Photothermal therapies are relatively non-invasive, facile to implement, and therefore ideally suited to the treatment of otherwise inaccessible tumors. The approach focuses on localizing a photothermal converter material at a tumor site and then irradiating the site with a laser to cause cell death.

Paul J. Dyson, Qinghua Lu, and colleagues, Ecole Polytechnique Fédérale de Lausanne, Switzerland, have demonstrated a facile method to prepare single-walled carbon nanotubes (SWNTs) coated with gold nanaoparticles (Au NPs) by using a thiol-functionalized ionic liquid (IL) as a type of glue (pictured).

The resulting material has an ideal absorption and heating profile for a photothermic converter. Furthermore, they are biocompatible (not cytotoxic) and selectively enter lysosomes in tumor cells because of the enhanced permeability and retention (EPR) effect, in which macromolecules exploit the structural changes in tumor tissue allowing them to enter and accumulate. Due to an enhanced near-infrared (NIR) adsorption, irradiation with a NIR laser is effectively transferred into heat to cause localized hyperthermia, resulting in rapid cell death.

• Gold Nanoparticles Grown on Ionic Liquid-Functionalized Single-Walled Carbon Nanotubes: New Materials for Photothermal Therapy,
  L. Meng, L. Niu, L. Li, Q. Lu, Zhaofu Fei, Paul J. Dyson,
  Chem. Eur. J. 2012.
  DOI: 10.1002/chem.201201811