Most immunoassays are based on the ELISA technique, which uses enzyme-linked antibodies to recognise and detect the substance being measured. Recently ELISA techniques have been combined with biosensors to form immunosensors, in order to increase their range, speed and sensitivity.

A common immunosensor configuration is that in which the biosensor merely replaces the traditional colorimetric detection system with an electrochemical system.

More advanced immunosensors are being developed, however, which rely on the direct detection of antigen bound to the antibody-coated surface of the biosensor. Piezoelectric and FET-based biosensors are particularly suited to such applications, as are other methods based around microchip fabrication techniques.

SSt is primarily interested in electrochemical and electronic immunosensors, where the electronic assay signal can be captured for subsequent processing. These sensors can be combined with MEMS and nanotechnology techniques such as microfluidics.

There is a large amount of research and development effort being put into the development of multi-analyte biosensor arrays, driven largely by the interest in genomics and proteomics testing.

Sensor arrays for genomics and proteomics are often complex and expensive, however, as they have to detect large numbers of targets simultaneously to be of value in these fields.

Many biosensor array technologies could be adapted to perform a relatively small number of tests, providing the potential for low cost arrays for use in future SSt products for a wide range of applications.