TAT-conjugated nanodiamond for the enhanced delivery of doxorubicin

The unique properties of nanodiamonds (NDs) such as chemical stability, surface modifiability and remarkable biocompatibility impart them with a great opportunity to be versatile platforms for drug delivery. In this study, chemotherapeutic doxorubicin (DOX) and cell penetrating peptide TAT were conjugated to the surface of NDs in sequence through carbodiimide coupling in order to avoid premature release and enhance the intracellular delivery of DOX. The cytotoxicity, intracellular location and cellular uptake of DOX-conjugated NDs with or without TAT were evaluated in C6 glioma cells. Our results revealed that conjugation of TAT to ND-DOX could enhance the translocation across the cell membrane and exhibit a higher cytotoxicity effect than free DOX. This antitumor drug and penetrating peptide-conjugated ND drug delivery system therefore represents a novel delivery system with promoted antineoplastic activity of therapeutics and minimized side effects.