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Artykuły w czasopismach na temat "Nanoparticles"
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Li, Meng, Liqiang Lin, Ruyan Guo, Amar Bhalla i Xiaowei Zeng. "Numerical investigation of size effects on mechanical behaviors of Fe nanoparticles through an atomistic field theory". Journal of Micromechanics and Molecular Physics 02, nr 03 (wrzesień 2017): 1750010. http://dx.doi.org/10.1142/s2424913017500102.
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At nanoscale, the mechanical response of nanoparticles is largely affected by the particle size. To assess the effects of nanoparticle size (e.g., nanoparticle’s volume, cross-sectional area and length) on mechanical behaviors of bcc Fe nanoparticles under compressive loading, an atomistic field theory was introduced in current study. In the theory, atomistic definitions and continuous local density functions of fundamental physical quantities were derived. Through the atomistic potential-based method, the mechanical responses of bcc Fe nanoparticles were analyzed in different sizes. The simulation results reveal that the ultimate stress decreases as Fe nanoparticle’s volume, cross-sectional area or length increases under compressive loading. Nonetheless, the Young’s modulus increases as nanoparticle size increases. In addition, for a fixed finite volume nanoparticle, this study indicates that the ultimate stress will increase as strain rate increases, but Young’s modulus will decrease with increasing strain rate. A loading–unloading study illustrates the energy dissipation due to irreversible structure changes in Fe nanoparticles.
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Karatrantos, Argyrios, Yao Koutsawa, Philippe Dubois, Nigel Clarke i Martin Kröger. "Miscibility and Nanoparticle Diffusion in Ionic Nanocomposites". Polymers 10, nr 9 (10.09.2018): 1010. http://dx.doi.org/10.3390/polym10091010.
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We investigate the effect of various spherical nanoparticles in a polymer matrix on dispersion, chain dimensions and entanglements for ionic nanocomposites at dilute and high nanoparticle loading by means of molecular dynamics simulations. The nanoparticle dispersion can be achieved in oligomer matrices due to the presence of electrostatic interactions. We show that the overall configuration of ionic oligomer chains, as characterized by their radii of gyration, can be perturbed at dilute nanoparticle loading by the presence of charged nanoparticles. In addition, the nanoparticle’s diffusivity is reduced due to the electrostatic interactions, in comparison to conventional nanocomposites where the electrostatic interaction is absent. The charged nanoparticles are found to move by a hopping mechanism.
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Shannahan, Jonathan. "The biocorona: a challenge for the biomedical application of nanoparticles". Nanotechnology Reviews 6, nr 4 (28.08.2017): 345–53. http://dx.doi.org/10.1515/ntrev-2016-0098.
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AbstractFormation of the biocorona on the surface of nanoparticles is a significant obstacle for the development of safe and effective nanotechnologies, especially for nanoparticles with biomedical applications. Following introduction into a biological environment, nanoparticles are rapidly coated with biomolecules resulting in formation of the nanoparticle-biocorona. The addition of these biomolecules alters the nanoparticle’s physicochemical characteristics, functionality, biodistribution, and toxicity. To synthesize effective nanotherapeutics and to more fully understand possible toxicity following human exposures, it is necessary to elucidate these interactions between the nanoparticle and the biological media resulting in biocorona formation. A thorough understanding of the mechanisms by which the addition of the biocorona governs nanoparticle-cell interactions is also required. Through elucidating the formation and the biological impact of the biocorona, the field of nanotechnology can reach its full potential. This understanding of the biocorona will ultimately allow for more effective laboratory screening of nanoparticles and enhanced biomedical applications. The importance of the nanoparticle-biocorona has been appreciated for a decade; however, there remain numerous future directions for research which are necessary for study. This perspectives article will summarize the unique challenges presented by the nanoparticle-biocorona and avenues of future needed investigation.
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Sutthavas, Pichaporn, Matthias Schumacher, Kai Zheng, Pamela Habibović, Aldo Roberto Boccaccini i Sabine van Rijt. "Zn-Loaded and Calcium Phosphate-Coated Degradable Silica Nanoparticles Can Effectively Promote Osteogenesis in Human Mesenchymal Stem Cells". Nanomaterials 12, nr 17 (24.08.2022): 2918. http://dx.doi.org/10.3390/nano12172918.
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Nanoparticles such as mesoporous bioactive glasses (MBGs) and mesoporous silica nanoparticles (MSN) are promising for use in bone regeneration applications due to their inherent bioactivity. Doping silica nanoparticles with bioinorganic ions could further enhance their biological performance. For example, zinc (Zn) is often used as an additive because it plays an important role in bone formation and development. Local delivery and dose control are important aspects of its therapeutic application. In this work, we investigated how Zn incorporation in MSN and MBG nanoparticles impacts their ability to promote human mesenchymal stem cell (hMSC) osteogenesis and mineralization in vitro. Zn ions were incorporated in three different ways; within the matrix, on the surface or in the mesopores. The nanoparticles were further coated with a calcium phosphate (CaP) layer to allow pH-responsive delivery of the ions. We demonstrate that the Zn incorporation amount and ion release profile affect the nanoparticle’s ability to stimulate osteogenesis in hMSCs. Specifically, we show that the nanoparticles that contain rapid Zn release profiles and a degradable silica matrix were most effective in inducing hMSC differentiation. Moreover, cells cultured in the presence of nanoparticle-containing media resulted in the highest induction of alkaline phosphate (ALP) activity, followed by culturing hMSC on nanoparticles immobilized on the surface as films. Exposure to nanoparticle-conditioned media did not increase ALP activity in hMSCs. In summary, Zn incorporation mode and nanoparticle application play an important role in determining the bioactivity of ion-doped silica nanoparticles.
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Wang, Shenqing, Xiliang Yan, Gaoxing Su i Bing Yan. "Cytotoxicity Induction by the Oxidative Reactivity of Nanoparticles Revealed by a Combinatorial GNP Library with Diverse Redox Properties". Molecules 26, nr 12 (14.06.2021): 3630. http://dx.doi.org/10.3390/molecules26123630.
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It is crucial to establish relationship between nanoparticle structures (or properties) and nanotoxicity. Previous investigations have shown that a nanoparticle’s size, shape, surface and core materials all impact its toxicity. However, the relationship between the redox property of nanoparticles and their toxicity has not been established when all other nanoparticle properties are identical. Here, by synthesizing an 80-membered combinatorial gold nanoparticle (GNP) library with diverse redox properties, we systematically explored this causal relationship. The compelling results revealed that the oxidative reactivity of GNPs, rather than their other physicochemical properties, directly caused cytotoxicity via induction of cellular oxidative stress. Our results show that the redox diversity of nanoparticles is regulated by GNPs modified with redox reactive ligands.
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Zhang, Yong, Xiao Jing Zhao, Qiang He, Ye Jun i Qin Po Niu. "Experimental Study of Nanoparticle as Oil Additives". Advanced Materials Research 230-232 (maj 2011): 288–92. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.288.
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Cu nanoparticles as N32 base oil additives were studied in the paper. The structure of Cu nanoparticlcs was characterized by Transmission Electron Microscopy (TEM) and X-ray powder diffraction spectroscope (XRD). The widely used steel-steel friction system was chosen to test the feasibility and practicality of Cu nanoparticles as bearing lubricant additives. The results show that N32 base oil with 0.5% Cu nanoparticle can improve the test sample contact fatigue life than pure N32 base oil.
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Wang, Xijun. "The Magnetic Nanoparticle Movement in Magnetic Fluid Characterized by the Laser Dynamic Speckle Interferometry". Journal of Nanomaterials 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/287813.
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A dual scanning laser speckle interferometry experiment was designed to observe the dynamic behavior of the magnetic fluid actuated by a magnetic field. In order to improve the spatial resolution of the dynamic speckle measurement, the phase delay scanning was used to compensate the additional phase variation which was caused by the transverse scanning. The correlation coefficients corresponding to the temporal dynamic speckle patterns within the same time interval scattering from the nanoparticles were calculated in the experiment on nanoscale magnetic clusters. In the experiment, the speckle of the magnetic nanoparticle fluid movement has been recorded by the lens unmounted CCD within the interferometry strips, although the speckle led to the distinguished annihilation of the light coherence. The results have showed that the nanoparticle fluid dynamic properties appeared synergistically in the fringe speckles. The analyses of the nanoparticle's relative speed and the speckle pattern moving amount in the fringes have proved the nanoparticle’s movement in a laminar flow in the experiment.
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Caballero-Florán, Isaac H., Hernán Cortés, Fabiola V. Borbolla-Jiménez, Carla D. Florán-Hernández, María L. Del Prado-Audelo, Jonathan J. Magaña, Benjamín Florán i Gerardo Leyva-Gómez. "PEG 400:Trehalose Coating Enhances Curcumin-Loaded PLGA Nanoparticle Internalization in Neuronal Cells". Pharmaceutics 15, nr 6 (25.05.2023): 1594. http://dx.doi.org/10.3390/pharmaceutics15061594.
