A protein-coated electrode offers a sensitive test for people with gluten intolerance.

Thomas Balkenhohl and Fred Lisdat at the University of Applied Sciences Wildau in Germany have invented a sensor that detects antibodies involved in coeliac disease. Coeliac disease is an autoimmune reaction to gluten - found in wheat, rye and barley - that prevents the absorption of essential nutrients in the gut.

The method works by immobilising gliadins, proteins found in gluten, on the surface of gold electrodes. People with coeliac disease produce antigliadin antibodies in reaction to gluten. When the electrodes are immersed in blood serum samples from coeliac sufferers, these antibodies bind to the gliadins and the electrodes' electrical properties change in proportion to the antibody concentration. The method is even sensitive enough to detect antigliadin antibodies in samples taken from people who do not suffer from coeliac disease. Balkenhohl and Lisdat have transferred their system to screen-printed electrodes, which will allow the sensors to be mass produced.

Coeliac disease prevents essential nutrients being absorbed in the gut

But antigliadin antibodies are not the whole story. Anti-tissue transglutaminase antibodies, which are currently not detected by the system, are also implicated in coeliac disease. Being able to detect both antibodies will guarantee improved sensitivity and specificity of the test, said Lisdat. And more work needs to be done on the electrical measurements, which are 'still limited to an advanced laboratory,' he warned. The duo hopes that more practical methods will be developed as the technique is used for different kinds of biochemical detection.

Colin Batchelor