Synergistic Chemo–Photothermal Therapy of Breast Cancer by Mesenchymal Stem Cell-Encapsulated Yolk–Shell GNR@HPMO-PTX Nanospheres

Mesenchymal stem cells (MSCs) have attracted increasing attention as vehicles for cancer treatment. Herein, MSC-based synergistic oncotherapy strategy is presented for the first time. To achieve this goal, yolk-shell structured gold nanorod embedded hollow periodic mesoporous organosilica nanospheres (GNR@HPMOs) with high paclitaxel (PTX) loading capability and excellent photothermal transfer ability upon near-infrared (NIR) light irradiation are first prepared. Cytotoxicity and migration assays show that the viability and tumor-homing capability of MSCs are well-retained after internalization of high content of PTX loaded GNR@HPMOs (denoted as GNR@HPMOs-PTX). In vitro experiments show the GNR@HPMOs-PTX loaded MSCs (GNR@HPMOs-PTX@MSCs) possess synergistic chemo-photothermal killing effects for breast cancer cells. Also, photoacoustic imaging shows that the MSCs can improve dispersion and distribution in tumor tissue for GNR@HPMOs-PTX after intratumoral injection. In vivo experiments in breast cancer model of nude mice further demonstrate that the GNR@HPMOs-PTX@MSCs significantly inhibit tumor growth, suggesting their great potential for synergistic therapy of cancer.