White Light triggered zwitterionic polymer nanoparticles based on AIE-active photosensitizer for photodynamic antimicrobial therapy

Photodynamic antimicrobial therapy (PDAT) has got enormous attention due to its excellent spatiotemporal accuracy, noninvasive and anti-multidrug resistance properties compared with chemotherapy. However, traditional PDAT methods possess numerous disadvantages like high dark toxicity, poor chemical stability and typically occur to fluorescence quenching and relatively low ROS efficiency in water. In this work, we successfully fabricated a kind of pH-responsible zwitterionic polyurethane nano-micelles possessing great reactive oxygen species (ROS) generation efficiency due to its smaller singlet−triplet energy gap of AIE PS moiety. This nano-system also has near-infrared bioimaging function that can detect the bacteria in real time. In addition, the hydrophilic zwitterionic polyurethanes played a vital role of antifouling properties to enhance biocompatibility and prolong circulation time at normal condition (pH 7.4). While at acidic condition (pH 5.4), zwitterionic moiety would be suddenly protonated to enable positively charged nano-micelles target to bacterial infection site, resulting in great anti-bacterial efficiency, which is superior to the existing PDAT method.