Green synthesis of silver nanoparticles with high antimicrobial activity and low cytotoxicity using catechol-conjugated chitosan

In this study, catechol-conjugated chitosan (CSS) was synthesized to prepare silver nanoparticles in aqueous solution as both a reducing and stabilizing agent. The entire reaction process complied with the principles of green chemistry. The stability and physicochemical properties of CSS-coated silver nanoparticles (CSS-Ag NPs) were well characterized by a series of techniques. A narrow diameter distribution and excellent stability were observed in the target CSS-Ag NPs. Determination of the minimum inhibitory concentration (MIC) and the disk diffusion test were applied to evaluate the antibacterial activities with respect to quantity and quality, respectively. The cytotoxic effects on HepG2 cells were also evaluated with a series of assays. The resulting CSS-Ag NPs combined the unique properties of chitosan and silver nanoparticles, showing effective antibacterial activities and low cytotoxicity. The effective toxic concentration of CSS-Ag NPs towards E. coli and S. aureus is too low to damage HepG2 cells. The results demonstrated that CSS-Ag NPs could be a potential candidate for use in biological and pharmaceutical areas to prevent infections caused by microorganisms.