Porphyrin-based composite coatings with spatiotemporally controlled phototherapeutic antibacterial activity on biomedical surfaces

Bacterial infections have become a major global medical challenge and pose a serious threat to human health. As drug-resistant bacteria become more prevalent, conventional antibacterial strategies largely rely on antibiotic release or a single bactericidal mechanism. These approaches may accelerate the emergence of multidrug-resistant bacteria and are often limited by insufficient biocompatibility and poor controllability of therapeutic activity. To overcome these limitations, here we designed and fabricated a photothermal/photodynamic synergistic antibacterial coating (PDA/PEI-TCPP) via a co-deposition strategy using TCPP as the core functional component. The as-prepared coating exhibits favorable spatiotemporal controllability and superior biocompatibility, along with remarkable synergistic photothermal and photodynamic antibacterial effects, achieving bacterial inactivation efficiencies of over 99% against both Staphylococcus aureus and Escherichia coli. The obtained results demonstrate that the PDA/PEI-TCPP coating has promising potential for antibacterial surface modification of medical devices (implantable medical devices). Furthermore, this study provides an innovative reference for the rational design and facile fabrication of functional antibacterial coatings for biomaterial engineering.