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This work proposes a combination of polyethylene glycol 400 (PEG) and trehalose as a surface modification approach to enhance PLGA-based nanoparticles as a drug carrier for neurons. PEG improves nanoparticles’ hydrophilicity, and trehalose enhances the nanoparticle’s cellular internalization by inducing a more auspicious microenvironment based on inhibiting cell surface receptor denaturation. To optimize the nanoprecipitation process, a central composite design was performed; nanoparticles were adsorbed with PEG and trehalose. PLGA nanoparticles with diameters smaller than 200 nm were produced, and the coating process did not considerably increase their size. Nanoparticles entrapped curcumin, and their release profile was determined. The nanoparticles presented a curcumin entrapment efficiency of over 40%, and coated nanoparticles reached 60% of curcumin release in two weeks. MTT tests and curcumin fluorescence, with confocal imaging, were used to assess nanoparticle cytotoxicity and cell internalization in SH-SY5Y cells. Free curcumin 80 µM depleted the cell survival to 13% at 72 h. Contrariwise, PEG:Trehalose-coated curcumin-loaded and non-loaded nanoparticles preserved cell survival at 76% and 79% under the same conditions, respectively. Cells incubated with 100 µM curcumin or curcumin nanoparticles for 1 h exhibited 13.4% and 14.84% of curcumin’s fluorescence, respectively. Moreover, cells exposed to 100 µM curcumin in PEG:Trehalose-coated nanoparticles for 1 h presented 28% fluorescence. In conclusion, PEG:Trehalose-adsorbed nanoparticles smaller than 200 nm exhibited suitable neural cytotoxicity and increased cell internalization proficiency.
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Chandra, Arun, i Nalina C. "Review on nanoparticles technology and applications based on drug delivery". IP International Journal of Comprehensive and Advanced Pharmacology 6, nr 3 (15.10.2021): 117–20. http://dx.doi.org/10.18231/j.ijcaap.2021.021.
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This review is about nanocrystal technology and applications of nanocrystals based on drug delivery. Nanocrystal technology is applied to the drug molecules to access for good drug delivery as nano dimensioned carrier. Nanoparticle has at least one dimension smaller than 100 nanometers. The major properties of nanoparticles are increases dissolution velocity by surface area enlargement and increase in saturation solubility. Nanoparticle’s productions are done with different methods such as precipitation method, Milling method, and homogenized method. Nanoparticles has got wide range of applications based on drug delivery such as gastrointestinal tract, brain, tumor cell targeting, respiratory tract, and gene delivery.
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Paulraj, Prabhavathi, Sankareswaran Muruganantham, Anbalagan S, Manikandan A i Karthikeyan G. "GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM WITHANIA SOMNIFERA (L.) DUNAL". Asian Journal of Pharmaceutical and Clinical Research 9, nr 5 (1.09.2016): 34. http://dx.doi.org/10.22159/ajpcr.2016.v9i5.13204.
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ABSTRACTThe metal nanoparticle synthesis is highly explored the field of nanotechnology. The biological methods seem to be more effective because of slowreduction rate and polydispersity of the final products. The main aim of this study is too the rapid and simplistic synthesis of silver nanoparticlesby Withania somnifera Linn. at room temperature. The exposure of reaction mixtures containing silver nitrate and dried leaf powder of W. somniferaresulted in reduction of metal ions within 5 minutes. The extracellular synthesized silver nanoparticles were characterized by ultraviolet-visible,infrared (IR) spectroscopy, X-ray diffraction studies, zeta potential, Fourier transform IR, and scanning electron microscopy. The antibacterial andantifungal studies showed significant activity as compared to their respective standards. From the results, W. somnifera sliver nanoparticle has attainedthe maximum antimicrobial against clinical pathogens and also seen very good stability of nanoparticle throughput processing. As we concluded, thistype of naturally synthesized sliver nanoparticle could be a better green revolution in medicinal chemistry.Keywords: Antimicrobial activity, Silver nanoparticles, Withania somnifera.
Rozprawy doktorskie na temat "Nanoparticles"
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Lemaître, Caroline. "Contribution à l'étude théorique, numérique et expérimentale des nanoantennes patch optiques". Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22742/document.
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Dans le domaine des biocapteurs, une absorption efficace du champ électromagnétique dans un espace restreint est essentielle. L’utilisation de nanoparticules métalliques assimilables à des métamatériaux est le meilleur moyen à ce jour pour amplifier le champ. En effet, en plaçant un film diélectrique entre une plaque métallique et ces particules, on permet la propagation d’un gap-plasmon sous les particules. Cela localise le champ magnétique sous les particules et le champ électrique sur le bords de ces nanoparticules. Les résonances de ce système sont très sensible à l’environnement du gap-plasmon ce qui permet une analyse très précise. Bien que nous pouvons expliquer d’où proviennent ces résonances, l’efficacité à absorber de ces structures reste encore mal comprise. Le contrôle interférométrique est une réponse à cette efficacité. Dans ce rapport, je montre qu’une modélisation interférométrique de ce système peut parfaitement expliquer l’absorption. En effet, le contrôle interférométrique explique bien la présence de résonances à des longueurs d’ondes précises ou encore l’apparition de résonances lorsque l’angle d’incidence n’est plus normal. Cette étude est très importante pour comprendre et mieux maîtriser les biocapteurs. En outre, cette modélisation pourra expliquer l’amplification du champ dans ces structures et permettra de prévoir les résonances d’un système dans divers environnementsIn the field of biosensors, efficient absorption of the electromagnetic field in a confined space is essential. The use of metallic nanoparticules comparable to metamaterials is the best way, to date, to amplify the field. In fact, by placing a dielectric film between a metal substrate and these particules, we allow the propagation of a gap-plasmon under these particules. This locates the magnetic field under these particules and the electric field on the edges of these nanoparticules. The resonances of this system are very sensitive to the environment of the gap-plasmon which allows very precise analysis. Although we can explain where these resonances come from, the efficiency to absorb of these structures remains poorly understood. The interferometric control is a response to this efficiency. In this report, I show that interferometric modeling of this system can fully explain the absorption. Indeed, the interferometric control well explains the presence of resonances at specific wavelenghts or the appearance of resonances when the angle of incidence is not normal. This study is very important to understand and master biosensors. In addition, this model can explain the amplification of the field in these structures and will allow us to provide the resonances of a system in various environments
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Barbero, Francesco. "Physicochemical characterization of the evolution of metal nanoparticles in biological and environmental media: from synthesis to interaction with living organisms". Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/670187.
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La producció creixent de Nanopartícules (NPs) conduirà inevitablement a un augment d’exposició humana i ambiental a aquests materials. En conseqüència, han sorgit preocupacions raonables sobre els seus possibles riscos per a la seguretat, donant lloc a la disciplina de nanotoxicologia/nanoseguretat.
A causa de l’alta reactivitat, les NP exposades a diferents escenaris biològics i ambientals, solen arribar a un estat termodinàmic més estable mitjançant l’agregació, la interacció amb les molècules presents al medi, l’adsorció a matèria macro-orgànica, les transformacions químiques i la dissolució. Totes aquestes transformacions poden generar una nova identitat dels nanoobjectes o produir noves entitats químiques, canviant així el seu comportament i, per tant, el risc potencial associat. Així, els mateixos NP poden tenir un destí totalment diferent i, en conseqüència, un impacte totalment diferent sobre els organismes vius i el medi ambient depenent del microambient (per exemple, el medi d’exposició) on es trobin. A més, les característiques primigènies del nanomaterial influeixen molt en la seva destinació biològica i ambiental. Des d’aquesta perspectiva, és fonamental comprendre les característiques de l’objecte final que toparà amb els organismes vius i analitzar les seves propietats, per tal de correlacionar les característiques prèvies i finals de NP amb els efectes potencials sobre els organismes vius.
En aquest context, aquesta tesi s’ha centrat en la transformació fisicoquímica dels NP model exposats a medis biològics i ambientals. Per a aquests estudis, es van triar NPs Au i Ag, ja que són models NP molt utilitzats i per les seves nombroses aplicacions. En primer lloc, l’estudi es va centrar en la influència de la composició de medis de cultiu cel·lular en el procés de formació de protein corona (PC), la composició final i l’estat d’agregació de NPs i els efectes consegüents sobre la captació de cèl·lules NP. També es va realitzar una caracterització fisicoquímica de la naturalesa de la bicapa CTAB - Au NP Au per estudiar l’impacte d’aquest recobriment de superfície NP àmpliament utilitzat en l’exposició de la partícula a fluids biològics, en la formació de la proteïna corona i en el disseny i interpretació de Proves de toxicitat NP. Finalment, es va explorar l’evolució del NP en aigua dolça natural mitjançant un estudi de la naturalesa d’interacció de les NP i de la matèria orgànica natural i de les característiques derivades del NP.La creciente producción de nanopartículas (NP) conducirá inevitablemente a un aumento de la exposición humana y ambiental a estos materiales. En consecuencia, han surgido preocupaciones razonables con respecto a sus posibles riesgos de seguridad, dando lugar a la disciplina de nanotoxicología/nanoseguridad. Debido a la alta reactividad, los NP expuestos a diferentes escenarios biológicos y ambientales tienden a alcanzar un estado termodinámico más estable a través de la agregación, la interacción con las moléculas presentes en el medio ambiente, la adsorción a la materia macro-orgánica, las transformaciones químicas y la disolución. Todas estas transformaciones pueden generar una nueva identidad de los nanoobjetos o producir nuevas entidades químicas, cambiando así su comportamiento y, en consecuencia, su riesgo asociado potencial. Por lo tanto, los mismos NP pueden tener un destino totalmente diferente y, en consecuencia, un impacto totalmente diferente en los organismos vivos y el medio ambiente dependiendo del microambiente (por ejemplo, el medio de exposición) en el que se encuentran. Además, las características prístinas del nanomaterial influyen mucho en su destino biológico y medioambiental. Desde esta perspectiva, resulta fundamental comprender las características del objeto final que encontrará organismos vivos y analizar sus propiedades, a fin de correlacionar las características de NP prístinas y finales con los posibles efectos sobre los organismos vivos. En este contexto, el objetivo de esta tesis ha sido el estudio de la transformacion fisicoquímico de NP modelo expuestos a medios biológicos y ambientales. Para estos estudios, se eligieron NPs de Au y Ag, ya que son modelos de NP ampliamente utilizados y debido a sus numerosas aplicaciones. En primer lugar, el estudio se centró en la influencia de la composición de los medios de cultivo celular en el proceso de formación de protein corona, la composición final y el estado de agregación de NP y los efectos consiguientes en la absorción de células NP. También se realizó una caracterización fisicoquímica de la naturaleza de la bicapa CTAB - Au NP para estudiar el impacto de este recubrimiento de superficie NP ampliamente utilizado en la exposición de la partícula a los fluidos biológicos, en la formación de la corona de proteínas y en el diseño e interpretación de Pruebas de toxicidad NP. Finalmente, la evolución de NP en agua dulce natural se exploró mediante la realización de un estudio de la naturaleza de interacción de NP y materia orgánica natural y las características derivadas de NP.
