Alternative medicine

Researchers at

, University of London, are investigating an external radio frequency (RF) drug-delivery technique that could provide a non-toxic alternative to cancer treatment.

The process works by using RF to heat targeted gold nanoparticles and nanorods embedded in polymer shells of 10-20nm. The increase in temperature alters the capsule permeability to release loaded drugs into targeted areas of disease without damaging the surrounding tissue.

Similar techniques have been explored using the absorbance of light in the near-infrared (NIR) spectrum to heat nanoparticles. A European project, led by

, has been examining the use of ultrasound pulses to trigger drug release in targeted areas of the body (

).

However, researchers at Queen Mary claim that the use of RF to heat gold nanoparticles could prove a more effective tool. Dr Dongsheng Wen explained: 'RF is more powerful in relation to ultrasound. In theory, it can damage the body's cells, but the frequencies we use have a strong reaction to gold particles, which can absorb energy from RF. This raises the temperature of the particles very quickly, causing less damage to surrounding cells.'

A previous study into the use of gold nanoparticles recorded their effectiveness in drug release when exposed to NIR light. However, this approach was limited to malignant tumours close to the surface of the skin and only worked at a tissue penetration of 2-3cm. RF increases this range to include the rest of the body, and, unlike ultrasound, can work at higher temperatures without damaging healthy cells.

Prof Gleb Sukhorukov of Queen Mary said: 'We've found that gold is an ideal metal to make the capsules sensitive enough for RF. Silver also works quite well, but it is less defined and so for the purposes of our study we wanted something that would be easy to modify for the attachment of antibodies.'

In addition to binding easily with other molecules, gold nanoparticles have no intrinsic toxic effects on human tissue and are able to release significant heat when exposed to RF treatment. Wen claims that the potential applications for this could be far-reaching and in the future extend to any treatment that requires targeted drug delivery.

The research is still at its early stages and the university has opened applications for a three-year studentship. Further work will focus on fabrication of the capsules and understanding of the composite behaviour under RF conditions in order to make the treatment applicable for clinical trials.