Academic literature on the topic 'Nanoparticels'
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Journal articles on the topic "Nanoparticels"
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Yang, Chun, Feng Yan Ge, Jin Cai Li, Zai Sheng Cai, and Fang Fang Qin. "Silver Nanoparticles with Enhanced Fluorescence Effects on Fluorescein Derivative." Advanced Materials Research 602-604 (December 2012): 187–91. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.187.
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Silver nanoparticles were prepared by sodium borohydride reduction method for analyzing metal-enhanced fluorescence property. Some variables including the dosage of reagent, reacting temperature and pH value had been investigated. Subsequently, a comparison of metal-enhanced fluorescence efficiency was made between two kinds of fluorescent dyes, namely fluorescein and 6-carboxyfluorescein at different silver concentrations. The experimental results show that the fluorescence of both dyes are remarkably enhanced. It is interesting to note that the increase of emission intensity is stronger than that of their corresponding excitation ones. Furthermore, a 5.038-fold increase in fluorescence for 6-carboxyfluorescein while a 2.506-fold increase for fluorescein are observed. This may attribute to the interaction between dyes and silver nanoparticels.
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Trzaskus, K. W., A. J. B. Kemperman, and D. C. Nijmeijer. "Fouling Behavior of Silver Nanoparticels During Membrane Filtration." Procedia Engineering 44 (2012): 2096–97. http://dx.doi.org/10.1016/j.proeng.2012.09.058.
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Shan, Feng, and Tong Zhang. "Shape and Size Dependent Light Absorption Enhancement of Silver Nanostructures in Organic Solar Cells." Solid State Phenomena 266 (October 2017): 90–94. http://dx.doi.org/10.4028/www.scientific.net/ssp.266.90.
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Metal nanoparticles (MNPs) induced light absorption enhancement using for the improvement of power conversion efficiency of organic solar cells (OSCs) is a new research direction in photovoltaics. However, the device performance influence of the shape and size of MNPs has not been well investigated. In this paper, we focused on the comparison study of the optical absorption enhancement between silver nanospheres (Ag-NSs) and silver nanocubes (Ag-NCs) which are embedded in the active layer of OSCs using finite element method (FEM) simulation. Influence of the structural parameters, including the size and shape of nanoparticels, and their relative distance are systematically discussed. The results indicated that the light absorption enhancement employing Ag-NCs is much higher than that of Ag-NSs in the 300–800 nm wavelength range. Meantime, once the distance between the adjacent nanoparticles is well controlled, the optimal absorption enhancement factor of OSCs can be obtained. As the scattering cross-section of Ag-NCs is much higher than that of Ag-NSs over a broad wavelength range, the optimized light enhancement of Ag-NCs reaches 19 % which is 1.26 times higher than that of Ag-NSs.
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Kilic, Mehmet Emin, and Sakir Erkoc. "Structural Properties of ZnO Nanoparticels and Nanorings: Molecular Dynamics Simulations." Journal of Computational and Theoretical Nanoscience 10, no. 6 (June 1, 2013): 1490–96. http://dx.doi.org/10.1166/jctn.2013.2878.
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Ruan, Li Li, Da Xin Wang, You Wei Zhang, Jiong Xin Zhao, Min Wu Wang, Xiu Fang Zhang, and Nan Liang Chen. "Study on Preparation and Property of Drug Loading of AZM-PCL Nanoparticels." Applied Mechanics and Materials 121-126 (October 2011): 1764–68. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.1764.
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This study was to prepare polycaprolactone (PCL) nanoparticles. The biodegradable PCL was used as the carrier, and Azithromycin (AZM) was used as the model drug. AZM-PCL nanoparticles (AZM-PCL-NPS) were prepared by desolvation method. The effect of preparation condition: concentration of PCL, molecular weight of PCL, organic solvents, dosage ratio and so on, were specially noted and compared. A homogeneous size distribution and good dispersion were observed, the average diameter was around 70~400 nm, and the distribution index was 0.036~0.136. The drug loading reached 27.69 %, and the efficiency of encapsulation reached as high as 93.25%. The results were better than the other similar researches, this preparation way was successful.
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Wang, X., Z. Yang, Y. Zhang, L. Jing, Y. Zhao, Y. Yan, and K. Sun. "MnO2Supported Pt Nanoparticels with High Electrocatalytic Activity for Oxygen Reduction Reaction." Fuel Cells 14, no. 1 (December 10, 2013): n/a. http://dx.doi.org/10.1002/fuce.201300102.
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A. A. Aljabali, Alaa, Hamid A. Bakshi, Faruck L. Hakkim, Yusuf A. Haggag, Khalid M. Al-Batanyeh, Mazhar S. Al Zoubi, Bahaa Al-Trad, et al. "Albumin Nano-Encapsulation of Piceatannol Enhances Its Anticancer Potential in Colon Cancer Via Downregulation of Nuclear p65 and HIF-1α." Cancers 12, no. 1 (January 1, 2020): 113. http://dx.doi.org/10.3390/cancers12010113.
