Microsystems Technology: Jack of Medical Trades (Part 1)

by Wiebke Heiss / MEDICA.de

Actually, it is a made-up-word: microsystems technology. In fact, the term describes many things as long as they are optical, mechanical or electrical and as long as the systems are tiny. Moreover they hover around everywhere: In CD players, airbags or printers - and with great potential in medical applications.15/03/2009

When Jörg Müller thinks of microsystems technology, a huge playground will come to his mind. This seems natural as the professor at the Hamburg-Harburg University of Technology in Germany and his colleagues do research on several projects to their heart’s content in order to gain control of clinical problems. The research efforts seem not to be totally free from selfish motives, though: “In the worst case I also benefit from my projects”, he says and laughs. The head of the institute of microsystems technology might have been thinking about aching ears: Scientists are developing a measuring system which supports the treatment of chronic middle ear inflammation.

To control the healing of wounds in the middle ear the doctor has to measure the prevailing pressure at the ear drum. “But the thin membrane is extremely sensitive”, Müller explains. Therefore, the measuring system has to be tiny, for instance an ultra-thin silicone foil with an ultra-thin metal stripe on it. In the case of high pressure the measuring stripe in the middle ear curves outward, in the case of low pressure it curves inward. The doctor receives the measured data wireless via radio frequency signals. At the same time the foil is to support the healing “by generating electric currents in the ear drum”. This may speed the transport of healthy cells to the wound which helps the membrane to cure faster.

Stability copied from the bee

Moreover, Müller and his colleagues want to take away the horror of one of the most feared strokes of fate: paraplegia. Each year about 1,800 people become wheelchair-bound in Germany for the rest of their lives as a result of accidents or diseases. That is due to the fact that after a spinal cord injury the nerves do not grow together, but scar over. Müller and his colleagues want to avoid that “by offering the nerve cord a mechanical construction”. Therefore, engineers have developed a pinhead-sized ring with a stabilising honeycomb structure in its inner circle. Right in the centre, there is a tiny cavity which is only 200 micrometres small. The cut nerve endings come together there, after the whole spinal nerve cord was sucked into the ring from both ends via generating a pressure difference.

To make sure that the nerves really grow together, chemicals are led to the meeting point of the nerves via tiny tubes. These are to avoid cicatrisation on the one side and encourage cell growth on the other side. Rat experiments have already shown that cut spinal cord grew through the ring instead of scarring over as usual. Although the rats could not move like before, the test results are promising. “We hope that we will be able to cure paraplegia via micro systems technology one day”, says Müller. In two years at the earliest, tests will be carried out with patients.


- Part 1: Jack of Medical Trades
- Part 2: Most important - being tiny