Sulphur‐doped carbon dots as a highly efficient nano‐photodynamic agent against oral squamous cell carcinoma

OBJECTIVES: Photodynamic therapy (PDT) is a novel non‐invasive therapeutic method, which has been widely applied for the treatment of human oral cancers. However, the problems of undesirable singlet oxygen ((1)O(2)) quantum yields and long‐term phototoxicity were inevitable during the application of traditional photosensitizers. Therefore, it is necessary to explore novel photosensitizers for the improvement of therapeutic effects. In our study, the sulphur‐doped carbon dots (S‐CDs) of high yield of singlet oxygen ((1)O(2)) were synthesized as a nano‐photosensitizer for OSCC to improve the PDT efficacy in clinical practice. MATERIALS AND METHODS: After synthesis of the novel S‐CDs, the size, morphologic characteristics, surface potential and yield of singlet oxygen ((1)O(2)) were determined. In vitro study was performed to compare the therapeutic effect as well as the biocompatibility of the novel S‐CDs to those of 5‐ALA. Besides, possible mechanism of action was illustrated. RESULTS: After synthesis of the novel S‐CDs, the size, morphologic characteristics, surface potential and yield of singlet oxygen ((1)O(2)) were determined. In vitro study was performed to compare the therapeutic effect as well as the biocompatibility of the novel S‐CDs to those of 5‐ALA. Besides, possible mechanism of action was illustrated. CONCLUSIONS: These data from the in vitro study demonstrated the promising safety profile of the low dose (nmol/L) S‐CDs, which indicated the novel S‐CDs could be used as a promising photodynamic agent for oral cancer therapy.