of Insulin." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/85866.

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Diabetes mellitus is a chronic metabolic disorder. To improve patient compliance and alleviate the unwanted side effects that are associated with insulin injections, the project aimed to evaluate the potential of nanoparticles in oral delivery of insulin. The developed nanoparticles maintained the bioactivity of the entrapped insulin, and demonstrated a balance in mucoadhesiveness strength and muco-penetrating capacity. The nanoparticles could preserve the physicochemical properties upon storage, and induce glucose uptake in skeletal muscle cells.

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Roux-Pertus, Charles. "Investigation de la Pulvérisation Électrohydrodynamique du Chitosan." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0335.

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Les méthodes électrohydrodynamiques (EHD) permettent avec un dispositif peu coûteux de mettre en forme un polymère sous forme de film ou de particules par pulvérisation électrohydrodynamique (P-EHD) ou encore sous forme de fibres par électrofilage. Les structures obtenues peuvent être très régulières et avoir des dimensions micrométriques ou submicrométriques. En raison de ces avantages, ces méthodes sont étudiées pour la mise en forme du chitosan. Ce polymère biosourcé présente de nombreuses qualités telles que la biocompatibilité, la biodégradabilité, l’activité antibactérienne ou encore la muco-adhésion.Cette thèse aborde les méthodes EHD et principalement la P-EHD du chitosan, un sujet attractif dont les applications étudiées sont vastes : on peut notamment compter le médical (ingénierie tissulaire, vectorisation), l’alimentaire (additifs et films alimentaires), le traitement des effluents ou encore le textile. Cependant cette méthode possède certaines limitations. Tout d’abord, le procédé présente une grande variabilité selon le chitosan utilisé, la préparation des solutions et la configuration utilisée. Ensuite les particules obtenues dans la littérature sont inhomogènes en taille, ce qui limite leur application, notamment en vectorisation. La question est alors de savoir comment obtenir des particules de chitosan de tailles contrôlées et homogènes. Pour répondre à cette question, une analyse critique de la littérature a permis de préparer une démarche expérimentale menée en quatre étapes : (1) caractérisation des chitosans employés, (2) mesure des propriétés physiques des différentes solutions, (3) étude de la stabilité du procédé, (4) détermination de la morphologie et de la distribution en taille des particules obtenues. Cette étude a permis de mettre en avant des paramètres permettant une P-EHD stable, le contrôle de la taille et de l’homogénéité des particules. Enfin, dans une démarche biomimétique la mise en forme du chitosan a été étudiée pour tenter de reproduire les structures qui confèrent des propriétés remarquables comme l’hygrochromie ou l’hydrophobicité pour des insectes tels que les scarabées et les cigales
Electrohydrodynamic (EHD) methods enable to produce with one low cost set-up polymeric films/particles by electrospray or polymeric fibres by electrospinning. Particles or fibres produced by these methods can be very uniform in size. Therefore, electrospray and electrospinning of chitosan are appealing topics of re-search. Chitosan is a bio-based material possessing numerous qualities such as biocompati-bility, biodegradability, antibacterial activity and muco-adhesion. This thesis deals with EHD methods with a focus on chitosan electrospray whose applications are abundant in health (tissue engineering, drug delivery), food (nutrients en-capsulation, cling film), wastewater treatment and textiles. However electrospray has several limitations. First, effective electrospray depends of the grade of the chitosan, of the preparation of the solution and of used set-up. Second, particle-size distribution reported in literature are broad whereas applications such as drug delivery require monodisperse particle-size distributions. Then, the question is to know how to produce chitosan particles of monodisperse controlled size. To answer this question, a critical analysis of literature led to an experimental approach divided in four steps : (1) characterization of chitosan, (2) measurement of chitosan solution properties, (3) study of stability of electrospray process, (4) assessment of deposit morphology and particle-size distribution. Finally, as part of a biomimetic approach, imitation with chitosan of natural shapes has been studied. These shapes are part of structures that confer striking properties such as hygrochromic behavior and hydrophobicity to insects

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39

Cai, Yuhang. "Ionically Crosslinked Chitosan Nanocarriers." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo149988637813977.

