Evanescence wave-based technology for the rapid and sensitive quantification of biological analytes

Abstract

Time has become the most crucial factor in modern precision medicine. The quick availability of the results of diagnostic procedures has direct economic consequences in all clinical settings, and especially in emergency-medicine laboratories, where results are required as soon as possible to ensure an immediate initiation of the correct medical treatments. 1 Currently immunoassays are powerful and sensitive technologies widely used for in vitro diagnostics (IVD), analyses of biomarkers for the prediction of outcomes and disease endotyping as tools of precision medicine, as well as in research and development. 2 Since the first description of a radioimmunoassay in 1959, 3 many modifications of the radioimmunoassay in different formats including enzyme-, chemiluminescence-, or fluorescence-linked assays have been described. 4 Classical ELISAs are still eminently suitable for both research and development and IVD applications due to a high flexibility, sensitivity, and specificity. They represent the criterion standard for the detection of many biomarkers and include numerous heterogeneous assay formates. 4 Technical aspects of ELISA such as antigen or antibody coating, buffer compositions, detection chemistry, substrates, automation, and assay standardization have been developed thoroughly, making ELISA a well-characterized and validated technology. Despite excellent performance in terms of sensitivity and specificity, ELISA suffers from a time-to-results of several hours due to the long incubation time and multiple washing steps. Moreover, the technology relies on end-point measurements, which depend on Detector Penetration depth 200nmLight intensity Distance from the surface