Internal memos

UK researchers are developing implantable medical sensors powered by body movement.

UK researchers are developing the next generation of implantable medical sensors, powered by body movement and miniaturised fuel cells, which will be able to tell the difference between a heart attack and a bout of exercise.

A team at Imperial College will develop the wireless sensors, which will combine information on the patient’s physical activity, such as running for a bus, with vital signs such as ECG, blood oxygenation level and temperature, to produce a detailed picture of their condition.

The sensors could be used to monitor patients after surgery and those on complex drug regimes such as chemotherapy, as well as people with chronic diseases including diabetes, heart or lung disease.

By detecting a range of chemicals within the body they could even monitor mental health patients to ensure they are complying with their drug treatment.

Developing an adaptable network based on multiple sensors will help reduce false alarms, according to Morris Sloman, professor of distributed systems management at Imperial and the project’s leader. ‘Some heart surgeons have told us that if your heart is being monitored and you vigorously brush your teeth, that can be detected as a heart attack and the defibrillator could give you a shock,’ he said.

The network will be capable of configuring itself by automatically detecting which sensors are available and if any are faulty.

As the aim is to implant the sensors in the body, frequent battery changes will not be possible. So the researchers will develop electronics and novel algorithms to reduce the power consumed by the devices. The team will also build on world-leading research previously carried out at the university into energy scavenging devices, to develop a system to use the motion and vibration of the body or heart to generate energy. The researchers hope to produce a motion scavenging device just a few millimetres in size.

The implanted sensors will use ultra-wideband technology to communicate, and to reduce power use will transmit information through the skin to an on-body relay device.

The team will work with companies including Tyco, Cardionetics, Docobo, ultra-low power chip developer Toumaz Technology, and medical technology specialist Medtronic, which develops implantable heart sensors.

The university’s bioengineering department is also developing a millimetre-scale biofuel cell to generate power from glucose oxidation in the blood. The biofuel cell is to be commercialised, and work on this will form part of the project.