Fiber Optic Biosensors for Hazardous Material Analysis and Monitoring

There are a wide variety of needs for improved monitoring and analysis of trace chemicals in several different industries. These needs are increasingly being addressed with immunoassays specific of individual analytes or for restricted chemical classes. The sensitivity, selectivity, and cost of standard assay kits has earned wide acceptance for this approach. Relatively recently, some immunosassay for chemically hazardous materials such as pesticides, polychlorinated biphenyls, and petroleum hydrocarbons have become commercially available. Our work will combine immunoassay techniques with evanescent-wave fiber-optic fluorescence spectroscopy to fabricate a continuously operating sensor. The ability of evanescent-wave spectorscopy to discriminate between fluorescent molecules on the surface of the fiber probe and those in the bulk solution eliminates the need for a washing step. Our work will combine the picomolar sensitivity of previously demonstrated fiber-optic immunoassays with a semipermeable membrane to contain the immunoreagents in a continuously operating probe. This type of sensor will, therefore, retain the advantages of selectivity and sensitivity offered by immunoassay. The capability ot function as a continuously operating probe while retaining this level of performance, however, opens up significantly new opportunities not offered by any existing technology.