Silicon quantum dots delivered phthalocyanine for fluorescence guided photodynamic therapy of tumor**Project supported by the National Natural Science Foundation of China (Grant Nos. 21374074, 21422404, and U1532108) and the Undergraduate Training Program for Innovation and Entrepreneurship of Soochow University, China (Grant No. 2016xj010).

Abstract

Imaging-guided cancer therapy provides a simultaneous tumor imaging and treatment, which helps to eliminate the excessive toxicity to the healthy tissues. For this purpose, multifunctional probes capable of both imaging and curing are needed. In this work, we synthesize water-soluble silicon quantum dots (Si QDs) smaller than 5 nm. Such Si QDs are used for delivering the hydrophobic drug phthalocyanine (Pc). The as-prepared Si/Pc nanocomposite particles show efficient transmembrane delivery into cells and feasible biocompatibility. Moreover, these composite particles emit dual-channel fluorescence signals even after cellular internalization and demonstrate robust photostability in the Si channel. More interestingly, the Si/Pc composite particles show efficient photodynamic therapy effects against tumors both in vitro and in vivo.