Mesoporous Silica Nanoparticles Capped with Graphene Quantum Dots for Potential Chemo–Photothermal Synergistic Cancer Therapy

In this study, mesoporous silica nanoparticles (MSNs) have been successfully capped with graphene quantum dots (GQDs) to form multifunctional GQD–MSNs with the potential for synergistic chemo–photothermal therapy. The structure, drug-release behavior, photothermal effect, and synergistic therapeutic efficiency of GQD–MSNs to 4T1 breast cancer cells were investigated. The results showed that GQD–MSNs were monodisperse and had a particle size of 50–60 nm. Using doxorubicin hydrochloride (DOX) as a model drug, the DOX-loaded GQD–MSNs (DOX–GQD–MSNs) not only exhibited pH- and temperature-responsive drug-release behavior, but using near-infrared irradiation, they efficiently generated heat to kill cancer cells. Furthermore, GQD–MSNs were biocompatible and were internalized by 4T1 cells. Compared with chemotherapy and photothermal therapy alone, DOX–GQD–MSNs were much more effective in killing the 4T1 cells owing to a synergistic chemo–photothermal effect. Therefore, GQD–MSNs may have promising applications in cancer therapy.