Self-Assembly of Stimuli-Responsive Au-Pd Bimetallic Nanoflowers Based on Betulinic Acid Liposomes for Synergistic Chemo-Photothermal Cancer Therapy.

Synergistic cancer therapy through the combination of chemotherapy with photothermal therapy has been gained more and more insights. Bimetallic nanostructures with near-infrared (NIR) plasmonic responses are considered prime candidates based on their superior photothermal conversion properties. Herein, novel poly branched Au-Pd bimetallic-nanoflowers-coated betulinic acid liposomes (BA-Lips@Pd@Au NFs) were designed and developed. The as-prepared BA-Lips@Pd@Au NFs with optimal size (144.4 nm) possessed good photostability under NIR-irradiation, high photothermal conversion efficiency (64.6%), and good biocompatibility. Moreover, the hyperthermia of drug delivery induced by NIR-irradiation dramatically improved the cell uptake of nanocapsules and enhanced the chemotherapeutic efficacy of tumor. Upon illumination by NIR light, the BA-Lips@Pd@Au NFs exhibited prominent synergetic effects of chemo-photothermal therapy with a tumor inhibition ratio (91.7%), which was higher than that of chemotherapy or photothermal therapy alone. Therefore, this rational design of nanocapsule with stimuli-responsive capability showed a versatile strategy to provide smart nanocapsule paradigms for cancer therapy.