Kinetics of Salmonella typhimurium binding with antibody by immunoassays using a surface plasmon resonance biosensor

This study examined the kinetics of Salmonella typhimurium binding to an antibody using a direct assay and sandwich assay with a surface plasmon resonance (SPR) biosensor. A kinetic model was proposed based on curve-fitting of the experimental SPR sensorgrams using an integral rate equation. The SPR sensitivity in the sandwich assay was significantly higher than that in the direct assay. The association rate constants and affinities of the cell in the sandwich assay were double those in the direct assay. The enhanced binding attraction between the cell and detection antibody in the sandwich assay improved the lower limit of detection.