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40

Binase, Ntombikayise. "Novel gold nanoparticles of drought tolerance enabler GYY4137." University of the Western Cape, 2019. http://hdl.handle.net/11394/6986.

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>Magister Scientiae - MSc
Different nanoparticles have the ability to improve plant tolerance to drought stress. In the study we report for the first time novel morpholin-4-ium 4-methoxyphenyl (morpholino) phosphinodithioate capped- gold nanoparticles (GYY4137-capped AuNPs). The GYY4137 is a slow releasing hydrogen sulfide (H2S) donor. The GYY4137 AuNPs compared to preliminary experiments of L-serine and L-threonine gold nanoparticles. The nanoparticles were prepared using a simple reflux reduction method in a rolling boil flask at 80 oC. The uncapped GYY4137-AuNPs were relatively stable and had surface plasmon resonance at 562 nm compared to 524 nm and 560 nm of serine-AuNPs and threonine-AuNPs. The nanoparticles were capped with different concentrations (0.1-5 %) of water-soluble poly (ethylene) glycol (PEG) (Mw300) and 0.2% chitosan. The PEG did not fully encapsulate the gold nanoparticles, while the chitosan successfully produced positively charged gold nanoparticles. The formation of chitosan capped GYY4137-AuNPs were verified with UV-Visible spectroscopy (UV-Vis), High Resolution Transmission electron microscopy (HRTEM), Dynamic Light scattering (DLS) and the Zetasizer. The UV-Vis, HRTEM and STEM verified chitosan capped nanoparticles had a surface plasmon resonance peak at 560 nm, with icosahedral, tetrahedron and spherical shaped nanoparticles as the serine-AuNPs that absorb at 560 nm. The agglomerated threonine-AuNPs had a maximum absorbance peak at 524 nm. The chitosan GYY4137-AuNPs had hydrodynamic size of 347.9 nm and zeta potential of + 47 mV, while serine-AuNPs and threonine-AuNPs had hydrodynamic size of 110 nm, zeta potential of -2.9 mV and -230 mV respectively. The polydispersity index (PDI) of the chitosan capped gold nanoparticles was 0.357 compared to 0.406 of both the amino acid gold nanoparticles. The polydispersity index (PDI) showed that the nanoparticles were polydispersed nanoparticles with broad size range as confirmed by the HRTEM and STEM results/ of chitosan capped GYY4137-AuNPs. The sizes of the nanoparticles were 100 nm and 60 nm for GYY4137-AuNPs while the size serine-AuNPs were 60 nm. The gold nanoparticles structural compositions were further confirmed by energy-dispersive X-ray spectrometry (EDX) and Attenuated total reflection infrared spectroscopy (ATR-IR). EDX results proved successful gold nanoparticles synthesis by presence of the element Au in all three nanoparticles and the chitosan GYY4137-AuNPs had 48. 56 wt. % of gold. The FTIR-ATR new bands formation shows that new chemical bonds are formed between the reducing agents, the precursor gold salt solution and capping agents. The shifts showed successful encapsulation with chitosan in GYY4137-AuNPs. The chitosan encapsulation improved surface charge and reactivity of the gold nanoparticles to improve delivery of the hydrogen sulfide donor GYY4137 for later applications to plants.
2021-08-01

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41

lu, Yu-Fen, and 呂郁芬. "Cells activation and permeability of chitosan nanoparticle carriers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/00793847436111837672.

