EVA - Evanescent Biosensor Technology
The EVA-Biosensor Technology is an innovative biosensor technology with the potential to replace ELISA test (Enzyme Linked Immunosorbent Assay) - today’s standard test method. The EVA-Biosensor Technology overcomes the disadvantages of ELISA - especially the long measurement time is shortened to 10minutes and the multiple washing and manipulation steps are reduced to very few steps. The advantages however, namely the high sensitivity and specificity of ELISA are maintained.
EVA-Biosensor Technology: The exciting light beam is reflected under TOTAL INTERNAL REFLECTION (TIR) at the liquid - solid interface at the bottom of a well of a biosensor chip (Fig. a). By this optical phenomenon a 200 nanometer bottom layer of the adjacent liquid is illuminated. Only fluorophors localized in this EVANESCENCE FIELD will absorb and emit photons – independent of other background molecules present in the liquid as liquid above the 200nm range is not illuminated at all.
The EVA-Biosensor Technology exploits the advantage of the optical phenomenon of evanescent fluorescence excitation that leads to maximal sensitivity and highly optimized signal/noise performance. In addition, this technology is suitable also for simultaneous multiple parameter testing as required in allergy and other diagnostic test. The test volume is 20 microliter per well economizing on reagents. There is neither biochemical nor optical crosstalk between individual wells.
Davos Diagnostics can directly profit from 40 years existence of ELISA-tests and more than 3000 different commercially available ELISAs. Davos Diagnostics has the expertise to convert existing ELISAs directly to an EVA-Tests by using fluorescently labeled conjugates instead of the enzyme conjugate. Biochemical compatibility with existing ELISA protocols is achieved by using the identical polystyrene for manufacturing EVA-Chips as used for standard microtiterplates. Processes and protocols such as coating, washing, blocking and drying procedures are identical to the well-established ELISA technology.