Highly sensitive and rapid detection of shigella flexneri in liquid sample by an immunomagnetic assay with shear horizontal surface acoustic wave sensors

A rapid and sensitive method for the detection of Shigella flexneri based on capture of the bacteria with immunomagnetic particles is described. The antibody-specific capture technique on a microfluidic platform is shown based on shear horizontal surface acoustic wave (SH-SAW) sensors. With the specific antibodies conjugated onto the surface of the SH-SAW sensors, the specific protein could be specifically recognized in the regents. SAW sensors vary the SAW phase velocity and attenuation as the target protein captured in the chemical interface with antibody. The chemical interface is chemical or biochemical compounds over the SAW propagation path, and selectively and reversibly interacts with the specific analyte vapor and liquid molecule. The antibody-coated SAW immunosensors exhibited linear frequency responses to the concentrations of anti-IpaB antibodies with sensitivities of 0.6 kHz (3μg/mL). The detection is highly sensitive, these results illustrate that mass change generated from combination of protein and antibody can be utilized in the proposed biosensor to reduce measurement time and cost associated with disease detection.