High reactive oxygen species produced from fluorescence carbon dots for anticancer and photodynamic therapies: A review

High-photoluminescence carbon dots (CDs) were synthesized from various sources and various methods using two approaches, namely bottom up and top down, with emission-dependent excitation wavelength. Electronic transition from the higher- occupied molecular orbital (HOMO) state to the lowest-unoccupied molecular orbital(LUMO) state, surface defect states, wider excitation spectrum, higher quan- tum yield, efficient energy transfer, and element doping affected the fluorescence properties of CDs. Using 102 references listed in this review, the authors studied the relationship between fluorescence mechanism and reactive oxygen species (ROS)produced for photodynamic therapy (PDT) and materials anticancer applications. We described how the radical atom or ROS work as anticancer therapy and PDT and described the chemical reaction of high-resolution fluorescence CDs. We summa- rized experimental techniques that are used for producing CDs and discussed their characteristics. Finally, conclusions and future prospects in this field are also dis- cussed. The important characteristics of CD-based design for high ROS may usher in new prospects and challenges for high efficiency and stability of PDT and anticancer therapy. In conclusion, we have provided perspectives and challenges of the future development of CD s.