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碩士
大葉大學
生物產業科技學系
93
There were two major objectives in this thesis. First, investigation the process of preparing different molecular weight chitosan hydrochloride and then finding the optimal condition for forming nanoparticle in suspensions and studying the properties of these nanoparticles. Secondly, investigation the activity of chitosan hydrochloride nanoparticles by studying the effect of nanoparticles on Caco-2 in vitro cell cytotoxicity and permeability. Results showed that the molecular weight of chitosan hydrochloride was decreased from 1300 kDa to 730 and 400 kDa by prolonging ultrasonic degradation. The optimal pH value for preparation chitosan hydrochloride nanoparticle suspension was 6.4. Transmittance electron microscope (TEM) images of the suspensions showed that chitosan hydrochloride nanoparticle was spherical with mean diameter in the range of 50~130 nm. The activation and permeability tests of chitosan hydrochloride nanoparticle on Caco-2 proliferating cell and monolayer cell showed that these particles can increase both cells viability and enhance the opening of tight junction between cells and then increase the permeability. It is concluded from this study that chitosan hydrochloride nanoparticle was highly safe with their potential use as drug carriers.

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Peng, Liching, and 彭麗靜. "Albumin-Chitosan Oligosaccharide Hybrid Nanoparticle for Transdermal Insulin Delivery." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/51902115786667316272.

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博士
靜宜大學
應用化學系
101
The first aim of this study was to develop a novel system for nanoemulsion preparation. The formation of water-in-oil (W/O) nanoemulsions in isohexadecane /mixed nonionic surfactant/water system has been achieved by a using the phase inversion temperature (PIT) emulsification method. Effects of polyoxyethylene- 2 lauryl ether (C12E2) and polyoxyethylene- 4 lauryl ether (C12E4) on the water in isohexadecane emulsions were systematically studied. Ratios of the two-surfactant mixture, surfactant concentrations, and oil fraction were evaluated by gauging droplet size with the aid of photon correlation spectroscopy. Hydrophilic–lipophilic balance temperature (THLB) and phase diagram were used to characterize the nanoemulsion system. The stability of the emulsions prepared was assessed based on the change in droplet size as a function of time. Instability mechanisms including coalescence and Ostwald ripening for the nanoemulsion system are discussed. The addition of a second surfactant could provide more stable nanoemulsions with the minimum size than only one surfactant. The nanoemulsion composition was optimized and found to be highly stable over a 200-day storage period. The optimum composition for W/O nanoemulsion is isohexadecane/C12E2 /C12E4/water (70:6:4:20) wt%. The second aim of this study was to prepare the chitosan oligosaccharide (COS) and bovine serum albumin (BSA) hybrid nanoparticle for insulin delivery. The nanoparticle preparation, insulin encapsulation efficiency (EE) and in vitro skin permeation were systematically investigated. The BSA/COS hybrid nanoparticles were synthesized by using water-in-oil (W/O) nanoemulsion as the template and using 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide hydrochloride (EDC) as the cross-linking agent. The hybrid nanoparticles were collected by using the phase inversion temperature procedure and centrifugation. The hybrid nanoparticles were characterized with respect to their particle size and zeta potential. We found that the encapsulation efficiency of insulin on BSA/COS hybrid nanoparticles was 88.5% and the permeation flux was 81.04 μg /cm2 hr in porcine skin. The optimal procedure for nanoparticle preparation was 4% BSA, 2% COS and 2% EDC at a pH 5.5 condition reacted for 2 hours. The insulin-loaded nanoparticles showed a successful permeation through the porcine skin and the sustained release for insulin could be obtained. Our results highlighted the potentials of the hybrid nanoparticles for the insulin transdermal delivery.

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Chang, Szu-Min, and 張思敏. "Effect of ultrasound induced gene transfection by chitosan/alginate nanoparticle." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/49653412621727269311.

