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Semchuk, O. Yu, O. O. Havryliuk i A. A. Biliuk. "Kinetic theory of surface plasmon resonance in metal nanoparticles". Surface 12(27) (30.12.2020): 3–19. http://dx.doi.org/10.15407/surface.2020.12.003.
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In recent years, interest in studying the optical properties of metallic nanostructures has grown. This interest is primarily related to the possibility of practical application of such nanostructures in quantum optical computers, micro- and nanosensors. These applications are based on the fundamental optical effect of surface plasmon excitation. The consequence of this phenomenon is surface plasmon resonance (SPR) - an increase in the cross section of energy absorption by a metal nanoparticle as the frequency of incident light (laser radiation) approaches the SPR frequency of the nanoparticle. Plasmon structures are used to improve the efficiency of thin-film SC. In such structures, metal nanoparticles can primarily act as additional scattering elements for the long-wavelength component of sunlight illuminating SC. As a collective phenomenon, SPR can be described using kinetic approaches, ie using the Boltzmann kinetic equation for the conduction electrons of metal nanoparticles. In this work, the theory of SPR based on the kinetic equation for the conduction electrons of nanoparticles is constructed. to the well-known results derived from the Drude-Sommerfeld theory. Second, the kinetic method makes it possible to study metal nanoparticles with sizes larger or ptical conductivity tensor for spheroidal metal nanoparticles. It is shown that the effect of nanoparticle asymmetry on the ratio of the components of the optical conductivity tensor differs not only smaller than the average electron free path length. The developed theory is used to calculate the oquantitatively but also qualitatively in high-frequency and low-frequency surface scattering. It was found that in metal nanoparticles in a dielectric matrix, under SPR conditions, the full width of the SPR line in a spherical metal nanoparticle depends on both the radius of the particle and the frequency of the electromagnetic (laser) radiation exciting this SPR. It is shown that oscillations of the SPR line width with a change in the dielectric constant of the medium in which they are located can be observed in metal nanoparticles. The magnitude of these oscillations is greater the smaller the size of the nanoparticle and increases significantly with increase. As the radius of the spherical nanoparticle increases, the width of the SPR line decreases significantly and prevails around a certain constant value in media with a higher value of dielectric constant.
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Albarki, Mohammed A., i Maureen D. Donovan. "Uptake of Cationic PAMAM-PLGA Nanoparticles by the Nasal Mucosa". Scientia Pharmaceutica 90, nr 4 (25.11.2022): 72. http://dx.doi.org/10.3390/scipharm90040072.
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Nanoparticles provide promising advantages in advanced delivery systems for enhanced drug delivery and targeting. The use of a biodegradable polymer such as PLGA (poly lactic-co-glycolic acid) promotes improved nanoparticle safety and, to some extent, provides the ability to modify nanoparticle surface properties. This study compared the effect of altering the surface charge on the translocation of PLGA nanoparticles across excised nasal mucosal tissues. Nanoparticles (average diameter of 60–100 nm) loaded with Nile Red (lipophilic fluorescent dye) were fabricated using a nanoprecipitation method. The effects of nanoparticle surface charge were investigated by comparing the transfer of untreated nanoparticles (negatively charged) and positively charged PLGA nanoparticles, which were modified using PAMAM dendrimer (polyamidoamine, 5th generation). All nanoparticles were able to be transferred in measurable quantities into both nasal respiratory and olfactory mucosae within 30 min. The total nanoparticle uptake was less than 5% of the nanoparticle mass exposed to the tissue surface. The cationic nanoparticles showed a significantly lower transfer into the mucosal tissues where the amount of nanoparticles transferred was 1.8–4-fold lower compared to the untreated negatively charged nanoparticles. The modification of the nanoparticle surface charge can alter the nanoparticle interaction with the nasal epithelial surface, which can result in decreasing the nanoparticle transfer into the nasal mucosa.
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Zhang, Fei Hu, Xiao Zong Song, Yong Zhang i Dian Rong Luan. "Polishing of Ultra Smooth Surface with Nanoparticle Colloid Jet". Key Engineering Materials 404 (styczeń 2009): 143–48. http://dx.doi.org/10.4028/www.scientific.net/kem.404.143.
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A nanoparticle colloid jet machining system has been developed for polishing ultra smooth surface of brittle materials. Interaction between nanoparticles and work surface in nanoparticle colloid jet machining has been given, and the theoretical dependence of the material removal rate with various important process parameters of the nanoparticle colloid jet machining have been investigated through material removal experiments. Some material removal results of nanoparticle colloid jet machining show that it is possible to obtain removal rates of one nanometer level per minute for glass surfaces with appropriate machining process parameters. A K9 glass surface was polished for obtaining ultra smooth surface. The surface roughness value of atomic force microscopy (AFM) observations is under 1nm Rms.
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Lee, Hwankyu. "Molecular Modeling of Protein Corona Formation and Its Interactions with Nanoparticles and Cell Membranes for Nanomedicine Applications". Pharmaceutics 13, nr 5 (29.04.2021): 637. http://dx.doi.org/10.3390/pharmaceutics13050637.
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The conformations and surface properties of nanoparticles have been modified to improve the efficiency of drug delivery. However, when nanoparticles flow through the bloodstream, they interact with various plasma proteins, leading to the formation of protein layers on the nanoparticle surface, called protein corona. Experiments have shown that protein corona modulates nanoparticle size, shape, and surface properties and, thus, influence the aggregation of nanoparticles and their interactions with cell membranes, which can increases or decreases the delivery efficiency. To complement these experimental findings and understand atomic-level phenomena that cannot be captured by experiments, molecular dynamics (MD) simulations have been performed for the past decade. Here, we aim to review the critical role of MD simulations to understand (1) the conformation, binding site, and strength of plasma proteins that are adsorbed onto nanoparticle surfaces, (2) the competitive adsorption and desorption of plasma proteins on nanoparticle surfaces, and (3) the interactions between protein-coated nanoparticles and cell membranes. MD simulations have successfully predicted the competitive binding and conformation of protein corona and its effect on the nanoparticle–nanoparticle and nanoparticle–membrane interactions. In particular, simulations have uncovered the mechanism regarding the competitive adsorption and desorption of plasma proteins, which helps to explain the Vroman effect. Overall, these findings indicate that simulations can now provide predications in excellent agreement with experimental observations as well as atomic-scale insights into protein corona formation and interactions.
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Sit, Izaac, Haibin Wu i Vicki H. Grassian. "Environmental Aspects of Oxide Nanoparticles: Probing Oxide Nanoparticle Surface Processes Under Different Environmental Conditions". Annual Review of Analytical Chemistry 14, nr 1 (5.06.2021): 489–514. http://dx.doi.org/10.1146/annurev-anchem-091420-092928.
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Surface chemistry affects the physiochemical properties of nanoparticles in a variety of ways. Therefore, there is great interest in understanding how nanoparticle surfaces evolve under different environmental conditions of pH and temperature. Here, we discuss the use of vibrational spectroscopy as a tool that allows for in situ observations of oxide nanoparticle surfaces and their evolution due to different surface processes. We highlight oxide nanoparticle surface chemistry, either engineered anthropogenic or naturally occurring geochemical nanoparticles, in complex media, with a focus on the impact of ( a) pH on adsorption, intermolecular interactions, and conformational changes; ( b) surface coatings and coadsorbates on protein adsorption kinetics and protein conformation; ( c) surface adsorption on the temperature dependence of protein structure phase changes; and ( d) the use of two-dimensional correlation spectroscopy to analyze spectroscopic results for complex systems. An outlook of the field and remaining challenges is also presented.
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Mukha, Iu P., N. V. Vityuk, A. M. Eremenko i M. A. Skoryk. "Stabilization of metal nanoparticles in highly concentrated colloids". Surface 12(27) (30.12.2020): 337–45. http://dx.doi.org/10.15407/surface.2020.12.337.
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Gold and silver nanoparticles (NPs) have a great potential in nanomedicine. For their use in biological studies there is a need to increase significantly the metal content (active substance) in the dose volume for the injection. Therefore, an urgent task is to find the experimental ways to prevent NPs aggregation in highly concentrated colloidal systems. In this work colloids of Ag NPs, Au NPs and AgAu NPs were prepared in the presence of amino acid as metal ion reducer and particle stabilizer. The polymer pluronic F68 was proposed to increase the stability of NPs and the experimental conditions for the long-term stabilization of colloidal systems with a metal content of 0.4-0.8 mg/ml were developed. It was shown that nanoparticles in all systems maintained nanodimensionality during and after the increasing metal concentration in colloids by 40 times, namely the average size of formed particles was around 10-20 nm. Their optical characteristics remained unchanged, namely, the maxima of the localized surface plasmon resonance band in the absorption spectra had typical position and were placed between 415 and 528 nm depending on molar ratio of metal in nanoparticle.
