ELECTROCHEMICAL AND FIBER OPTIC BIOSENSORS FOR HIGHLY SELECTIVE MOLECULAR TARGETING

Ultrasensitive and specific biosensors have been developed in our group, based either on electrochemical or optical transducers closely associated with a sensing layer including specific immobilized enzyme systems. H2O2 generated in enzymic reactions catalyzed by oxidases, could be either detected electrochemically on a platinum electrode or optically monitored in the presence of peroxidase using luminol mediated chemiluminescence. The detection of ATP and NAD(P)H involved in numerous analysis of biological samples could be also achieved at the picomole level with photobiosensors using bioluminescence enzymes either from firefly or bacterial origin. By using auxiliary enzymes in combination with these enzymic systems, the stereoselective detection of variety of analytes could also be conducted in complex mixtures. No pretreatment of the sample, even turbid, was required, avoiding difficulties encountered when classical spectroscopic methods are used. Only a few microliters of sample were necessary making such devices attractive in various domains of biotechnology, biomedical engineering or environment control.