One-step synthesis of Ag nano-assemblies and study of their antimicrobial activities

Three kinds of Ag nano-assemblies have been fabricated separately in a one-step reaction. These are designated as 3D–3D, shell-3/1D and 3D–1D nano-architectures. These nano-architectures were synthesized by polyol reduction method in the presence of polyvinyl pyrrolidone (PVP) at 120, 140, and 160 C, respectively. During the experiment, controlled temperature decrease has been carried out which successfully developed 3D–3D, and 3D–1D conjunction. The shell-3/1D nano-assembly was successfully developed at 140 C by gradual decreasing and subsequently increasing of temperature. The size and morphology of each product was characterized by transmission electron microscope (TEM). Surface plasmon resonance (SPR) behavior was analyzed by UV– Vis spectroscopy. The antimicrobial activities were also analyzed for gram positive bacteria like Enterococcus faecalis and Staphylococcus aureus, and gram negative like E. coli 0157:H7 and DH5a by scanned optical density (OD) and Kirby-Bauer process. The OD was measured by taking scanned UV–Vis absorption from 700–300 nm wavelength in LB (Luria–Bertani) broth media. Similarly Kirby-Bauer process was applied over LB agar media. The material was found unique in terms of morphology as well as in displaying its antimicrobial activities both for gram positive and gram negative bacteria.