Green synthesis of antimicrobial silver nanoparticles with Brassicaceae seeds

Abstract

Herein, we demonstrate a facile and green route for the synthesis of silver nanoparticles (AgNPs) from silver nitrate and seed extracts of different vegetable seeds of Brassicaceae family. All the nanocomposites were fully characterized in the solid-state via various techniques such UV–vis spectrophotometer (UV–Vis); x-ray diffraction (XRD), High-resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectroscopy (EDS), and Fourier transform infrared (FTIR) spectrometry. The experimental parameters such as variation in seeds extract concentration, temperature, stirring time and pH were noted and optimum condition of concentration (20 ml), temperature (80 °C) and pH 8.5 was selected for the synthesis of NPs. Optical absorbance of AgNPs at ≈425 nm indicated the formation of metallic silver through surface plasmon resonance. The successful capping of biological macromolecules was confirmed by FTIR spectroscopy. XRD pattern depicted the formation of face-centered cubic silver nano-composite with average crystal size ranges from ≈14–20 nm. Bio-synthesized Ag nanoparticles showed enhanced antibacterial potential against gram-positive (B. safensis, B. subtilis, B. pumilis and S. aureus) and negative gram (E. coli and S.typhi) strains by disc diffusion method. Highest antimicrobial activity was given by sample S3 (17 mm) against B. pumilis whereas, sample S2 and S5 also showed significant bactericidal potential against B. pumilis that is 15 mm. While highest zone of inhibition for sample S1 and S4 is 14 mm.