Polydopamine-mediated NIR-responsive photothermal/carbon monoxide dual-modal antibacterial catheter coating

Bacterial infection poses a major challenge for medical implantable catheters, frequently causing serious complications. One effective approach to addressing this issue is a catheter surface coating strategy that combines robust antibacterial properties with long-term stability and excellent biocompatibility. In this work, we developed a multifunctional antibacterial coating (MSN@FeCO@PDA) for medical catheters through a sequential fabrication approach. Initially, mesoporous silica nanoparticles (MSNs) were functionalized as nanocarriers for the carbon monoxide (CO) donor iron dodecacarbonyl (Fe 3 (CO) 12 ), to yield MSN@FeCO nanoparticles. Subsequently, these nanoparticles were uniformly immobilized onto the catheter surface via polydopamine (PDA)-mediated adhesion, resulting in a stable and biocompatible MSN@FeCO@PDA nanocomposite coating. The PDA within the coating demonstrates photothermal activity upon near-infrared (NIR) irradiation, resulting in localized temperature elevation and subsequent controlled CO release from Fe 3 (CO) 12 . We conducted an investigation into the correlation between NIR-induced temperature variations and CO generation, followed by an evaluation of the antibacterial efficacy of combined CO therapy and photothermal therapy. Results show that upon 10-min NIR irradiation (808 nm), the nanocomposite coating concurrently facilitated CO release and induced moderate hyperthermia, resulting in a highly effective synergistic antibacterial efficiency (> 97 %). Furthermore, in vivo studies demonstrated that the coated catheter markedly attenuated inflammatory responses in murine models while exhibiting enhanced antibacterial efficacy. This nanomaterial-based composite coating represents a safe and effective multifunctional antibacterial strategy for medical implants, with promising clinical applications.