Sustainable synthesis of ZnO–CeO₂ nanocomposites and their enhanced antibiofilm, anti-inflammatory and wound healing activities

The present study reports the green synthesis of ZnO–CeO₂ nanocomposites using Syzygium cumini seed extract as a natural reducing and stabilizing agent. UV–Vis spectroscopy exhibited a characteristic absorption peak at 355.87 nm, confirming the formation of ZnO-based nanostructures. FTIR analysis revealed the presence of hydroxyl and metal–oxygen functional groups involved in nanocomposite formation and stabilization. XRD patterns confirmed the coexistence of hexagonal ZnO and cubic CeO₂ crystalline phases, while SEM and TEM analyses demonstrated porous, agglomerated, and heterogeneous nanostructures with particle sizes ranging from approximately 10–150 nm. The biological activities of the synthesized ZnO–CeO₂ nanocomposites were evaluated through antioxidant, anti-inflammatory, antibacterial, antibiofilm, and in vitro scratch wound-closure assays. The nanocomposites exhibited significant antioxidant activity with IC50 values of 87.08 µg/ ml and 77.93 µg/ ml in DPPH and ABTS assays, respectively. A maximum anti-inflammatory activity of 68.11% inhibition was observed at 640 µg/ ml in the protein denaturation assay. The nanocomposite demonstrated notable antibacterial activity against Gram-negative bacterial pathogens, with the highest activity observed against Pseudomonas aeruginosa. Confocal microscopy revealed substantial inhibition of P. aeruginosa biofilm formation following nanocomposite treatment. Furthermore, the nanocomposite promoted enhanced fibroblast cell migration, achieving 99.54% wound closure after 72 h in an in vitro scratch assay. Overall, the findings demonstrate that Syzygium cumini -mediated ZnO–CeO₂ nanocomposites possess multifunctional biological activities and represent a sustainable platform for biomedical applications. However, further studies involving cytotoxicity evaluation, mechanistic investigations, colloidal stability assessment, and in vivo biocompatibility studies are required before clinical or translational applications can be considered.