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Zobel, Mirijam. "Observing structural reorientations at solvent–nanoparticle interfaces by X-ray diffraction – putting water in the spotlight". Acta Crystallographica Section A Foundations and Advances 72, nr 6 (6.10.2016): 621–31. http://dx.doi.org/10.1107/s2053273316013516.
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Nanoparticles are attractive in a wide range of research genres due to their size-dependent properties, which can be in contrast to those of micrometre-sized colloids or bulk materials. This may be attributed, in part, to their large surface-to-volume ratio and quantum confinement effects. There is a growing awareness that stress and strain at the particle surface contribute to their behaviour and this has been included in the structural models of nanoparticles for some time. One significant oversight in this field, however, has been the fact that the particle surface affects its surroundings in an equally important manner. It should be emphasized here that the surface areas involved are huge and, therefore, a significant proportion of solvent molecules are affected. Experimental evidence of this is emerging, where suitable techniques to probe the structural correlations of liquids at nanoparticle surfaces have only recently been developed. The recent validation of solvation shells around nanoparticles has been a significant milestone in advancing this concept. Restructured ordering of solvent molecules at the surfaces of nanoparticles has an influence on the entire panoply of solvent–particle interactions during, for example, particle formation and growth, adhesion forces in industrial filtration, and activities of nanoparticle–enzyme complexes. This article gives an overview of the advances made in solvent–nanoparticle interface research in recent years: from description of the structure of bulk solids and liquidsviamacroscopic planar surfaces, to the detection of nanoscopic restructuring effects. Water–nanoparticle interfaces are given specific attention to illustrate and highlight their similarity to biological systems.
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Kim, Ji-Su, Byung-Kook Kim i Yeong-Cheol Kim. "Effect of Cu Alloying on S Poisoning of Ni Surfaces and Nanoparticle Morphologies Using Ab-Initio Thermodynamics Calculations". Journal of Nanoscience and Nanotechnology 15, nr 10 (1.10.2015): 8205–10. http://dx.doi.org/10.1166/jnn.2015.11287.
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We investigated the effect of Cu alloying on S poisoning of Ni surfaces and nanoparticle morphologies using ab-initio thermodynamics calculations. Based on the Cu segregation energy and the S adsorption energy, the surface energy and nanoparticle morphology of pure Ni, pure Cu, and NiCu alloys were evaluated as functions of the chemical potential of S and the surface orientations of (100), (110), and (111). The constructed nanoparticle morphology was varied as a function of chemical potential of S. We find that the Cu added to Ni for NiCu alloys is strongly segregated into the top surface, and increases the S tolerance of the NiCu nanoparticles.
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Zhu, Chunxiao, Hugh Daigle i Steven L. Bryant. "Paramagnetic nanoparticles as nuclear magnetic resonance contrast agents in sandstone: Importance of nanofluid-rock interactions". Interpretation 4, nr 2 (1.05.2016): SF55—SF65. http://dx.doi.org/10.1190/int-2015-0137.1.
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Nuclear magnetic resonance has been applied in well logging to investigate pore size distribution with high resolution and accuracy based on the relaxation time distribution. However, due to the heterogeneity of natural rock, pore surface relaxivity, which links relaxation time and pore size, varies within the pore system. To analyze and alter pore surface relaxivity, we saturated Boise sandstone cores with positively charged zirconia nanoparticle dispersions in which nanoparticles can be adsorbed onto the sandstone pore wall, while negatively charged zirconia nanoparticles dispersions were used as a control group to provide the baseline of nanoparticle retention due to nonelectrostatic attraction. We have performed core flushing with deionized water, pure acid, and alkali with different pH values; compared properties of zirconia nanoparticles before and after exposure to Boise sandstone; analyzed the portion of zirconia nanoparticles retained in the rock; altered pore surface relaxivity; and linked the adsorbed nanoparticle concentration on the pore surface to the modified surface relaxivity. Our work has indicated that after two pore volumes of core flooding, there was approximately 1% of negatively charged nanoparticles trapped in the Boise sandstone core, whereas approximately 8%–11% of positively charged nanoparticles was retained in the Boise sandstone cores. Our results indicated that besides van der Waals attraction, electrostatic attraction was the driving force for retention of nanoparticles with a positive surface charge in sandstone cores. The attachment of nanoparticles onto sandstone surfaces changed the mineral surface relaxivity. Exposure to acidic or strong alkaline conditions increased the Boise sandstone surface relaxivity. After contact with Boise sandstone, the nanoparticles themselves exhibited increased relaxivity due to interactions between nanoparticles dispersion and mineral surface under different pH conditions.
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Xu, Chang, Albert Wan, Xianchang Gong, N. V. S. Dinesh K. Bhupathiraju, James D. Batteas i Charles Michael Drain. "Reorganization of porphyrin nanoparticle morphology driven by surface energetics". Journal of Porphyrins and Phthalocyanines 20, nr 01n04 (styczeń 2016): 438–43. http://dx.doi.org/10.1142/s1088424616500292.
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Organic nanoparticles (ONp) of an Fe(III) porphyrin appended with four [Formula: see text]-polyethyleneglyco-pyridinium moieties prepared in acetonitrile were deposited onto hydrophilic or hydrophobic Si surfaces. Self-organized by intermolecular interactions, ONp reorganize in response to environmental changes. Mechanisms for the control of nanoparticle morphologies and surface patterning by varying surface energies are discussed.
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Wang, Shenqing, Xiliang Yan, Gaoxing Su i Bing Yan. "Cytotoxicity Induction by the Oxidative Reactivity of Nanoparticles Revealed by a Combinatorial GNP Library with Diverse Redox Properties". Molecules 26, nr 12 (14.06.2021): 3630. http://dx.doi.org/10.3390/molecules26123630.
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It is crucial to establish relationship between nanoparticle structures (or properties) and nanotoxicity. Previous investigations have shown that a nanoparticle’s size, shape, surface and core materials all impact its toxicity. However, the relationship between the redox property of nanoparticles and their toxicity has not been established when all other nanoparticle properties are identical. Here, by synthesizing an 80-membered combinatorial gold nanoparticle (GNP) library with diverse redox properties, we systematically explored this causal relationship. The compelling results revealed that the oxidative reactivity of GNPs, rather than their other physicochemical properties, directly caused cytotoxicity via induction of cellular oxidative stress. Our results show that the redox diversity of nanoparticles is regulated by GNPs modified with redox reactive ligands.
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Gong, Shuting, Tianyi Wang, Jiaping Lin i Liquan Wang. "Patterning of Polymer-Functionalized Nanoparticles with Varied Surface Mobilities of Polymers". Materials 16, nr 3 (1.02.2023): 1254. http://dx.doi.org/10.3390/ma16031254.
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The polymers can be either dynamically tethered to or permanently grafted to the nanoparticle to produce polymer-functionalized nanoparticles. The surface mobility of polymer ligands with one end anchored to the nanoparticle can affect the surface pattern, but the effect remains unclear. Here, we addressed the influence of lateral polymer mobility on surface patterns by performing self-consistent field theory calculations on a modeled polymer-functionalized nanoparticle consisting of immobile and mobile brushes. The results show that except for the radius of nanoparticles and grafting density, the fraction of mobile brushes substantially influences the surface patterning of polymer-functionalized nanoparticles, including striped patterns and patchy patterns with various patches. The number of patches on a nanoparticle increases as the fraction of mobile brushes decreases, favored by the entropy of immobile brushes. Critically, we found that broken symmetry usually occurs in patchy nanoparticles, associated with the balance of enthalpic and entropic effects. The present work provides a fundamental understanding of the dependence of surface patterning on lateral polymer mobility. The work could also guide the preparation of diversified nanopatterns, especially for the asymmetric patchy nanoparticles, enabling the fundamental investigation of the interaction between polymer-functionalized nanoparticles.
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Kano, Shinya, i Harutaka Mekaru. "Proton transport over nanoparticle surface in insulating nanoparticle film-based humidity sensor". Japanese Journal of Applied Physics 61, SE (5.04.2022): SE1011. http://dx.doi.org/10.35848/1347-4065/ac4b0e.
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Abstract We study proton transport on the surface of insulating nanoparticles for humidity sensors. We use this approach to reveal proton transfer mechanisms in humidity-sensitive materials. Hydrophilic and hydrophobic ligand-terminated silica nanoparticle films are adopted for evaluating the temperature dependence of the ion conductivity. According to the activation energy of the conductivity, we explain that Grotthuss (H+ transfer) and vehicular (H3O+ transfer) mechanisms are mainly dominant on hydrophilic (−OH terminated) and hydrophobic (acrylate terminated) surfaces of the nanoparticles, respectively. This investigation gives us a clue to understanding the proton transfer mechanism in solution-processed flexible humidity-sensitive nanomaterial films.