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Piceatannol (PIC) is known to have anticancer activity, which has been attributed to its ability to block the proliferation of cancer cells via suppression of the NF-kB signaling pathway. However, its effect on hypoxia-inducible factor (HIF) is not well known in cancer. In this study, PIC was loaded into bovine serum albumin (BSA) by desolvation method as PIC–BSA nanoparticles (NPs). These PIC–BSA nanoparticles were assessed for in vitro cytotoxicity, migration, invasion, and colony formation studies and levels of p65 and HIF-1α. Our results indicate that PIC–BSA NPs were more effective in downregulating the expression of nuclear p65 and HIF-1α in colon cancer cells as compared to free PIC. We also observed a significant reduction in inflammation induced by chemical colitis in mice by PIC–BSA NPs. Furthermore, a significant reduction in tumor size and number of colon tumors was also observed in the murine model of colitis-associated colorectal cancer, when treated with PIC–BSA NPs as compared to free PIC. The overall results indicate that PIC, when formulated as PIC–BSA NPs, enhances its therapeutic potential. Our work could prompt further research in using natural anticancer agents as nanoparticels with possible human clinical trails. This could lead to the development of a new line of safe and effective therapeutics for cancer patients.
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Zamorina, S. A., P. V. Khramtsov, M. B. Rayev, V. P. Timganova, M. S. Bochkova, A. I. Nechaev, E. O. Shunkin, O. G. Khaziakhmatova, V. V. Malaschenko, and L. S. Litvinova. "Graphene Oxide Nanoparticels Interaction with Jurkat Cell Line in Cell-IQ System." Doklady Biochemistry and Biophysics 501, no. 1 (November 2021): 438–43. http://dx.doi.org/10.1134/s1607672921060089.
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ZHANG Yang, 张杨, 李学红 LI Xue-hong, and 彭成晓 PENG Cheng-xiao. "Tunable Photoluminescence of ZnO Films with Different Surfaces by The Coating of Au Nanoparticels." Chinese Journal of Luminescence 33, no. 12 (2012): 1299–303. http://dx.doi.org/10.3788/fgxb20123312.1299.
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Droigk, Christine, Marco Maass, and Alfred Mertins. "Direct multi-dimensional Chebyshev polynomial based reconstruction for magnetic particle imaging." Physics in Medicine & Biology 67, no. 4 (February 16, 2022): 045014. http://dx.doi.org/10.1088/1361-6560/ac4c2e.
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Abstract Magnetic Particle Imaging is a tomographic imaging technique that measures the voltage induced due to magnetization changes of magnetic nanoparticle distributions. The relationship between the received signal and the distribution of the nanoparticels is described by the system function. A common method for image reconstruction is using a measured system function to create a system matrix and set up a regularized linear system of equations. Since the measurement of the system matrix is time-consuming, different methods for acceleration have been proposed. These include modeling the system matrix or using a direct reconstruction method in time, known as X-space reconstruction. In this work, based on the simplified Langevin model of paramagnetism and certain approximations, a direct reconstruction technique for Magnetic Particle Imaging in the frequency domain with two- and three-dimensional Lissajous trajectory excitation is presented. The approach uses Chebyshev polynomials of second kind. During reconstruction, they are weighted with the frequency components of the voltage signal and additional factors and then summed up. To obtain the final nanoparticle distribution, this result is rescaled and deconvolved. It is shown that the approach works for both simulated data and real measurements. The obtained image quality is comparable to a modeled system matrix approach using the same simplified physical assumptions and no relaxation effects. The reconstruction of a 31 × 31 × 31 volume takes less than a second and is up to 25 times faster than the state-of-the-art Kaczmarz reconstruction. Besides, the derivation of the proposed method shows some new theoretical aspects of the system function and its well-known observed similarity to tensor products of Chebyshev polynomials of second kind.
Dissertations / Theses on the topic "Nanoparticels"
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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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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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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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Rousseau, Youri. "Hybridation des technologies de jets de nanoparticules et de PVD pour la réalisation d’architectures nanocomposites fonctionnelles." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS347.
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Les films nanocomposites sont des revêtements composés de nanoparticules enrobées dans une matrice solide d’un matériau différent. L’intérêt de ces matériaux réside dans leur capacité à exploiter les caractéristiques inédites des nano-objets qu’ils contiennent tout en bénéficiant des propriétés de résistance mécanique et chimique de la matrice. Ces composites disposent de propriétés très prometteuses pour un grand nombre d’applications comme le photovoltaïque ou la photocatalyse. Plusieurs procédés de synthèse existants permettent de produire des matériaux nanocomposites par des méthodes physiques ou chimiques (co-pulvérisation, sol-gel,…). Cependant, aucun n’est assez flexible pour envisager la synthèse d’une large gamme de nanocomposites par le même procédé. Ceci est un frein au développement à l’échelle industrielle de ce type de matériaux. Le premier objectif de la thèse est de développer un procédé original de synthèse de films nanocomposites. Ce procédé présente un caractère universel en ce qu’il permet un choix a priori illimité dans la nature des nanoparticules et celle de la matrice. Le procédé développé combine un jet de nanoparticules sous vide formé par une lentille aérodynamique à un dispositif de pulvérisation magnétron qui permet de déposer la matrice. Le jet de nanoparticules permet de coupler toute source de nanoparticules à la pulvérisation. Les nanoparticules peuvent être soit synthétisées in situ en phase gazeuse, soit synthétisées préalablement en voie liquide. Une grande variété de nanoparticules peut donc être utilisée. La pulvérisation magnétron permet par ailleurs de disposer d’une très large gamme de matériaux pour la matrice (métaux, céramique, polymère). Dans le cadre de cette thèse, deux types de sources de nanoparticules ont été utilisés. Le premier est un réacteur de pyrolyse laser et le second un générateur d’aérosol. Le réacteur de pyrolyse laser permet une synthèse in-situ des nanoparticules en phase gazeuse alors que le générateur d’aérosol permet d’utiliser une suspension de nanoparticules préalablement synthétisées. Afin d’éprouver la robustesse du procédé de co-dépôt, deux types de matériaux nanocomposites ont été développés. Le premier matériau étudié est composé de nanoparticules d’or sphériques de 35 nm de diamètre, synthétisées préalablement par voix liquide, dans une matrice de silice. Le but ici est de bénéficier