Synthesis of sericin coated silver nanoparticles (Ag-Ser) by modified Tollens’ method and evaluation of colloidal stability

Abstract

In this study, sericin extracted from Bombyxmori silk cocoons was integrated into the well-known Tollens’ method for synthesizing Ag-NPs. Sericin successfully acted as a stabilizer while silver amine complex [Ag(NH3)2]+ was reduced by maltose. As a result, silver nanoparticles with high stability are formed. Possible functional groups related to the stabilization of NPs were investigated by Fourier-transforms infrared spectroscopy (FT-IR). Ag-Ser NPs were characterized using particle size measurements based on dynamic light scattering (DLS) and transmission electron microscopy (TEM). According to the characterization investigations, Ag-Ser NPs have characteristic (111) face-centered cubic (FFC) plane and were spherical in shape with a narrow size distribution of 20.23 ± 6.25 nm. Overall, the sericin-modified Tollens’ method for synthesizing Ag-NPs offers a simple and non-toxic production method to form nanoparticles. Colloidal stability of nanoparticles displays an essential role since their enhanced nano-properties can be diminished by an increase in size due to aggregation and agglomeration. Therefore, the effect of pH and electrolyte concentration on particle stability was investigated through the surface charge of Ag-Ser NPs using a Zeta-potential analyzer and change in absorption spectra by UV–Vis Spectroscopy. Results obtained from this study propose a potential synthesis route for Ag NP synthesis and may extend the applicability of silver nanoparticles in biotechnological researches as aseptic and therapeutic usages.