Shape-specific silver nanoparticles prepared by microwave-assisted green synthesis using pomegranate juice for bacterial inactivation and removal

Herein, we have synthesized four different shapes (spherical, oval, rod and flower shape) of silver nanoparticles (AgNPs) using a green synthesis approach via microwave-assisted synthesis. The nanoparticles were synthesized using pomegranate juice as a novel reducing agent. The synthesized AgNPs were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and tunnelling electron microscopic (TEM) analysis. The as-prepared AgNPs show a very rapid, effective, shape-specific and dose-dependent bacteriostatic/bactericidal effect towards four different bacterial strains (two Gram negative and two Gram positive). The analysis was determined by different methods such as a disc diffusion study, growth curve analysis, minimum inhibitory concentration and minimum bactericidal concentration determinations. Amongst the four different shaped AgNPs, the flower shaped AgNPs demonstrated the best results and mediated the fastest bactericidal activity against all the tested strains at similar bacterial concentrations. The results were also confirmed by confocal microscopic analysis. Additionally, the flower shaped AgNPs have the ability to non-specifically remove various bacterial strains from a real water sample with similar to 98% removal efficiency, as compared to other synthesized different shaped nanoparticles.