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Zhai, Shengjie, i Hui Zhao. "Enhancement of Sensitivity of the Solution-Phase Localized Surface Plasmon by a Nanostructured Substrate". MRS Advances 1, nr 28 (2016): 2059–64. http://dx.doi.org/10.1557/adv.2016.367.
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AbstractWe describe a simple and inexpensive method to enhance the sensitivity or improve the detection limit of solution-phase localized surface plasmon (LSPR) sensors of metallic nanoparticles. The substrate surface contains metallic nanostructures which are replicated from DVD disks via the standard soft lithography. By mixing BSA molecules with nanoparticle solution, we demonstrate that the wavelength shift due to the absorption of BSA molecules on nanoparticle surfaces is amplified by more than an order of magnitude in comparison to that over a smooth flat surface.
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Hong, Jingjing, Xingping Zhou, Rui Zhuang, Wei Peng, Jiawei Liu, Aiping Liu i Qin Wang. "Nanoparticle trapping by counter-surface plasmon polariton lens". Chinese Optics Letters 20, nr 2 (2022): 023601. http://dx.doi.org/10.3788/col202220.023601.
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Advincula, Rigoberto C. "Surface Initiated Polymerization from Nanoparticle Surfaces". Journal of Dispersion Science and Technology 24, nr 3-4 (7.01.2003): 343–61. http://dx.doi.org/10.1081/dis-120021794.
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Tsirikis, Peter, Kirsty Wilson, Sue Xiang, Wei Wei, Guanghui Ma, Cordelia Selomulya i Magdalena Plebanski. "Immunogenicity and biodistribution of nanoparticles in vivo". Journal of Immunology 196, nr 1_Supplement (1.05.2016): 75.28. http://dx.doi.org/10.4049/jimmunol.196.supp.75.28.
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Abstract Nanoparticles have been widely used in vaccine design as both adjuvants and antigen delivery vehicles. In a seminal study, 40–50 nm nanoparticles with conjugated antigen were shown to induce high antibody titers and IFN-γ production in mice but with no added inflammatory stimuli. Subsequent research has shown that similar levels of immunogenicity can be achieved via the co-injection of naked 40–50 nm nanoparticles adjuvants and larger 500 nm nanoparticles with conjugated antigen. Furthermore, recent works indicate that particle shape can also influence the immune response. As such, we investigate the influence of surface morphology using 40–50 nm smooth and rough surfaced nanoparticle adjuvants and report their differential immunogenicity via ELISA, ELISpot and flow cytometry. Further, we determine the biodistribution of fluorescent 40–50 nm nanoparticle adjuvants with smooth and rough surfaces and larger 500 nm nanoparticles. Nanoparticle size is shown to be a discriminating factor in lymph node drainage, using a Carestream FX PRO in vivo imaging system and fluorescence microscopy of lymph nodes sectioned ex vivo. To elucidate the safety profile of this vaccine construct, we also investigate the biodistribution of nanoparticles within the major organs. The outcomes from this study provide key design criteria in the development of novel nanoparticle immunotherapeutics for the treatment of disease.
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Yuan, Juan, Qing Quan Guo, Xiang Zhu He i Yan Ping Liu. "Researching on the Adsorption of Protein on Gold Nanoparticles". Advanced Materials Research 194-196 (luty 2011): 462–66. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.462.
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Because of their unique properties, gold nanoparticles(NPs) show a wide range of applications such as surface-enhanced raman characteristics, biological sensing, biomedical and other fields. Different initial concentrations of Bull Serum Albumin(BSA) and egg white lysozyme respectively react with different size of gold nanoparticles. The condition of adsorption is determined by spectrometry method, then the area of protein with different molecular mass on the surface of a gold nanoparticle is calculated. The results show that the larger particle size of a gold nanoparticle is, the more protein the surface a gold nanoparticle adsorbs; the smaller the molecular mass of protein is, the more protein is adsorbed by gold nanoparticles surface.
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Dhar, Sunandan, Vishesh Sood, Garima Lohiya, Harini Deivendran i Dhirendra S. Katti. "Role of Physicochemical Properties of Protein in Modulating the Nanoparticle-Bio Interface". Journal of Biomedical Nanotechnology 16, nr 8 (1.08.2020): 1276–95. http://dx.doi.org/10.1166/jbn.2020.2958.
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Nanoparticles, on exposure to the biological milieu, tend to interact with macromolecules to form a biomolecular corona. The biomolecular corona confers a unique biological identity to nanoparticles, and its protein composition plays a deterministic role in the biological fate of nanoparticles. The physiological behavior of proteins stems from their physicochemical properties, including surface charge, hydrophobicity, and structural stability. However, there is insufficient understanding about the role of physicochemical properties of proteins in biomolecular corona formation. We hypothesized that the physicochemical properties of proteins would influence their interaction with nanoparticles and have a deterministic effect on nanoparticle-cell interactions. To test our hypothesis, we used model proteins from different structural classes to understand the effect of secondary structure elements of proteins on the nanoparticle-protein interface. Further, we modified the surface of proteins to study the role of protein surface characteristics in governing the nanoparticle-protein interface. For this study, we used mesoporous silica nanoparticles as a model nanoparticle system. We observed that the surface charge of proteins governs the nature of the primary interaction and the extent of subsequent secondary interactions causing structural rearrangements of the protein. We also observed that the secondary structural contents of proteins significantly affected both the extent of secondary interactions at the nanoparticle-protein interface and the dispersion state of the nanoparticle-protein complex. Further, we studied the interactions of different protein-coated nanoparticles with different cells (fibroblast, carcinoma, and macrophage). We observed that different cells internalized the nanoparticle-protein complex as a function of secondary structural components of the protein. The type of model protein had a significant effect on their internalization by macrophages. Overall, we observed that the physicochemical characteristics of proteins had a significant role in modulating the nanoparticle-bio-interface at the level of both biomolecular corona formation and nanoparticle internalization by cells.
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Shannahan, Jonathan. "The biocorona: a challenge for the biomedical application of nanoparticles". Nanotechnology Reviews 6, nr 4 (28.08.2017): 345–53. http://dx.doi.org/10.1515/ntrev-2016-0098.
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AbstractFormation of the biocorona on the surface of nanoparticles is a significant obstacle for the development of safe and effective nanotechnologies, especially for nanoparticles with biomedical applications. Following introduction into a biological environment, nanoparticles are rapidly coated with biomolecules resulting in formation of the nanoparticle-biocorona. The addition of these biomolecules alters the nanoparticle’s physicochemical characteristics, functionality, biodistribution, and toxicity. To synthesize effective nanotherapeutics and to more fully understand possible toxicity following human exposures, it is necessary to elucidate these interactions between the nanoparticle and the biological media resulting in biocorona formation. A thorough understanding of the mechanisms by which the addition of the biocorona governs nanoparticle-cell interactions is also required. Through elucidating the formation and the biological impact of the biocorona, the field of nanotechnology can reach its full potential. This understanding of the biocorona will ultimately allow for more effective laboratory screening of nanoparticles and enhanced biomedical applications. The importance of the nanoparticle-biocorona has been appreciated for a decade; however, there remain numerous future directions for research which are necessary for study. This perspectives article will summarize the unique challenges presented by the nanoparticle-biocorona and avenues of future needed investigation.
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Rubio, F., Sofia Pérez-Villar, Miguel Angel Garrido, Juan Rubio i J. L. Oteo. "Application of Gradient and Confocal Raman Spectroscopy to Analyze Silver Nanoparticle Diffusion in Medieval Glasses". Journal of Nano Research 8 (wrzesień 2009): 89–97. http://dx.doi.org/10.4028/www.scientific.net/jnanor.8.89.
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In this work it has been carried out the diffusion of silver ions in medieval glasses by a heat treatment process. Silver ions are transformed into both silver nanoparticles and nanoclusters after redox reactions with reducing glass ions. Changes in glass colour due to the formation of these silver nanoparticles have been analysed by means of visible spectroscopy. At the same time, changes in glass structure have been analysed by means of Raman scattering. By using confocal Raman spectroscopy the in deep glass structural changes occurring after silver ion diffusion and silver nanoparticle formation have been studied. These changes have been corroborated by means of gradient Raman spectroscopy where the silver ion and silver nanoparticle diffusion have been analysed on a fractured glass surface. In all cases have been observed that silver nanoparticles produce a depolymerisation of the glass structure and that such depolymerisation increases with the amount of silver nanoparticles. By using Microprobe Analysis it has been found that the higher silver nanoparticle concentration is on the glass surface and it decreases with the distance to the surface according to a diffusion process. By using nanoindentation measurements on original and gradient glass surfaces it has been found an increase of the Young modulus from 60 to 85 GPa, being the first value that corresponding to the glass surface with high silver nanoparticle concentration, and the second one for the glass without silver. This result is in accordance with Raman and Microprobe analysis.