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碩士
國立臺灣大學
醫學工程學研究所
96
Recently, several studies demonstrated that interaction of ultrasound with nanoparticles; perfluorocarbon nanoparticles, liposomes, cationic polymers (micelles, PEI, DOTMA etc.) and microbubbles, may enhance drug and gene delivery in vitro and in vivo. Here, we first introduced ultrasound to a chitosan-mediated gene delivery system, and investigated its effect on the transfection efficiency of this system. During ionic gelation, chitosan and pAcGFP1-C1 plasmid DNA spontaneously interacted to yield Chitosan-DNA nanoparticles (Chi-DNA NPs) with mean Z-average diameters range of 227–292 nm while Chitosan-alginate-DNA nanoparticles (Chi-alg-DNA NPs) had diameters range of 536–654 nm at various N:P ratio, which could potentially protect DNA from nuclease attack and provide beneficial properties for gene delivery. In 293T cells, the transfection efficiency could be enhanced by ultrasound up-to 30% in Chi-DNA NPs (at 3:1 & 5:1 N:P ratio) and 25% improvement of total transfected cells in Chi-alg-DNA NPs (at all ratio we tested). In comparison, transfection efficiency in Hela cells of our system was similar to Lipofectamine™2000. In sum, the combination of the two promising gene transfection strategies, chitosan-based nanoparticle and ultrasound-induced gene delivery system, could enhance gene transfection in vitro depending on the cell type with relatively minor cytotoxicity compared to the commercial liposome gene delivery agent.

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Chang, Szu-Min. "Effect of ultrasound induced gene transfection by chitosan/alginate nanoparticle." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-3007200816473500.

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TZENG, YU-SAN, and 曾鈺珊. "Studies on the Permeability of Chitosan Nanoparticle in Oral Mucosa Cell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/91621896239102298105.

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碩士
大葉大學
生物產業科技學系
96
Five solutions of 5 mg/mL chitosan hydrochloride with different concentration (0, 0.25, 0.5, 0.75, and 1 mg/mL) genipin as crosslinking agent were prepared. These solutions were spray-dried to obtain chitosan hydrochloride particles A, B, C, D, and E, respectively. These particles were characterized by field emission scanning electron microscopy (FESEM). The FESEM indicated that the average size of the chitosan hydrochloride particles ranged between 223 and 264 nm. It was found that the particle size decreased and formed a folded surface morphology with increasing crosslinking agent concentration. Phase-contrast images of the filter-grown human squamous cell carcinoma KOSC-3 indicated that the cells appeared to be squamous cell. Results after KOSC-3 inoculation, 2~4 days was logarithmic growth phase. The MTT assay was used to test cytotoxicity of five samples to cultured cells. The experiments showed that crosslinked particles with a concentration less than 100 µg/mL in the culture medium were nontoxic to cell. The microscopic features displayed in the KOSC-3 histological sections showed the morphology similar to stratified squamous epithelium. Most cells tend to be unstable, and easily to languish. From the TEER results, the nanoparticles were found to cause the opening of cell junctions. The TEER tests had no deleterious effects on the cells as determined by trypan blue exclusion. Results showed that chitosan hydrochloride nanoparticles were capable to increase the permeability on the cells.

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LIN, Cheng-wei, and 林政衛. "Preparation of N,O-carboxymethyl Chitosan Nanoparticle as an Insulin Carrier." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/67647655940267538496.

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碩士
國立雲林科技大學
化學工程與材料工程研究所
95
The aim of this research is to Preparation N,O-carboxymethyl chitosan (NOCC)which is derivative of chitosan. Insulin- N,O-carboxymethyl chitosan nanoparticle were prepared by ionic gelation of N,O- carboxymethyl chitosan and tripolyphosphate pentasodium(TPP). The NOCC/TPP mass ratio and insulin initial concentration were studied and how influence insulin release phenomena. The physicochemical properties of nanoparticles were determined by particle size, zeta potential analysis, transmission electron microscope, FTIR, SS-NMR and XRD. Release study was conducted by in vitro investigation to simulate intestinal fluid and gastric fluid at 37℃. Insulin release were analysed by RP-HPLC. The result shows particles size increased with increasing NOCC/TPP mass ratio. All nanoparticles prepared by ionic gelation which zeta potential was positive. Release rate were decreased with decreasing NOCC/TPP mass ratio and increased with decreasing insulin initial concentration. The release profiles were fitted very well by the Higuchi release model.

