Green approach to synthesize zinc oxide nanoparticles using leaf extract of Aloe vera and its effect against Bacillus cereus

Abstract

Nanoparticles of zinc oxide (ZnO) have been investigated in numerous studies to determine their potential therapeutic properties, including antibacterial activity. It has been discovered that nanoparticles of zinc oxide exhibit antibacterial activities against a variety of pathogens, including B. cereus. This study focuses on the biosynthesis of ZnO NPs using an extract from the Aloe vera plant. A total of 100 stool samples were obtained from children suffering from diarrhea, aged between 3 months and 9 years, from various hospitals between November 2022 and February 2023. Out of 100, 55 B. cereus bacteria were identified using selective medium (Mannitol egg yolk polymyxin agar), of which 21 were B. cereus bacteria confirmed using the VITEK 2 System. Genomic DNA was isolated from the isolates, with DNA concentrations ranging from 15-19 ng/μl. Aloe vera samples were collected from the local market in Baghdad in January 2023. Aqueous extracts of Aloe vera leaves were obtained using conventional methods. ZnO nanoparticles were prepared using the Aloe vera extract, then identified and characterized. The nanoparticles were characterized using: Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission microscopy (FEM), and ultraviolet-visible spectroscopy (UV). The two samples were inoculated in culture media containing different concentrations of the nanocomposite nanoparticles (1, 2, 3 mg/ml) and the same concentrations of the Aloe vera plant extract, which showed different effects on the growth of B. cereus bacteria. The minimum inhibitory concentration (MIC) was determined to be 15.6 mg/ml.