The increasing production of engineered Nanoparticles (NPs) will inevitably lead to an increase of human and environmental exposition to these materials. Consequently reasonable concerns have arisen regarding their potential safety risks, giving rise to the nanotoxicology/nanosafety discipline. Because of the high reactivity, NPs exposed to different biological and environmental scenarios, tend to reach a more stable thermodynamic state via aggregation, interaction with the molecules present in the environment, adsorption to macro-organic matter, chemical transformations and dissolution. All these transformations can generate a new identity of the nano-objects or produce new chemical entities, thereby changing their behaviour and consequently their potential associated risk. Thus, the same NPs can have a totally different fate and consequently a totally different impact on living organisms and the environment depending on the microenvironment (e.g., the exposure medium) in which they are. Furthermore, the pristine features of nano-material highly influence their biological and environmental fate. From this perspective, it becomes fundamental to understand the characteristics of the final object that will encounter living organisms and analyze its properties, in order to correlate the pristine and final NP features with the potential effects on living organisms. In this context, the focus of this thesis has been on the physicochemical transformation of model NPs exposed to biological and environmental media. For these studies, Au and Ag NPs were chosen as they are widely used NP models and because of their numerous applications. Firstly, the study focused on the influence of the cell culture media composition on the protein corona (PC) formation process, final composition and NPs aggregation state and the consequent effects on NP cell uptake. A physicochemical characterization of the nature of the CTAB - Au NP bilayer was also carried out to study the impact of this widely used NP surface coating on the particle’s exposition to biological fluids, on the formation of the protein corona and on the design and interpretation of NP toxicity tests. Finally, the NP evolution in natural fresh water was explored by carrying out a study of the interaction nature of NPs and natural organic matter and the deriving NP features.
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Díaz, Ocaña Raquel. "Recombinant self-assembling nanoparticles for cancer therapy based on toxin and venom compounds". Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/670483.
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La plataforma desenvolupada d’enginyeria de proteïnes auto-acoblables permet dissenyar nanopartícules únicament proteiques (NPs) capaces d’atacar i actuar selectivament sobre les cèl.lules canceroses mitjançant la interacció amb receptors que es sobreexpressen. Les estructures esfèriques estables de les NPs desenvolupades i la seva mida adequada, en combinació amb els pèptids d’orientació , milloren la seva especificitat. A més, la incorporació de segments de toxina i verí ha millorat els efectes terapèutics d’aquestes estructures que són totalment biocompatibles i que no tenen cap portador extern o material agregat, complint d’aquesta manera amb el nou concepte per a medicaments de precisió, que involucra un fàrmac recombinant lliure de vehicle, auto-acoblat, auto-dirigit i eficient.
Una versió modificada de la cadena catalítica ricina A, amb la capacitat de disminuir els efectes secundaris no desitjats de la síndrome de vessament vascular però conservant la seva citotoxicitat natural, es va adaptar a la plataforma de proteïnes. El disseny es va desenvolupar amb el pèptid T22, que s’uneix a CXCR4, en l’extrem N-terminal, i una cua d’histidines a la terminal-C, en combinació amb un fragment del lloc escindible de furina per alliberar la proteïna intracel.lularment, i una seqüència KDEL per evitar la secreció del reticle endoplàsmic. Les NPs de cadena de ricina A solubles purificades dirigides a CXCR4 amb un diàmetre mitjà de 11 nm, van assolir un increment de 100 vegades en la seva citotoxicitat amb un IC50 de 13 ± 0,5 x 10 -9 M en cèl.lules HeLa. També es van produir per mètodes recombinants i es van purificar cossos d’inclusió insolubles de 400-600 nm, amb resultats citotòxics parcials. El mecanisme d’entrada dependent del receptor d’T22-MRTA-H6 es va verificar i avaluar en un model de ratolí amb leucèmia mieloide aguda (AML) mitjançant la injecció sistèmica a la vena de la cua on es va verificar un bloqueig important de les cèl.lules leucèmiques sense toxicitat sistèmica o histològica lateral en els òrgans sans.
De manera similar, la clorotoxina (CTX) també es va incorporar a la plataforma de proteïnes per tal d’aprofitar la seva d’orientació i efecte terapèutic en glioblastoma (GBM), ambdues funcions en un sol pèptid. Es van dissenyar dues versions que s’uneixen a la proteïna anexina-2 i la metaloproteinasa de matriu MMP-2; CTX-GFP-H6 i CTX-KRKRK-GFP-H6. Les NPs solubles d’un diàmetre mitjà de 12 nm es van incubar en cèl·lules HeLa, sobreexpressant annexina-2, i en cèl.lules U87MG, sobreexpressant MMP2. Les dues versions eren completament fluorescents, però CTX-GFP-H6 va presentar efectes citotòxics lleus, mentre que CTX-KRKRK-GFP-H6 va mostrar ser més citotòxic en les cèl.lules U87MG que en les cèl.lules HeLa. L’afinitat selectiva de CTX es va confirmar mitjançant l’avaluació de la seva selectivitat utilitzant anticossos monoclonals i un sèrum policlonal contra la proteïna de la superfície cel.lular, actuant com un receptor de la CTX.La plataforma desarrollada de ingeniería de proteínas autoensamblables permite diseñar nanopartículas únicamente proteicas (NPs) capaces de atacar y actuar selectivamente sobre las células cancerosas mediante la interacción con receptores que se sobreexpresan. Las estructuras esféricas estables de las NPs desarrolladas y su tamaño adecuado, en combinación con los péptidos de direccionamiento involucrados, mejoran su especificidad. Además, la novedosa incorporación de segmentos de toxina y veneno ha mejorado los efectos terapéuticos de estas estructuras que son totalmente biocompatibles y que no tienen ningún portador externo o material agregado, cumpliendo de esta manera con el concepto emergente para medicamentos de precisión que involucra un fármaco recombinante libre de vehículo, autoensamblado, auto-dirigido y eficiente. Una versión modificada de la cadena catalítica de ricina A, con la capacidad de disminuir los efectos secundarios no deseados del síndrome de derrame vascular, pero conservando su citotoxicidad natural, se adaptó a la plataforma de proteínas. El diseño se desarrolló con el péptido T22, que se une a CXCR4, en el extremo N-terminal, y una cola de histidinas en el extremo C-terminal, en combinación con un fragmento del sitio escindible de furina para liberar la proteína intracelularmente, y una secuencia KDEL para evitar secreción del retículo endoplásmico. Las NPs de cadena de ricina A solubles purificadas dirigidas a CXCR4, con un diámetro promedio de 11 nm, alcanzaron un incremento de 100 veces en su citotoxicidad con un IC50 de 13 ± 0,5 x 10 -9 M en células HeLa. Pero también se produjeron por métodos recombinantes y se purificaron cuerpos de inclusión insolubles de 400-600 nm, con resultados citotóxicos parciales. El mecanismo de entrada dependiente del receptor de T22-mRTA-H6 se verificó y evaluó en un modelo de ratón con leucemia mieloide aguda (AML) mediante la inyección sistémica en la vena de la cola, donde se verificó un bloqueo importante de las células leucémicas sin toxicidad sistémica o histológica lateral en los órganos sanos. De manera similar, la clorotoxina (CTX) también se incorporó a la plataforma de proteínas con el fin de aprovechar su direccionamiento y efecto terapéutico en glioblastoma (GBM), ambas funciones en un solo péptido. Se diseñaron dos versiones que se unen a la proteína anexina-2 y la metaloproteinasa de matriz MMP-2; CTX-GFP-H6 y CTX-KRKRK-GFP-H6. Lss NPs solubles, de un diámetro promedio de 12 nm, se incubaron en células HeLa sobreexpresando anexina-2, y en células U87MG, sobreexpresando MMP2. Ambas versiones eran completamente fluorescentes, pero CTX-GFP-H6 presentó efectos citotóxicos leves, mientras que CTX-KRKRK-GFP-H6 mostró ser más citotóxico en las células U87MG que en las células HeLa. La afinidad selectiva de CTX se confirmó mediante la evaluación de su direccionamiento utilizando anticuerpos monoclonales y un suero policlonal contra la proteína de la superficie celular, actuando como un receptor de la CTX.
