Titania-coated gold nanorods as an effective carrier for gambogic acid

Gambogic acid (GA), a natural product, exhibits potent anticancer effects. Unfortunately, further clinical application of this drug is limited by its poor solubility in aqueous solutions. In the present study, titanium dioxide (TiO2)-coated gold nanorod (GNR/TiO2) nanostructures were used as a carrier for GA. The GNR/TiO2 nanostructure-based delivery was found to provide a stable aqueous dispersion of GA. Compared with the free form, enhanced intracellular GA delivery was achieved by using the GNR/TiO2 nanostructures. An in vitro cytotoxicity study indicated that the GA-loaded GNR/TiO2 nanostructures were much more effective in inhibiting the proliferation of human glioblastoma U-87 MG cells than free GA, particularly at lower working concentrations. Furthermore, the GNR/TiO2 nanostructures displayed a high photothermal conversion efficiency, and irradiation at a low dose (5.3 W cm(-2), 2 min) with an 808 nm laser also synergistically enhanced the anticancer effect of the GA-loaded GNR/TiO2 nanostructures. Therefore, our results suggest that GNR/TiO2 nanostructure-based drug delivery is a promising method to improve the therapeutic efficacy of GA.