Buckysomes: fullerene-based nanocarriers for hydrophobic molecule delivery

We report the preparation and preliminary in vitro studies of nanocarriers termed "buckysomes," which are self-assembled, spherical nanostructures composed of the amphiphilic fullerene AF-1. By inducing AF-1 self-assembly at an elevated temperature of 70 degrees C, dense spherical buckysomes with diameters of 100-200 nm were formed, as observed by electron microscopy and dynamic light scattering. The amphiphilic nature of AF-1 results in the formation of many hydrophobic regions within the buckysomes, making them ideal for embedding hydrophobic molecules to be tested in a drug delivery scheme. After confirming the cellular internalization of buckysomes embedded with the hydrophobic fluorescent dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate, we embedded paclitaxel, a highly hydrophobic anticancer drug. The in vitro therapeutic efficacy of the paclitaxel-embedded buckysomes toward suppression of MCF-7 breast cancer cell growth was compared to that of Abraxane, a commercially available, nanoparticle-albumin-bound formulation of paclitaxel. Notably, the paclitaxel-embedded buckysomes demonstrated a similar efficacy to that observed with Abraxane in cell viability studies; these results were confirmed microscopically. Moreover, negative control studies of MCF-7 viability using empty buckysomes demonstrated that the buckysomes were not cytotoxic. The results of our studies suggest that buckysomes prepared from self-assembly of AF-1 at 70 degrees C are promising nanomaterials for the delivery of hydrophobic molecules.