Fabrication of magnetite hollow porous nanocrystal shells as a drug carrier for paclitaxel

A facile and simple route is employed to synthesise a new type of magnetite hollow porous nanocrystal shells (HPNSs) as hydrophobic drug delivery vehicles. The morphological evolution of spherical clusters from solid to hollow porous shells is controlled in a straightforward fashion through the reaction time. The obtained magnetite HPNSs possesses high magnetization, well-defined structure, and porous shell, the channels and cavity in HPNSs benefit the drug storage, delivery, and release. The structure of HPNSs was characterized by SEM, TEM and XRD, VSM (vibrating sample magnetometer) data showed that the saturation magnetization values of the Fe3O4 HPNSs are 67.5, 73.2, 79.4, and 88.7 emu/g, corresponding to reaction times of 6, 8, 12, and 16.5 h, respectively. This result clearly proved that the crystallinity could be improved by Ostwald ripening of nanocrystals through a dissolution-recrystallization process, the formation of the hollow porous structure was promoted as well. FT-IR and TGA results showed that the porous shell facilitated paclitaxel diffusion into the cavity of hollow structure, and the drug loading of magnetite HPNSs for paclitaxel is very high (20.2 wt%). The antitumor efficacy of the drug-loaded HPNSs measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was clearly enhanced, compared with free drugs.