Battery-inspired electrochemically charged polyimide coating for ion-electric synergistic rapid bacteria-killing

Broad-spectrum bacteria-killing strategies based on inorganic metal ions or electrical stimulation have good application prospects in conferring implant-associated infections. However, balancing biocompatibility and antibacterial properties remains challenging. Inspired by aqueous zinc-ion batteries (AZIBs), this work proposed an innovative electrochemically charged hydrated-derived polyimide (HPI) coating on titanium implants to achieve safe and rapid sterilization by ion-electric synergistic effect. The electrochemically charged HPI coating enables controlled storage and release of Zinc ions and electrons via redox reactions, achieving excellent antibacterial rates against both S. aureus and E. coli. The antibacterial mechanism includes membrane perforation, reactive oxygen species (ROS) generation, and respiratory chain disturbance. Additionally, the coating enhances fibroblasts' adhesion, spreading and migration while maintaining excellent biocompatibility after charging, demonstrating excellent soft tissue compatibility. In vivo studies further validate the coating's efficacy, showing a remarkable reduction in bacterial proliferation within 24 h, suppressed inflammatory responses, and no adverse effects on major organs. By leveraging the redox properties of HPI and the charge carrier role of zinc ions, this work bridges the gap between AZIBs and biomedical applications, offering a new approach for designing transcutaneous implants with enhanced antibacterial and biocompatible properties.