Phytochemical-mediated CuO nanoparticles disrupt bacterial membranes and promote dermal fibroblast migration

Chronic wound repair is frequently impaired by bacterial infection, creating a need for antibacterial materials that can suppress microbial growth without compromising skin-cell function. In this study, phytochemical-mediated copper oxide nanoparticles (CuO NPs) were synthesized using Aegle marmelos leaf extract and investigated for their antibacterial mechanism and effects on adult dermal fibroblasts. Structural and surface analyses confirmed the formation of monoclinic CuO NPs with particle dimensions of approximately 18-22 nm, Cu²⁺-rich surface states, and oxygen-containing phytochemical functionalities. The CuO NPs exhibited concentration-dependent antibacterial activity against Escherichia coli and Staphylococcus aureus, with S. aureus displaying greater susceptibility. Colony-forming unit analysis confirmed a marked reduction in bacterial survival. Ultrastructural examination revealed close nanoparticle cell association, deformation of the bacterial envelope, membrane discontinuity, and loss of intracellular contents. Consistently, increased extracellular nucleic-acid release demonstrated that the antibacterial activity was associated with disruption of membrane integrity and increased cellular permeability. The nanoparticles additionally exhibited concentration-dependent radical-scavenging activity, indicating retention of redox-active phytochemical constituents on their surfaces. At biologically compatible concentrations, the CuO NPs maintained adult dermal fibroblast viability and enhanced fibroblast migration in an in vitro scratch assay. The concentration-dependent erythrocyte response observed in the hemolysis assay emphasized the importance of dose optimization. Collectively, these findings demonstrate that phytochemical-mediated CuO NPs combine membrane-disruptive antibacterial activity with fibroblast-compatible, migration-supporting effects, supporting their further investigation as bioactive materials for infected wound management.