A Water-Soluble Aggregation-Induced Emission Photosensitizer with Intrinsic Antibacterial Activity as an Antiplanktonic and Antibiofilm Therapeutic Agent

Photosensitizers (PSs) with aggregation-induced emission (AIE) properties have gained popularity for treating bacterial infections. However, most AIE PSs have a poor water solubility and low selectivity, limiting their applications in biological systems. Herein, we report a water-soluble and bacteria-targeting AIE PS that exhibits minimum cytotoxicity toward human cells with and without light irradiation. Acting as a narrow-spectrum antibacterial agent without light irradiation, TPA-1 eradicates planktonic <i>Staphylococcus aureus</i> and inhibits biofilm formation by targeting the <i>S. aureus</i> membrane, inhibiting the supercoiling activity of <i>S. aureus</i> DNA gyrase, and causing the downregulation of multiple essential proteins. Upon light irradiation, TPA-1 generates reactive oxygen species (ROS) that cause membrane damage, resulting in excellent antiplanktonic and antibiofilm activities against <i>S. aureus</i> and <i>Pseudomonas aeruginosa</i>, significantly reducing the number of viable bacteria in biofilms and promoting wound healing <i>in vivo</i>.