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Song, Xiaozong, Shundong Ge, Xiaorong Wang i Shengkai Liu. "Experimental Investigation on the Effects of Photocatalysis in Ultraviolet-Induced Nanoparticle Colloid Jet Machining". Materials 14, nr 5 (25.02.2021): 1070. http://dx.doi.org/10.3390/ma14051070.
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In this paper, ultraviolet (UV)-induced nanoparticle colloid jet machining is proposed to achieve ultrasmooth surface polishing by using the interaction between nanoparticles and the workpiece surface under the action of the ultraviolet field and the hydrodynamic pressure field. In the process of UV-induced nanoparticle colloid jet machining, the effects of photocatalysis on the interaction between nanoparticles and the workpiece surface need to be further studied in order to better understand the polishing process. This paper presents the interaction between TiO2 nanoparticles and a Si workpiece surface with and without ultraviolet irradiation. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were applied to investigate the differences in the interaction of TiO2 nanoparticles with Si workpieces. The SEM and XPS results indicate that the photocatalysis of UV light can promote the interaction between TiO2 nanoparticles and a Si surface by creating more interfacial reaction active centers between the TiO2 nanoparticles and the Si workpiece. The FT-IR and XPS spectra show that TiO2 nanoparticles are chemically bonded to the Si workpiece by oxygen-bridging atoms in Ti-O-Si bonds. Due to the effects of photocatalysis, UV-induced nanoparticle colloid jet machining has a higher polishing efficiency than nanoparticle colloid jet machining with the same polishing parameters.
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Huang, Shan, i Jun-Jie Zhu. "Linkage Pathways of DNA–Nanoparticle Conjugates and Biological Applications". Chemosensors 11, nr 8 (10.08.2023): 444. http://dx.doi.org/10.3390/chemosensors11080444.
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DNA–nanoparticle conjugates have extraordinary optical and catalytic properties that have attracted great interest in biosensing and biomedical applications. Combining these special qualities has made it possible to create extremely sensitive and selective biomolecule detection methods, as well as effective nanopharmaceutical carriers and therapy medications. In particular, inorganic nanoparticles, such as metal nanoparticles, metal–organic framework nanoparticles, or upconversion nanoparticles with relatively inert surfaces can easily bind to DNA through covalent bonds, ligand bonds, electrostatic adsorption, biotin–streptavidin interactions and click chemistry to form DNA–nanoparticle conjugates for a broad range of applications in biosensing and biomedicine due to their exceptional surface modifiability. In this review, we summarize the recent advances in the assembly mechanism of DNA–nanoparticle conjugates and their biological applications. The challenges of designing DNA–nanoparticle conjugates and their further applications are also discussed.
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Okawa, Tomio, Koki Nakano i Yutaro Umehara. "Variations of nanoparticle layer properties during nucleate pool boiling". Journal of Physics: Conference Series 2116, nr 1 (1.11.2021): 012002. http://dx.doi.org/10.1088/1742-6596/2116/1/012002.
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Abstract The nanoparticle layer detachment during nucleate pool boiling and its influences on heat transfer surface properties were explored experimentally. The material of the heat transfer surface was copper and the nanoparticle layer was formed on the heat transfer surface by nucleate boiling in the water-based TiO2 nanofluid. It was found that the detachment of the nanoparticle layer during nucleate boiling in pure water is significant. In the present experiment, more than half of nanoparticles deposited on the heated surface were detached before the CHF condition was reached. The thickness and roughness decreased accordingly. However, the wettability and wickability that are the influential parameters on the CHF value were maintained even after the occurrence of nanoparticle layer detachment and deteriorated only after the CHF condition was reached. It is therefore considered that the onset of CHF brings qualitative change to the capillary suction performance of the layer of nanoparticles. In exploring the effect of the nanoparticle layer properties on the nucleate boiling heat transfer, sufficient attention should be paid to the variation of the nanoparticle layer properties during nucleate boiling.
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Levratovsky, Y., i E. Gross. "High spatial resolution mapping of chemically-active self-assembled N-heterocyclic carbenes on Pt nanoparticles". Faraday Discussions 188 (2016): 345–53. http://dx.doi.org/10.1039/c5fd00194c.
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The properties of many functional materials critically depend on the spatial distribution of surface active sites. In the case of solid catalysts, the geometric and electronic properties of different surface sites will directly impact their catalytic properties. However, the detection of catalytic sites at the single nanoparticle level cannot be easily achieved and most spectroscopic measurements are performed with ensemble-based measurements in which the reactivity is averaged over millions of nanoparticles. It is hereby demonstrated that chemically-functionalized N-heterocyclic carbene molecules can be attached to the surfaces of Pt nanoparticles and utilized as a model system for studying catalytic reactions on single metallic nanoparticles. The formation of a carbene self-assembled layer on the surface of a Pt nanoparticle and its stability under oxidizing conditions were investigated. IR nanospectroscopy measurements detected the chemical properties of surface-anchored molecules on single nanoparticles. A direct correlation was identified between IR nanospectroscopy measurements and macroscopic ATR-IR measurements. These results demonstrate that high spatial resolution mapping of the catalytic reactivity on single nanoparticles can be achieved with this approach.
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Pedraza, A. J., J. D. Fowlkes, D. A. Blom i H. M. Meyer. "Laser-induced nanoparticle ordering". Journal of Materials Research 17, nr 11 (listopad 2002): 2815–22. http://dx.doi.org/10.1557/jmr.2002.0409.
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Nanoparticles were produced on the surface of silicon upon pulsed-laser irradiation in the presence of an inert gas atmosphere at fluences close to the melting threshold. It was observed that nanoparticle formation required redeposition of ablated material. Redeposition took place in the form of a thin film intermixed with extremely small nanoparticles possibly formed in the gas phase. Through the use of nonpolarized laser light, it was shown that nanoparticles, fairly uniform in size, became grouped into curvilinear strings distributed with a short-range ordering. Microstructuring of part of the surface prior to the laser treatment had the remarkable effect of producing nanoparticles lying along straight and fairly long (approximately 1 mm) lines, whose spacing equaled the laser wavelength for normal beam incidence. In this work, it is shown that the use of polarized light eliminated the need of an aiding agent: nanoparticle alignment ensued under similar laser treatment conditions. The phenomenon of nanoparticle alignment bears a striking similarity with the phenomenon of laser-induced periodic surface structures (LIPSS), obeying the same dependence of line spacing upon light wavelength and beam angle of incidence as the grating spacing in LIPSS. The new results strongly support the proposition that the two phenomena, LIPSS and laser-induced nanoparticle alignment, evolve as a result of the same light interference mechanism.
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Idriss, Hajo, M. Habib M. Habib, A. I. Alakhras i H. M. El Khair. "Nano-sized Metal Oxides and Their use as a Surface Disinfectant Against COVID-19: (Review and Perspective)". Oriental Journal Of Chemistry 38, nr 6 (30.12.2022): 1328–37. http://dx.doi.org/10.13005/ojc/380601.
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Contamination of surfaces has long been identified as a significant factor in viral transmission. Therefore, sustained efforts are required to address this issue. This work aims to build a scientific database on nano-sized metal oxides as intelligent materials for surface disinfection against corona viruses, synthesize and characterize nano-sized MgO, and discuss the possibility of using it in virus eradication. The MgO nanoparticle was prepared through the heating method. Meanwhile, XRD diffractometer, Scan electron microscope, and nitrogen adsorption were used to characterize the MgO nanoparticle. The synthesized MgO nanoparticle showed an average crystallite size of 18.55nm, lattice strain 0.0053, surface area 27.56 m2/g and d-spacing 2.1092. The outcomes of this review highlight the advantage and challenges of AgO, CuO, ZnO, TiO2 and MgO nanoparticles and their utilization for surface disinfection against coronaviruses.
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Cagliani, Roberta, Francesca Gatto i Giuseppe Bardi. "Protein Adsorption: A Feasible Method for Nanoparticle Functionalization?" Materials 12, nr 12 (21.06.2019): 1991. http://dx.doi.org/10.3390/ma12121991.
