Calcination-Tuned, Plant-Derived ZnO in Chitosan: A Sustainable Dual-Action Antimicrobial and Regenerative Dressing

Safe-by-design antimicrobials that are green to produce and effective against environmentally relevant pathogens are central to One-Health infection control. We report an aqueous, plant-mediated synthesis of zinc oxide nanoparticles (ZnO NPs) using Anagyris foetida leaf extract, followed by calcination at 500, 600, and 700°C to tune crystal quality, surface cleanliness, and defect chemistry. The powders were embedded in a biocompatible chitosan (CS) matrix to create a paste-like Phyto-ZnO/CS dressing intended for sustainable wound management and environmental health applications (minimal solvent use, benign reagents, scalable processing). XRD, FTIR, UV–Vis diffuse reflectance (DRS), FESEM, and EDS confirmed phase-pure wurtzite ZnO with temperature-dependent peak sharpening, clean Zn–O lattices with only trace C–O features, quasi-spherical primaries with tightened size distributions (mean ± SD: 23.15 ± 3.80 nm at 500°C; 22.75 ± 3.98 nm at 600°C; 18.86 ± 2.49 nm at 700°C), and decreasing adventitious light elements after calcination. DRS showed a slight red shift of the absorption edge (band-gap narrowing) consistent with strain/defect re-equilibration. In an infected excisional rat model with once-daily application for 15 days, wound contraction improved from 68% (control) and 86% (CS) to 96% (ZnO-500), 98% (ZnO-600), and 99% (ZnO-700). Histopathology corroborated near-complete re-epithelialization, dense aligned collagen, and minimal residual inflammation for the 700°C formulation, without necrosis. The results link calcination-driven cleaning and defect tuning to enhanced antibacterial and pro-healing performance, positioning Phyto-ZnO/CS-700 as a sustainable, non-toxic, dual-action material aligned with JECE’s focus on green/safer novel materials for pathogen control and environmental health.