Facile Ultrasound-Assisted Green Synthesis of NiO/Chitosan Nanocomposite from Mangosteen Peel Extracts as Antibacterial Agents

Abstract

In this study, NiO/chitosan (NiO/CS) nanocomposite was synthesized via a green method in which nickel nitrate hexahydrate as a precursor and mangosteen (Garcinia mangostana L.) peel extract as a reducing agent using an ultrasound-assisted coprecipitation method. The NiO/CS nanoparticles were characterized by X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy, and dynamic light scattering. NiO/CS nanocomposite had a cubic spinel structure and contained NiO nanoparticles with good crystallinity. The appearance of the Ni–O band at 465 cm−1 in the FTIR spectrum confirmed the formation of NiO. The NiO/CS nanocomposite sizes ranged from 14–30 nm with an average particle size of 28 nm. Magnetic characterization results show that the saturation magnetism is quite high, contributing to NiO/CS being available in many applications. The antibacterial efficacy of NiO/CS nanocomposites was tested against Saccharomyces cerevisiae along with Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria using the disc diffusion method and determined the minimum inhibitory concentration (MIC).