Papers by Keyword: Nanosilver

Abstract: Morphology of silver nanoparticle coated on ZSM-5, mordenite, and Y-Type zeolite by Stöber’s and Tollen’s methods was characterized. The silver element was confirmed by SEM, EDX spectrum and XRD. Nanoparticle size of the silver fabricated on the surface of all three types of zeolite by Stöber’s method appeared in 1.8-7.9 times smaller than the Tollen’s methods depending on the Si/Al ratio of the zeolite. The ZSM-5, containing the highest Si/Al ratio and the largest crystal size, provided the best adhesion to the silver nanoparticles. Analysis of the SEM image showed a well distribution of silver nanoparticles on all types of zeolites, but only for the Stöber’s coating technique. A 4.54% coverage area of the silver nanoparticles on the Y-Type zeolite was enough for transformation the crystalline structure of zeolite surface to amorphous as consequent of the broad peak XRD spectrum. Since the zeolite surface was not fully obscured by silver nanoparticles as confirmed by FTIR, its absorption property of zeolite was also preserved. The Raman signal enhancement was evident when zeolite was coated with silver nanoparticle.

Abstract: The performance of nanosilver loaded bamboo-based activated carbon as an adsorbent used for the adsorptive removal of formaldehyde in the air. The size porous of the active carbon is predominantly on the size of mesoporous and microporous. Adsorption tests have been evaluated in laboratory scale fixed-bed column, at different temperatures and initial formaldehyde concentration. In order to investigate is both equilibrium and thermodynamic aspects. The experimental data was fitted with Langmuir model and fit well with the adsorption capacity of 91-110 mg/g. The increase in temperature reduces the adsorption capacity. The thermodynamic parameters show that the values of ∆G^o obtained to confirm the feasibility of activated carbon effective sorbents of formaldehyde. The formaldehyde adsorption process is exothermic and adsorbent has a good affinity to formaldehyde.

Abstract: We showed the results of immunohistochemical investigation of outbred albino rat’s neural tissue exposed to 9-day exposure of nanobiocomposite, which consist silver nanoparticles encapsulated in natural biopolymer matrix - arabinogalactan. Investigation of white rats was composed of 2 stages: half of the rats in each group were sacrificed immediately after exposure (early period) and other rats – through 6 months after end of exposure (distant period). We showed that test substance causes functional changes in nervous tissue. After subacute administration of nanobiocomposite - argentumarabinogalaktan (nAG) we have observed changes of content of apoptotic and anti-apoptotic proteins caspase-3 and bcl-2 in nervous tissue of white rats. number of normal neurons producing the protein caspase-3 was increased sharply and number of immunonegative normal neurons was significantly reduced. Along with this there was a high level of bcl – 2, one function of which is to prevent apoptosis trigger. We revealed in samples a significant increase in number of neurons with bcl-2, but protective effect of this protein not fully realized, which leads to significant increase of amount ofdamaged hyperchromatic cells. Assessment of results of immunohistochemical study of white rat’s nervous tissue, according to the expression of the protein caspase-3 and bcl – 2, may lead conclusion about ability of nanosilver encapsulated in a polymer matrix to penetrate blood-brain barrier and induced start apoptotic cascade in cortical neurons.

Abstract: Objective: To explore the effect of nanosilver on inducement of differentiation of neural stem cells of SD rats. Method: nanosilver film and newborn SD rat neural stem cell co-culture method is adopted to perform primary and subculture on SD rat neural stem cells and to induce differentiation. Nestin staining is adopted to identify the characteristics of neural stem cells. Immunohistochemistry method (β-III-tubulin, GFAP staining) is adopted to detect the status of differentiation from neural stem cells into neurons and neurogliocytes. Result: The neural stem cells of newborn SD rats can form Nestin positive cell balls in case of no serum culture. After induction of differentiation, NF-positive cells and GFAP-positive cells can be seen through immunofluorescence staining, wherein for nanosilver intervention group, the proportion of hippocampal NSCs differentiating to group neurons is smaller than that of the control group, with significantly reduced impact on astrocyte differentiation. Conclusion: nanosilver has adverse effect on normal differentiation of hippocampal NSCs to neurons and astrocytes.

