In situ formation and immobilization of silver nanoparticles using thermo-responsive microgel particles and their cytotoxicity evaluation

In this study, a simple environmentally greener “in situ” chemical synthesis has been developed to prepare silver nanoparticles (Ag NPs) from chemically reduced AgNO₃ in an aqueous media of thermo-responsive microgel, using glucose as a reducing agent and by adopting a microwave irradiation technique. The thermo-responsive microgel poly-N-isopropylacrylamide-co-2-hydroxyethyl acrylate, poly (NIPAM-co-HEA) 200 nm in size was prepared by surfactant free emulsion polymerisation of a selected mixture of N-isopropylacrylamide, methylene-bis-acrylamide and 2-hydroxyethyl acrylate. This microgel acts as a mere support to immobilize Ag NPs. The formation of Ag NPs and the thermo-responsive properties of the mixture were studied using UV–visible Spectroscopy. Their structures were characterised by FE-SEM and TEM. The Ag NPs prepared by this approach appear to be monodispersed with sizes which are <15 nm. Excellent biocompatibility, cell viability and environmentally responsive properties suggested that as-prepared composite particles are ideal candidate for antibacterial, biosensors and drug delivery applications.