Photonic Crystal-Enhanced Photodynamic Antibacterial Therapy

Photodynamic antibacterial therapy (PDAT) is a kind of rejuvenating strategy that combats bacterial infection due to its admirable characteristics of noninvasiveness and broad-spectrum antibacterial capability. However, the efficiency of PDAT can be greatly hindered by limited light irradiation. Herein, we propose an enhanced PDAT by employing photonic composite films (PCFs) via slow photon and multiple scattering effects. The PCFs are obtained by UV light-initiated polymerization of poly(ethylene glycol) phenyl ether acrylate with a self-assembled SiO₂ colloidal particle array, followed by the deposition of photosensitizers (PSs). The PCFs can prompt the PSs with matched absorption, which are deposited on their surface, to sufficiently utilize the incident light and generate more reactive oxygen species based on the slow photon phenomenon of photonic crystals and multiple scattering effects of the SiO₂ colloidal particles. This finding demonstrates the great potential and significance of PCFs in the field of PDAT, which may reduce the requirements of excitation equipment and avoid damage to normal tissues from exposure to huge light energy.