Papers by Keyword: Silver Nanoparticle

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Authors: Sahana Bajracharya, Sroisiri Thaweboon, Boonyanit Thaweboon, Amornrat Wonglamsam, Theerathavaj Srithavaj
Abstract: The aim of this study is to investigate the candidal biofilm formation on the silver nanoparticles (AgNPs) incorporated denture base heat-polymerized (poly methyl methacrylate), PMMA, resinand its flexural strength.Materials and methods:A total of 36PMMA resin specimens (15×15×2 mm3) were fabricated and divided into 4 groups based on their AgNPs contents (0%,0.5%, 1% and 1.5% w/w of polymer). The biofilm of clinical and reference strainsof C.albicanswere grown on PMMA resin specimens in the presence of yeast nitrogen base broth supplemented with 100 mM glucose at 37oC for 48 h and evaluated by tetrazolium reduction assay. The flexural strength of PMMA resin specimens (65×10×3.3 mm3) were tested by using three-point bending test. Data were analyzed by Kruskal-Wallis and Mann-Whitney U test at p<0.05. result:all="" 3="" groups="" with="" agnps="" showed="" significant="" reduction="" in="" biofilm="" formation="" of="" both="" strains="" i="">C.albicans compared to control (0% AgNPs) (p<0.05). Decreased flexural strength was observed with AgNPs groups compared with the control but within acceptable limit of ISO 20795-1. Conclusion:The reduction of the C. albicans biofilm was observed on the heat-polymerized PMMA resin incorporated with AgNPs. Regarding the flexural strength, the values were within ISO limit. These modified PMMA resin can be developed for the prevention or treatment of the candidal infection associated with the denture base material.
Authors: Ling Chen, De Suo Zhang, Hong Lin, Yu Yue Chen
Abstract: The chief aim of the present work is to investigate the preparation for silver nanoparticles antimicrobial agent and its antibacterial activity on cotton fabric. In this study, antimicrobial agent was fabricated by a reaction between an amino-terminated hyperbranched polymer (HBP-NH2) and silver nitrate solution of certain concentration. Meanwhile, cotton fabric was oxygenated to afford aldehyde groups which could connect with the amino groups of the HBP-NH2 to provide cotton fabric with durable antimicrobial properties. The effects of different biocides made of various molecular structures of synthetic material (HBP-NH2) on antimicrobial properties of nano-silver colloid solution were discussed, and three different agents generated then were characterized in following aspects as silver nanoparticles size and distribution by using DLS, TEM and UV-vis. Furthermore, the fabric structure, mechanical properties and antimicrobial property of treated cotton fabric were also tested. Included in this part of experiment were transverse micro morphology of cotton fibre by SEM, fabric strength retention after finishing, silver nanoparticles molecular conformation on fabric and content analysis via ICP-AES. The results showed that stable silver nanoparticles collide solution with 20-30 nano, applied on oxidized cotton fabric under certain condition, could produce ideal antibacterial rate over 94% of bacterial reduction to both Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) after 50 consecutive washings.
Authors: Can Gao, Tan Guo, Xiu Shen Ye, Hui Fang Zhang, Hai Ning Liu, Zhi Jian Wu
Abstract: Uniform films of silver nanoparticles (Ag NPs) were fabricated by self-assembly on 3-aminopropyltriethoxysilane (APTES) and [3-(2-aminoethyl) aminopropyl] trimethoxysilane (AEAPTES) modified glass slides. A stable Ag NPs suspension was synthesized via the reduction of silver nitrate using sodium citrate. Bulk characteristics of Ag NPs in aqueous solution were carried out by measuring their absorption spectrum, morphology and particle shape using the UV-vis absorption spectroscopy and transmission electron microscopy (TEM), respectively. The average diameter of Ag NPs is about 50 nm. The coverage of adsorbed particles on the modified glasses was measured by scanning electron microscopic imaging (SEM). The SEM images indicate that the Ag NPs films on the glasses are uniform. It is supposed that the adsorption processes are mainly controlled by electrostatic interactions. The adsorption amount of Ag NPs on APTES modified glass slides is much more than the amount on AEAPTES modified glass slides.