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Nanomaterials are now well-established components of many sectors of science and technology. Their sizes, structures, and chemical properties allow for the exploration of a vast range of potential applications and novel approaches in basic research. Biomedical applications, such as drug or gene delivery, often require the release of nanoparticles into the bloodstream, which is populated by blood cells and a plethora of small peptides, proteins, sugars, lipids, and complexes of all these molecules. Generally, in biological fluids, a nanoparticle’s surface is covered by different biomolecules, which regulate the interactions of nanoparticles with tissues and, eventually, their fate. The adsorption of molecules onto the nanomaterial is described as “corona” formation. Every blood particulate component can contribute to the creation of the corona, although small proteins represent the majority of the adsorbed chemical moieties. The precise rules of surface-protein adsorption remain unknown, although the surface charge and topography of the nanoparticle seem to discriminate the different coronas. We will describe examples of adsorption of specific biomolecules onto nanoparticles as one of the methods for natural surface functionalization, and highlight advantages and limitations. Our critical review of these topics may help to design appropriate nanomaterials for specific drug delivery.
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Hajdu, Péter, István Lampé, Richárd Rácz, Sándor Biri, Attila Csík, Ferenc Tóth, Melinda Szalóki i in. "Optimized Size and Distribution of Silver Nanoparticles on the Surface of Titanium Implant Regarding Cell Viability". Applied Sciences 10, nr 20 (12.10.2020): 7063. http://dx.doi.org/10.3390/app10207063.
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Though the antibacterial effect is advantageous, silver and silver nanoparticles can negatively affect the viability of human tissues. This study aims to check the viability of cells on surfaces with different particle size and to find the biologically optimal configuration. We investigated the effect of modified thickness of vaporized silver and applied heat and time on the physical characteristics of silver nanoparticle covered titanium surfaces. Samples were examined by scanning electron microscopy, mass spectrometry, and drop shape analyzer. To investigate how different physical surface characteristics influence cell viability, Alamar Blue assay for dental pulp stem cells was carried out. We found that different surface characteristics can be achieved by modifying procedures when creating silver nanoparticle covered titanium. The size of the nanoparticles varied between 60 to 368 nm, and hydrophilicity varied between 63 and 105 degrees of contact angle. Investigations also demonstrated that different physical characteristics are related to a different level of viability. Surfaces covered with 60 nm particle sizes proved to be the most hydrophilic, and the viability of the cells was comparable to the viability measured on the untreated control surface. Physical and biological characteristics of silver nanoparticle covered titanium, including cell viability, have an acceptable level to be used for antibacterial effects to prevent periimplantitis around implants.
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Song, Xiao Zong, i Fei Hu Zhang. "Research on the Characterization of Ultra-Smooth K9 Glass Surface Polished by Nanoparticle Colloid Jet Machining". Key Engineering Materials 609-610 (kwiecień 2014): 552–56. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.552.
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In this work, optical K9 glass surface has been flattened by nanoparticle colloid jet machining, which is an ultra-smooth surface processing technique utilizing surface chemical effect between work surface atoms and nanoparticles in alkaline colloid to remove the uppermost surface atoms. The surface removal process of nanoparticle colloid jet machining has been investigated through K9 glass polish experiments. And the characterizations of ultra-smooth K9 glass surface polished by nanoparticle colloid jet machining have also been studied in this paper. Surface profiler and atomic force microscopy (AFM) are used to observe the surface microscopic morphological characteristics of K9 glass sample before and after polishing by nanoparticle colloid jet machining. The measurement results of processed surface prove that the primary scratches on the original surface have been completely wiped off by nanoparticle colloid jet machining and the roughness of the K9 glass surface has been improved to be less than 1 nm (Rq). Autocovariance (ACF) is investigated along a cross section of the K9 glass surface to determine the dominant spatial frequencies. The ACF curves show that the surface morphology of K9 glass processed by nanoparticle colloid jet machining is completely different from the preprocessed surface. The final K9 glass surface has been flattened by nanoparticle colloid jet machining. The microscopic morphological profile of the final K9 glass surface becomes increasingly smooth and eventually close to a flat state.
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Olinger, Alexander D., Eric J. Spangler, P. B. Sunil Kumar i Mohamed Laradji. "Membrane-mediated aggregation of anisotropically curved nanoparticles". Faraday Discussions 186 (2016): 265–75. http://dx.doi.org/10.1039/c5fd00144g.
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Using systematic numerical simulations, we study the self-assembly of elongated curved nanoparticles on lipid vesicles. Our simulations are based on molecular dynamics of a coarse-grained implicit-solvent model of self-assembled lipid membranes with a Langevin thermostat. Here we consider only the case wherein the nanoparticle–nanoparticle interaction is repulsive, only the concave surface of the nanoparticle interacts attractively with the lipid head groups and only the outer surface of the vesicle is exposed to the nanoparticles. Upon their adhesion on the vesicle, the curved nanoparticles generate local curvature on the membrane. The resulting nanoparticle-generated membrane curvature leads in turn to nanoparticle self-assembly into two main types of aggregates corresponding to chain aggregates at low adhesion strengths and aster aggregates at high adhesion strength. The chain-like aggregates are due to the fact that at low values of adhesion strength, the nanoparticles prefer to lie parallel to each other. As the adhesion strength is increased, a splay angle between the nanoparticles is induced with a magnitude that increases with increasing adhesion strength. The origin of the splay angles between the nanoparticles is shown to be saddle-like membrane deformations induced by a tilt of the lipids around the nanoparticles. This phenomenon of membrane mediated self-assembly of anisotropically curved nanoparticles is explored for systems with varying nanoparticle number densities, adhesion strength, and nanoparticle intrinsic curvature.
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Niu, Bin, i Gengxin Zhang. "Effects of Different Nanoparticles on Microbes". Microorganisms 11, nr 3 (21.02.2023): 542. http://dx.doi.org/10.3390/microorganisms11030542.
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Nanoparticles widely exist in nature and may be formed through inorganic or organic pathways, exhibiting unique physical and chemical properties different from those of bulk materials. However, little is known about the potential consequences of nanomaterials on microbes in natural environments. Herein, we investigated the interactions between microbes and nanoparticles by performing experiments on the inhibition effects of gold, ludox and laponite nanoparticles on Escherichia coli in liquid Luria–Bertani (LB) medium at different nanoparticle concentrations. These nanoparticles were shown to be effective bactericides. Scanning electron microscopy (SEM) images revealed the distinct aggregation of cells and nanoparticles. Transmission electron microscopy (TEM) images showed considerable cell membrane disruption due to nanoparticle accumulation on the cell surfaces, resulting in cell death. We hypothesized that this nanoparticle accumulation on the cell surfaces not only disrupted the cell membranes but also physically blocked the microbes from accessing nutrients. An iron-reducing bacterium, Shewanella putrefaciens, was tested for its ability to reduce the Fe (III) in solid ferrihydrite (HFO) or aqueous ferric citrate in the presence of laponite nanoparticles. It was found that the laponite nanoparticles inhibited the reduction of the Fe (III) in solid ferrihydrite. Moreover, direct contact between the cells and solid Fe (III) coated with the laponite nanoparticles was physically blocked, as confirmed by SEM images and particle size measurements. However, the laponite particles had an insignificant effect on the extent of aqueous Fe (III) bioreduction but slightly enhanced the rate of bioreduction of the Fe (III) in aqueous ferric citrate. The slightly increased rate of bioreduction by laponite nanoparticles may be due to the removal of inhibitory Fe (II) from the cell surface by its sorption onto the laponite nanoparticle surface. This result indicates that the scavenging of toxic heavy metals, such as Fe (II), by nanoparticles may be beneficial for microbes in the environment. On the other hand, microbial cells are also capable of detoxifying nanoparticles by coagulating nanoparticles with extracellular polymeric substances or by changing nanoparticle morphologies. Hence, the interactions between microbes and nanoparticles in natural environments should receive more attention.
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Bousiakou, Leda G., Hrvoje Gebavi, Lara Mikac, Stefanos Karapetis i Mile Ivanda. "Surface Enhanced Raman Spectroscopy for Molecular Identification- a Review on Surface Plasmon Resonance (SPR) and Localised Surface Plasmon Resonance (LSPR) in Optical Nanobiosensing". Croatica chemica acta 92, nr 4 (2019): 479–94. http://dx.doi.org/10.5562/cca3558.
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Surface plasmon resonance (SPR) allows for real-time, label-free optical detection of many chemical and biological substances. Having emerged in the last two decades, it is a widely used technique due to its non-invasive nature, allowing for the ultra-sensitive detection of a number of analytes. This review article discusses the principles, providing examples and illustrating the utility of SPR within the frame of plasmonic nanobiosensing, while making comparisons with its successor, namely localized surface plasmon resonance (LSPR). In particular LSPR utilizes both metal nanoparticle arrays and single nanoparticles, as compared to a continuous film of gold as used in traditional SPR. LSPR, utilizes metal nanoparticle arrays or single nanoparticles that have smaller sizes than the wavelength of the incident light, measuring small changes in the wavelength of the absorbance position, rather than the angle as in SPR. We introduce LSPR nanobiosensing by describing the initial experiments performed, shift-enhancement methods, exploitation of the short electromagnetic field decay length, and single nanoparticle sensors are as pathways to further exploit the strengths of LSPR nanobiosensing. Coupling molecular identification to LSPR spectroscopy is also explored and thus examples from surface-enhanced Raman spectroscopy are provided. The unique characteristics of LSPR nanobiosensing are emphasized and the challenges using LSPR nanobiosensors for detection of biomolecules as a biomarker are discussed.
