Inhibition of Microbial Growth by Silver-Starch Nanocomposite Thin Films

Abstract

A sago starch biopolymer with embedded silver nanoparticles has been studied as a material for the prevention of microbial growth. Approximately 8 nm in size, silver nanoparticles have been synthesized by reduction of the silver salt in aqueous solution in the presence of sago starch using sodium borohydride as a reducing agent. The obtained solutions were cast on glass plates to obtain thin supported silver-starch nanocomposite films. The morphology of the nanocomposites was investigated by scanning and transmission electron microscopy. UV-Vis absorption spectroscopy showed that during the film formation a part of the silver nanoparticles has been trapped in the water present in the sample, which enabled their partial oxidation into active Ag(+) species. The oxidation of the silver nanoparticles was confirmed by X-ray photoelectron spectroscopy. The antimicrobial activity tests have shown that the nanocomposite material can be successfully employed to prevent the viability and growth of the common pathogens Staphylococcus aureus, Escherichia coli and Candida albicans.