Authors: Anjali A. Athawale, Prachi P. Katre
Abstract: Silver nanoparticles were synthesized by irradiating silver nitrate solution (10-4 M) (methanol:water as a solvent) with different concentrations of aniline as a stabilizer in a 60Co g-ray source at a dose rate of 1.1 kGy. The particles exhibiting maximum stability up to a period of 7 days were obtained at the concentration of 0.1M aniline. The average particle size of the nanoparticles as estimated from XRD and TEM was found to be ~23 nm. Silver-Polyaniline (Ag-Pani) nanocomposite was prepared by oxidative polymerization of aniline. The applicability of synthesized nanocomposite as a sensor was tested by exposing the same to different chemical vapors viz. alcohols, amines, ammonia, chloroform etc. The results revealed its selectivity towards ammonia vapors and a long term stability of response is observed up to a period of two months. The above results are well supported by FT-IR spectroscopy.
Authors: Fang Liu, Wu Yi Zhou, Zhuo Hong Yang, Su Yao Xiao, Yong Cao
Abstract: Silver-incorporated titania (Ag/TiO2) nano-membrane were formed on the surface of domestic ceramic substrates by a sol-gel method with the use of tetrabutyl titanate and silver nitrate as precursors, acetyl acetone and nitric acid as a catalytic inhibitor, absolute ethyl alcohol as the solvent. In the same way, titanium dioxide (TiO2) films were also prepared on the same ceramic substrates. The surface morphology and the crystal structure of the Ag/TiO2 nano-membrane obtained through the method mentioned with different calcination treatment have been discussed by XRD, SEM, DRS and FTIR respectively. Compared with TiO2 nano-membrane, the XRD analysis shows that no significant shift in the crystal structure is presented because of silver ion-doping. From SEM and EDS, it is shown that spheric silver particles are spread on the surface of the nano-membrane and the insights into the compositions were provided by FTIR. DRS analysis showed that the red shift of the fundamental absorption edge of titania could be caused by silver ion-doping.
Authors: Hathaichanok Tamiyakul, Somboon Tanasupawat, Stephan Thierry Dubas, Warangkana Warisnoicharoen
Abstract: Antibacterial potential of metallic silver nanoparticles (AgNPs) is considered to be influenced by their size and stability. In this study, the stable AgNPs capped with poly (4-styrenesulfonic acid-co-maleic acid) or PSSMA were successfully synthesized by using a chemical reduction method. The PSSMA-stabilized AgNPs (PSSMA-AgNPs) were characterized and tested for antibacterial activity against eight bacterial strains. Transmission electron microscopic studies showed that PSSMA-AgNPs were monodisperse spherical particles with an average size of 5.21 nm. From bacterial growth curve studies, PSSMA-AgNPs exhibited an antibacterial effect on Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 6538p, Staphylococcus aureus ATCC 43300, Staphylococcus epidermidis ATCC 12228 and Bacillus subtilis ATCC 6633) and Gram-negative bacteria (Escherichia coli ATCC 25922, Enterobacter aerogenes ATCC 13048 and Pseudomonas aeruginosa ATCC 27853). Moreover, the Gram-negative bacteria were found to be more susceptible to the AgNPs.
