On target

Nanotechnology could be used to improve the treatment of brain tumours by reducing the serious side effects associated with anti-cancer drugs.

Researchers at the University of Nottingham are developing particles 100-200nm in size capable of carrying drugs to tumours without affecting other areas of the body.

Anti-cancer drugs are carried in the blood round the body to slow down or kill the rapidly proliferating cancer cells. But they also attack healthy cells causing side effects such as hair loss, anaemia, liver and stomach problems and an increased risk of infection.

The size of the special particles means they can only move out of the bloodstream at either the tumour or the liver, as the cells of the walls of most other blood vessels are too tightly arranged. Unwanted effects in other areas of the body are therefore prevented.

The nanoscale particles are formed from a mixture of soluble and insoluble polymers. These assemble themselves to create a structure with the insoluble polymer on the inside trapping the anti-cancer drug molecules in the centre, said Dr. Martin Garnett, researcher in drug delivery at the university’s school of pharmaceutical sciences.

The soluble polymer covering the particle significantly reduces the amount of drug taken up by the liver, as its smooth surface means the components of the immune system have nothing to recognise and attach to, ensuring the drug travels to the tumour. ‘It hides the particles from the immune system meaning they circulate for longer, and have a better chance of reaching the disease site,’ said Garnett.After enough time has elapsed for the nanoparticles to reach the tumour, they release the drug through a process of diffusion.

Polymers previously developed for drug delivery were only able to carry small amounts for short periods of time.

While the researchers are now investigating the use of the particles to treat brain tumours, their size should make them suitable for tackling other types of tumour, said Garnett. The aim is to develop the polymers so they can be used with a wider variety of drugs.