Green synthesis of silver nanoparticles with an antibacterial activity using Salvia officinalis aqueous extract

Abstract

This report searched the rapid and simple green biosynthesis of silver nanoparticles (AgNPs) using Salvia officinalis aqueous extract. The visual color change from colorless/yellow to reddish brown was noticed indicating the phytosynthesis AgNPs during the process. The presence of functional groups in plant extract acted as reducing and capping agents for the formation of AgNPs was confirmed by FTIR. The fabricated AgNPs were characterized by ultraviolet–visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). The UV–Visible spectrum showed a characteristic absorption peak for Ag at around 457 nm with optical bandgaps of about 2.22 eV of AgNPs. XRD patterns at (111), (020), (022), (131), and (222) lattice planes depicted the production of face-centered cubic silver nano-structure with approximate crystal size ranges from≈20 nm by Scherrer’s formula. The predominantly spherical nanoparticles having an average size of 20 nm showed enhanced antibacterial activity against Salmonella typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli with more activity toward P. aeruginosa. Our green synthesis protocol required only 15 min for the conversion of silver ions into silver nanoparticles by heating is an efficient, rapid, simple, sustainable, cheap, and energy-efficient, alternative to conventional chemical/physical methods, a one-step application.