The developed self-assembling platform allows the engineering of protein-only nanoparticles (NPs) capable to target and act selectively over cancer cells by means of the interaction with overexpressed receptors. The stability of the spherical NP structures and their adequate size, in combination with the involved targeting peptides, enhance their specificity. Also, the novel incorporation of toxin and venom segments have improved the therapeutic effects of these fully biocompatible materials, without the need of any external carrier or added material, thus fulfilling the newfangled concept for precision medicines that involve self-assembled, self-targeted and efficient vehicle-free recombinant drugs. A modified version of the catalytic ricin A chain, with the ability to diminish the undesired vascular leak syndrome side effects but retaining its natural cytotoxicity, was adapted to the protein platform. The design was developed with the peptide T22 in the N-terminal, which binds CXCR4, and a his-tag in the C-terminal. This was combined with a furin cleavable site fragment in order to release the protein intracellularly, and a KDEL sequence to avoid endoplasmic reticulum secretion. Purified soluble CXCR4-targeted ricin A chain NPs with an average diameter of 11 nm, reached a 100-fold cytotoxic improvement with an IC50 of 13 ± 0.5 x 10 -9 M in HeLa cells. Also, insoluble 400-600 nm inclusion bodies were produced by recombinant methods and purified, with partial cytotoxic results. The receptor-dependent mechanism of T22-mRTA-H6 was verified and evaluated in an acute myeloid leukemia (AML) mouse model by systemic administration through a vein tail injection where an important blockage of the leukemic cells was verified without side systemic or histological toxicity in healthy organs. In a similar way, chlorotoxin (CTX) was also incorporated to the protein platform in order to take advantage of its targeting and therapeutic effect in glioblastoma (GBM), both functions in one peptide. Two versions that target protein Annexin-2 and the matrix metalloproteinase MMP-2 were engineered, namely CTX-GFP-H6 and CTX-KRKRK-GFP-H6. The soluble NPs of an average dimeter of 12 nm were incubated with HeLa cells, overexpressing annexin-2, and in U87MG cells, overexpressing MMP2. Both versions were fully fluorescent but CTX-GFP-H6 presented mild cytotoxic effects, whereas CTX-KRKRK-GFP-H6 showed to be more cytotoxic in U87MG cells than in HeLa cells. The selective affinity of CTX was confirmed by means of evaluating its targeting using a monoclonal antibody and a polyclonal serum against the cell surface protein, acting as a CTX receptor.
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Luo, Zhongrui. "In vivo interactions between food availability and nanoparticles in Caenorhabditis elegans". Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/671182.
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Durant les darreres dècades, les nanopartícules (NP) s’han utilitzat en diversos camps, especialment en aplicacions mèdiques com ara medicaments, agents d’imatge i d’alliberament de fàrmacs. No obstant això, també es van plantejar preocupacions sobre les possibles reaccions adverses sobre la salut humana. Així, s’han invertit esforços d’investigació a nivell global en la ciència dels materials i la biologia per determinar els mecanismes de la toxicitat de diferents NPs.
En aquest treball de tesi, hem dedicat grans esforços a aplicar el (Caenorhabditis elegans) C. elegans com un organisme model robust i simple per a avaluacions de toxicitat de NPs. L’objectiu general d’aquesta tesi ha estat la interacció de l’alimentació dels cucs amb les NPs. En específic, les interaccions nano-bio entre nanopartícules d’òxid de ferro superparamagnètiques (SPION) o AuNPs de 10 nm en C. Elegans alimentats o no, així demostrar que aquest petit animal es pot utilitzar per estudiar els efectes alimentaris.
En primer lloc, hem estudiat els efectes de la disponibilitat de menjar sobre les toxicitats induïdes per l’exposició de SPIONs després de 24 h (exposició aguda) o 72 h (exposició perllongada). Hem trobat que el menjar proporcionava certa protecció als C. elegans determinada per la supervivència i la reproducció. Els cucs en la condició d’exposició aguda van tenir una eficiència de captació de SPIONS més alta facilitada pel menjar en comparació amb la condició sense menjar. La utilització de la microspectroscòpia infraroig en el sincrotró (SR-μFTIR), ens va permetre demostrar que l’exposició llarga (24 h versus 4 h) i les altes concentracions d’SPIONs (500 µg/mL versus 100 µg/mL) indueixen un estrès oxidatiu més sever determinat per l’augment dels nivells d’oxidació dels lípids.
En segon lloc, vam investigar les conseqüències de la ingesta de menjar sobre els cucs després de 24 h d’exposició a AuNPs de 10 nm. El paper protector del menjar es va identificar en la reducció dels efectes tòxics, com la supervivència i la reproducció. Utilitzant SR-μFTIR, vam trobar que les AuNPs de mida petita (10 nm versus 150 nm) o la exposició perllongada (24 h versus 4 h) provocaven un augment del nivell d’oxidació dels lípids que es relacionava amb les respostes a l’estrès oxidatiu. D’altra banda, vam avaluar preliminarment la possibilitat de realitzar la teràpia fototèrmica en cucs que contenien AuNPs de 150 nm. Hem trobat danys degut a la fotoablació a les zones d’irradiació làser dels cucs, cosa que suggereix que és possible utilitzar els cucs, però cal optimitzar els diversos paràmetres experimentals.
Al final de la tesi, també presentem col·laboracions on vam realitzar experiments amb diferents nanomaterials com luteïna i MOFs (metal·lo-organic framework) i els vam avaluar en els C. elegans. Vam estudiar les propietats antioxidants de la luteïna en C. elegans models de malaltia associades al síndrome de Leigh i vam demostrar la possibilitat d’aplicar la microscòpia d’infraroig (SR-μFTIR) en aquests estudis. Així, també vam realitzar l’avaluació preliminar de la toxicitat de MOFs, MIL-127 i CS-MIL-127 recoberts de quitosà (CS). A més, hem investigat els efectes del recobriment de quitosà (CS) sobre la captació i eficiència d’excreció en els C. elegans .
En resum, la disponibilitat d’aliments podria disminuir els efectes adversos, parcialment associats a l’estrès oxidatiu, induïts per SPION o AuNPs a C. elegans. També suggerim que els C. elegans tenen un gran potencial d’utilitzar-se com a model d’administració oral per diversos materials. A més, combinat amb altres tècniques avançades, podríem tenir una comprensió més general del mecanisme de toxicitat i ampliar la gamma d’aplicacions de tècniques de ciència de materials per a la investigació biològica.Durante las últimas décadas, las nanopartículas (NPs) se han utilizado ampliamente en distintos campos, especialmente en aplicaciones médicas como fármacos, agentes de formación de imágenes y como liberadores de fármacos. Sin embargo, también han planteado dudas respecto a las posibles reacciones adversas sobre la salud humana. Así, se han realizado grandes esfuerzos de investigación en el campo de las ciencias biológicas para elucidar los mecanismos de toxicidad de distintas NPs. En este trabajo de Tesis, hemos dedicado esfuerzos a aplicar el (Caenorhabditis elegans) C. elegans como un organismo modelo robusto y simple para las evaluaciones de toxicidad de NPs. El objetivo general de esta tesis ha sido estudiar la interacción de la comida de estos gusanos con las NPs. En particular, el estudio de las interacciones nano-bio entre nanopartículas de óxido de hierro superparamagnéticas (SPIONs) o AuNPs de 10 nm en C. elegans alimentados o no; así demostrar que este pequeño animal puede utilizarse para estudiar efectos alimentarios. En primer lugar, estudiamos los efectos de la disponibilidad de alimento sobre las toxicidades inducidas por la exposición de SPIONs tras 24 h - exposición aguda - o 72 h - exposición prolongada. Descubrimos que la comida brinda cierta protección a los C. elegans, la cual se determinó midiendo la supervivencia y la reproducción. Los gusanos en la exposición aguda tuvieron una mayor eficiencia de absorción de SPIONs facilitada por la comida en comparación con la condición sin alimento. La utilización de la microespectroscopía infrarroja de Sincrotrón (SR-μFTIR) nos permitió demostrar que la exposición prolongada (24 h versus 4 h) y altas concentraciones de SPIONs (500 µg/mL versus 100 µg/mL) inducen un estrés oxidativo más severo debido a el aumento de la oxidación de lípidos. En segundo lugar, investigamos las consecuencias de la ingesta de comida sobre los gusanos después de 24 h de exposición a AuNP de 10 nm. Se identificó el papel protector de los alimentos en la reducción de efectos tóxicos. Usando SR-μFTIR, encontramos que las AuNPs de pequeño tamaño (10 nm frente a 150 nm) o la exposición prolongada (24 h frente a 4 h) causaron un mayor nivel de oxidación de lípidos que se relacionó con las respuestas contra el estrés oxidativo. Por otro lado, evaluamos preliminarmente la posibilidad de realizar la terapia fototérmica en gusanos que contenian AuNP de 150 nm. Encontramos daños por fotoablación en los puntos de irradiación láser sobre los gusanos, sugiriendo que se podría usar este gusano para evaluar NPs, pero para ello es necesario optimizar la configuración experimental. En la parte final, presentamos algunas colaboraciones donde realizamos experimentos con diferentes nanomateriales como luteína y metal-organic frameworks (MOFs), evaluados empleando C. elegans. Estudiamos las propiedades antioxidantes de la luteína en C. elegans modificados para ser modelos de enfermedades asociadas con el síndrome de Leigh y demostramos la posibilidad de aplicar microscopia de infrarrojo (SR-μFTIR) en estos estudios. Por otro lado, realizamos la evaluación preliminar de toxicidad de MOF, MIL-127 y CS-MIL-127 recubierto de quitosano (CS). Además, investigamos los efectos del recubrimiento de CS en la absorción y excreción por los C. elegans. En resumen, hemos encontrado que la disponibilidad de comida puede disminuir los efectos adversos, parcialmente asociados con el estrés oxidativo, inducidos por SPIONs o AuNPs en C. elegans. Nuestros resultados también sugieren que los C. elegans tienen un gran potencial como modelo de administración oral ya que pueden emplearse para probar diferentes materiales. Además, en combinación con otras técnicas avanzadas, nos pueden ayudar a comprender de forma más general los mecanismos de toxicidad y ampliar el rango de aplicación de las técnicas de ciencia de materiales para la investigación biológica.
