Conjugation of paclitaxel to iron oxide nanoparticles for tumor imaging and therapy

A strategy for conjugating an antitumor agent to superparamagnetic iron oxide nanoparticles (SPIONs) via a biocleavable ester binding is reported. Paclitaxel (PTX) was selected as a model drug. Both the in vitro and in vivo performance of the conjugates of SPION-PTX was investigated respectively. PTX can be released slowly through the hydrolysis of the ester bond in a pH-dependent manner and the SPION-PTX has near equal cytotoxity to the clinical PTX injection (Taxol) at the equivalent dose of PTX. Furthermore, the SPION-PTX can accumulate in tumor tissues as demonstrated by MRI and exhibit better tumor suppression effect than Taxol in vivo. The above good performance of the SPION-PTX together with the good biocompatibility of the SPIONs would promote greatly the application of the SPIONs in the biomedicine field.