Comparison of antibacterial and antifungal activities of 5-amino-2-mercaptobenzimidazole and functionalized NiO nanoparticles

5-Amino-2-mercaptobenzimidazole (AMB), non-functionalized nickel oxide (n-NiO), and functionalized nickel oxide (f-NiO) nanoparticles were studied for antibacterial and antifungal activities, where the functionalization of nickel oxide nanoparticles was carried out by AMB. The particle sizes of synthesized n-NiO and f-NiO nanoparticles were measured to be 16.07 and 20.86 nm, respectively. The XRD results of n-NiO and f-NiO nanoparticles were in perfect match with the diffraction pattern of NiO published in the JCPDS File No. 89-5881, which indicates that there is no effect on the crystal structure due to functionalization. FT-IR spectral studies show that f-NiO nanoparticles effectively bind with AMB by azomethine nitrogen. Furthermore, HR-SEM and EDAX results confirm the surface morphology and functionalization, respectively. The antimicrobial activity of AMB, n-NiO, and f-NiO nanoparticles dispersed in water was investigated. The antibacterial activity was evaluated against the bacteria Staphylococcus aureus and Pseudomonas aeruginosa, while the antifungal activity was evaluated against the fungi Aspergillus niger by using the agar well-diffusion method. The f-NiO nanoparticles exhibit excellent antibacterial and antifungal activities compared with n-NiO nanoparticles and AMB. The increased effect of f-NiO nanoparticles might be due to enhanced dispersibility and interaction of NiO nanoparticles with membrane and intracellular proteins of bacteria and fungi.