Chitosan-coated ZnO nanocomposites of Lantana camara and Rhamnus triquetra for effective antimicrobial activity

Abstract

The sustainability agenda has been greatly influenced by numerous studies, particularly in the field of green revolution involving plants. The innovative aspects of green synthesis have opened up new avenues of research in the scientific community. In this study, we conducted a systematic investigation into the plant-based synthesis of zinc oxide nanoparticles coated with chitosan polymer, using the leaf extracts of Lantana camara and Rhamnus triquetra. To verify the nano-scale size, structural, and morphological characteristics, the synthesized zinc oxide nanoparticles were subjected to various characterization techniques such as UV–Vis spectroscopy, SEM, FTIR, XRD, and Zeta Potential. The XRD results confirmed the crystalline structure of ZnO NPs in the hexagonal wurtzite phase. The magnitude of zeta potential supported the stability of the nano compounds. The FESEM analysis revealed that all the nanocomposites exhibited uniform, dense, and agglomerated particle arrangements with diameters ranging from 22.93 nm to 32.58 nm. FTIR spectroscopy identified the presence of various functional groups. The antibacterial activities were assessed against human pathogenic bacteria, Staphylococcus aureus, and Escherichia coli. The nanocomposites (sample 2) displayed the highest antibacterial zone against Staphylococcus aureus (22.66 mm), while the highest antibacterial zone of inhibition was observed for (sample 4) against E. coli (20.66 mm). In addition, the anticandidal activities were analyzed against the human pathogenic microorganism Candida albicans, and the maximum activity was shown for sample 3 (23.33 mm). Sample 2 also exhibited the greatest growth inhibition against the plant pathogenic fungus Rosellinia necatrix with (33.33%). Our research demonstrates the potential of Lantana camara and Rhamnus triquetra as green sources for the environmentally friendly production of ZnO NPs, which possess strong antibacterial properties against harmful microbes. This study emphasizes the significance of exploring green synthesis techniques for environmentally friendly nanotechnology practices.