Combined Near Infrared Photothermal Therapy and Chemotherapy Using Gold Nanoshells Coated Liposomes to Enhance Antitumor Effect.

Novel antitumor system based on the targeting photothermal and pH-responsive nanocarriers, gold nanoshells coated oleanolic acid liposomes mediating by chitosan (GNOLs), is designed and synthesized for the first time. The GNOLs present spherical and uniform size (172.03 nm) with zeta potential (20.7 ± 0.4 mV), which are more easily accumulated in tumor. Meanwhile, the GNOLs exhibit a slow and controlled release of oleanolic acid at pH 7.4, as well as a rapid release at pH 5.5, which is beneficial for tumor-targeting drug release. Under near infrared (NIR) irradiation, hyperthermia can be generated by activated gold nanoshells to perform photothermal therapy effect, which triggers drug release from the carriers by activating the gel to liquid crystalline phase transition of the liposomes. Moreover, the NIR assisting drug release can be easily and selectively activated locally due to the spatially and real-timely controllable property of light. The experimental results also verify that the GNOLs with NIR irradiation achieve more ideal antitumor effects than other oleanolic acid formulations in vitro and in vivo. Hence, the drug delivery system exhibits a great potential in chemo-photothermal antitumor therapy.