Transferrin Modified Graphene Oxide for Glioma-Targeted Drug Delivery: In Vitro and in Vivo Evaluations

Transferrin (Tf), an iron-transporting serum glycoprotein that binds to receptors overexpressed at the surface of glioma cells, was chosen as the ligand to develop Tf-conjugated PEGylated nanoscaled graphene oxide (GO) for loading and glioma targeting delivery of anticancer drug doxorubicin (Dox) (Tf-PEG-GO-Dox). Tf-GO with lateral dimensions of 100-400 nm exhibited a Dox loading ratio up to 115.4%. Compared with Dox-loaded PEGylated GO (PEG-GO-Dox) and free Dox, Tf-PEG-GO-Dox displayed greater intracellular delivery efficiency and stronger cytotoxicity against C6 glioma cells. A competition test showed that Tf was essential to glioma targeting in vitro. The HPLC assay for Dox concentration in tumor tissue and contrapart tissue of the brain demonstrated that Tf-PEG-GO-Dox could deliver more Dox into tumor in vivo. The life span of tumor bearing rats after the administration of Tf-PEG-GO-Dox was extended significantly compared to the rats treated with saline, Dox, and PEG-GO-Dox. In conclusion, we developed Tf-PEG-GO-Dox which exhibited significantly improved therapeutic efficacy for glioma both in vitro and in vivo.