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Song, Xiaozong, i Gui Gao. "Removal Mechanism Investigation of Ultraviolet Induced Nanoparticle Colloid Jet Machining". Molecules 26, nr 1 (25.12.2020): 68. http://dx.doi.org/10.3390/molecules26010068.
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Ultraviolet induced nanoparticle colloid jet machining is a new ultra-precision machining technology utilizing the reaction between nanoparticles and the surface of the workpiece to achieve sub-nanometer ultra-smooth surface manufacturing without damage. First-principles calculations based on the density functional theory (DFT) were carried out to study the atomic material removal mechanism of nanoparticle colloid jet machining and a series of impacting and polishing experiments were conducted to verify the mechanism. New chemical bonds of Ti-O-Si were generated through the chemical adsorption between the surface adsorbed hydroxyl groups of the TiO2 cluster and the Si surface with the adsorption energy of at least −4.360 eV. The two Si-Si back bonds were broken preferentially and the Si atom was removed in the separation process of TiO2 cluster from the Si surface realizing the atomic material removal. A layer of adsorbed TiO2 nanoparticles was detected on the Si surface after 3 min of fixed-point injection of an ultraviolet induced nanoparticle colloid jet. X-ray photoelectron spectroscopy results indicated that Ti-O-Si bonds were formed between TiO2 nanoparticles and Si surface corresponding to the calculation result. An ultra-smooth Si workpiece with a roughness of Rq 0.791 nm was obtained by ultraviolet induced nanoparticle colloid jet machining.
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Ozmaian, Aye, Rob D. Coalson i Masoumeh Ozmaian. "Adsorption of Polymer-Grafted Nanoparticles on Curved Surfaces". Chemistry 3, nr 1 (8.03.2021): 382–90. http://dx.doi.org/10.3390/chemistry3010028.
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Nanometer-curved surfaces are abundant in biological systems as well as in nano-sized technologies. Properly functionalized polymer-grafted nanoparticles (PGNs) adhere to surfaces with different geometries and curvatures. This work explores some of the energetic and mechanical characteristics of the adhesion of PGNs to surfaces with positive, negative and zero curvatures using Coarse-Grained Molecular Dynamics (CGMD) simulations. Our calculated free energies of binding of the PGN to the curved and flat surfaces as a function of separation distance show that curvature of the surface critically impacts the adhesion strength. We find that the flat surface is the most adhesive, and the concave surface is the least adhesive surface. This somewhat counterintuitive finding suggests that while a bare nanoparticle is more likely to adhere to a positively curved surface than a flat surface, grafting polymer chains to the nanoparticle surface inverts this behavior. Moreover, we studied the rheological behavior of PGN upon separation from the flat and curved surfaces under external pulling force. The results presented herein can be exploited in drug delivery and self-assembly applications.
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Sutthavas, Pichaporn, Matthias Schumacher, Kai Zheng, Pamela Habibović, Aldo Roberto Boccaccini i Sabine van Rijt. "Zn-Loaded and Calcium Phosphate-Coated Degradable Silica Nanoparticles Can Effectively Promote Osteogenesis in Human Mesenchymal Stem Cells". Nanomaterials 12, nr 17 (24.08.2022): 2918. http://dx.doi.org/10.3390/nano12172918.
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Nanoparticles such as mesoporous bioactive glasses (MBGs) and mesoporous silica nanoparticles (MSN) are promising for use in bone regeneration applications due to their inherent bioactivity. Doping silica nanoparticles with bioinorganic ions could further enhance their biological performance. For example, zinc (Zn) is often used as an additive because it plays an important role in bone formation and development. Local delivery and dose control are important aspects of its therapeutic application. In this work, we investigated how Zn incorporation in MSN and MBG nanoparticles impacts their ability to promote human mesenchymal stem cell (hMSC) osteogenesis and mineralization in vitro. Zn ions were incorporated in three different ways; within the matrix, on the surface or in the mesopores. The nanoparticles were further coated with a calcium phosphate (CaP) layer to allow pH-responsive delivery of the ions. We demonstrate that the Zn incorporation amount and ion release profile affect the nanoparticle’s ability to stimulate osteogenesis in hMSCs. Specifically, we show that the nanoparticles that contain rapid Zn release profiles and a degradable silica matrix were most effective in inducing hMSC differentiation. Moreover, cells cultured in the presence of nanoparticle-containing media resulted in the highest induction of alkaline phosphate (ALP) activity, followed by culturing hMSC on nanoparticles immobilized on the surface as films. Exposure to nanoparticle-conditioned media did not increase ALP activity in hMSCs. In summary, Zn incorporation mode and nanoparticle application play an important role in determining the bioactivity of ion-doped silica nanoparticles.
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Shaikh, M. Nasiruzzaman. "Thiolated Gd(III) Chelate Coated Gold Nanoparticles: Synthesis, Characterization, X-Ray CT and MRI Relaxivity Studies". Materials Science Forum 754 (kwiecień 2013): 121–30. http://dx.doi.org/10.4028/www.scientific.net/msf.754.121.
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Gadolinium complex of 2-aminothiophenol conjugated DTPA (DTPA=diethylenetriamine N,N,N',N",N" pentacetic acid) bis (amide) has been synthesized and characterized by various analytical techniques such as elemental analysis (EA), NMR, FAB-MS, IR, UV etc. This thiolated GdL (where L is a conjugate of DTPA and 2-aminothiophenol) has been anchored on the gold nanoparticles surfaces through thiols functionalites. These gold nanoparticles (AuNPs) have been synthesized by the reduction of gold tetrachloride (HAuCl4) using sodium citrate as reducing agent. The surface functionalization has been performed by the replacement of citrate coat on the gold nanoparticle surface with thiolated Gd-chelate, Au@GdL. The Au@GdL has been analyzed by XRD, transmission electron microscope (HRTEM), UV, ICP-MS etc. The average size of nanoparticles is about 22 nm with a uniform spherical shape. A very high number of GdL has been loaded on nanoparticle surface reaching up to 7.9x103 of Gd (III)- chelates per nanoparticle and they demonstrate very high r1 relaxivity and the r1 relaxivity per [G is much higher than the Gd (III)-chelate alone. The bimodality has also been tested using in-vitro x-ray computed tomography (x-ray CT). These nanoparticles (GNPs) are very stable and homogeneously dispersed in aqueous solution.
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Lastra, Ruben O., Tatjana Paunesku, Barite Gutama, Filiberto Reyes, Josie François, Shelby Martinez, Lun Xin i in. "Protein Binding Effects of Dopamine Coated Titanium Dioxide Shell Nanoparticles". Precision Nanomedicine 2, nr 4 (2.10.2019): 393–438. http://dx.doi.org/10.33218/prnano2(4).190802.1.
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Non-targeted nanoparticles are capable of entering cells, passing through different subcellular compartments and accumulating on their surface a protein corona that changes over time. In this study, we used metal oxide nanoparticles with iron-oxide core covered with titanium dioxide shell (Fe3O4@TiO2), with a single layer of covalently bound dopamine covering the nanoparticle surface. Mixing nanoparticles with cellular protein isolates showed that these nanoparticles can form complexes with numerous cellular proteins. The addition of non-toxic quantities of nano-particles to HeLa cell culture resulted in their non-specific uptake and accumulation of protein corona on nanoparticle surface. TfRC, Hsp90 and PARP were followed as representative protein components of nanoparticle corona; each protein bound to nanoparticles with different affinity. The presence of nanoparticles in cells also mildly modulated gene expression on the level of mRNA. In conclusion, cells exposed to non-targeted nanoparticles show subtle but numerous changes that are consistent from one experiment to another.
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Song, Xiao Zong, Yong Zhang i Fei Hu Zhang. "Ultra-Precision Shaping and Ultra-Smooth Polishing Investigation of High-Purity Quartz Glass in Nanoparticle Colloid Jet Machining". Advanced Materials Research 426 (styczeń 2012): 396–99. http://dx.doi.org/10.4028/www.scientific.net/amr.426.396.
