US scientists have designed a chip that can analyse chemical changes in the brain.

Nicholas Cellar and Robert Kennedy at the University of Michigan have made a sensor that can be used to monitor levels of neurotransmitters in vivo. Kennedy says the device could be used by neuroscientists to study chemical changes associated with behaviour and disease.

Chip to analyse changes in the brain

Kennedy described how the chip has been adapted to allow users to analyse brain chemicals remotely. Nanolitre samples of fluid are taken from the brain and flow into channels in the device. Here the neurotransmitters react to form fluorescent products which are separated and then detected externally.

'The chip combines sampling, on-line analysis, high efficiency separation and low detection limits,' Kennedy explained. It makes it 'possible to monitor chemicals in the complex environment of the central nervous system, with high selectivity and sensitivity over extended periods.'

James Landers, an expert in bioanalytical chemistry at the University of Virginia, US, welcomed the findings. 'This work shows that what has been done in the past in capillary-based systems can be achieved on-chip without loss of resolution or sensitivity. Such integrated systems represent an important element in the future of analytical techniques that will be used to interrogate biological systems,' said Landers.
 
Kennedy explained that 'at present, the chip can detect five neurotransmitters but, since there are over 200 neurotransmitters, there are many more assays to develop.'

'In the future, it may be possible to use the device to assess brain damage in people with trauma injuries as the sensor could look at small regions of the brain or probe multiple regions at once,' said Kennedy. 'It may also be a way of delivering drugs to particular brain regions.'

Alison Stoddart