Silk Sericin Protein: Turning Discarded Biopolymer into Ecofriendly and Valuable Reducing, Capping, and Stabilizing Agent for Nanoparticles Synthesis Using Sonication

This current study is designed to incorporate sericin protein as a reducing, capping, and stabilizing agent to synthesize sonication-mediated silver nanoparticles. Fabrication of sericin-reduced silver nanoparticles (Sr-AgNPs) is confirmed using UV-visible spectrophotometry, zeta sizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), and thermogravimetric analysis (TGA). UV-Vis spectral peak of Sr-AgNPs is observed at 420-440nm while the average size is found between 3 to 30 nm. SEM also confirms the reduction of large-sized (1-40 & mu;m) sericin macromolecules into nanometric hexagonal and triangular silver nanoparticles with a normal distribution (polydispersity index > 0.5). FTIR peaks from 500 to 4000cm(-1) are analyzed for sericin while Sr-AgNPs peaks with minor shifts (700-1000 cm(-1) (CO-O-CO stretching) in Sr-AgNPs) are also observed. XRD peaks of 2 & theta; at 27 & DEG; with multiple low peaks at 38.2 & DEG;, 47 & DEG;, 49 & DEG;, and 63.8 & DEG; authenticate the amorphous nature of sericin and sharp peaks at 36 & DEG;, 48 & DEG;, 54.3 & DEG;, and 61.9 & DEG; with miller indices (hkl) of 98, 111, 200, and 211, assess the crystalline structure of Sr-AgNPs. TGA reveals that sericin enhances the stability of silver NPs at high temperature (200-600 & DEG;C) by lowering the percentage weight loss from 70-80% to 60-65%.