Phosphate-Assisted Transformation of Methylene Blue to Red-Emissive Carbon Dots with Enhanced Singlet Oxygen Generation for Photodynamic Therapy
Yalan Xu, Chan Wang, Guoxia Ran, Dan Chen, Qingfeng Pang, Qijun Song
Abstract
Photodynamic therapy (PDT) has attracted wide attention due to its distinct advantages in cancer treatment. Herein, a kind of red emissive carbon dots (R-CDs) was synthesized from methylene blue (MB) and phosphate through a hydrothermal method. The resultant R-CDs display good biocompatibility, photostability, and high singlet oxygen (1O2) yield (0.91); thus, they have been successfully applied to the PDT study in vitro. More importantly, the R-CDs show noninfective property to DNA, which is substantially different to their precursor MB. The structure of R-CDs was comprehensively characterized both experimentally as well as by density functional theory (DFT) calculations. This study not only provides a rational strategy for preparation of highly efficient PDT material but also gives insight into the mechanism of 1O2 generation.