des propriétés optiques uniques des nanoparticules d’or dans un film résistant mécaniquement et chimiquement. Les caractérisations réalisées sur ces matériaux ont permis d’optimiser la concentration en nanoparticules d’or dans les films de manière à garder des propriétés mécaniques et chimiques compatibles avec les applications tout en gardant des propriétés optiques satisfaisantes. Le second type de matériaux étudiés est composé de nanoparticules semi-conductrices synthétisées in situ par pyrolyse laser et d’une matrice métallique. La synthèse de ce matériau permet de démontrer la flexibilité du procédé de co-dépôt à synthétiser une large gamme de films nanocomposites. Enfin, la robustesse du procédé ayant été démontrée, la conception d’un pilote industriel a été entreprise. Le but final étant de disposer d’une machine répondant aux exigences industrielles dans l’optique d’un transfert technologiqueThe nanocomposite films are coatings of nanoparticles embedded in a solid matrix of a different material. The advantage of these materials is their ability to exploit the unique properties of nano-objects while benefiting of the mechanical and chemical resistance properties of the matrix. These composites have very promising properties for many applications such as photovoltaics and photocatalysis. Several existing synthetic methods can produce nanocomposite materials by physical or chemical methods (co-sputtering, sol-gel, ...). However, none is flexible enough to consider the synthesis of a wide range of nanocomposites by the same method. This is an obstacle to the development on an industrial scale of this type of material. The first objective of the thesis is to develop an original synthesis process of nanocomposite films. This method is universal in which it presents no limit in the choice of nanoparticles and matrix. The developed method combines vacuum nanoparticle jets formed by an aerodynamic lens with a magnetron sputtering device for depositing the matrix. The nanoparticle jets can be coupled with any source of nanoparticles. Nanoparticles may be synthesized in situ in the gas phase or beforehand solution synthesis. A wide variety of nanoparticles can be used. Magnetron sputtering also enables to have a very wide range of materials for the matrix (metal, ceramic, polymer). During this thesis, two types of nanoparticles sources were used. The first one is a laser pyrolysis reactor and the second is an aerosol generator. The laser pyrolysis reactor enables in-situ gas phase synthesis of the nanoparticles while the aerosol generator use a suspension of previously synthesized nanoparticles. To test the robustness of the co-deposition process, two types of nanocomposite materials have been developed. The first material is composed of 35 nm spherical gold nanoparticles, chemically synthesized, in a silica matrix. The goal here is to benefit from the unique optical properties of gold nanoparticles in a film mechanically and chemically resistant. The characterizations carried out on these materials have optimized the gold nanoparticle concentration in the films to keep the mechanical and chemical properties compatible with applications while maintaining satisfactory optical properties. The second type of materials studied is composed of semiconductor nanoparticles in situ synthesized by laser pyrolysis and a metal matrix. The synthesis of this material demonstrates the flexibility of the co-deposition method to synthesize a wide variety of nanocomposite films. Finally, the design of an industrial pilot was undertaken. The final goal is to have a pilot-scale setup that meets industry requirements in the context of a technology transfer
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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.
Full textAbstract:
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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Chiewpattanakul, Paramaporn. "Isolation and structure elucidation of biosurfactant from microorganism and its application model in drug delivery system." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL004N/document.
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Des microorganismes produisant des molécules tensioactives ont été isolés à partir d’échantillons de sols contaminés par des huiles, en provenance des provinces de Songkhla et Chiangmai (Thaïlande) et de Shianghai (Chine). Les différentes souches ont été sélectionnées de façon à obtenir les biosurfactants ayant les meilleures propriétés tensioactives et d’émulsification. Parmi 102 souches isolées, 6 microorganismes produisaient des biosurfactants. La souche SK80 a conduit aux meilleures propriétés tensioactives. Des observations morphologiques macroscopiques et microscopiques ont permis de caractériser la souche SK80. L’analyse de la séquence ARNr 28S indique que cette souche appartient à la famille Exophiala Dermatitidis. La composition du milieu de culture (source de carbone et d’azote) et les conditions de culture de ce microorganisme ont été adaptées de façon à obtenir des quantités importantes de biosurfactant. Des analyses spectroscopiques (RMN 1H, RMN 13C, COSY et de masse, APCI MS) ont révélé que ce biosurfactant était un monooléate de glycérol. La monomyristine a été choisie comme constituent synthétique modèle dans des études d’encapsulation. Deux méthodes de préparation, émulsion/évaporation de solvant, nanoprécipitation, ont été employées pour encapsuler la monomyristine dans des nanoparticules recouvertes de dextrane et dont le cœur était constitué de poly(acide lactique) ou de dextrane hydrophobisé. Les conditions d’encapsulation ont été variées afin de maximiser le rendement d’encapsulation et la stabilité colloïdale des particulesBiosurfactant producing microorganisms were isolated from oil contaminated soils collected from Songkhla and Chiangmai province, Thailand and Shianghai, China. Their culture broths were screened for obtaining biosurfactants with the highest surface activity and emulsification ability. Among 102 isolates, 6 microorganisms produced biosurfactants. The culture supernatant of SK80 strain exhibited the highest surface activity. SK80 was identified by macroscopic morphology, microscopic morphology and showed that it is a black mold. The 28S rRNA sequence homology analysis suggested that SK80 belongs to Exophiala dermatitidis. The composition of culture medium such as carbon source, nitrogen source, and culture condition of this microorganism was optimized to obtain high amounts of biosurfactant. 1H NMR, 13C NMR, COSY and Mass Spectrometer (APCI MS) results indicated that this biosurfactant was monoolein (oleoyl glycerol), a kind of monoacylglycerol. Monomyristin was chosen as a monoacylglycerol model to be synthesized and used as nanoparticle encapsulated drug. Two preparation methods, emulsion/solvent evaporation and nanoprecipitation, were used to encapsulate monomyristin in dextran-covered nanoparticles with poly(lactic acid) of hydrophobized dextran as the core material. Encapsulation conditions were optimized with regard to the yield encapsulation and the colloidal stability
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Fernandez, Maxence. "Auto-assemblage de nanoparticules métalliques et semi-conductrices dirigé par reconnaissance entre protéines artificielles." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S129.
