Array biosensor for simultaneous detection of multiple analytes

The array biosensor has been developed for simultaneous analysis of multiple samples for multiple analytes. A patterned array of capture antibodies is immobilized on the surface of a planar waveguide and a sandwich immunoassay conducted using a cocktail of fluorescent tracer antibodies. Upon excitation of the fluorescent label using a 635 nm diode laser, a CCD camera detects the pattern of fluorescent antigen:antibody complexes on the sensor surface. Image analysis software correlates the position of fluorescent signals with the identity of the analyte. The assays are fast, sensitive, and specific. This immunosensor was used to detect physiologically relevant concentrations of staphylococcal enterotoxin B (SEB), F1 antigen from Yersinia pestis, and D-dimer, a marker of sepsis and thrombotic disorders, in spiked clinical samples. Analysis of blind samples also demonstrated the capability of the sensor to analyze for bacteria, viruses, and proteins in simultaneous assays. Neither clinical fluids nor environmental contaminants create false positives or false negatives. A sensor prototype has been tested which includes a flow cell permanently mounted on the waveguide and a novel fluidics component milled in a plastic cube (1.5 cubic inches). With the miniaturization of the fluidics and electronics, the biosensor fits inside a 1.5 cubic foot case.