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In this paper, ultra-precision shaping and ultra-smooth polishing investigations have been done upon a high-purity quartz glass substrate with an aspheric surface in nanoparticle colloid jet machining, which is an ultra smooth surface processing technique utilizing surface chemical reaction between work surface atoms and nanoparticles to remove the uppermost surface atoms. The shaping and polishing characters of high-purity quartz glass in nanoparticle colloid jet machining has been researched. The surface profile of the high-purity quartz glass workpiece before and after shaping has been measured by surface profilometer. And the surface microscopic morphological characteristics of high-purity quartz glass surface polished by nanoparticle colloid jet machining have been observed by atomic force microscopy (AFM). The measurement results indicate that nanoparticle colloid jet machining has good shaping ability for surface shape correction in ultra-precision machining. And the AFM observation results show that the roughness of the high-purity quartz glass surface has been reduced from 1.919 nm RMS to 0.784 nm RMS by nanoparticle colloid jet machining.
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Alhajj, Nasser, Idanawati Naharudin, Paolo Colombo, Eride Quarta i Tin Wui Wong. "Probing Critical Physical Properties of Lactose-Polyethylene Glycol Microparticles in Pulmonary Delivery of Chitosan Nanoparticles". Pharmaceutics 13, nr 10 (29.09.2021): 1581. http://dx.doi.org/10.3390/pharmaceutics13101581.
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Pulmonary delivery of chitosan nanoparticles is met with nanoparticle agglomeration and exhalation. Admixing lactose-based microparticles (surface area-weighted diameter~5 μm) with nanoparticles mutually reduces particle agglomeration through surface adsorption phenomenon. Lactose-polyethylene glycol (PEG) microparticles with different sizes, morphologies and crystallinities were prepared by a spray drying method using varying PEG molecular weights and ethanol contents. The chitosan nanoparticles were similarly prepared. In vitro inhalation performance and peripheral lung deposition of chitosan nanoparticles were enhanced through co-blending with larger lactose-PEG microparticles with reduced specific surface area. These microparticles had reduced inter-microparticle interaction, thereby promoting microparticle–nanoparticle interaction and facilitating nanoparticles flow into peripheral lung.
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Ju, Dong Ying, Pei Bian, Ge Letu Qing, Da Ling Lu i Hong He. "Magnetite Nanoparticles Surface Coating SiO2 and Magnetic Properties Evaluation". Key Engineering Materials 368-372 (luty 2008): 1366–69. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1366.
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Magnetite nanoparticles were obtained by liquid phase precipitation method in which the pH value of [FeCl2⋅4H2O], [FeCl3⋅6H2O] and [NaOH] solution were controlled. Then the magnetite nanoparticle were scattered in water solution and put in [Na2SiO3] and [HCl], the resultant of reaction SiO2 can be coated on magnetite nanoparticles surface. The morphology and magnetite properties of the coated nanoparticles were evaluated by XRD, TEM, FTIR and VSM. The SiO2 thin film with nanometer size was coated on surface of nanoparticle, so that the magnetic value is decreased with the coating thickness increasing.
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Stanglmair, Christoph, Frank Neubrech i Claudia Pacholski. "Chemical Routes to Surface Enhanced Infrared Absorption (SEIRA) Substrates". Zeitschrift für Physikalische Chemie 232, nr 9-11 (28.08.2018): 1527–39. http://dx.doi.org/10.1515/zpch-2018-1132.
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Abstract Bottom-up strategies for fabricating SEIRA substrates are presented. For this purpose, wet-chemically prepared gold nanoparticles are coated with a polystyrene shell and subsequently self-assembled into different nanostructures such as quasi-hexagonally ordered gold nanoparticle monolayers, double layers, and honeycomb structures. Furthermore elongated gold nanostructures are obtained by sintering of gold nanoparticle double layers. The optical properties of these different gold nanostructures are directly connected to their morphology and geometrical arrangement – leading to surface plasmon resonances from the visible to the infrared wavelength range. Finally, SEIRA enhancement factors are determined. Gold nanoparticle double layers show the best performance as SEIRA substrates.
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Wang, Chungang, Ying Chen, Zhanfang Ma, Tingting Wang i Zhongmin Su. "Generalized Fabrication of Surfactant-Stabilized Anisotropic Metal Nanoparticles to Amino-Functionalized Surfaces: Application to Surface-Enhanced Raman Spectroscopy". Journal of Nanoscience and Nanotechnology 8, nr 11 (1.11.2008): 5887–95. http://dx.doi.org/10.1166/jnn.2008.222.
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A universal and facile approach for the self-assembly of surfactant-coated anisotropic metal nanoparticles on the amino-functionalized planar and spherical surfaces based on electrostatic attraction has been explored. Large-scale and different surface coverage of monolayer film and metallodielectric core–shell nanostructures of anisotropic metal nanoparticles, including Au nanorods, AucoreAgshell nanorods and Ag nanoprisms, have been fabricated. The optical response in the visible and the near infrared (NIR) of resulting nanostructures can be easily controlled by varying the concentration of the anisotropic nanoparticle, the amount of silica particles, and the immersion time of the substrates. Large-scale anisotropic metal nanoparticle monolayer films with subtle control over the surface coverage and tunable plasmon resonance as surface-enhanced Raman spectroscopy (SERS) substrates for probing 4-aminothiophenol were investigated, which exhibited high SERS activity, stability and reproducibility.
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Siegel, Jakub, Tatiana Savenkova, Jana Pryjmaková, Petr Slepička, Miroslav Šlouf i Václav Švorčík. "Surface Texturing of Polyethylene Terephthalate Induced by Excimer Laser in Silver Nanoparticle Colloids". Materials 14, nr 12 (12.06.2021): 3263. http://dx.doi.org/10.3390/ma14123263.
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We report on a novel technique of surface texturing of polyethylene terephthalate (PET) foil in the presence of silver nanoparticles (AgNPs). This approach provides a variable surface morphology of PET evenly decorated with AgNPs. Surface texturing occurred in silver nanoparticle colloids of different concentrations under the action of pulse excimer laser. Surface morphology of PET immobilized with AgNPs was observed by AFM and FEGSEM. Atomic concentration of silver was determined by XPS. A presented concentration-controlled procedure of surface texturing of PET in the presence of silver colloids leads to a highly nanoparticle-enriched polymer surface with a variable morphology and uniform nanoparticle distribution.
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Fuchise-Fukuoka, Moe, Masatoshi Oishi, Shisei Goto i Akira Isogai. "Preparation of CaCO3 nanoparticle/pulp fiber composites using ultrafine bubbles". Nordic Pulp & Paper Research Journal 35, nr 2 (25.06.2020): 279–87. http://dx.doi.org/10.1515/npprj-2019-0078.
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AbstractIn this study, CaCO3 nanoparticle/pulp fiber composites were prepared by formation of ultrafine bubbles of CO2 gas in aqueous Ca(OH)2 solution containing beaten or unbeaten pulp fibers. Scanning electron microscopy images of the fiber/CaCO3 composites showed that primary CaCO3 nanoparticles with average diameters of 50–80 nm densely formed on the pulp fiber surfaces. The average sizes and morphologies of the precipitated CaCO3 nanoparticles can be controlled by controlling the CO2 flow rate into the pulp slurry. From dynamic drainage analysis of the CaCO3/pulp slurries with high shear force, retention of the CaCO3 nanoparticles on the pulp fiber mats was ∼10 % higher for the slurry formed by the ultrafine bubble method than for that formed by mixing precipitated CaCO3 and pulp fiber. Therefore, precipitated CaCO3 nanoparticles stably formed on the pulp fiber surfaces in the slurry by the ultrafine bubble method. Compared with reference handsheets, handsheets prepared with the CaCO3 nanoparticle/pulp fiber composites had higher CaCO3 contents and had consequently higher specific surface areas and surface smoothness values. In contrast, the tensile strength and elongation at break decreased because the sheet density decreased with increasing CaCO3 content in the handsheets.
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Zhao, Xin, Jialiang Li, Shaopeng Cheng, Shouming Li, Xiao Bai i Jie Xi. "Study on the Role of Paclitaxel Nano-Drug Delivery System in Inhibiting Intimal Hyperplasia and Improving Vascular Remodeling in Abdominal Aortic Injury Model". Journal of Nanoscience and Nanotechnology 21, nr 2 (1.02.2021): 1385–89. http://dx.doi.org/10.1166/jnn.2021.18653.
