Engineering a Bi-BiOI Schottky Junction Rich in Oxygen Vacancies in PLLA Scaffolds to Amplify Photoelectricity-Catalysis Coupling for Accelerating Infectious Nerve Repair

Bismuth iodide oxide (BiOI) has significant potential for promoting the repair of infectious nerve defects due to its excellent photoelectric conversion and carrier mobility properties. Nevertheless, their applications are restricted by inefficient near-infrared light absorption and excessive electronic transition barriers. Herein, bismuth (Bi) nanoparticles are hydrothermally deposited on BiOI, which introduces oxygen vacancies (OV) and form a Bi-BiOI Schottky junction, and then added into a poly-L-lactic acid (PLLA) scaffold. Concretely, Bi nanoparticles induce a collective oscillation of free electrons, expanding the photoresponse range. The generated hot electrons are then injected into the built-in electric field of BiOI via the heterojunction, thereby enhancing the photoelectric effect. More ingeniously, OV can introduce defect energy levels, which lower the electron injection barrier and improve electron-hole separation, thus promoting the photocatalytic effect. The results proved that the photoresponse extended to the near-infrared region and that the photoelectricity effect was confirmed by a 50% increase in transient photocurrent and an output voltage of 5 mV. Electrical signals promoting neuronal differentiation were evidenced by 40-fold and 20-fold increases in Nestin/GFAP protein and neural mRNA expression, respectively. ROS production increased by 51.8%, which effectively eradicated biofilms, and penetrated bacteria, inducing GSH depletion and protein leakage. Consequently, the antibacterial rates reached 92.5% (E. coli) and 93.1% (S. aureus).