Papers by Keyword: Nanoparticle

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Authors: Shen Zhou Lu, Juan Wang, Li Mao, Gui Jun Li, Jian Jin
Abstract: Silk nanoparticles were easily obtained from regenerated Antheraea Pernyi Silk Fibroin (ASF). The morphology and average size of the silk particles was sensitive to pH value of fibroin solution. The diameter of nanoparticles prepared was in the range of 30 nm to 1000 nm with a narrow size distribution. On this process, the molecular conformation of regenerated ASF changed from α-helix to β-sheet structure. The shape of prepared nanoparticles were regular spherical structure when the pH value was about 4.3 (pI) in ASF solution. Doxorubicin hydrochloride (DOX) was loaded in the ASF particles as drug release model and the drug-loading ratio was 3.4 %. The release rate of DOX from ASF nanoparticles was pH sensitive. After 23 days release, there was still 84% DOX in the ASF nanoparticles. The result suggested that the ASF nanoparticles might be suitable microcarriers for drug delivery.
Authors: Jiang Tao Shi, Qing Feng Sun, Jian Li
Abstract: Titanium dioxide nanoparticles were produced in xylem cell of living tree by in situ hydrolysis of tetrabutyl orthotitanate (TBOT) under ambient pressure and temperature. The specimens were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDXA) and X-ray powder Diffraction (XRD) spectroscopy. From these results, spherical and uniform dispersion particles in nanoscale and anatase TiO2 crystalline phase presence in xylem cell wall of Populus ussuriensis. This work demonstrates that it is possible to generate of wood-nano biological composite material in xylem cell of living tree.
Authors: Naznin Sultana, Min Wang
Abstract: Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) was used to make composite scaffolds for bone tissue engineering in our previous studies. To control the degradation rate and process of composite scaffolds, PHBV was blended with poly(L-lactic acid) (PLLA), which has a much higher degradation rate than PHBV, and PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Composite scaffolds based on these blends and containing nano-sized hydroxyapatite (nHA) were fabricated using an emulsion freezing / freeze-drying technique. Non-porous films of PHBV/PLLA blends were prepared using the solvent casting method. In vitro degradation tests of non-porous PHBV/PLLA blends and porous composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of films and scaffolds. For PHBV/PLLA-based scaffolds, the incorporated nHA particles also significantly increased water uptake within the initial immersion time. Both PHBV/PLLA blends and composite scaffolds underwent rapid weight losses within the first few weeks. The degradation of composite scaffolds arose from the dissolution of nHA particles and degradation of the PLLA component of polymer blends. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein, in the current study.
Authors: Di Chang, Zhen Qing Hou, Xiang Rui Yang
Abstract: We prepared FA-targeted and 10-hydroxycamptothecin loaded chitosan nanoparticles (FA-HCPT-NPs) with a combination of emulsion-solvent evaporation and chemical crosslinking method. In vitro cytotoxicity test to the Human Cervix Carcinoma cells (HeLa) was evaluated by cell morphology and internalization observation. The specicity of the FA-HCPT-NPs targeting cancerous cells was demonstrated by comparative intracellular uptake of HCPT-NPs and commercial availible HCPT injection. Laser confocal scanning imaging proved that FA-HCPT-NPs could greatly enhance up-take by HeLa cells. The morphological changes of HeLa cells showed the FA-HCPT-NPs could inhibit HeLa cells more effectively than HCPT-NPs and HCPT. The results indicated that the novel FA-HCPT-NPs could be a potential drug delivery system for tumor cell-selective targeting therapy.
