The first fully implantable biochip has been developed by Cambridge University scientists to monitor aspects of a person's metabolism from within their body.
A prototype device to allow diabetics to analyse their blood sugar levels instantly has been successfully tested in vitro at the Institute of Biotechnology.
The invention is proof in principle of a system predicted to play an important role in future health monitoring.
The biochip's creators, Matthew Steinberg and Chris Lowe, professor of biotechnology and director of the institute, have filed a patent application covering the system.
At present, diabetics use disposable plastic strip tests that analyse glucose levels in a spot of blood.
Sufferers from the disease need to know how this biological indicator varies to time the administration of insulin. Seven billion insulin injection kits were sold last year.
Electronic sensors made to date have been bulky and require connections outside the body.
The biochip is 1cm square. It contains a radio frequency inductive coil transceiver that converts a signal from a remote unit into electrical power that enables the device to function.
Enzymes attached to sensors on the device allow it to detect fluctuations in specific biological indicators. The patented version could monitor different signals simultaneously.
The information is then converted into a radio signal that can be picked up outside the body.
This allows analytical measurements to be made in real time.
The biochip could be implanted into the thigh muscle in a simple operation while the remote unit need be no larger than a watch.
The biochip could function as a hypoglycaemic alarm to wake a sleeping patient if their blood-sugar level dropped below a critical value.
Other biochips could monitor vital functions within a patient during anaesthesia or allow athletes to monitor their metabolism during exercise.
The Cambridge team is looking for the funds to back clinical trials of the technology.