31 October 2011

Physicists rethink cancer treatments

Physics and medicine are collaborating on new groundbreaking research on cancer treatments. At the Niels Bohr Institute, Lene Oddershede, who heads the biophysics group Optical Tweezers, has received a grant of 2½ million kroner from the Lundbeck Foundation along with assistant professor Poul Martin Bendix and professor Andreas Kjær from the Panum Institute. Together they will investigate an entirely new method using tiny gold particles to treat cancer.

Lene Oddershede, who heads the biophysics group Optical Tweezers, has received a grant of 2½ million kroner from the Lundbeck Foundation to investigate an entirely new method to treat cancer.

Cancer treatments have not changed significantly over the last 30 years, where the progress has consisted primarily of small steps in improving the standard chemotherapy or radiation therapy. There have been no revolutionary new treatment methods. There is hope for this with a brand new research project, with physicists on the job.

"As physicists we think differently than they do in medical field. While medicine tries to understand cancer from chemistry and biology, we look at living cells as a material that can be controlled using methods and principles of physics”, explains Lene Oddershede.

Kills diseased cells

Lene Oddershede and her research group are researching how to use tiny gold beads as a tool to increase the temperature locally and kill the diseased cells. The gold beads are between 50 and 80 nanometers in size. A nanometer is one millionth of a millimeter. The extremely small gold particles are captured using optical tweezers, which is an advanced instrument that holds the beads with an extremely laser light. The beads absorb the infrared light from the optical trap and heat up. In experiments, the researchers have moved this hot bead close to a membrane consisting of lipids resembling a cellular membrane. The heat from the gold particles causes the lipid membrane to melt. Likewise, the heat from the irradiated gold particles will probably cause cellular membranes in living cells to melt and then the cell dissolves and dies. It is this effect they want to use to kill cancer cells. 

”In experiments we will introduce nano gold particles into cells and illuminate them from the outside using laser light and by turning the laser light up and down you can presicely control the heat. The heat is very localised so only the cells in the immediate vicinity of the irradiated gold beads die”, explains Lene Oddershede.

The next step is to experiment on mice with cancerous tumours. By injecting the gold particles into the bloodstream they will spread through the body and into cells where they will be absorbed because they are so small. Cancer cells will absorb many of the gold beads because the cancerous tumours create new blood vessels, so they get extra supplies of blood and also act as a sieve for the gold particles.

When the gold beads are absorbed you can ‘shoot’ the tumours with focused laser light, which then heats the gold beads. The heat will then most likely dissolve the lipid membranes of the cancer cells and the cells will die. Only the cancer cells die – while the healthy cells are not affected by the treatment because they have not been irradiated by the laser light. The research project starts 1. January 2012.