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The surface-modified paclitaxel nanoparticles were prepared to observe its inhibitory effect on the intimal and mediator proliferation and the improvement of vascular remodeling after rabbit abdominal aortic injury. First, paclitaxel nanoparticles were prepared by ultrasonic emulsification solvent evaporation method. The surface of paclitaxel nanoparticles was modified by physical adsorption, the nanoparticles were characterized and the encapsulation efficiency was evaluated. Secondly, the endometrial thickness was measured by hematoxylin and eosin staining, and a spheroid with a smooth surface was observed under a scanning electron microscope. Finally, compared with the control group, local infusion of paclitaxel nanoparticles could effectively inhibit the proliferation of vascular endothelium in a dose-dependent manner. Local intravascular infusion of paclitaxel nanoparticle suspension can effectively inhibit the proliferation of vascular endothelial cells, and its inhibitory effect increases with the increase of the concentration of nanoparticle suspension. The paclitaxel nanoparticle suspension at a concentration of 30 mg/ml can play a good inhibitory role.
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Jafari Daghlian Sofla, Saeed, Lesley Anne James i Yahui Zhang. "Toward a mechanistic understanding of wettability alteration in reservoir rocks using silica nanoparticles". E3S Web of Conferences 89 (2019): 03004. http://dx.doi.org/10.1051/e3sconf/20198903004.
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Traditional concepts of simple liquid spreading may not apply to nanoparticle-fluids. Most investigations pertaining to the wettability alteration of solid surfaces due to the presence of nanoparticles in the fluid are oversimplified, i.e. nanoparticles dispersed in DI-water and smooth, homogeneous, and clean surfaces have been used. From a practical enhanced oil recovery (EOR) point of view, the nanoparticles must be dispersed in either seawater or high salinity formation water containing diverse types and concentrations of ions. These ions interact with the electrostatic properties of the nanoparticles. Likewise, the oil phase may contain many surface active components like asphaltene and naphthenic acids which can interact with nanoparticles at oil-water and oil-rock interface. In reality, the rock sample is a heterogeneous, non-smooth, mixed-wet substrate with a diverse mineralogical composition. The electrical charge of minerals can vary when contacted with an ionic fluid. This can alter the electrostatic repulsion between substrate and nanoparticles and consequently the substrate can either attract or repel charged particles, including nanoparticles. Hence, the role of nanoparticles must be evaluated considering multicomponent complex fluids and real formation rock. Despite numerous reports regarding the wettability alteration of reservoir rock from oil-wet to water-wet by nanoparticles, some inherent limitations in the wettability alteration experiments prevent conclusions about the performance of nanoparticles in practical complex conditions. For instance, the wettability alteration by nanoparticles is often determined by contact angle measurements. In this method, the substrates are either aged with (immersed in) nanoparticle-fluids before conducting the experiments or contacted with nanoparticle-fluids before attachment of the oil droplet on the rock surface. Hence, in both cases, before initiating the contact angle measurements, the nanoparticles would already exist at the oil-rock interface possibly giving inaccurate measurements. The objective of this work is to investigate the mechanism of wettability alteration by silica nanoparticles pre-existing on the rock interface (conventional contact angle measurements) and using a new displacement contact angle method to better mimic the scenario of injecting a nanoparticle fluid into the reservoir already containing formation brine. The impact of pre-existing nanoparticles at the oil-rock interface (in the conventional contact angle measurements) on the contact angle measurements are examined for simple (n-decane, NaCl brine, and pure substrates) and complex (crude oil, seawater, and reservoir rock) systems on various wetting conditions of substrates (water-wet and oil-wet). The nanoparticles are dispersed in seawater using our H+ protected method [1]. Then, the effect of surface and nanoparticle charge on the contact angle is evaluated by adjusting the aqueous phase salinity. We also differentiate between the disjoining pressure mechanism and diffusion of silica nanoparticles through the oil phase by testing the attachment of nanoparticles on the rock surface.
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Montes, Melissa, Christopher G. Pierce, Jose L. Lopez-Ribot, Amar S. Bhalla i Ru Yan Guo. "Properties of Silver and Copper Nanoparticle Containing Aqueous Suspensions and Evaluation of their In Vitro Activity against Candida albicans and Staphylococcus aureus Biofilms". Journal of Nano Research 37 (grudzień 2015): 109–21. http://dx.doi.org/10.4028/www.scientific.net/jnanor.37.109.
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Most microorganisms grow on surfaces as biofilms rather than as individual planktonic cells, and cells within biofilms show high levels of resistance against antimicrobial drugs. Thereby biofilm formation complicates treatment and contributes to high morbidity and mortality rates associated with infections. This study explores the physical, optical, and nano-structural properties of silver and copper nanoparticles dispersed in aqueous suspensions (nanoparticulate colloidal water) and examines their in vitro activity against microbial biofilms. Silver and copper nanoparticulate colloidal water of various concentrations were prepared and studied. Their surface energies, surface charge and surface plasmonic resonance properties were determined using contact angle measurement, zeta potential measurement and optical spectrometry, respectively. A model of biofilm formation on the wells of microtiter plates was used to determine the activity of the nanoparticulate suspensions against fungal and bacterial biofilms. Scanning electron microscopy (SEM) was used to observe the nanoparticle interactions with microbial cells within the biofilms. Results show that silver nanoparticle-containing liquids have higher surface energy than their copper counterparts; and that the surface energy increases as the concentration of silver nanoparticles increases. Altogether, the effectiveness of silver nanoparticle colloidal suspensions in controlling biofilm formation is observed and reported. For a given size of silver nanoparticles studied, it is found that the effective concentrations against microbial biofilms are far lower than their cytotoxic concentrations, indicating an overall safety and a good therapeutic index thus substantial application potential.
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Cui, Wen Ying, Hyun Jin Yoo, Yun Guang Li, Changyoon Baek i Junhong Min. "Electrospun Nanofibers Embedded with Copper Oxide Nanoparticles to Improve Antiviral Function". Journal of Nanoscience and Nanotechnology 21, nr 8 (1.08.2021): 4174–78. http://dx.doi.org/10.1166/jnn.2021.19379.
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Many studies on anti-bacterial/antiviral surfaces have been conducted to prevent epidemic spread worldwide. Several nanoparticles such as those composed of silver and copper are known to have antiviral properties. In this study, we developed copper oxide (CuO) nanoparticle-incorporated nanofibers to inactivate or remove viruses. The CuO nanoparticle-incorporated nanofiber was fabricated with a hydrophobic polymer—polyvinylpyrrolidone (PVP)—using electrospinning, and CuO nanoparticles were exposed from the PVP polymer surface by etching the nanofiber with oxygen plasma. The fabrication conditions of electrospinning and oxygen plasma etching were investigated by scanning electron microscopy (SEM), and field emission transmission electron microscopy (FETEM)/ energy dispersive spectrometry (EDS). H1N1 virus was utilized as the target sample and quantified by RT-qPCR. The antiviral efficacy of CuO nanoparticle-incorporated nanofibers was compared against bare CuO nanoparticles. Overall, 70% of the viruses were inactivated after CuO nanoparticle-incorporated nanofibers were incubated with 102 pfu/mL of H1N1 virus solution for 4 h. This indicates that the developed CuO nanoparticle-incorporated nanofibers have noticeable antiviral efficacy. As the developed CuO nanoparticle-incorporated nanofibers exerted promising antiviral effects against H1N1 virus, it is expected to benefit global health by preventing epidemic spread.
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Tsirikis, Peter, Kirsty Wilson, Ying Kong, Sue Xiang, Cordelia Selomulya i Magdalena Plebanski. "Differential antibody induction to surface textured silica nanoparticle adjuvants (VAC3P.1055)". Journal of Immunology 194, nr 1_Supplement (1.05.2015): 71.2. http://dx.doi.org/10.4049/jimmunol.194.supp.71.2.
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Abstract Nanoparticles have been shown to be a potent adjuvant in vaccine design. Previous studies demonstrated that carboxylated 40-50 nm polystyrene nanoparticles (PSNPs) with covalently bound antigen offer a new class of vaccine with only two elements (antigen and particle) but with no added inflammatory stimuli. Herein, we report on a deconstructed two-part vaccine whereby the adjuvant and protein carrier are co-administered to elicit potent antibody responses in vivo. Recent works indicate that particle shape can also influence the immune response. As such, we investigate the influence of surface morphology using smooth and rough surfaced silica nanoparticle adjuvants, showing smooth nanoparticles as the more potent antibody inducers. MTT assay confirms that both silica nanoparticle adjuvant and polystyrene protein carrier display excellent biocompatibility with over 95% viability with COS-7 cells. Preliminary in vitro dendritic cell (DC) culture experiments indicate that silica nanoparticle adjuvants, similarly to PSNPs, do not induce the up-regulation of maturation markers, CD80, CD86 and MHC II on CD11c+ gated DCs. This suggests the particle carrier itself is non-inflammatory, a required feature for our vaccine approach. Ongoing studies are focusing on the cytokines induced in vitro and in vivo by these novel constructs. The outcomes from this study provide key design criteria in the development of novel nanoparticle immunotherapeutics for the treatment of disease.