PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

We report here, the biosynthesis of silver nanoparticles embedded in chitosan. Prawn shells were treated with 5% sodium hydroxide and 5N HCl to remove protein and calcium, respectively. To convert chitin present in the shells into chitosan, they were treated with 40% NaOH at 180oC for 10hrs and the resultant product i.e chitosan was dissolved in 0.1 N HCl. It was then converted into chitosan scaffolds by adding 500�l ethylene glycol to it and cast into a thin film. The chitosan dissolved in 0.1N HCl was treated with aqueous solution of AgSO4 (1X10-4 M) and NaBH4 (1 M) till the solution attained gold brown colour. To this solution 500 �l of ethylene glycol was added and cast into a thin film. The control chitosan scaffolds and silver nanoparticles impregnated chitosan scaffolds (Ag-chitosan) were characterized for FT-IR, TGA, EDS, X-RD and SEM. FT-IR absorption spectra conclude that the compounds attached with silver nanoparticles could be amide group. The increased thermal stability property was found in Ag-chitosan scaffolds compared to control chitosan scaffolds during TGA assay. Ag-chitosan showed the presence of silver with increased signal during EDX analysis compared to control chitosan. X-RD patterns of both the samples showed that they were belonging to the same group. SEM analysis confirmed the development of silver nanoparticles. The antibacterial assay was done on human pathogenic E.coli by standard diffusion disc method. Ag-chitosan showed a clear well defined inhibition zone compared to control chitosan scaffolds.