'Drops' of Gold Burn Tumors

New research into the detection and treatment of cancer has emerged that uses gold nanoparticles illuminated with laser light.

The idea is to introduce gold nanoparticles into tumor cells, to which laser light would subsequently be applied. According to French researcher Romain Quidant, who made the discovery, the nanoparticles would then heat up to such a degree that the damaged cells would be completely burned.

Nanoparticles are metal structures that measure just one millionth of a meter with a diameter 10,000 times less than that of a hair. What is revolutionary about this novel use of nanoparticles is that they can be designed such that they penetrate only damaged cells. Thus, the treatment would affect tumor tissues without damaging healthy ones, in contrast to chemotherapy and radiotherapy.

The interaction between gold nanostructures and light is useful not only for the treatment of cancer but also for its diagnosis. Universitat Politècnica de Catalunya.

The system is based on the twofold outcome of the nanoparticle engineering carried out by the researchers. Firstly, the nanoparticles must be able to recognize damaged cells and, secondly, they must become excellent nanosources of heat. The former is achieved by coating the nanoparticles with molecules that detect and go into the cancer cells. In the latter case, the minute metal structures are designed so that their shape optimizes the generation of heat in response to an external light source.

The project is still at the experimental stage and is being undertaken in collaboration with experts in medicine and biology. One of the key processes in the experimental work is the selection of the particles from the damaged cells, which are inserted once their possible toxicity has been minimized. In principle, gold is biocompatible and is readily evacuated by body fluids, but the researchers must make sure that the chemistry involved in the process does not affect the cells.

A nanolaboratory in a drop of blood

The interaction between gold nanostructures and light is useful not only for the treatment of cancer but also for its diagnosis. Quidant is working on a chip that is made up of a multitude of metal nanostructures that are able to send a light signal when they come into contact with cancer markers.

This “nanolaboratory” performs a vast number of analyses in parallel from a single drop of blood. Each metal nanostructure is coated in molecules (receptors) that are able to recognize and trap a specific cancer marker. When this happens, the nanostructure responds to the external light in a way that is different from when no markers are trapped.

Quidant’s team has already developed a nanosensor prototype designed to detect doping substances in the blood, such as the steroids used by some athletes.

The main advantages of this type of device are its small size (which makes it easy to use in developing countries where there are no laboratories, for example) and its great sensitivity, which enable it to detect cancer in its early stages, when there is a low density of markers.

Quidant anticipates that the detector will be ready within the next 10 years and that its applications will range from agrofood controls to the detection of hazardous industrial substances.

Recently awarded the 2009 Fresnel Prize, which recognizes the highest level of excellence among emerging researchers in the field of photonics, Quidant is an ICREA researcher at the Universitat Politécnica de Catalunya Institute of Photonic Sciences (ICFO) and a fellow of the Cellex Foundation Barcelona.

Quidant is among the leading researchers of a strategy called “plasmonic oncology” that some say will revolutionize cancer treatment. He is working on this research program thanks to the support of the Cellex Foundation Barcelona.

For more information, visit: www.upc.edu