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L’auto-assemblage de nanoparticules dirigé par des biomolécules constitue une approche prometteuse pour la mise au point de nanomatériaux structurés présentant des propriétés optiques collectives originales. L’objet de cette thèse concerne l’auto-assemblage de nanoparticules métalliques et semi-conductrices dirigé par des protéines artificielles appelées α-Repeat. Dans cette optique, des nanocristaux semi-conducteurs (CdSe/ZnS ou CdSe/CdS) et des nanoparticules d’or sphériques ou anisotropes ont été préparés. Ces nanoparticules ont été fonctionnalisées avec des ligands peptidiques PEGylés, qui leur confère une stabilité colloïdale satisfaisante tout en conservant leurs propriétés optiques. Une stratégie de fonctionnalisation basée sur des étiquettes d’affinité poly-cystéine et poly-histidine a permis de greffer les protéines sur la surface des nanoparticules inorganiques. Les nanoparticules ainsi fonctionnalisées avec les protéines artificielles ont ensuite été utilisées pour l’auto-assemblage de nanoparticules semi-conductrices et l’auto-assemblage hybride entre des nanoparticules semi-conductrices et des nanoparticules métalliques. L’étude structurale des ensembles obtenus a montré, dans certains cas, une interdistance bien définie et inférieure à 10 nm. Finalement, l’étude des propriétés optiques a révélé des transferts d’énergie non radiatifs entre nanoparticules semi-conductrices et nanoparticules métalliques, qui témoignent d’interactions exciton—plasmon très fortes induites par l’auto-assemblageNanoparticles self-assembly driven by biomolecules is a promising approach for developing nanostructured materials with new optical properties. The purpose of this work is the self-assembly of metal and semiconductor nanoparticles directed by artificial proteins called α-Repeat. For this purpose, semiconductor nanocrystals (CdSe/ZnS or CdSe/CdS) and spherical or anisotropic gold nanoparticles have been prepared. These nanoparticles have been functionalized with PEGylated peptide ligands providing them adequate colloidal stability while maintaining their optical properties. A functionalization strategy based on polycysteine and poly-histidine tags has allowed the proteins to be grafted onto the surface of inorganic nanoparticles. Nanoparticles functionalized with artificial proteins were then used for the self-assembly of semiconductor nanoparticles and hybrid self-assembly between semiconductor nanoparticles and metal nanoparticles. The structure study of self-assembled nanostructures has shown, in some cases, a very well defined sub-10 nm interparticle distance. Finally, the study of optical properties revealed very strong exciton-plasmon interactions induced by self-assembly. This self-assembling process strongly affected the emission properties of the semiconductor nanoparticles in hybrid ensembles
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Tang, Lu. "Nanoparticules mimes des propriétés biologiques des GAGs : vers un inhibiteur sélectif de CXCL12." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS072.
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L'Héparane Sulfate (HS), un polysaccharide linéaire, module les activités biologiques de nombreuses protéines. Afin d'élucider les interactions entre l'HS et les protéines, la synthèse chimique d'HS est un outil précieux, mais elle peut être difficile. Notre équipe a montré que des mélanges combinatoires obtenus par auto-assemblage de différentes combinaisons de dérivés disaccharidiques (lactose et lactose persulfaté) sur surfaces planes d'or peuvent reconnaître spécifiquement certaines protéines se liant à l'HS, telles que les isoformes de la chimiokine CXCL12 ou IFNγ. Avec ces dérivés, nous avons réalisé un auto-assemblage sur des nanoparticules d'or. Mais à cause de la toxicité des nanoparticules d'or, nous avons aussi adapté cette méthode à des nanoparticules lipidiques. En utilisant les conditions qui ont déjà été améliorées pendant la synthèse des dérivés lactose et lactose persulfaté, nous avons préparé deux autres dérivés disaccharidiques plus proches de la structure réelle d'HS. Ces nouveaux dérivés sont utilisés pour réaliser des nanoparticules d'or et nanoparticules lipidiques afin de comparer les propriétés avec les lactose et lactose persulfaté. Les tests d'affinité avec différentes protéines sont en cours de réalisationHéparan Sulfate (HS) is a linear polysaccharide that modulates the biological activities of numerous proteins. In order to elucidate the interaction between HS and proteins, the synthesis of HS is an invaluable tool, but the synthesis is sometimes difficult. Our group has demonstrated that the combinatorial mixtures obtained by self-assembly of different combinations of disaccharide derivatives (lactose and persulfated lactose) on gold plan surfaces could recognize specifically some HS binding proteins, such as the isoforms of the chemokine CXCL12 or IFNγ. Because of the toxicity of gold nanoparticles, we have also adapted this method to lipid nanoparticles. Using the conditions that have already improved during the synthesis of lactose and persulfated lactose derivatives, we have synthesized two other disaccharide derivatives, which were closer to the real structure of HS. These new derivatives were used to prepare the gold and lipid nanoparticles at the aim of comparing the properties with lactose and persulfated lactose. The tests of affinities with different proteins are in progress
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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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Bordat, Alexandre. "Stratégies alternatives pour la délivrance d'anticancéreux par encapsulation physique dans des nanoparticules polymère thermosensibles ou par couplage chimique en prodrogues polymères." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS595.
