Green synthesis of NiO nanoparticles using Aloe vera gel extract and evaluation of antimicrobial activity

Abstract

A cost effective and eco-benign green synthesis was adopted for the synthesis of nickel oxide (NiO) nanoparticles (NPs) using Aloe vera gel and effect of temperature (300, 400 and 500 °C) of annealing was investigated on NPs properties. XRD showed formation of pure NiO NPs (face-centered-cubic) and the grain size was increased with temperature. Band gap of NiO NPs was 3.2 eV and refractive index was 2.65. Specific surface area annealed at 300 °C, 400 °C and 500 °C are 58.41 m2/g, 42.19 m2/gand 40.89 m2/g, respectively. The antibacterial activity was evaluated against bacteria, Gram-negative (Escherichia coli, Pasturella multocida), Gram-positive (Bacillus subtilis, Staphylococcus aureus) and fungal (Aspergillus niger, Aspergillus flavus, Penicillium notatum) strains. The NPs annealed at 500 °C showed promising antibacterial activity in comparison to standards (Rifampicin and Fluconazol for bacterial and fungal strains, respectively). The antibacterial activity of NiO was higher versus antifungal activity. Results revealed that the Aloe vera gel has potential to prepare NiO NPs with promising antimicrobial activity for application in medical field.