Authors: Akhtar Jahan Siddiqa, Koel Chaudhury, Basudam Adhikari
Abstract: The present work focuses on the development of biodegradable PLGA nanoparticles (NPs) for controlled release of a breast cancer drug, letrozole. NPs of different drug-polymer ratio formulations (F1, F2, F3, F4) were fabricated using solvent evaporation technique. Physico-chemical characteristics of these NPs were assessed using dynamic light scattering (DLS) spectrophotometer. In-vitro drug release study was carried out over an extended period of 30 days at 37 °C in simulated physiological fluid. To evaluate the release kinetics, data was fitted to different models. NPs with various sizes and size distributions were obtained by altering the drug-polymer ratio. Zeta potential of PLGA and drug loaded NPs were found to be-29.4± 1.3 mV and-21.0±0.6 mV, respectively. The release kinetics of the drug from NPs was in good agreement with Korsmeyer-Peppas model, ensuring controlled release of the drug from the NPs. In-vitro release studies showed high correlation coefficient (R2 = 0.90) for formulation F2 and F3 up to 30 days. It is concluded that NPs with F2 and F3 formulations provide a controlled release of the incorporated drug and, therefore, hold promise to be investigated further in detail.
Authors: D.D. Green, G.S.K. Kannangara, Adriyan Milev, Besim Ben-Nissan
Authors: Rabab Khalid Sendi, Shahrom Mahmud, Amna Sirelkhatim
Abstract: Zinc oxide-based varistors are semiconductor ceramics. Their excellent nonlinear electrical behaviors are induced from their grain boundaries and depend on their microstructural characteristics. From a theoretical aspect, finer primary particles with narrow size distributions provide better electrical and optical properties. Thus, these properties are related to the morphology and size of ZnO grains. In this study, ZnO-Bi2O3-Mn2O3 varistors fabricated from ZnO micro-and nanoparticle powders are prepared via conventional ceramic processing. The effects of ZnO particle size and different annealing ambients on the properties of ZnO varistors are also investigated. The strong solid-state reaction during sintering may be attributed to the high surface area of the 20 nm ZnO nanoparticles that promote strong surface reaction. The annealing process also improves grain crystallinity, as shown in the decrease in intrinsic compressive stress based on the X-ray diffraction lattice constant and full-width at half-maximum (FWHM) data. The reduced particle size significantly influences the electrical properties, showing a sharp drop in the breakdown voltage. Thus, the ZnO nanoparticles can be used to manufacture of varistors with superior properties and lower breakdown voltage compared with commercial ones.
Authors: Jing Wang, Yong Zhang, Wen Li Guo, Tong Xiang Liang, Chang Sheng Deng, Jing Ming Xu
Abstract: La0.8Sr0.2FeO3 electrodes modified with nanoparticles of La0.8Sr0.2MnO3 (LSF/LSM) were prepared by infiltration method. LSM solution had good wettability on LSF surfaces and good electrochemical compatibility with LSF. The impedance of half-cells incorporating the electrodes was also examined. The deconvolution of the impedance spectrum indicated that the peak positions are changed after the LSF infiltration. The LSF/LSM electrode exhibited smaller polarization resistance than pure LSF electrode. Finally, a transform from asymmetry to symmetry appeared in the polarization curves of LSF/LSM electrode with the increase of temperature.
Authors: Carlo Baldisserri, Davide Gardini, Carmen Galassi
Abstract: Cobalt ferrite (CoFe2O4) and magnetite (Fe3O4) nanoparticles suspensions in diethylene glycol were tested as candidate systems for the EPD of CoFe2O4 and Fe3O4. It was found that despite the high stability and high zeta potential of such suspensions and the occurrence of mass transport at the electrode, they are not viable systems for EPD, due to coagulation failure. However, dilution of both suspensions with ethanol caused film coagulation at electric field between 20 and 60 V cm-1. Combinations of electric field and DEG volume fraction in ethanol/suspension mixtures that allow EPD to take place are detailed, and a description of the outcome of EPD trials is provided. A qualitative discussion of the causes of film consolidation in the presence of ethanol is presented.
Authors: X.Q. Chen, Y.Y. Liu, K.H. Qi, X. Zhou, J.H. Xin
Abstract: Monodisperse silica particles containing available active C=C bonds were directly prepared by a simple two-step sol-gel method. In the first step the hydrolysis of vinyltrimethoxysilane (VTMS) was performed under acidic conditions in an aqueous solution. In the second step the condensation of the siloxane precursors progressed under basic conditions, resulting in production of silica nanoparticles containing available active C=C bonds. The products were characterized using SEM and FTIR.
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