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Cette thèse s’articule autour de systèmes innovants de délivrance d’anticancéreux pour répondre aux limitations actuelles des systèmes de type nanoparticules. Celles-ci permettent l’encapsulation d’anticancéreux pour prolonger leur temps de circulation dans le sang et diminuer leurs effets secondaires. Néanmoins les produits disponibles en cliniques ne permettent pas un contrôle précis de la libération de la substance active, ni un ciblage de la tumeur.Pour répondre à ces deux limitations, nous avons synthétisé un copolymère thermosensible ayant une température critique haute de solubilité (upper critical solution temperature, UCST) pour formuler des nanoparticules encapsulant physiquement la doxorubicine. Celles-ci permettent la libération contrôlée de la substance active par hyperthermie modérée à 43 °C. Nous avons étudié notre système d’un point de vue physico-chimique et évalué sa cytotoxicité in vitro sur des cellules de cancer de l’ovaire.Nous avons également opté pour une approche via couplage chimique entre une substance active, le paclitaxel, et le polymère afin de permettre l’administration par la voie sous-cutanée d’anticancéreux. En effet, cette voie d’administration est peu utilisée pour les anticancéreux car certains d’entre eux induisent une toxicité locale au site d’injection de type irritation / nécrose de la peau. Nous avons évalué si d’une part, l’approche prodrogue polymère hydrophile permet d’empêcher cette toxicité locale et si d’autre part, l’approche prodrogue polymère UCST permet d’obtenir des nanoparticules stables à température ambiante en vue d’une administration par la voie sous-cutanée. Une fois administrées, les nanoparticules deviennent hydrophiles par le changement de température, 34 °C dans le tissu sous-cutané, et peuvent donc diffuser librement jusqu’à atteindre la circulation sanguine. Nos travaux ont permis d’évaluer l’approche prodrogue polymère hydrophile in vivo chez la souris nude, ainsi que de décrire pour la première fois la synthèse de prodrogues polymères UCSTThis thesis focuses on innovative drug delivery systems of anticancer drugs to tackle the current limitations of formulations based on nanoparticles. These allow encapsulation of anticancer drugs to prolong their circulation time in the blood stream and to decrease side effects. Yet, nanoparticle formulations available in the clinic do not allow a precise control on the drug release nor targeting of the tumor.To overcome these hurdles, we have synthesized a thermoresponsive copolymer exhibiting an upper critical solution temperature (UCST) to formulate nanoparticles physically encapsulating doxorubicin. These allow controlled release of the anticancer drug by mild hyperthermia at 43 °C. We have studied our system from a physico-chemical point of view and evaluated its cytotoxicity in vitro on ovarian cancer cells.We have also tried a chemical coupling approach between the polymer and the anticancer drug, paclitaxel, to allow innocuous subcutaneous administration. In did, this route of administration is seldom used for anticancer drugs as some of them induce local toxicity at the site of injection in the form of skin irritation / necrosis. We assessed if a hydrophilic polymer prodrug approach allows innocuous subcutaneous administration of an irritant drug; and if a UCST polymer prodrug approach enables formation of stable nanoparticles at room temperature for subcutaneous administration. Once in the subcutaneous tissue at 34 °C, they would solubilize and become hydrophilic thus could freely diffuse to reach the blood circulation. We have managed to evaluate the hydrophilic polymer prodrug approach in vivo on nude mice and we are the first to describe the synthesis of UCST polymer prodrug
Books on the topic "Nanoparticels"
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Guet, C., P. Hobza, F. Speigelman, and F. David, eds. 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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Schmid, Günter, ed. Nanoparticles. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527631544.
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Schmid, Gnter, ed. Nanoparticles. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2003. http://dx.doi.org/10.1002/3527602399.
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Rotello, Vincent, ed. 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, ed. 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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1967-, Feldheim Daniel L., and Foss Colby A, eds. Metal nanoparticles: Synthesis, characterization, and applications. New York: Marcel Dekker, 2002.
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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, and Vijay Kumar Thakur, eds. 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, and Estefânia Vangelie Ramos Campos, eds. Green Nanoparticles. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-39246-8.
