Papaya Peel Extract-Capped Copper Oxide Nanoparticle-Based Hydrogel: Enhanced Efficacy for Wound Healing.

Food wastes with relatively lower bioactive components can be enriched by capping onto nanoparticles, capitalizing on the high surface area and positively charged metallic core. Thus, the present investigation was undertaken to cap papaya peel extract onto copper nanoparticles and develop their hydrogel for potential application in wound healing. Green papaya peel aqueous extract was used to synthesize copper nanoparticles with a mean diameter of 18 nm and a zeta potential of -16.33 mV. The effect of extract concentration, volume, temperature, pH, and reaction time was studied and optimized for the synthesis of CuNPs. Furthermore, CuNPs were loaded in HPMC K4M (0.7% w/v) and xanthan gum (0.4% w/v) hydrogel and characterized for applicability, compatibility, and stability. A wound healing study on Wistar albino rats was performed, and wound contraction was recorded. Biopsies were taken on the 10th day of the study for histological examination. This revealed significantly higher efficacy of the PAE-CuNP hydrogel in healing the wounds than the control, standard, and PAE-hydrogel. While it masked the antimicrobial properties of copper, it enhanced the wound healing efficacy, supporting the hypothesis that capping extracts onto metallic cores can potentiate the effectiveness of bioactives. Considering the demand for nonantibiotic wound dressings, this PAE-CuNP hydrogel can be a potential alternative following further validation.