Recent advances and prospects of carbon dots in phototherapy

Carbon dots (CDs) are novel zero-dimensional carbonaceous nanomaterial, and they are featured with an attractive combination of physical, chemical, and biomedical properties including wide absorption spectrum, tunable fluorescence, excellent water solubility, outstanding photostability, and biocompatibility, which leads to their diverse applications as optically functional materials in various fields, e.g., fluorescence sensing, bioimaging, and drug delivery. Recently, it was revealed that CDs could be used as an effective photosensitizer to generate reactive oxygen species under light excitation, and/or a photothermal agent to convert light energy into heat, which enable them to be applied in photodynamic therapy or photothermal therapy for cancer treatment. In this review, we summarize the latest progress of research on CDs in phototherapy, including their use as nanocarriers for organic phototherapy agents, and highlight the strategies which are adopted to improve the therapeutic efficacy of CDs-based phototheranostics. Furthermore, we also discuss the challenges and prospects of the CDs-based phototheranostics towards clinical applications. We hope this review will provide critical insights to inspire new exciting discoveries on CDs from both fundamental and practical views so as to prompt their advances in the phototherapy.