Bifunctional Role of Thiosalicylic Acid in the Synthesis of Silver Nanoparticles

Abstract

Conventional synthesis of silver nanoparticles employs a reducing agent and a capping agent. Surfactants are effective capping agents as they prevent the aggregation of nanoparticles during storage and use. However, the biocompatibility of several of the surfactants is questionable. In this report, the use of thiosalicylic acid as both reducing and capping agent is reported. Compared to conventional synthesis, this methodology requires higher temperature for synthesis, which then is expected to result in aggregates of larger size. The ability of three different synthesis methodologies – direct heating, photochemical and microwave dielectric treatment were evaluated and assessed on the basis of the size, size distribution and stability of the particles. Microwave irradiation was found to be most suitable for achieving parti- cles with a hydrodynamic diameter of 10 nm. Our studies indicate that -COO- group is involved in the reduction of Ag+ and –SH group of TSA is involved in the capping of the nanoparticles.