During the last decades, nanoparticles (NPs) have been widely used in various fields, especially in medical applications such as drugs, imaging agents, and drug-delivery carriers. However, they also raised public concerns regarding the potential adverse influences on human health. Collective efforts from worldwide researchers in materials and biological science have been invested in investigating the toxicity mechanisms of different NPs. In this thesis, we dedicated major efforts to apply (Caenorhabditis elegans) C. elegans as a robust and simple model organism for toxicity assessments of assorted NPs. The general objective of this thesis was to study effects of food availability on nano-bio interactions between superparamagnetic iron oxide nanoparticles (SPIONs) or 10 nm AuNPs and C. elegans, and prove that this small animal can be used to study alimentary effects. Firstly, we studied the effects of food availability on toxicities induced by exposure to SPIONs after 24 h (acute exposure) or 72 h (prolonged exposure). We found that food provided some protection to C. elegans determined by measuring multiple toxicity endpoints such as survival and reproduction. Worms in the acute exposure condition had a higher uptake efficiency of SPIONS facilitated by food compared with the condition without the addition of food. The utilization of synchrotron Fourier transform infrared microspectroscopy (SR-μFTIR), allowed us to demonstrate that long-exposure (24 h versus 4 h) and high concentrations of SPIONs (500 µg/mL versus 100 µg/mL) induce more severe oxidative stress determined by increased levels of lipid oxidation. Secondly, we investigated food’s influences on worms after 24 h exposure to 10 nm AuNPs. The protective role of food was identified in reducing toxic effects, such as survival and reproduction. Using SR-μFTIR, we found that small-sized AuNPs (10 nm versus 150 nm) or long-exposure (24 h versus 4 h) caused an increased level of lipid oxidation which was related to responses against oxidative stress. On the other hand, we preliminarily evaluated the possibility of performing the photothermal therapy in worms containing 150 nm AuNPs. We found photoablated damages on the laser irradiation spots of worms, suggesting that multiple experimental settings needed to be optimized. At the end of the thesis, also we presented some collaborations where we performed some experiments with different nanomaterials such as lutein and (metal-organic frameworks) MOFs and evaluated them on C. elegans. We studied antioxidative properties of lutein in C. elegans disease models associated with Leigh Syndrome and demonstrated the possibility to apply synchrotron Fourier transform infrared microspectroscopy (SR-μFTIR) on this topic. On the other hand, we performed the preliminary toxicity assessment of MOFs, MIL-127 and chitosan (CS) coated MIL-127 (CS-MIL-127). Additionally, we investigated about effects of the chitosan (CS) coating on C. elegans’ uptake and excretion efficiencies of MIL-127 and CS-MIL-127. We reported the potential of applying C. elegans as an oral administration model of studying metal-organic frameworks’ (MOFs’) in vivo toxicities. In summary, food availability could decrease adverse effects, partially associated with oxidative stress, induce by SPIONs or AuNPs on C. elegans. It also suggested that C. elegans has a great potential of being employed as an oral administration model of testing various materials. Furthermore, combined with other advanced techniques, we could have a more general understanding of the toxicity mechanism and broaden the application range of material science techniques for biological research.
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Pantidos, Nikolaos. "Biological synthesis of stable copper nanoparticles". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29532.
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Many nonferrous industries such as mining and surface treatment plants produce co-products that are high in heavy metals and therefore toxic to the environment. A less obvious producer of heavy metal containing co-products is the whisky industry. Current methods of copper removal from such co-products include electrolysis and membrane filtration which are impractical and costly. When copper is found as a salt, current methods of removal include settlement, filtration and precipitation. Alternatives such as biological copper ion removal from effluents has also been shown to be effective. This study aimed to develop a biological method for the synthesis of stable copper nanoparticles. Morganella psychrotolerans was used to reduce Cu2+ to insoluble Cu0 nanoparticles. The nanoparticles were purified and characterised using X-Ray Photoelectron Spectroscopy (XPS) and High-Resolution Transmission Electron Microscopy (HR-TEM). Whisky distillery co-products were tested as a growth medium for M. psychrotolerans with concomitant copper nanoparticle synthesis. The copper nanoparticles were also studied for their application in electronics in order to make conductive circuits. Genomics studies combined with proteomics, helped develop possible models for copper nanoparticle synthesis by M. psychrotolerans, as well as identify proteins and genes not previously thought to be related to this pathway. The genome sequence of M. psychrotolerans obtained in this work allowed for a far more detailed study on the mechanism of copper nanoparticle synthesis than previously possible. This thesis also focused on understanding this mechanism better through proteomics and qRT-PCR. In order to study the identified copper ion reduction pathway in the future, a genetic modification toolkit was developed for M. psychrotolerans.
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Buchy, Eric. "Conception de bioconjugués squalénisés dotés de propriétés d'auto-assemblage : vers une méthode générale de vectorisation nanoparticulaire". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS267.
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Des bioconjugués squalénisés du semaxanib et du sunitinib , deux inhibiteurs puissants de l'angiogénèse et de tyrosine kinases, ont été synthétisés avec un bras espaceur pH sensible de type hémiaminal . Les prodrogues sont préparées selon une séquence en trois étapes impliquant : (i) la N- alkylation avec du chlorométhoxy - triisopropylsilane ; (ii) désilylation ; et (iii) acylation avec l'acide trisnorsqualenique . Ces prodrogues squalénisées ont la capacité de s'auto-assembler en nanoparticules en milieu aqueux sans nécessité de tensioactif . Les agrégats de taille nanométrique ont été caractérisés par diffraction dynamique de la lumière et microscopie électronique à transmission , et semblent être stables dans l'eau sur plusieurs jours. Les études biologiques in vitro ont montré que les nanoparticules de sunitinib sont cytotoxiques contre la lignée de cellules ombilicale veineuse endothéliale humaine ( HUVEC), qui est impliqué dans la formation de vaisseaux de la tumeurSqualenoyl conjugates of semaxanib and sunitinib, two potent antiangiogenic (pyrrolyl)methylidenyl-substituted oxindole multitarget tyrosine kinase inhibitors, were synthesized with a hemiaminal-based pH-sensitive linker. The prodrugs were prepared according to a three-step sequence involving (i) N-alkylation with chloromethoxy-triisopropylsilane; (ii) desilylation; and (iii) acylation with trisnorsqualenic acid. These squalenoyl prodrugs were found to selfassemble into nanoassemblies in aqueous media without the need for any surfactant. The nanosized aggregates were characterized by dynamic light scattering and transmission electron microscopy, and appeared to be stable in water for several days, as determined by particle-size measurement. In vitro biological studies showed that squalenoyl sunitinib nanoassemblies are notably cytotoxic against the human umbilicalvein endothelial cell line (HUVEC), which is involved in the tumor vessel formation
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Dzumedzey, Yuliya. "Mobility of manufactured nanoparticles within a natural organic gel". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0159/document.
