Metal-Free Nanozyme-Hydrogel Enabled by Conductive Polymer Nanofibers for Multimodal Antibacterial Therapy

The nanozyme antibacterial materials have been of great interest due to their broad-spectrum activity and minimal drug resistance. A variety of metal-based nanozymes have been designed as bactericidal agents, whereas their biosafety issues are still serious concerns. Accordingly, the development of metal-free nanozymes and the corresponding hydrogel dressings is of great importance for antibacterial applications. Herein, a classical conductive polymer, polyaniline nanofibers (PANI NF), has been developed as a three-pronged metal-free enzyme-like antibacterial material. They exhibited high oxidase-like and peroxidase-like activities for reactive oxygen species (ROS) production, positively charged surfaces capable of capturing/trapping bacteria to reduce ROS diffusion distance, and unique photothermal ablation effect. By harnessing the intrinsic merits of PANI NF, a PANI/poly(vinyl alcohol) (PANI/PVA) nanocomposite hydrogel, with high stability, soft-tissue adhesion properties, self-healing capability, remoldability, and biocompatibility, has been fabricated as biomedical dressings to promote bacteria-infected wound healing. The studies on antibacterial activities of polyaniline nanofibers shed light on the conductive polymer as promising metal-free enzyme-like antibacterial materials. The prepared PANI/PVA hydrogel provides a stable hydrogel dressing without toxic metal leakage for biomedical applications.