Development of a capillary based Helicobacter hepaticus biosensor

Helicobacter hepaticus is a bacterium that causes chronic active hepatitis in mice. Infections with H. Hepaticus can invalidate research studies. Early detection is necessary to curtail the spread of infection. Current sensing mechanisms are time consuming and not suitable for preventative diagnostics. The objective of this study was to develop a quick and accurate biosensor platform for the detection of H. Hepaticus in fecal samples.; This research investigated an optical immunosensor using capillary waveguides. A competitive immunoassay was adapted for use in this biosensor. H. Hepaticus was immobilized to the inner wall of the capillary. A fixed amount of H. Hepaticus antibody was conjugated to Alexa Fluor 546 to serve as the fluorescent tracer and added to samples containing H. Hepaticus. Sample H. Hepaticus (analyte) bound to the antibodies in solution, thereby preventing the antibodies from attaching to the immobilized H. Hepaticus. An increase in sample H. Hepaticus decreased the number of antibodies bound to the capillary wall and increased the number of antibodies in solution. Several methods were utilized to analyze the fluorescence resulting from the immunoassay. Sample mixture analysis analyzed the labeled antibodies remaining in solution and had a 10 ng minimum limit of detection. Immobilized capillary analysis examined the amount of labeled antibodies bound to the capillary walls and had a 1.0 ng minimum limit of detection with an assay time of approximately one hour. The biosensor was shown to reliably detect low levels of H. Hepaticus in a fast and reliable manner.