EGF－functionalised Single－walled Carbon Nanotubes for Targeting Delivery of Etoposide
To enhance the therapeutic potential of etoposide (ETO), we devised a targeted drug delivery system (TDDS) of epidermal growth factor–chitosan–carboxyl single-walled carbon nanotubes–ETO (EGF/CHI/SWNT–COOHs/ETO) using modified SWNTs (m-SWNTs) as the carrier, EGF-functionalized SWNTs (f-SWNTs) as the targeted moiety and ETO as the drug. After SWNT–COOHs were conjugated with CHI (CHI/SWNT–COOHs/ETO), they displayed high solubility and stable dispersion in aqueous solution. The drug loading capacity was approximately 25–27%. The m-SWNTs and f-SWNTs had only slight cytotoxicity. ETO was released from EGF/CHI/SWNT–COOHs/ETO at low pH and taken up by tumour cells via adenosine triphosphate (ATP)-dependent endocytosis. The cell death induced by EGF/CHI/SWNT–COOHs/ETO was as much as 2.7 times that due to ETO alone. In summary, these results demonstrated that our TDDS had a greater anticancer effect than free ETO in vitro.