We have developed mitochondria-targeted self-assembled nanoparticles (NPs) based on amphiphilic triphenylphosphine-quercetin (TPP-Que) conjugates, which were further modified by poly(ethylene glycol) via a pH-responsive coordination bond to form TQ-PEG NPs. And it is revealed that the TQ-PEG NPs were more effective therapeutic agents compared with Que in vitro and in vivo.

Multi-drug resistance (MDR) of tumor has greatly hindered the therapeutic effect of chemotherapeutic drugs, resulting in chemotherapy failure, and overexpression of ATP-binding cassette (ABC) transporters in cell membrane is the main cause of MDR.