Abstract: The effects of colloidal silver are determined by concentration, sizes and stability of the finely-divided nanoparticles. Studies of silver-based drugs acting against antibiotic-resistant microorganisms are of significant scientific and practical interest. Silver does not effect on the infection, but directly on the cell structure. The main disadvantages of the current nanosilver-based compositions include low aggregative stability, polydispersity and oxidation of silver nanoparticles during prolonged storage. The main attention should be paid to the preservation of activity and bioavailability of the active substance, and ideally the increase in efficiency through synergy with other components of the formulation. Scientists of different special fields should focus not only on the development of new technologies for production of new nanomedicines, but on the possible health and environmental side effects

Abstract: Fabrication of polyvinyl alcohol (PVA) fibers loaded with evenly distributed nanosilver has been sucessfully done using electrospinner. The electrospinner is set at 15 kV DC voltage with distance between electrodes 13 cm, using a syringe hole diameter 0,5 mm. The feeding solution for the electrospinning was prepared by directly mixing the solution of PVA in water with a stable colloid of nanosilver at room temperature. The fibers morphology was characterized using scanning electron microscope. The optical property was tested using spectrometer. The distribution of silver nanoparticles in the fibers was tested using transmission electron microscope. The result indicates that the fibers still showing plasmonic property of silver having peak at 410 nm with no crystaline changes. The diameter of fibers loaded with nanosilver are smaller compared to that of the ones without nanosilver.The distribution of nanosilver in fibers made of PVA and the ones made of PVA and chitosan are compared and discussed.

Abstract: Abstract. Bacterial cellulose-silver (BC-silver) composites are known as biomaterials with good antimicrobial properties. The aim of this paper is to present a green route to produce antibacterial BC-silver composites using Curcuma longa tuber powder (turmeric) extract as reducing agent. The effect of medium pH and immersion time in the turmeric extract upon the silver nanoparticles was studied. The synthesis of silver nanoparticles deposited on bacterial cellulose was confirmed by ultraviolet-visible (UV-VIS) spectral studies, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The antibacterial activity of the nanocomposites was studied by inhibition zone method against Escherichia coli K12-MG1655, all the composites having a good antimicrobial activity.

Abstract: Research the nanosilver and other composite materials with the chitosan in the best composition with orthogonal test method. According to the best use concentration of nanosilver and composite materials carry out the orthogonal experiment. By using the ultrasonic method test the adhesion strength between chitosan membrane and the breeding net through calculating the loss of the membrane. With bacteriostatic circle method to determine the bacteriostatic effect of membrane. The results show that the main factors influence the adhesion of membrane and the effectiveness of bacteriostatic is adhesives and nanosilver. The orthogonal experiment results show that the optimum conditions of film forming as follows: the adhesion agent A3% , adhesion reagent B3% ,nanosilver solution 2% nanoantibacterial powder 3% ,tea saponin solution 60 mg/L. Under these conditions, the loss of the membranewas14.6%, the inhibition zone was 2.35cm. Orthogonal test was applied to the ratio of composite materials can get the best composite columns. Creating a better performance of target product and has a promising prospect for practical application.

Abstract: This study proposes a development for the nanosilver adhesive, which is applicable to high efficiency LED light. The important issue of LED light is heat exhaust from LED. Generally, the middle area of LED light is increased up to 380K. Therefore, the bottleneck between LED chip and heat sink are caused by high temperature. In this work, the adhesive material between LED Chip and heat sink was newly developed for improvement of bottleneck. The nanosilver was adopted to solve heat problem of chip on board package for LED light. In order to evaluate the performance of the nanosilver adhesive, the thermal analysis was performed. Moreover both adhesive performance and heat exhaust were verified through the prototype test. From the experimental test results, it is found that the developed nanosilver adhesive has the high performance.

Abstract: Obiective is studing the bacteriostasis of nanosilver on the pathogenic fungus Botryti cinerea from illed plants. Five strains of Botrytis cinerea were used as the experimental materials. 0.3 % carbendazim and 0.3 % chlorothalonil were used as comparing chemistry bacteriostatic agents. The inhibitionand effects of bacteriostatic agents on the growth of mycelia, spore’s germination, size of the inhibitory zone, electrical conductivity, morphology and structure of Botrytis cinerea were studied. Results is that the bacteriostatic effects of nanosilver is significantly better than blank comparing experiment, and there are differentiation in strains. The bacteriostasis effece of carbendazim is better than chlorothalonil. The chlorothalonil is better than nanosilver. Conclusion is that There is better bacteriostasis against Botrytis cinerea for nanosilver. The The principle of bacteriostasis is that nanosilver disrupts permeation of cell mombrance of Botrytis cinerea.