Multifunctional mesoporous silica nanoplatform based on silicon nanoparticles for targeted two-photon-excited fluorescence imaging-guided chemo/photodynamic synergetic therapy in vitro.

Currently, the nanocomposites based on silicon nanoparticles (SiNPs) are usually limited to a single therapeutic modality, and the design of the SiNPs nanohybrids with multi-modal synergistic therapeutic functions is still worth being explored to achieve more effective treatment. Herein, we used mesoporous silica nanoparticle (MSN) as a nanoplatform, SiNPs and the photosensitizer 5,10,15,20-tetrakis (1-methyl 4-pyridinio) porphyrin tetra (p-toluenesulfonate) (TMPyP) were first embedded in the MSN and was further modified with folic acid (FA) to obtain the mesoporous silica nanocomposite (MSN@SiNPs@TMPyP-FA) for targeted two-photon-excited fluorescence imaging-guided photodynamic therapy (PDT) and chemotherapy. The embedded TMPyP could generate singlet oxygen to perform PDT under light irradiation, meanwhile the anticancer drugs doxorubicin (DOX) could be loaded for chemotherapy. Moreover, due to the two-photon excited fluorescence of SiNPs, the nanocomposite successfully achieved targeted two-photon fluorescence cellular imaging at the near-infrared (NIR) laser excitation, which could effectively avoid the interference of biological auto-fluorescence. And in vitro cytotoxicity assays revealed that the synergistic therapy combining PDT and chemotherapy exhibited high therapeutic efficacy for cancer cells.