Antibacterial and cytotoxicity activities of biosynthesized silver oxide (Ag2O) nanoparticles using Bacillus paramycoides

Abstract

Bionanotechnology is one of the leading research which helps to synthesize nanoparticles through biological resources. In the present study silver oxide nanoparticles (Ag2O NPs) were biosynthesized using culture supernatant of Bacillus paramycoides and evaluated for its antibiofilm activity and cytotoxic potentiality. Characteristic absorption peak for Ag2O NPs was observed at 420 nm in UV–visible spectrum. X-ray diffraction pattern shows planes of face centered cubic crystalline Ag2O NPs and narrow peak confirms their crystalline nature. High Resolution Transmission Electron Microscopy exhibited spherical particles in the range of 25–70 nm diameter. Fourier transform infrared spectroscopic analysis of Ag2O NPs represents the peaks corresponding to the functional groups of metabolites present in the supernatant. The biosynthesized Ag2O NPs showed significant antibacterial activity against marine biofilm forming bacteria (Vibrio parahaemolyticus, Salmonella sp., Enterobacter sp. and Micrococcus sp.) as observed under confocal laser scanning microscope. The present study revealed that Ag2O NPs cause release of intracellular constituents including proteins through membrane damage leading to the bacterial cell death. Silver oxide nanoparticles also showed significant cytotoxicity on A549 lung cancer cells (IC50 = 58.5 μg mL−1) by MTT assay. A549 cells treated with Ag2O NPs showed signs of apoptosis as observed under fluorescent microscope. The present study highlights the possible use of Ag2O NPs as potential antibacterial, antibiofilm and anticancer agent.