Green synthesis of Brassica carinata microgreen silver nanoparticles, characterization, safety assessment, and antimicrobial activities.

Nanotechnology has been a central focus of scientific investigation over the past decades owing to its versatile applications. The synthesis of silver nanoparticles (AgNPs) through plant secondary metabolites is a cost-effective and eco-friendly approach. The present study employed Brassica carinata microgreen extracts (BCME) to promote the reduction of silver nitrate (AgNO) salt into Brassica carinata microgreen silver nanoparticles (BCM-AgNPs). The physicochemical properties of the biosynthesized AgNPs were characterized through both spectroscopy and microscopy techniques. Furthermore, the antimicrobial property of the biosynthesized AgNPs was assessed against six selected pathogenic microorganisms, and finally, their safety was evaluated on a normal Vero cell line through an MTT cytotoxicity assay. The UV-visible spectrum revealed that BCM-AgNPs exhibited an absorption peak at 420 nm. The potential functional groups involved in the biosynthesis of AgNPs were identified by Fourier transform infrared (FTIR) analysis. Scanning electron microscopy (SEM) revealed a spherical nature of the biosynthesized AgNPs. Transmission electron microscopy (TEM) analysis revealed the crystallinity of the AgNPs, averaging 34.68 nm in size. X-ray diffraction (XRD) investigation further confirmed the crystalline structure of the AgNPs. The zeta potential exhibited a significant value of - 22.5 ± 1.16 mV. Regarding the antimicrobial potential, BCM-AgNPs exhibited promising antimicrobial activity against the tested pathogens, with a minimum inhibitory concentration (MIC) of 62.5 µg/mL observed in Pseudomonas aeruginosa. Further cytotoxicity assessment of BCM-AgNPs conducted on Vero cells demonstrated their safety. This study presents a novel approach to synthesizing AgNPs using a nutraceutical microgreen, offering a biocompatible and promising alternative for combating multi-drug resistance.