Heterostructured nanorod array with piezophototronic and plasmonic effect for photodynamic bacteria killing and wound healing

Bacteria induced infectious diseases have threated the lives and health of millions people each year. Nanosized titanium dioxide (TiO₂) have been developed for photodynamic bacterial killing with minimal drug resistance, but the efficiency was restricted by their large band gap, limited light-absorption region, and rapid electron-hole recombination. In this work, we rationally fabricated a TiO₂/BTO/Au multilayered coaxial heterostructured nanorod array by inserting a ferroelectric semiconductor barium titanate (BaTiO₃) nanolayer between TiO₂ nanorod and gold nanoparticles (AuNPs). The TiO₂/BTO/Au heterostructure showed greatly enhanced reactive oxygen species (ROS) (superoxide (O₂•^-) and hydroxyl radicals (•OH)) generation, and incident photo-electron conversion efficiency (IPCE) in UV/visible light region. On the basis of experimental observations, the detailed photodynamic mechanism of the enhanced ROS generation was proposed, mainly ascribed to the piezophototronic effect and plasmonic property of the nanorod array. The nanorod array was used as an antibacterial coating to kill gram-negative bacterium E. coli and gram-positive bacterium S. Aureus with an antibacterial efficiency up to 99.9% under simulated sunlight. It also showed an efficient promotion of infectious wound regeneration in mice with S. aureus infected dermal wounds.