Full textBook chapters on the topic "Nanoparticels"
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de Mello Donegá, Celso. "The Nanoscience Paradigm: “Size Matters!”." In 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, and Zeger Hens. "Solution NMR Toolbox for Colloidal Nanoparticles." In 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, and Celso de Mello Donegá. "Size Effects on Semiconductor Nanoparticles." In 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, and A. Femius Koenderink. "Metal Nanoparticles for Microscopy and Spectroscopy." In 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., and Tamara M. Eggenhuisen. "Nanoporous Materials and Confined Liquids." In 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., and Petra E. de Jongh. "Supported Nanoparticles." In 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, and Celso de Mello Donegá. "The Challenge of Colloidal Nanoparticle Synthesis." In 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., and Heiner Friedrich. "Electron Microscopy Techniques." In 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, and Daniël Vanmaekelbergh. "Scanning Probe Microscopy and Spectroscopy." In 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, and Jan Schmidt. "Electron Paramagnetic Resonance Based Spectroscopic Techniques." In Nanoparticles, 257–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-44823-6_9.
Full textConference papers on the topic "Nanoparticels"
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Wu, Xuan, Ranganathan Kumar, and Parveen Sachdeva. "Calculation of Thermal Conductivity in Nanofluids From Atomic-Scale Simulations." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80849.
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Nanofluids that consist of nanometer sized particles and fibers dispersed in base liquids have shown the potential to enhance the heat transfer performance. Although three features of nanofluids including anomalously high thermal conductivities at very low nanoparticle concentrations, strongly temperature dependent thermal conductivity and significant increases in critical heat flux have been studied widely, and layering of liquid molecules at the particle-liquid interface, ballistic nature of heat transport in nanoparticles, and nanoparticle clustering are considered as the possible causations responsible for such kind of heat transfer enhancement, few research work from atomic-scale has been done to verify or explain those fascinating features of nanofluids. In this paper, a molecular dynamic model, which incorporates the atomic interactions for silica by BKS potential with a SPC/E model for water, has been established. To ensure the authenticity of our model, the position of each atom in the nanoparticle is derived by the crystallographic method. The interfacial interactions between the nanoparticle and water are simplified as the sum of interaction between many ions. Due to the electrostatic interaction, the ions on the nanoparticle’s surface can attract a certain number of water molecules, therefore, the effect of interaction between the nanoparticle and water on heat transfer enhancement in nanofluids is studied. By using Green-Kubo equations which set a bridge between thermal conductivity and time autocorrelation function of the heat current, a model which may derive thermal conductivity of dilute nanofluids that consist of silica nanoparticles and pure water is built. Several simulation results have been provided which can reveal the possible mechanism of heat enhancement in nanofluids.
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Zhu, Youyi, Peng Yu, and Jian Fan. "Study on Nanoparticle Stabilized Emulsions for Chemical Flooding Enhanced Oil Recovery." In 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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Li, Lirong, and Yong Tae Kang. "Three-Dimensional Simulation of Bubble Behavior and Mass Transfer for CO2 Absorption in Nanoabsorbents." In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-3944.
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Abstract CO2 absorption performance in gas-liquid system is affected by nanoparticles. The enhancement mechanisms involved have been extensively paid attention. The CO2 gas bubble behaviors and the characteristics of the nanoparticle motion have been clarified in the present study. The equivalent substitution method is used to regard the liquid with nanoparticles as a continuous term with changed physical properties, that is, nanofluid. Therefore, the volume-of-fluid (VOF) method is employed to well predict the gas bubble behaviors and mass transfer coefficient in nanofluid. It is found that the mass transfer coefficient in the gas-liquid system for CO2 absorption can be significantly enhanced by Al2O3 nanoparticles. With the increase of nanoparticles volume concentration, the surface renewal frequency increases dramatically. The discrete-particle-method (DPM) is adopted to track the motion of nanoparticles. In this way, the deformation of the bubbles and the motion of the nanoparticle are well captured. It is concluded that the enhanced mass transfer coefficient in gas-liquid-nanoparticle system is not only related to the Brownian motion of the particles, but also related to the nanoparticle deduced turbulence in the liquid field.
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Yu, Qun, Chao Zhu, Robert Pfeffer, and Rajesh N. Dave. "Experimental Study on Fluidization Characteristics of Nanoparticles." In 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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Yuksel, Anil, Michael Cullinan, and Jayathi Murthy. "Thermal Energy Transport Below the Diffraction Limit in Close-Packed Metal Nanoparticles." In 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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Ma, Qianli, and Haisheng Fang. "Viscosity Prediction of Water-Based Silver Nanofluid Using Equilibrium Molecular Dynamics." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65831.
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Nanofluids containing silver (Ag) nanoparticles have been used in three dimensional ink-jet printing (3DP) in recent years. Rheological properties of the nanofluids, for example, viscosity, play significant roles during the application. In this paper, viscosity of Ag-water nanofluid has been predicted using the equilibrium molecular dynamics method. The influencing factors of the viscosity, including temperature, nanoparticle size, nanoparticle concentration and nanoparticle aggregation, have been investigated. By screening the existing water models, TIP4P/2005 model is found the most suitable for viscosity calculation under the temperature range. The weight fraction of the nanoparticles, which proves more appropriate, is used during the study of the concentration effect instead of volume fraction. The results show that the viscosity of the nanofluid goes up by decreasing temperature or increasing nanoparticle concentration. Furthermore, as the nanoparticles get smaller, or aggregate, the viscosity increases slightly.
