Breast cancer is the most common cancer in women and occurs mostly with poor outcomes. Our objective was to endow synthetic lethality to the phytoconstituent chikusetsusaponin IVa methyl ester (CSME, S), a special phytoconstituent from traditional Chinese medicine (TCM), Panax japonicus, with the photodynamic agent chlorin e6 (Ce6, C) and enhance the therapeutic efficacy against breast cancer using cell membrane-coated liposome nanoparticles (liposome, L). The delivery system based on liposomes was camouflaged by a hybrid cell membrane (RBC mem...