Uses of biosensor technology in the development of probes for viral diagnosis

Background: Since 1990, a new biosensor technology based on surface plasmon resonance makes it possible to visualize molecular recognition as a function of time, in terms of change in mass concentration occurring on a sensor chip surface. One of the reactants is immobilized on a dextran matrix while the other is introduced in a flow passing over the surface. The binding is followed in real time by the increase in refractive index caused by the mass of bound species. Objectives: In the present review, the applications of this new technology for developing probes intended for viral diagnosis will be described. Study design: In contrast with other immunoassay systems, the biosensor technique preserves the conformational integrity of the reactants since no labelling is required. It also makes it possible to follow every step of a multiple-layer assay and allows interaction measurements in real time. Suitable antigen and antibody probes can be selected on the basis of the conditions of the diagnostic assay that is being developed, especially in terms of affinity and specificity. Results: Our results suggest that when the cyclic peptide 209-222 of the E1 protein of hepatitis C virus (HCV) is immobilized on the sensor chip via a biotin moiety, it retains a constrained conformation which is better recognized by HCV antibodies than the linear form. Data are presented which indicate that the biosensor technique facilitates the screening and selection of anti HIV-I antibodies that are likely to possess the most potent neutralizing potential. Conclusion: Since there is a good correlation between BIA core and ELISA data, it seems likely that the biosensor technology will be increasingly used for developing reagents intended for viral diagnosis.