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Wang, Y., Anaïs Pitto-Barry, A. Habtemariam, I. Romero-Canelón, P. J. Sadler, and Nicolas P. E. Barry. "Nanoparticles of chitosan conjugated to organo-ruthenium complexes." 2016. http://hdl.handle.net/10454/11262.

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Yes
The synthesis of nanoparticles of conjugates of caffeic acid-modified chitosan with ruthenium arene complexes is described. The chemical structure and physical properties of the nanoparticles were characterised by electronic absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), 1H NMR spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and circular dichroism (CD) analysis. The multi-spectral results revealed that caffeic acid is covalently bound to chitosan and chelates to {Ru(p-cymene)Cl}+. The DLS studies indicated that the Ru–caffeic acid modified chitosan nanoparticles are well-defined and of nanometre size. Such well-defined nanocomposites of chitosan and metal complexes might find a range of applications, for example in drug delivery.
We thank the National Natural Science Foundation of China (Project No. 21571154), the Jiangsu Overseas Research & Training Program for University Prominent Young & Middle-aged Teachers and Presidents, Leverhulme Trust (Early Career Fellowship No. ECF-2013-414 to NPEB), the ERC (Grant No. 247450 to PJS), EPSRC (EP/F034210/1 to PJS) and Science City (AWM/ERDF) for support, and EU COST Action CM1105 for stimulating discussions.

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48

Pontes, Jorge Filipe Rodrigues. "Chitosan/dextran sulfate nanoparticles: stability evaluation and assessment of the effect of different acidic media on nanoparticle preparation." Master's thesis, 2016. http://hdl.handle.net/10400.1/9913.

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Dissertação de mestrado, Ciências Farmacêuticas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016
Nanoparticles present great potential in drug delivery applications, yet there are some issues regarding their stability. In this context, this study was conducted to define the conditions to stabilize polysaccharide (chitosan/dextran sulfate, CS/DS) nanoparticles by a process of freeze-drying, assessing the cryoprotectant capacity of two sugars (sucrose and glucose). Additionally, it was also intended to find if the solubilisation of chitosan in different acids affected nanoparticle preparation and characteristics. CS/DS nanoparticles were produced by polyelectrolyte complexation and the suspensions adjusted to 1 mg/mL or 2 mg/mL. For the study of stabilisation by freeze-drying, three approaches were conducted: i) after production of nanoparticles, 5% or 10% (w/v) of glucose or sucrose were included in the suspension before freezing, being nanocarriers characterized for size and zeta potential before freeze-drying and immediately after freeze-drying and reconstitution; ii) nanoparticles were produced, and then stored at 4 ºC (no cryoprotectants added); iii) nanoparticles were produced, freeze-dried with cryoprotectants and then stored, in a desiccator, at room temperature, being characterized (size and zeta potential) every 15 days, after the needed reconstitution. Acetic acid and hydrochloric acid (HCl) at 0.1 and 0.01 M were used to solubilise chitosan. CS dissolved in HCl 0.1 M did not enable the production of nanoscale particles. When the remaining acids were test, nanoparticles had sizes above 500 nm. Furthermore, zeta potential presented an unexpected behaviour. Thus, it was concluded that this study needs optimisation. The storage of nanoparticle suspensions at 4 ºC resulted in instability after 50 days. Therefore, a freeze-drying approach was established. In general, the choice of cryoprotectant was the most important factor affecting the preservation of nanoparticle physicochemical characteristics. Moreover, results indicated that in short- and long-term periods, glucose presented a more suitable behaviour despite some variations.
As nanopartículas apresentam-se como uma interessante estratégia de veiculação de fármacos. Contudo, a sua estabilidade é uma limitação desenhado este estudo que pretende estabelecer condições de estabilização de nanopartículas polissacarídicas (quitosano/sulfato de dextrano, CS/DS) através de um processo de liofilização, avaliando-se a capacidade crioprotetora de dois açúcares. Adicionalmente, procurou-se entender a influência de diferentes ácidos usados na dissolução do quitosano no tamanho e potencial zeta das nanopartículas produzidas. Nanopartículas de CS/DS foram preparadas por complexação polieletrolítica e as suspensões ajustadas a concentrações de 1 e 2 mg/mL. Para a abordagem da liofilização, foram delineados 3 ensaios: i) após a produção das nanopartículas, foi adicionado crioprotetor à suspensão antes do congelamento e a sua caracterização foi realizada imediatamente após a liofilização; ii) as nanopartículas foram produzidas e armazenadas a 4 ºC, sem qualquer adição de crioprotetor e iii) as nanopartículas foram produzidas, liofilizadas com crioprotetor, e armazenadas num exsicador, à temperatura ambiente, tendo sido caracterizadas de 15 em 15 dias. O ácido acético e o ácido clorídrico (HCl) a 0.1 M e 0.01 M foram os ácidos usados para solubilizar o quitosano. Os veículos derivados do uso de quitosano dissolvido em HCl 0.1 M encontraram-se fora da escala nanométrica. Por outro lado, nos restantes, os tamanhos ficaram acima dos 500 nm. Além disso, o potencial zeta demonstrou uma tendência inesperada, pelo que este estudo requer otimização. O armazenamento de nanosuspensões a 4 ºC resultou em parâmetros de caracterização instáveis, a partir do dia 50. Desta forma, estabeleceu-se um protocolo de liofilização em que, no geral, a escolha do crioprotector foi o fator determinante que afeta a preservação das características fisico-químicas das nanopartículas. Além disso, os resultados sugerem que a glucose possui uma melhor capacidade crioprotetora, a curto e longo prazos, apesar das grandes variações que os dados revelaram.

