Synthesis of Arabic gum-capped zinc oxide nanoparticles: A comparative study of the structural, optical, and antibacterial properties

In this study, Arabic gum-capped ZnO NPs (ZnO NPs-Cap) were synthesized via a simple precipitation method, and a comparative study was performed with uncapped ZnO. The synthesized nanoparticles (NPs) were characterized using UV–visible (UV-vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Energy-dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscopy (SEM). The absorption peak of ZnO NPs-Cap appeared at 366.5 nm, and the calculated band gap energy was 3.38 eV. Antibacterial activity was assessed against gram positive and negative foodborne pathogens. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of ZnO NPs and ZnO NPs-Cap against S. aureus , Bacillus cereus, E. coli and S. typhimurium bacterial strains revealed a clear superiority of ZnO NPs-Cap than uncoated ZnO. Time–kill assays performed at different concentrations and times has demonstrated a time-dependent reduction in bacterial viability for both formulations. The present study demonstrates that Arabic gum capping enhances the dispersion, stability, and antibacterial efficacy of ZnO NPs. The findings also provide useful insight into the biological activity and potential eco-toxicological implications of biopolymer-modified ZnO nanomaterials.