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Cette étude traite de la question de l’interaction des NPs avec les constituants de l’environnement, et comment celles-ci peuvent affecter le devenir et l’impact des NPs sur le biota. Les interactions de NPs de charge et taille variable (TiO2 NPs, analogues de celles typiquement relarguées des crèmes solaires, et Au NPs modèles) avec un polysaccharide pure YAS34 analogue de gel bactérien été étudié.Le relargage de NPs de TiO2 d’une crème solaire typique pendant sont altération en milieu aqueux a d’abord été étudié. Puis les interactions entre les NPs et le polysaccharide bactérien été étudié (1) en condition de suspension diluée, (2) par déposition sur la surface du gel en comparaison avec une surface de collecteur minérale de SiO2, et (3) en mesurant le transfert des nanoparticules à travers le gel. Des conditions favorables ou défavorables pour l’attachement des NPs au polysaccharide ont été préparées en sélectionnant un pH et un coating de NP.Sous conditions favorables, les NPs tendent à s’hétéroagréger avec le polysaccharide en suspension, et la déposition des NPs est influencée par les conditions physicochimiques. Elle est dépendante des interactions électrostatiques avec le collecteur, est aussi des interactions entre les NPs voisines.De manière surprenante, en conditions défavorables, des faibles interactions attractives sont encore mises en évidence en suspension et sur le collecteur, que nous avons attribuées comme étant dues au coating organique des NP qui entre en compétition avec le polysaccharide.Enfin, le transfert des NPs à travers le gel était favorisé en conditions de répulsions électrostatiques et affecté par la taille des NPs et le pH de la solutionThe mobility and fate of manufactured nanoparticles (NPs) in the environment drive the exposure behaviour. This study deals with the question on how NPs interact with environmental components, and how this interaction may alter the NPs fate and impact on the biota. We investigated the interaction of variably charged and sized NPs (TiO2 NPs, as analogues of those typically released from sunscreen, and Au NPs as models) with pure polysaccharide YAS34 as analogue of bacterial gels. The release of TiO2 NPs from a typical sunscreen under aqueous aging was first studied. The interaction between NPs and the bacterial polysaccharide was studied (1) in diluted suspension conditions, (2) by deposition on the gel surface as compared to a bare SiO2 mineral collector, and (3) by measuring the NPs transfer through the gel. Favorable and unfavorable conditions for NPs attachment to the polysaccharide were prepared by selecting appropriate pH and NPs coating.Under favorable conditions, the NPs tended to heteroaggregate with the EPS in suspension, leading to their partial sedimentation. On the EPS substrate, the NPs deposition was influenced by the physicochemical conditions. The NPs deposition is driven by electrostatic interactions with the collector and is also affected by the interactions between the neighbouring NPs. Surprisingly, under unfavourable conditions, some weak attractive interactions were again evidenced both in suspension and deposition experiments that we attributed to be dependent on the NP organic coating competing with the EPS.The NPs transfer through the gel was favored under repulsive electrostatic interaction, and affected by the NPs size and by the solution pH
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Le, Hong Duc. "Modelling of nanoparticles laden jet from a conveying pipe leakage". Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/21454/1/LE_Hong_Duc.pdf.
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Since a few years, nanomaterials are more and more used in industrial process. In order to protect the population and the environment from the consequences of an accidental release into the atmosphere, the risk assessment allowed to identify the accidental scenario in transport, manipulation and storage of those products. The accidental leakage of the conveying pipe may lead to a massive release of nanoparticles. In order to evaluate the consequences of this type of accident, our study focuses on the prediction of particles properties dispersed into the air, for example the particle number concentration and the particle diameter distribution. The first step of the study consists in the analyse of physical phenomena related to nanoparticles in order to choose the most predominant physical phenomena to model. The relevant physical phenomena in the present configuration are the agglomerate complex shape, the drag force on agglomerates, the agglomerate breakage by gas, the agglomerate collision and the agglomeration. After that, the modelling of physical phenomena chosen is developed in CFD tool Code\_Saturne. For each physical phenomenon, a simulation test case is realized in order to verify the development in CFD tool. A good agreement between CFD tool Code\_Saturne and 0D tool from Scilab and model in the literature is obtained. Also in the present study, new model for the collision probability of agglomerates is proposed. This new model is validated with the numerical experiment. After that, the numerical tool developed is applied in a simulation of an accidental pipe leakage. The field near the leakage is simulated by Code\_Saturne. The results from Code\_Saturne is used as the input data for ADMS tool, a simulation tool for the particle dispersion in large scale. The results show that the particles are dispersed more than 1 km from the release source, which is in agreement with the distance observed. In perspective, the influences of different parameters as the wind field and the particle properties, on the agglomerate size and number distribution can be tested. An experiment of the microparticle jet is realized at INERIS in order to be able to assess the nanoparticle jet experiment in the laboratory scale.
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Campioli, Elisa. "Functional fluorescent organic nanoparticles". Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00954407.
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During the past two decades, increasing research attention has been devoted to nanomaterials (materials in the range of 10-100 nm) because of their unique optoelectronic properties. In particular, inorganic nanomaterials, such as quantum dots, metal-based nanoparticles and silica nanoparticles, have been investigated extensively. Instead, nanomaterials based on organic molecules are been subject of research only since very recent years. This thesis presents an extensive study of novel fluorescent organic nanoparticles and fluorescent organic binary and ternary nanoassemblies. In particular the attention is focused on the preparation and characterization of organic nanoparticles and new nanocomposites obtained from different types of small organic chromophores, their stabilization and the use of these materials for biological and optoelectronics applications.
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Narayanan, Radha. "Shape-Dependent Nanocatalysis and the Effect of Catalysis on the Shape and Size of Colloidal Metal Nanoparticles". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6878.
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From catalytic studies in surface science, it has been shown that the catalytic activity is dependent on the type of metal facet used. Nanocrystals of different shapes have different facets. This raises the possibility that the use of metal nanoparticles of different shapes could catalyze different reactions with different efficiencies. The catalytic activity is found to correlate with the fraction of surface atoms located on the corners and edges of the tetrahedral, cubic, and spherical platinum nanoparticles. It is observed that for nanoparticles of comparable size, the tetrahedral nanoparticles have the highest fraction of surface atoms located on the corners and edges and also have the lowest activation energy, making them the most catalytically active.
Nanoparticles have a high surface-to-volume ratio, which makes them attractive to use compared to bulk catalytic materials. However, their surface atoms are also very active due to their high surface energy. As a result, it is possible that the surface atoms are so active that their size and shape could change during the course of their catalytic function. It is found that dissolution of corner and edge atoms occurs for both the tetrahedral and cubic platinum nanoparticles during the full course of the mild electron transfer reaction and that there is a corresponding change in the activation energy in which both kinds of nanoparticles strive to behave like spherical nanoparticles. When spherical palladium nanoparticles are used as catalysts for the Suzuki reaction, it is found that the nanoparticles grow larger after the first cycle of the reaction due to the Ostwald ripening process since it is a relatively harsh reaction due to the need to reflux the reaction mixture for 12 hours at 100 oC. When the tetrahedral Pt nanoparticles are used to catalyze this reaction, the tetrahedral nanoparticles transform to spherical ones, which grow larger during the second cycle.
In addition, studies on the effect of the individual reactant have also provided clues to the surface catalytic process that is taking place. In the case of the electron transfer reaction, the surface catalytic process involves the thiosulfate ions binding to the nanoparticle surface and reacting with the hexacyanoferrate (III) ions in solution. In the case of the Suzuki reaction, the surface catalytic mechanism of the Suzuki reaction involves the phenylboronic acid binding to the nanoparticle surface and reacting with iodobenzene via collisional processes.
Książki na temat "Nanoparticles"
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Schmid, Günter, red. Nanoparticles. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527631544.
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Schmid, Gnter, red. Nanoparticles. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2003. http://dx.doi.org/10.1002/3527602399.
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Rotello, Vincent, red. Nanoparticles. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4419-9042-6.
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de Mello Donegá, Celso, red. Nanoparticles. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6.
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Jelinek, Raz. Nanoparticles. Berlin: Walter de Gruyter GmbH & Co., KG, 2015.
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Guet, C., P. Hobza, F. Speigelman i F. David, red. Atomic clusters and nanoparticles. Agregats atomiques et nanoparticules. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-45621-x.
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Jana, Nikhil Ranjan. Colloidal Nanoparticles. Boca Raton : CRC Press, Taylor & Francis Group, 2018.: CRC Press, 2019. http://dx.doi.org/10.1201/9780429165603.
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Joshy, K. S., Thomas Sabu i Vijay Kumar Thakur, red. Magnetic Nanoparticles. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1260-2.
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Patra, Jayanta Kumar, Leonardo F. Fraceto, Gitishree Das i Estefânia Vangelie Ramos Campos, red. Green Nanoparticles. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39246-8.
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Thota, Sreekanth, i Debbie C. Crans. Metal Nanoparticles. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527807093.
Pełny tekst źródłaCzęści książek na temat "Nanoparticles"
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de Mello Donegá, Celso. "The Nanoscience Paradigm: “Size Matters!”". W Nanoparticles, 1–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_1.
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Hassinen, Antti, José C. Martins i Zeger Hens. "Solution NMR Toolbox for Colloidal Nanoparticles". W Nanoparticles, 273–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_10.
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Koole, Rolf, Esther Groeneveld, Daniel Vanmaekelbergh, Andries Meijerink i Celso de Mello Donegá. "Size Effects on Semiconductor Nanoparticles". W Nanoparticles, 13–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_2.
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Zijlstra, Peter, Michel Orrit i A. Femius Koenderink. "Metal Nanoparticles for Microscopy and Spectroscopy". W Nanoparticles, 53–98. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_3.
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de Jongh, Petra E., i Tamara M. Eggenhuisen. "Nanoporous Materials and Confined Liquids". W Nanoparticles, 99–120. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_4.
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Eggenhuisen, Tamara M., i Petra E. de Jongh. "Supported Nanoparticles". W Nanoparticles, 121–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_5.
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Groeneveld, Esther, i Celso de Mello Donegá. "The Challenge of Colloidal Nanoparticle Synthesis". W Nanoparticles, 145–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_6.
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van Huis, Marijn A., i Heiner Friedrich. "Electron Microscopy Techniques". W Nanoparticles, 191–221. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_7.
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Liljeroth, Peter, Bruno Grandidier, Christophe Delerue i Daniël Vanmaekelbergh. "Scanning Probe Microscopy and Spectroscopy". W Nanoparticles, 223–55. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_8.