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Feng, Zhi-Gang, Yusheng Feng, and Maria Andersson. "Shape Effects on the Drag Force and Motion of Nano and Micro Particles in Low Reynolds Number Flows." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89469.
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Particulate flows are commonly found in a variety of applications. For example, nanoparticles have been used in targeted drug delivery systems and improving heat transfer in nanofluids. Crucial to the development of technologies that incorporate nanoparticles is to understand the effect of a nanoparticle’s shape on its motion. The effect of shape on nanoparticles used in drug delivery, in particular, is a very active area of experimental investigation. Also, the determination of the coefficients of hydrodynamic forces or drag forces on nanoparticles of different shapes is crucial in designing effective nanoparticle-mediated therapies. In this study we present a resolved discrete particle method (RDPM), which is also called the Direct Numerical Simulation (DNS), to investigate the effect of shape on drag force in a vicious fluid. Three different shapes of particles are studied: a sphere, a probate ellipsoid, and an oblate ellipsoid. These particles have the same volume and are placed in contact with the bottom wall in simple shear flows. Their drag forces are computed numerically; it is found that the particle shape has a significant effect on the drag forces. In the case of a spherical particle, our results agree very well with the analytical results found in the literature. The motion of three particles of the same volume but different shape in a simple shear flows are also simulated. It shows that different particle shapes cause particles to experience different hydrodynamics forces, leading them to different velocities and paths.
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Jambhulkar, Sayli, and Kenan Song. "1D and 2D Nanoparticle Assembly Compliant With Tuned 3D-Printed Topology." In ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-85050.
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Abstract Nanoparticle-included polymeric composite coatings with preferential nanoparticle alignment and oriented structures show improved functional and structural properties than randomly oriented structures, suitable for broad applications in microelectronics, automobile, defense, and space missions. Traditionally used techniques, such as drop-casting, chemically modified surfaces, and external fields, have been used for self-assembly but with several disadvantages, such as material limitations. Thus, there is a need to develop a new approach for generating hierarchical nanoparticle structures. Our unique processing is based on advanced additive manufacturing with a colloidal suspension-based deposition approach for layer-by-layer deposition of anisotropic nanoparticles. Leveraging the colloidal deposition technique, these anisotropic nanoparticles were deposited onto the 3D printed substrates with designed patterning. The presence of micropatterns generates selective nanoparticle distribution and assembly along with hydrodynamic forces to initiate the region-specific microscale patterning and nanoscale alignment of 1D and 2D nanoparticles. The polymer and nanoparticle composite film showed different deposition morphologies (e.g., straight or wavy films). In addition, the influence of nanoparticle deposition morphology on functional properties was investigated. This novel technique shows the potential to scale up microelectronics production by 3D printing electronic structures, including interdigitated devices, supercapacitors, fuel cells, and circuits.
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Pandey, Anurag Pandey, Vishnu Roy, Himanshu Kesarwani, Govind Mittal, Shivanjali Sharma, and Amit Saxena. "Effect of Silicon Carbide on the Surface Tension and Adsorption of SDS on the Sandstone Formation." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31439-ms.
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Abstract Oil recovery in modern fields is challenging due to the reservoir complexity and heterogeneity. The need is to improve the efficacy of additives used in oil mobilization under higher pressure, temperature, and salinity conditions. The nanoparticles provide improved and sustainable solutions for improving oil recovery. Silicon carbide nanoparticle exhibits negligible agglomeration and impart higher thermal stability to the displacing fluid for oil mobilization at higher salinity. The SIC nanoparticles are being used in EOR Applications for the first time owing to their adsorption reduction potential and thermal stability at elevated temperatures. The study estimates this nanoparticle's enhanced oil recovery potential using electrical conductivity, surface tension reduction, and crude oil mobilization. The concentration of SDS was varied from zero-4000 ppm and that of SIC from 100 ppm to 300 ppm. The solution's surface tension and critical micelle concentration (CMC) conductivity were measured at elevated temperatures (30°C, 50°C, and 70°C) with and without nanoparticles. The adsorption studies were performed for 72 hours with 10 wt% of sand added to the solution. The loss of surfactant onto the sand was calculated by studying the variation electrical conductivity before and after adsorption. Surface tension reduces from 70.15 to 28.5 mN/m with increasing SDS and nanoparticles concentrations in the solution. The CMC values of the SDS+SIC solution were lower than that of the independent surfactant system, even at higher temperatures of 70°C. SDS adsorption increased from 0.80 to 6.27 mg/g as the surfactant concentration increased up to 4000 ppm. It was reduced by about 10% and 20% for 100 ppm and 200 ppm of the nanoparticles. However, at 300 ppm, the agglomeration of nanoparticles renders them ineffective in controlling adsorption.
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Tafazzoli, Afshin, and Metin Sitti. "Dynamic Behavior and Simulation of Nanoparticle Sliding During Nanoprobe-Based Positioning." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-62470.
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In this paper, the behavior of nanoparticles, manipulated by an atomic force microscope nanoprobe, is investigated. Manipulation by pushing, pulling or picking nanoparticles can result in rolling, sliding, sticking, or rotation behavior. The dynamic simulation of the nanoparticle manipulation, using atomic force microscope (AFM), is performed. According to the dynamics of the system, the AFM pushing force increases to the critical value required for nanoparticle motion. Nanoparticle positioning is designed based on when the nanoparticle is stopped by the AFM in order to move on the substrate. Simulation results for gold particles on a silicon substrate showed that sliding on the substrate is dominant in nanoscales.
