Abstract

Combination chemotherapy with a modulator and a chemotherapeutic drug has become one of the most promising strategies for the treatment of multidrug resistance (MDR) in cancer therapy. However, the development of nanocarriers with a high payload and sequential release of therapeutic agents poses a significant challenge. In this work, we report a type of hybrid nanocarriers prepared by polydopamine (PDA) mediated integration of the mesoporous MSN core and the microporous zeolite imidazolate frameworks-8 (ZIF-8) shell. The nanocarriers exploit storage capacities for drugs based on the high porosity and molecular sieving capabilities of ZIF-8 for sequential drug release. Particularly, large amounts of an anticancer drug (DOX, 607 μg mg–1) and a MDR inhibitor curcumin (CUR, 778 μg mg–1) were sequentially loaded in the mesoporous core via π–π stacking interactions mediated by PDA and in the microporous shell via the encapsulation during ZIF-8 growth. The sustained release of DOX was observed to follow earlier and faster release of CUR by acid-sensitive dissolution of the ZIF-8 shell. Furthermore, the nanoparticles showed good biocompatibility and effective cellular uptake in in vitro evaluations using drug-resistant MCF-7/ADR cancer cells. More importantly, the preferentially released CUR inhibited the drug efflux function of the membrane P-glycoprotein (P-gp), which subsequently facilitated the nuclear transportation of DOX released from the PDA-MSN core, and, in turn, the synergistic effects on killing MDR cancer cells. The hybrid mesoporous–microporous nanocarrier holds great promise for combination chemotherapy applications on the basis of sequential drug release.