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Baranov, Pavel G., Nikolai G. Romanov, Celso de Mello Donegá, Sergei B. Orlinskii i Jan Schmidt. "Electron Paramagnetic Resonance Based Spectroscopic Techniques". W Nanoparticles, 257–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_9.
Pełny tekst źródłaStreszczenia konferencji na temat "Nanoparticles"
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Yu, Qun, Chao Zhu, Robert Pfeffer i Rajesh N. Dave. "Experimental Study on Fluidization Characteristics of Nanoparticles". W ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56269.
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Recent studies show that nano-sized particles can be fluidized in the form of nanoparticle agglomerates. However, fluidization behavior such as the minimum fluidization velocity and fluidization regime differ significantly for different nanoparticles. Hence this paper is aimed to experimentally investigate the general fluidization characteristics of different nanoparticles. It is interesting to note that a fluidized bed of nanoparticle agglomerates is optically semi-transparent due to the extremely high porosity (typically over 99%) of the bed with respect to the primary materials of nanoparticles. Taking advantage of this unique feature, traditional optical measurement techniques are applied to visualize the flow structure as well as to measure the size of the fluidizing nanoparticle agglomerates. Based on measurements of four different nanoparticle materials, two types of fluidization behavior have been identified, which closely resemble those of classical Geldart Group A and Group B particles, respectively. It shows, however, that the bed of “Group A” nanoparticles expands as long as there is a flow through the bed, which is different from the classical fluidization of Geldart Group A particles where there is no bed expansion until reaching the minimum fluidization velocity. It is also noted that, based on the apparent density and size, the fluidization behavior of nanoparticle agglomerates do not precisely follow the Geldart classification. To differentiate these particles with very similar fluidization characteristics, terms the APF and ABF are introduced for the fluidization classification of nanoparticle agglomerates. Typical fluidization characteristics including bed expansion, bed pressure drop and hysteresis effects of both APF and ABF nanoparticles. The sizes of nanoparticle agglomerates also have been measured using an in-situ optical measurement system.
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Wang, Jun, i Guodong Xia. "Thermophoresis of Nanoparticles in Dilute Gases". W ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83005.
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The thermophoresis of nanoparticles in the free molecule regime plays an important role in the nucleation, collision and coagulation of nanoparticles. In this contribution, on the basis of a rigorous gas kinetic theory, the theoretical expressions for the thermophoretic force on nanoparticles suspended in dilute gas mixtures are derived, wherein the non-rigid-body interactions between the gas molecules and the nanoparticle are taken into account. The analytical formulas in the present work are consistent with those under the rigid-body collision assumption. Negative thermophoresis, is found to be possible for nanoparticles in the free molecule regime, by which the thermophoretic force exerted on the suspended nanoparticle is from low to high temperature, i.e., opposite to the direction of normal thermophoresis.
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Zhang, Martin Y., i Gary J. Cheng. "Nanoscale Size Dependence on Metallic Nanoparticles: Case Study of Titanium Nanoparticles on Pulsed Laser Sintering of Hydroxyapatite/Titanium Nanoparticles". W ASME 2011 International Manufacturing Science and Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/msec2011-50296.
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Nanoscale size effects on pulsed laser coating of hydroxyapatite/titanium nanoparticles on metal substrate is discussed in this article. Laser coating method has recently been developed to coat bioceramics material on Ti-6Al-4V substrate. Laser-coated bioceramics implants have several advantages due to the use of nanosized materials: strong interfacial bonding strength, good biocompatibility and potentially longer lifetime cycle. These advantages benefit from intrinsic properties of nanoparticles. Size effects on melting point, heat capacity, thermal and electrical conductivities have been discussed. Multiphysics model is built to reveal the mechanism of laser coating process. Two sub-modules are included in the model: electromagnetic module to represent the laser-nanoparticle interactions and heat transfer module to simulate the heat conduction. Both simulation and experimental results showed that nanoTi, functioning as nanoheaters, effectively enhances the laser coating sinterability. For large nanoTi (>100 nm), sinterability enhancement mainly attributes to the stronger laser-particle interactions due to higher plasmon resonance; for small nanoparticles (<100 nm), not only stronger laser-nanoparticle interactions, reduction on melting point also contributes to sinterability enhancement.
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Zhu, Youyi, Peng Yu i Jian Fan. "Study on Nanoparticle Stabilized Emulsions for Chemical Flooding Enhanced Oil Recovery". W International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21456-ms.
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Abstract Chemical flooding is one of enhanced oil recovery (EOR) methods. The primary mechanism of EOR of chemical flooding is interfacial tension reduction, mobility ratio improvement and wettability changes. Recent studies showed that enhancing emulsification performance was beneficial to improve oil displacement efficiency. The formation of Pickering emulsion by nanoparticles could greatly improve the emulsifying performance. Using nanoparticles stabilized emulsions for chemical EOR application is a novel method. In this study, six different types of nanoparticles were selected, including hydrophilic nano silica, modified nano silica, carbon nanotubes and bentonite, etc. The nanoparticle combine with petroleum sulfonate could form a stable emulsion. Particle wettability were measured by using contact angle measurement (OCA20). Emulsifying intensity index was measured for different nanoparticle-stabilized emulsions. The mechanisms of nanoparticle-stabilized emulsions and relationship between emulsion stability have been investigated. The influence of dispersant on nanoparticle-stabilized emulsions also has been investigated. Nanoparticles mainly play a role in improving the stability of emulsions while surfactant play a major role in enhancing the emulsifying dispersion. The wettability of solid particles was one of the most important factors that affects the stability of emulsions. Partial hydrophobic nanoparticles were much easier to form stable emulsions than hydrophilic nanoparticles. Nanoparticles could form a three-dimensional network structure, thereby the stability of the emulsion was improved. Use of surfactant to disperse nanoparticles could further improve the emulsion stability. Finally, three nanoparticles stabilized emulsion formulations were developed for chemical flooding EOR. Nanoparticle-stabilized emulsions could improve oil displacement efficiency in chemical combination flooding. This research was used to optimize chemical combination flooding formulation and has a guidance function for application of nanoparticles in chemical flooding EOR.
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Yuksel, Anil, Michael Cullinan i Jayathi Murthy. "Thermal Energy Transport Below the Diffraction Limit in Close-Packed Metal Nanoparticles". W ASME 2017 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/ht2017-4968.
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Fabrication of micro and nanoscale electronic components has become increasingly demanding due to device and interconnect scaling combined with advanced packaging and assembly for electronic, aerospace and medical applications. Recent advances in additive manufacturing have made it possible to fabricate microscale, 3D interconnect structures but heat transfer during the fabrication process is one of the most important phenomena influencing the reliable manufacturing of these interconnect structures. In this study, optical absorption and scattering by three-dimensional (3D) nanoparticle packings are investigated to gain insight into micro/nano heat transport within the nanoparticles. Because drying of colloidal solutions creates different configurations of nanoparticles, the plasmonic coupling in three different copper nanoparticle packing configurations were investigated: simple cubic (SC), face-centered cubic (FCC) and hexagonal close packing (HCP). Single-scatter albedo (ω) was analyzed as a function of nanoparticle size, packing density, and configuration to assess effect for thermo-optical properties and plasmonic coupling of the Cu nanoparticles within the nanoparticle packings. This analysis provides insight into plasmonically enhanced absorption in copper nanoparticle particles and its consequences for laser heating of nanoparticle assemblies.
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Min, Jung Yim, Seok Pil Jang i Stephen U. S. Choi. "Motion of Nanoparticles in Nanofluids Under an Electric Field". W ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80139.
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Nanofluids — fluids with unprecedented stability of suspension nanoparticles — have attractive features such as high thermal conductivities at very low nanoparticle concentrations, strongly temperature-dependent conductivity, and three-fold higher critical heat flux compared to base fluids. These features are not explained by traditional theories of solid/liquid suspensions, such as Maxwell’s theory or other macroscale approaches. Recently, Jang and Choi’s model has led to the discovery, primarily by extending Einstein’s theory of Brownian motion to energy transport in nanofluids, that Brownian motion of nanoparticles at the molecular and nanoscale level is a dominant mechanism governing their thermal behavior. In this paper we describe a theoretical model for controlling the motion of nanoparticles in nanofluids by means of an electric field and an analytical solution for particle motions in nanofluids. We show that the motion of nanoparticles can be controlled by use of an AC field and that the size and zeta potential of the nanoparticles are the key parameters to control nanoparticle motion beyond Brownian motion.
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Kelley, D. F., H. Tu i K. Mogoyrosi. "Photophysics of GaSe nanoparticles and nanoparticle aggregates". W Optics & Photonics 2005, redaktorzy Clemens Burda i Randy J. Ellingson. SPIE, 2005. http://dx.doi.org/10.1117/12.616960.
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Karnik, Rohit, Frank X. Gu, Suman Bose, Pamela Basto, Christopher Cannizzaro, Robert Langer i Omid C. Farokhzad. "Microfluidic Synthesis of Polymeric Nanoparticles". W ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62218.
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A central challenge in the development of drug-encapsulated polymeric nanoparticles is the inability to control the nanoparticle physicochemical properties that affect their biodistribution, drug release, and efficacy. Nanoparticles may be developed by mixing and nanoprecipitation of polymers and drugs dissolved in organic solvents with non-solvents. Inadequate control over this mixing process is a source of variability in the synthesis of these nanoparticles by nanoprecipitation. We demonstrate that rapid and tunable mixing through hydrodynamic flow focusing in a microfluidic device can be used to control nanoprecipitation of poly(lactic-co-glycolic acid)-bpoly(ethylene glycol) (PLGA-PEG) diblock copolymers as a model polymeric biomaterial for drug delivery.
