Biosynthesis and Characterization of Zinc Oxide Nanoparticles (ZnO-NPs) Utilizing Banana Peel Extract

In recent years, there has been a significant focus on the green synthetization of metal oxide nanoparticles due to their environmentally friendly features and cost-effectiveness. The aim of this study is to biosynthesize zinc oxide nanoparticles (ZnO NPs) through a green method, utilizing crude banana peel extract as reducing and capping agents, to characterize the synthesized ZnO NPs and test their antibacterial activity. ZnO NPs were biosynthesized using the peel extract of banana with various concentrations of zinc acetate dihydrate salt, followed by annealing at 400 °C for 2 h. The synthesized ZnO NPs were characterized using UV–visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), dynamic light scattering (DLS), attenuated total reflectance–Fourier-transform infrared (ATR-FTIR), and X-ray diffraction (XRD). Also, its antibacterial efficiency against different bacterial strains was tested. ZnO NPs were biosynthesized successfully using the extract of Musa Acumniata (cavendish) fruit peel with a UV-Vis wavelength range of 344 to 369 nm and an electrical band gap ranging from 3.36 to 3.61 eV. The size varied from 27 ± 4 nm to 89 ± 22, and the negative zeta potential (ζ) ranged from −14.72 ± 0.77 to −7.43 ± 0.35 mV. ATR-FTIR analysis showed that the extract phytochemical functional groups were present on ZnO NPs. XRD results confirm the formation of a highly pure wurtzite hexagonal structure of ZnO NPs. Moreover, the best obtained size of ZnO NPs was selected for the antibacterial tests, giving the highest inhibition growth rate against Staphylococcus epidermidis (98.6 ± 0.9%), while the lowest rate was against Pseudomonas aeruginosa (88.4 ± 4.4%). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were reported and compared to previous studies. The unique properties of greenly synthesized ZnO NPs and their antibacterial activity have potential for reducing environmental pollution and the use of antibiotics, which may contribute to solving the problem of bacterial resistance. Therefore, studies that aim to design an applicable dosage form loaded with biosynthesized ZnO NPs might be conducted in the future.