Reports on the topic "Nanoparticels"
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Venedicto, Melissa, and Cheng-Yu Lai. Facilitated Release of Doxorubicin from Biodegradable Mesoporous Silica Nanoparticles. Florida International University, October 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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Veloso, Rita Carvalho, Catarina Dias, Andrea Resende Souza, Joana Maia, Nuno M. M. Ramos, and 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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Johnson, David, Robert Boyd, Anthony Bednar, Cynthia Banks, Charles Weiss, Jessica Coleman, Burton Suedel, and Jeffery Steevens. Terrestrial fate and effects of nanometer-sized silver. Engineer Research and Development Center (U.S.), March 2022. http://dx.doi.org/10.21079/11681/43800.
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Although engineered nanomaterials are active components in a wide variety of commercial products, there is still limited information related to the effects of these nanomaterials once released into the terrestrial environment. A high number of commercial applications use silver nanoparticles (nAg) due to its anti-microbial activity. This may be of concern for waste management since nAg could be applied to soil (e.g., biosolids) or disposed of in traditional landfills, which could lead to possible leaching into surrounding soil. This report aims to provide additional insight into the fate and effects of nAg in terrestrial systems. The studies in this report examine the leachability of nAg in field soil and compares the soil migration to bulk (i.e., micron-sized) silver; examine the ecotoxicity of nAg to earthworms in four field soils spanning several different soil orders; and examine the behavioral effects of earthworms when exposed to engineered nanoparticles in field soil. These data provide additional insight into engineered nanoparticle fate and effects to terrestrial receptors in field soils, an important distinction from laboratory-generated soils. These data will also assist ecological risk assessors to better determine the acute environmental risks of nAg in terrestrial ecosystems with different soil compositions.
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Sagaiyaraj, Bernard. Increasing Energy Efficiency of Central Cooling Systems with Engineered Nanofluids. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau538344493.
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Buildings consume about 40% of the world’s energy consumption and of that, 65% is dedicated to cooling (or heating) systems. Central building cooling uses water as the main heat transfer medium. The nanoparticle fluid suspension exhibits thermal properties superior to water. The goal was to achieve the highest possible thermal properties with just the right amount of nanoparticles in a uniform and stable dispersion and suspension in water. This engineered nanofluid contains a uniform and stable suspension of graphene nanoparticles (GNP) in water. Using covalent functionalization, centrifugation and high-speed dispersion, the GNP remains in a stable suspension indefinitely. The nanofluid is applied to the closed loop of the chilled water system, where the heat transfer enhancement occurs at the fluid tubes within the evaporator and the tubing in the chilled water coils within the Air Handling Units(AHUs). The Proof of Concept (POC) completed in 2019 using laboratory-derived nanofluid resulted in energy saving that averaged at 32% compared with the baseline fluid (water). In 2022, a Scaled-Up mini plant produced GNP nanofluids in a commercial process environment, showing an average energy savings of 21%. These results were further verified and validated on small chilled water plants outside of the Scaled-Up plant with 25% and 29% average savings.
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Chefetz, Benny, Baoshan Xing, and Yona Chen. Interactions of engineered nanoparticles with dissolved organic matter (DOM) and organic contaminants in water. United States Department of Agriculture, January 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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Wiesmann, Harold, and Michael Furey. Manufacture of YBCO Superconducting Flexible Tapes from Nanoparticel Films Derived from Sedimentation and by Flame Depostion of Nanoparticles from Solution. Office of Scientific and Technical Information (OSTI), February 2008. http://dx.doi.org/10.2172/974563.
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Huang, Dan, Mirian Velay-Lizancos, and Jan Olek. Improving Scaling Resistance of Pavement Concrete Using Titanium Dioxide (TiO2 ) and Nanosilica. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317583.
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This project focused on the evaluation of the influence of nanoadditives on the hydration kinetics, mechanical properties, and durability of concretes with and without supplementary cementitious materials (SCMs). The types of nanomaterials used in the course of this study included nano-titanium dioxide (nano-TiO2) and two forms of nanosilica. A series of experimental tasks, including fabrication, curing, and conditioning of specimens, microstructure analysis, mechanical strength testing, and durability testing were conducted in the laboratory. Based on experimental results, it can be concluded that the addition of nanoparticles can accelerate the early-age hydration process of cementitious pastes, especially those containing fly ash and cured at low temperatures. Both the compressive and flexural strength of mortars and concretes were also enhanced by the addition of nanoparticles. In addition, incorporation of nanoparticles reduced the total amount and connectivity of pores present in concretes. That resulted in lowering the water permeability of concretes, regardless of the cementitious systems and curing temperatures used. The resistance of concretes to freeze-thaw cycles and scaling was also improved by the addition of nanoparticles, especially those containing fly ash. However, an excess of nanoparticles additions may reduce the scaling resistance of concretes.
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Chumanov, George. Asymmetric Hybrid Nanoparticles. Office of Scientific and Technical Information (OSTI), November 2015. http://dx.doi.org/10.2172/1225813.
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Havrilla, George Joseph. Nanoparticle standards. Office of Scientific and Technical Information (OSTI), December 2016. http://dx.doi.org/10.2172/1335590.
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Balch, William M., James Vaughn, and Joaquim I. Goes. Nanoparticles and Ocean Optics. Fort Belvoir, VA: Defense Technical Information Center, September 2008. http://dx.doi.org/10.21236/ada533234.
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