Eco-friendly Production of Metallic Nanoparticles in Polymeric Solutions and Their Processing into Biocompatible Composites

Silver and gold nanoparticles were produced and embedded in poly(vinyl alcohol) (PVA) and chitosan (CTS) solutions by the photoreduction of metallic salt precursors triggered by direct sunlight irradiation, in which the polymers acted as reducing, dispersing and stabilizing agents. Sunlight photoreduction can be standardized using a constant UV index regardless of the season. This strategy was found to be an improvement over other common energy sources used to trigger the reduction of metal ions, including UV light irradiation and high-temperature reduction with mechanical stirring. The resulting PVA/metal nanoparticle and CTS/metal nanoparticle composite solutions were processed into thin films and nanofiber composites. In vitro testing of the cytotoxicity and biocompatibility demonstrates that the film composites are non-toxic and biocompatible with the HT-29 human colon cancer cell line. Promotion of HT-29 cell growth using our hybrid composites was observed, in contrast to other studies in which colloidal NPs were tested. Therefore, a sustainable approach for the onestep preparation of biocompatible polymer/metallic nanoparticle composites is reported.