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SHIEH, MIN-WEN, and 謝敏雯. "Cell Activation and Permeability of Chitosan Nanoparticle Carriers Prepared by Spray Drying." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/08915308347090309786.

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碩士
大葉大學
生物產業科技學系
94
The studies were to evaluate the characteristics of chitosan hydrochloride nanoparticles cross-linked with a cross-linking reagent, genipin. These particles were prepared by an improved spray drying process. The size, surface morphology and the degree of cross-linking were investigated by FESEM, FTIR, and the Ninhydrin reaction. To further understand the cytotoxicity and cell permeability involved in these chitosan nanoparticles, the MTT test and the transepithelial electrical resistance (TEER) were performed using the Caco-2 cells, respectively. Results showed that the sizes (between 231 nm to 298 nm) and surface morphology of the nanoparticles were influenced by the crosslinking level. With increasing amount of genipin (less than 1 mg/mL) in the reaction, the average particle sizes were decreased. While these particle were prepared at higher genipin concentration (higher than 1 mg/mL), the particle size was increased with increasing the genipin concentration. The FTIR studies revealed that chitosan reacted with genipin. Both FTIR and the Ninhydrin reaction test showed that the degree of cross-linking was increased with increasing the genipin used. The MTT test revealed that the cells viability decreased as genipin concentration increased at the tests using 1000 ug/mL of nanoparticles concentration. With the nanoparticles concentration less than 100 ug/mL in the culture medium, MTT data showed that these nanoparticles were none-toxic. In TEER results, the nanoparticles were found to cause a reversible and time-dependent decrease in transepithelial electrical resistance. In the meantime, the trypan blue exclusion data showed that these nanoparticles had no deleterious effect to the cell monolayers. This suggested that the nanoparticles had effect on the cells junction. We concluded that the obtained nanoparticles are potent absorption enhancer. The potential use of these nanoparticles can be an important contribution towards the development of effective delivery systems for drugs and other molecules.

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Wen-YuHsieh and 謝文裕. "A novel concept of therapy for tuberculosis: SPD gene delivery via Chitosan nanoparticle." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45914126127356019408.

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