Organic dye-based photosensitizers for fluorescence imaging-guided cancer phototheranostics

Precise diagnosis and treatment of tumors is the current hotspot, which has also given rise to a new subject named "theranostics". It is an ideal precision treatment strategy if the agent can provide effective treatment while visually monitoring tumor occurrence and providing timely feedback on the efficacy. Fluorescence imaging-guided phototherapy technology is a non-invasive, simple-to-operate, highly safe and non-drug-resistant visual treatment method that can accurately monitor tumor sites, perform efficient phototherapy and feedback on tumor treatment effects. Photosensitizers with fluorescence imaging capabilities play a decisive role in the entire diagnosis and treatment process. In this review, we focus on four commonly used photosensitizers with fluorescence imaging functions, including cyanine, tetrapyrrole structures, BODIPY, and AIEgens. The design strategies and principles for improving imaging or/and therapeutic functions were highlighted based on these four organic molecular monomers or their nanoaggregates, nanocomposites, etc. The challenges and future opportunities of fluorescence imaging-guided phototherapy in the clinical translation of precision tumor treatment are also presented.