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Heller, Michael J., Dieter Dehlinger, Sadik Esener i Benjamin Sullivan. "Electric Field Directed Fabrication of Biosensor Devices From Biomolecule Derivatized Nanoparticles". W ASME 2007 2nd Frontiers in Biomedical Devices Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/biomed2007-38093.
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An electronic microarray has been used to carry out directed self-assembly of higher order 3D structures from Biotin/Streptavidin and DNA derivatized nanoparticles. Structures with more than forty layers of alternating biotin and streptavidin and DNA nanoparticles were fabricated using a 400 site CMOS microarray system. In this process, reconfigurable electric fields produced by the microarray device have been used to rapidly transport, concentrate and accelerate the binding of 40 and 200 nanometer biotin, streptavidin, DNA and peroxidase derivatized nanoparticles to selected sites on the microarray. The nanoparticle layering process takes less than one minute per layer (10–20 seconds for addressing and binding nanoparticles, 40 seconds for washing). The nanoparticle addressing/binding process can be monitored by changes in fluorescence intensity as each nanoparticle layer is deposited. The final multilayered 3-D structures are about two microns in thickness and 50 microns in diameter. Work is now focused on assembling “micron size” biosensor devices from bio-molecule derivatized luminescent and fluorescent nanoparticles. The proposed structure for a nanolayered glucose sensor device includes a base layer of biotin/streptavidin nanoparticles, a layer of glucose oxidase derivatized nanoparticles, a layer of peroxidase derivatized nanoparticles, a layer of quantum dots, and a final layer of biotin/streptavidin nanoparticles. Such a device will serve as a prototype for a wide variety of applications which includes other biosensor devices, lab-on a-chip devices, in-vivo drug delivery systems and “micron size” dispersible bio/chem sensors for environmental, military and homeland security applications.
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Lin, Dong, Sergey Suslov, Chang Ye, Yiliang Liao, C. Richard Liu i Gary J. Cheng. "Nanoparticles Embedding Into Metallic Materials by Laser Direct Irradiation". W ASME 2012 International Manufacturing Science and Engineering Conference collocated with the 40th North American Manufacturing Research Conference and in participation with the International Conference on Tribology Materials and Processing. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/msec2012-7379.
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We report a method to half-embed nanoparticles into metallic materials. Transparent and opaque nanoparticle (laser wavelength 1064 nm) were both successfully half-embedded (partial part of nanoparticles embedded into matrix while other parts still stay above the matrix) into metallic materials. Nanoparticles were coated on sample surface by dip coating before laser irradiation. After laser irradiation of different pulses and laser fluencies, nanoparticles were embedded into metal. The mechanism and process of embedding were investigated.
Raporty organizacyjne na temat "Nanoparticles"
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Venedicto, Melissa, i Cheng-Yu Lai. Facilitated Release of Doxorubicin from Biodegradable Mesoporous Silica Nanoparticles. Florida International University, październik 2021. http://dx.doi.org/10.25148/mmeurs.009774.
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Cervical cancer is one of the most common causes of cancer death for women in the United States. The current treatment with chemotherapy drugs has significant side effects and may cause harm to healthy cells rather than cancer cells. In order to combat the potential side effects, nanoparticles composed of mesoporous silica were created to house the chemotherapy drug doxorubicin (DOX). The silica network contains the drug, and a pH study was conducted to determine the conditions for the nanoparticle to disperse the drug. The introduction of disulfide bonds within the nanoparticle created a framework to efficiently release 97% of DOX in acidic environments and 40% release in neutral environments. The denotation of acidic versus neutral environments was important as cancer cells are typically acidic. The chemistry was proved with the incubation of the loaded nanoparticle into HeLa cells for a cytotoxicity report and confocal imaging. The use of the framework for the anticancer drug was shown to be effective for the killing of cancerous cells.
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Chumanov, George. Asymmetric Hybrid Nanoparticles. Office of Scientific and Technical Information (OSTI), listopad 2015. http://dx.doi.org/10.2172/1225813.
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Balch, William M., James Vaughn i Joaquim I. Goes. Nanoparticles and Ocean Optics. Fort Belvoir, VA: Defense Technical Information Center, wrzesień 2008. http://dx.doi.org/10.21236/ada533234.
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Balch, William M., James Vaughn i Joaquim I. Goes. Nanoparticles and Ocean Optics. Fort Belvoir, VA: Defense Technical Information Center, styczeń 2008. http://dx.doi.org/10.21236/ada519059.
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Balch, William M., James Vaughn i Joaquim I. Goes. Nanoparticles and Ocean Optics. Fort Belvoir, VA: Defense Technical Information Center, wrzesień 2007. http://dx.doi.org/10.21236/ada569308.
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Veloso, Rita Carvalho, Catarina Dias, Andrea Resende Souza, Joana Maia, Nuno M. M. Ramos i João Ventura. Improving the optical properties of finishing coatings for façade systems. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau541592743.
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The need to improve energy efficiency of the building stock has led to a continuous increase in the implementation of exterior thermal insulation systems, such as ETICS. Progressively, these systems are being applied with darker colours, increasing the concern for hygrothermal behaviour and durability. Despite the significant developed studies, very few reports regarding their optical properties are available. The optical and catalytic capacity turns nanomaterials into excellent candidates for use in finishing coatings with high solar reflectance with dark colours without affecting the aesthetic characteristics, thus improving the durability of such coatings. Our study targeted the development of innovative envelope systems by increasing their solar reflectance through new finishing coatings formulations with the inclusion of nanoparticles. For that, it is necessary to develop and optimize nanoparticles formulations to achieve a high near-infrared reflectance. Here, we studied how the incorporation of reflective nanomaterials influence the optical behaviour of a black colourant for a finishing coating, varying the concentration in the coating from 0 to 20%. Such optical performance was experimentally evaluated through spectral reflectance calculations using a modular spectrophotometer, which allowed an understanding of the relation between these properties and the morphological and structural characteristics of the nanoparticles. The results from such studies can help formulate new finishing coatings with increased near-infrared reflectance of buildings façades, using, for instance, more than one type of nanoparticle.
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Chefetz, Benny, Baoshan Xing i Yona Chen. Interactions of engineered nanoparticles with dissolved organic matter (DOM) and organic contaminants in water. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7699863.bard.
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Background: Engineered carbon nanotubes (CNTs) are expected to be increasingly released into the environment with the rapid increase in their production and use. The discharged CNTs may interact with coexisting contaminants and subsequently change environmental behaviors and ecological effects of both the CNTs themselves and the contaminants. Dissolved organic matter (DOM) plays a critical role in the transport of CNTs in the aquatic environment, affecting both CNT's surface properties through adsorption, and its colloidal stability in solution. Therefore, CNT-bound DOM complexes may interact with coexisting contaminants, thus affecting their environmental fate. With increasing production and use of CNTs, there is an increasing risk that humans could be exposed to CNTs mainly through ingestion and inhalation. Since CNTs can be carriers of contaminants due to their high adsorption affinity and capacity, the distribution of these nanoparticles in the environment holds a potential environmental and health risk. Project objectives: The overall goal of this project was to gain a better understanding of the environmental behavior of engineered nanoparticles with DOM and organic pollutant in aqueous systems. The scope of this study includes: characterizing various types of engineered nanoparticles and their interaction with DOM; binding studies of organic contaminants by nanoparticles and DOM-nanoparticle complexes; and examining interactions in DOM-nanoparticles-contaminant systems. Major conclusions, solutions and achievements: DOM has a pronounced effect on colloidal stability of CNTs in solution and on their surface chemistry and reactivity toward associated contaminants. The structure and chemical makeup of both CNTs and DOM determine their interactions and nature of formed complexes. CNTs, contaminants and DOM can co-occur in the aquatic environment. The occurrence of co-contaminants, as well as of co-introduction of DOM, was found to suppress the adsorption of organic contaminants to CNTs through both competition over adsorption sites and direct interactions in solution. Furthermore, the release of residual contaminants from CNTs could be enhanced by biomolecules found in the digestive as well as the respiratory tracts, thus increasing the bioaccessibility of adsorbed contaminants and possibly the overall toxicity of contaminant-associated CNTs. Contaminant desorption could be promoted by both solubilization and sorptive competition by biological surfactants. Scientific and agricultural implications: The information gained in the current project may assist in predicting the transport and fate of both CNTs and associated contaminants in the natural environment. Furthermore, the results imply a serious health risk from contaminant-associated CNTs.
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Burgett, Eric, Mohamad Al-Sheikhly i Christopher Summers. Development of Plasmonically Cloaked Nanoparticles. Office of Scientific and Technical Information (OSTI), maj 2015. http://dx.doi.org/10.2172/1253944.
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Armstrong, Robert L. Light Control of Fractal Nanoparticles. Fort Belvoir, VA: Defense Technical Information Center, marzec 2002. http://dx.doi.org/10.21236/ada413632.
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David, Anand. Bioinspired synthesis of magnetic nanoparticles. Office of Scientific and Technical Information (OSTI), styczeń 2009. http://dx.doi.org/10.2172/967072.
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