BIOSENSOR SURFACE CHARACTERIZATION - CONFIRMING MULTILAYER IMMOBILIZATION, DETERMINING COVERAGE OF THE BIOSPECIES AND ESTABLISHING DETECTION LIMITS

Sensor behaviour is strongly influenced by the surface geometry and mo rphology of the immobilised biolayer. In a non-amplification system th e detection limits are primarily determined by the number of active bi omolecules immobilised on the transducer. It is critical to be able to measure this number in a reliable and reproducible manner for sensor characterisation. Without this information, sensor to sensor calibrati on cannot be performed and the system detection limits are not known. A routinely used immunological assay, enzyme-linked immunosorbent assa y (ELISA), can be modified and used to detect the total number of mole cules and the number of active molecules immobilised on a variety of s urfaces. In conjunction with other surface techniques, scanning electr on microscopy (SEM) and ellipsometry, the modified ELISA technique is a useful analysis tool for biosensor characterisation. (C) 1997 Elsevi er Science S.A.