NIR light triggered size variable remote-controlled cluster bomb for deep penetration and tumor therapy

Poor penetration into tumor stem cells of nanomedicine leads to the low therapeutic efficacy, metastasis and recurrence of tumors. Herein, doxorubicin (DOX) modified gold nanorods (GNRs) and chlorin e6 (Ce6) were loaded simultaneously on the surface of polydopamine (PDA) nanospheres (PDA@ GNRs-DOX/Ce6), which was called structure-tunable remote-controlled cluster bomb. The cluster bomb were accumulated primarily to the tumor tissues via enhanced permeability and retention effect. Subsequently, the nanosystem was disintegrated to release DOX and singlet oxygen and kill the superficial tumor cells under NIR laser irradiation. Meanwhile, the small-size GNRs (48 nm x 15 nm) fall off from the primary nanocarriers and penetrated into the interior tumor tissue to damage the tumor stem cells. The novel variable structure nanosystem avoided the possibility of tumor metastasis and recurrence. The results also verified its excellent tumor therapeutic efficiency, the relative tumor volume was 0.47 +/- 0.31 in the PDA@ GNRs-DOX/Ce6 group, which was lower significantly than that of control group (26.50 +/- 0.98). We believe the design of structure-tunable remote-controlled cluster bomb can provide an inspiration for the future tumor therapy.