Multi-stimuli responsive nanosystem modified by tumor-targeted carbon dots for chemophototherapy synergistic therapy.

In this work, a tumor-targeted and multi-stimuli responsive drug delivery system combining infrared thermal imaging of cells with thermo-chemotherapy was developed. Oxidized mesoporous carbon nanoparticles (MCNs-COOH) with high photothermal conversion ability (photothermal transduction efficiency η = 27.4%) in near-infrared (NIR) region were utilized to encapsulate doxorubicin (DOX). The outer surfaces of MCNs-COOH were capped with multifunctional carbon dots (CD) as simultaneous smart gatekeepers, a tumor targeting moiety and a fluorescent probe. NIR laser irradiation killed cancer cells through NIR-light induced hyperthermia, facilitated chemotherapeutic drug release and enhanced the sensitivity of tumor cells to drugs. The therapeutic efficacy in two-dimensional (2D) and three-dimensional (3D) cells demonstrated that MC-CD loading DOX (MC-CD/DOX) had good chemo-photothermal synergistic antitumor effects (combination index of CI = 0.448). The biodistribution and pharmacodynamics experiments of MC-CD/DOX in the 4T1 tumor model indicated that MCNs-COOH prolonged the residence time of DOX in tumor tissues and therefore actualized effective synergistic photothermal chemotherapy. By combining these excellent capabilities, the tumor-targeted and multi-stimuli responsive drug delivery system can be utilized as a visible nanoplatform for chemophotothermal synergistic therapy.