Authors: Chellasamy Panneerselvam, Kadarkarai Murugan, Duraisamy Amerasan
Abstract: Metallic nanoparticles have received great attention from chemists, physicists, biologists and engineers who wish to use them for the development of a new generation of nanodevices. In the present Communication, a completely “green” chemistry method for producing silver nanoparticles is introduced. The process is simple, environmentally benign, and quite efficient. Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and ecofriendly reducing and capping agents. In particular, silver nanoparticles are proved to have potential antibacterial, antifungal and antiplasmodial and antimicrobial properties. The present study was aimed to identify the antiplasmodial activity of green synthesised silver nanoparticles (AgNPs) using aqueous extract of plant Euphorbia hirta against P.falciparum. Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant to generate extremely stable silver nanoparticles in water. The bio-reduced silver nanoparticles were appropriately characterized by UV–vis spectrum, Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The formation of the AgNPs synthesized from the XRD spectrum compared with the standard confirmed spectrum of silver particles formed in the present experiments were in the form of nanocrystals, as evidenced by the peaks at 2θ values of =28.01°, 32.41°, 46.44°, 55.05° and 57.75°. The scanning electron micrograph (SEM) showed structures of spherical, cubic shape, and the size range was found to be 30–60 nm. The EDX spectra showed the purity of the material and the complete chemical composition of the synthesized AgNPs. The parasitic inhibition was dose-dependent. The synthesized AgNPs showed considerable antiplasmodial activity than the crude methanol and aqueous leaf extract of E.hirta. The maximum efficacy was
Authors: Jing Zhu, Yang Liu, Juan He, Hong Liang Wei, Hui Juan Chu
Abstract: New water soluble multiwall carbon nanotubes (MWCNTs) containing silver nanoparticles-grafted-hyperbranched polyglycerols (HPG) nanocomposites were synthesized and characterized successfully. In this work, MWCNTs were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet chemcial method. Then MWCNTs containing silver nanoparticles (MWCNTs(Ag)) were used as macroinitiator for ring opening polymerization of glycidol and MWCNTs(Ag)-g-HPG nanocomposites were obtained. Structure of nanocomposites was evaluated by TEM, TGA and spectroscopy methods. With the solubility of MWCNTs(Ag)-g-HPG greatly improved, the new nanocomposites exhibit potential application in biomedicine and nanomedicine.
Authors: Maryam Jokar, Russly Abdul Rahman, Nor Azowa Ibrahim, Luqman Chuah Abdullah, Tan Chin Ping
Abstract: Silver nanoparticles are of interest due to their unique physicochemical and antimicrobial properties. The nanoparticles were produced by chemical reduction using short chain polyethylene glycol (PEG) as reducing agent, solvent and stabilizer in absence of other chemicals. Silver nanoparticles were separated from colloidal dispersion by ultra centrifuge at 14000 rpm. The reduction of silver ion (Ag+) to silver nanoparticles (Agº) was monitored by pH measurement and UV-visible spectroscopy of colloidal dispersion at fixed intervals. Silver nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and diphenyl-picrylhydrazyl (DPPH) radical scavenging method. Antimicrobial activity of silver nanoparticles was investigated against Escherichia coli, Staphylococcus aureus and Vibrio parahaemolyticus by agar plate test. Results indicated 51.5% conversion efficiency of silver ions to silver nanoparticles. Colloidal dispersion containing 4.12 mg/ml silver nanoparticles showed uniform size of 5.5 ± 1.1 nm with a typical visible spectra band at 447 nm. Silver nanoparticles showed significant (p < 0.05) antimicrobial efficiency and with concentration of 100 ppm resulted in 46.22%, 66.51% and 69.06% inhibition against S. aureus, E. coli and V. parahaemolyticus, respectively. The nanoparticles were also found to reduce DPPH free radical up to 88.9%. Results of this study proved that the silver nanoparticles produced by polyethylene glycol possess antimicrobial and antioxidant activity.
Authors: Zuraida Ahmad, A.K. Ahmad Ulwi, Tajuddin Maisarah, A. Maisarah
Abstract: This paper reported on the properties of sago starch (SS) films impregnated with different concentration of sliver nanoparticles (SNP) of 100, 2000, 5000 rpm with weight ratio of 1% and 10% to be used as wound healing material. The SS films were prepared through film moulding technique by mixing aqueous SNP with SS, glycerol and water at weight percentage of 6.5:3.5:90. The performance of SS-SNP films produced is studied. The morphology study shows the existence of SNP embedded in the SS particles. SNP with 2000ppm has the biggest particle width but small in particle sizes, which make the SS-SNP film of 2000ppm is superior in thickness, denser and has lower moisture content compared to other SS-SNP film with different composition. The highest water absorption occurred in the SS-SNP of 100ppm, due to the high existence of pores in the network of amylose content in starch. SNP act as particulate reinforcement in the SS film meaning higher number of ppm made the film more brittle and easy to rupture. Thus, the SS-SNP film of 5000ppm has the lowest tensile strength and modulus for tensile strength and modulus. It can be concluded that the SS-SNP film of 2000ppm is suitable to be used as wound healing material, as the addition of 2000ppm SNP inside the SS films help in improving the properties of SS-SNP film produced.
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