Strategies to Improve Photodynamic Therapy Efficacy of Metal-Free Semiconducting Conjugated Polymers

Photodynamic therapy (PDT) is a noninvasive therapy for cancer and bacterial infection. Metal-free semiconducting conjugated polymers (SCP_S) with good stability and optical and electrical properties are promising photosensitizers (PSs) for PDT compared with traditional small-molecule PSs. This review analyzes the latest progress of strategies to improve PDT effect of linear, planar, and three-dimensional SCP_S, including improving solubility, adjusting conjugated structure, enhancing PS-doped SCPs, and combining therapies. Moreover, the current issues, such as hypoxia, low penetration, targeting and biosafety of SCP_S, and corresponding strategies, are discussed. Furthermore, the challenges and potential opportunities on further improvement of PDT for SCPs are presented.