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.