Reassembled One-Dimensional VB2 Submicrorods with Enhanced Photosensitivity and H2O2 Supply for Efficient Antibacterial Therapy

Recent advances in photocatalytic micro-nanoarchitecture have enlightened emerging photosensitizer-based photodynamic bactericidal therapies, which have been fruitful in addressing the thorny issue of multidrug-resistant bacterial infections. Nevertheless, the clinical feasibility of current photodynamic sterilization has been constrained by the biosafety of the photosensitizer and the maintenance of a relatively mild physiological microenvironment during treatment. Herein, we assemble a rodlike monocrystal on the sub-microscale from bioactive vitamin B2 (VB2) through a precise control strategy. The internal VB2 single molecules form a one-dimensional submicrostructure driven by π–π stacking interactions and hydrogen bonds. As expected, the dimensional submicronization tuning strategy ameliorates the aqueous solubility and dispersion stability of ordinary VB2 crystals while endowing them with enhanced superoxide radical yield and H2O2 supply under illumination. Photodynamic therapy (PDT) based on VB2 submicrorods demonstrated remarkable in vitro killing effects against Gram-positive and Gram-negative bacteria by mediating ROS bursts. Furthermore, the superior biocompatibility of VB2 submicrorods enables them to accelerate the closure of exposed lesions during PDT of multidrug-resistant bacterial infections without inducing perceptible side effects. This work aims to pursue photosensitizers with high biosafety, efficiency, and practical feasibility and focuses on developing biologically active VB2 as an environmentally friendly and cost-effective multifunctional photodynamic bactericide.