Folate-Conjugated PEG on Single Walled Carbon Nanotubes for Targeting Delivery of Doxorubicin to Cancer Cells

A highly effective drug carrier is constructed by coating folic acid-terminated poly(ethylene glycol) (PEG-FA) on single walled carbon nanotubes (SWNTs) in a facile non-covalent method. The anti-cancer drug, doxorubicin (DOX), is further loaded on the surface of SWNTs at a very high loading efficiency, 149.3 +/- 4.1%. The drug system (DOX/PEG-FA/SWNTs) exhibits excellent stability under neutral pH conditions such as serum, but dramatically releases DOX at reduced pH typical of the tumour environment and intracellular lysosomes and endosomes. With the help of FA, DOX/PEG-FA/SWNTs tend to selectively attach onto cancer cells and enter the lysosomes or endosomes by clathrin-mediated endocytosis. This can greatly improve the pharmaceutical efficiency and reduce potential side effects.