NIR-Responsive Micropumps Enhance Antibiotic Treatment via Biofilm Destruction

A novel strategy for eradicating biofilms by enhancing antibiotic penetration is presented through the development of a photo-responsive, micropump-engineered surface. This surface features black titanium oxide (B-TiO₂) colloidal particles immobilized on a titanium substrate, a material commonly used in biomedical implants. When exposed to near-infrared (NIR) light, the engineered surface induces localized thermal convection flows within the biofilm and simultaneously generates reactive oxygen species (ROS). These physical and chemical effects act synergistically to disrupt the biofilm architecture. Remarkably, only 20 min of NIR irradiation leads to a significant reduction in the biomass of Staphylococcus aureus biofilms on the micropump surface. This effect is mediated by two complementary mechanisms: thermal convection-driven water flow and ROS-induced degradation of the extracellular polymeric substance (EPS), which forms the structural scaffold of the biofilm. As a result, the antibacterial activity of gentamicin is enhanced by approximately five-fold in vitro and ten-fold in vivo in a rat subcutaneous infection model. Furthermore, the B-TiO₂ micropump exhibits excellent biocompatibility, showing no adverse effects in either in vitro or in vivo assessments. This innovative photo-responsive approach provides a promising solution for addressing biofilm-related infections on medical device surfaces by effectively disrupting biofilms and markedly improving antibiotic efficacy.