Targeted delivery and controlled release of doxorubicin to cancer cells using modified single wall carbon nanotubes

A targeted drug delivery system that is triggered by changes in pH based on single wall carbon nanotubes (SWCNTs), derivatized with carboxylate groups and coated with a polysaccharide material, can be loaded with the anticancer drug doxorubicin (DOX). The drug binds at physiological pH (pH 7.4) and is only released at a lower pH, for example, lysosomal pH and the pH characteristic of certain tumor environments. By manipulating the surface potentials of the modified nanotubes through modification of the polysaccharide coating, both the loading efficiency and release rate of the associated DOX can be controlled. Folic acid (FA), a targeting agent for many tumors, can be additionally tethered to the SWCNTs to selectively deliver DOX into the lysosomes of HeLa cells with much higher efficiency than free DOX. The DOX released from the modified nanotubes has been shown to damage nuclear DNA and inhibit the cell proliferation. (C) 2009 Elsevier Ltd. All rights reserved.