Sunlight driven biosynthesis of silver nanoparticles using aqueous stem extract of Tinospora sinensis (Lour.) Merr. and evaluation of its catalytic and antibacterial activity

Abstract

Introduction and Aim: The present study investigated the biosynthesis of silver nanoparticles (AgNPs) using aqueous stem extract of Tinospora sinensis under the influence of sunlight irradiation. Materials and Methods: For the biosynthesis of AgNPs 90 ml of 10-3 M AgNO3 was mixed with 10 ml of the aqueous stem extract of Tinospora sinensis and the solution was kept under sunlight. The formation of AgNPs were monitored using UV-Vis spectroscopy. Furthermore, the characterization of the synthesized AgNPs were accomplished using X-ray diffraction (XRD), Fourier transforms infr ared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy Dispersive X-ray (EDX), Dynamic Light Scattering (DLS). Results: The reaction mixture changes its colour from pale yellow to dark brown within 30 minutes. The UV-Vis spectra of AgNPs showed an absorption peak at 445 nm, which indicated the formation of AgNPs. The SEM and the DLS analysis revealed the spherical shape of the AgNPs with an average particle size of 74.2 nm. The XRD analysis confirmed the crystalline nature of the AgNPs. Furthermore, the synthesized silver nanoparticles act as a catalyst in degradation of 4-nitrophenol by NaBH4. Moreover, the biosynthesized AgNPs showed antibacterial activity against three bacterial strains viz. Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027) and Staphylococcus aureus (ATCC 6538P). Conclusion: In the present study, AgNPs have been successfully synthesized using aqueous stem extract of Tinospora sinensis under the influence of sunlight irradiation. The synthesized AgNPs exhibits catalytic as well as antibacterial properties that makes it suitable for environmental remediation. Keywords: Silver nanoparticles; Tinospora sinensis; sunlight irradiation; antibacterial; dye degradation.