Photothermal ablation of tumor cells using a single-walled carbon nanotube-peptide composite

Single-walled carbon nanotubes (SWCNTs) are known to have great potential for biomedical applications such as photothermal ablation of tumor cells in combination with near-infrared (NIR) irradiation. In this study, the photothermal activity of a novel SWCNTs composite with a designed peptide having a repeated structure of H-(-Lys-Phe-Lys-Ala-)(7)-OH [(KFKA)(7)] against tumor cells was evaluated in vitro and in vivo. The SWCNT-(KFKA)(7) composite demonstrated high aqueous dispersibility that enabled SWCNTs to be used in tumor ablation. The NIR irradiation of SWCNT-(KFKA)(7) solution resulted in a rapid temperature increase dependent on the SWCNTs concentration up to 50 mu g/ml. Three minutes of NIR irradiation of a colon 26 or HepG2 cell culture incubated with SWCNT-(KFKA)(7) resulted in remarkable cell damage, while that by single treatment with SWCNT-(KFKA)(7) or NIR irradiation alone was moderate. The intratumoral injection of SWCNT-(KFKA)(7) solution followed by NIR irradiation resulted in a rapid increase of the temperature to 43 degrees C in the subcutaneously inoculated colon 26 tumor based on thermographic observation and remarkable suppression of tumor growth compared with treatment with only SWCNT-(KFKA)(7) injection alone or NIR irradiation alone. These results suggest the a great potential of an SWCNT- peptide composite for use in photothermal cancer therapy. (C) 2013 Elsevier B.V. All rights reserved.