Intelligent ROS-Regulating and Photothermal Micro-Nano Coatings for Biofunctional Properties in an In Vitro High-Glucose Model

Metallic implants in diabetic patients face a critical dual challenge: excessive reactive oxygen species (ROS) and advanced glycation end-products (AGEs) accumulation severely impair osteointegration, while suppressing ROS is beneficial for tissue repair but compromises antibacterial defense. Here, we report an innovative multifunctional coating composed of manganese oxide nanoparticles and polydopamine (PDA) on a nano-network metallic substrate (TAMP), which enables dynamic regulation of ROS and near-infrared-triggered antibacterial activation. Under near-infrared irradiation (NIR), the coating induces mild photothermal heating (PTT) and synergistic photodynamic therapy (PDT) effects, leading to moderate ROS generation and achieving over 95% bactericidal efficiency against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) without damaging host tissue. In the absence of light, controlled manganese ion release scavenges excess ROS, restores redox balance, and promotes human mesenchymal stem cell proliferation. The coating exhibits long-term antibacterial stability, maintaining more than 96% bactericidal activity after 7 days, and enhanced corrosion resistance with corrosion current reduced to 9.88% of that of the bare substrate. This dual-mode, light-controllable, and ROS-adaptive system provides an innovative solution to reconcile infection control and tissue regeneration in diabetic oxidative microenvironments, offering a promising strategy for next-generation metallic implants.