Research advances in BODIPY-assembled supramolecular photosensitizers for photodynamic therapy

Photodynamic therapy (PDT) is a promising therapeutic approach for anticancer and antibacterial treatment via photoinduced reactive oxygen species (ROS) generation. Photosensitizer, the most important element of PDT, plays a decisive role in PDT treatment. BODIPY dyes, as a class of well-developed fluorescent dyes, have emerged as a new class of PDT agents over the past decade owing to their versatile and remarkable properties including high molar extinction coefficients and singlet-to-triplet intersystem crossing efficiencies, tunable absorption and emission wavelengths, good ROS-generation ability, excellent photo- and chemical- stability, and easy functionalization. Several chemical approaches have been applied to tune BODIPY fluorophores into triplet photosensitizers via converting the typical fluorescence decay into a non-radiative intersystem crossing to the triplet state. However, the poor water solubility, low tumor selectivity and limited biocompatibility still hamper their biological application. Supramolecular assembly strategies have provided a promising avenue to overcome current problems of BODIPY-based molecular photosensitizers in photodynamic anticancer and antibacterial therapy. So far, numerous types of self-assembled nano-platforms have been established for construction of BODIPY-assembled supramolecular photosensitizers. This review presents the main molecular design approaches for constructing BODIPY-based photosensitizers and systematically summarizes the research progress of BODIPY-assembled supramolecular photosensitizers for PDT treatment to provide meaningful guidance for developing highly efficient BODIPY-based photosensitizers suitable for their clinical translation and application.