A pH-sensitive nanocarrier for co-delivery of doxorubicin and camptothecin to enhance chemotherapeutic efficacy and overcome multidrug resistance in vitro

To deliver chemotherapeutic drugs simultaneously, using drug carriers is a feasible strategy for a better synergetic effect. We have constructed hollow silica nanoparticles (HSNPs) sealed with ZnO quantum dots (QDs) as a pH-sensitive nanocarrier, where the HSNPs have large hollow interiors for delivering hydrophobic camptothecin (CPT) and a mesoporous structure for delivering hydrophilic doxorubicin (DOX·HCl). This cooperative drug loading has largely increased the drug encapsulation efficiency of both CPT and DOX up to 89.28% and 44.98%, respectively. Meanwhile, the ZnO QD lids in this drug delivery system are found to be rapidly dissolved in the acidic intracellular compartments to trigger pH-sensitive drug release. The co-delivery of multi-drugs with different anticancer mechanisms in the same nanocarrier enables the intracellular release of the drug combinations to greatly enhance chemotherapeutic efficacy and overcome multidrug resistance (MDR).