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

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 degrees 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 degrees C, 400 degrees C and 500 degrees C are 58.41 m(2)/g, 42.19 m(2)/gand 40.89 m(2)/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 degrees 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.

Automated summary

A cost-effective and eco-friendly green synthesis method was used to prepare NiO nanoparticles using Aloe vera gel. The NPs annealed at 500 degrees C exhibited promising antibacterial activity, outperforming antifungal activity, indicating the potential of Aloe vera gel in preparing NiO NPs with significant antimicrobial activity for medical applications.