The capture of Escherichia coli O157:H7 for Light addressable Potentiometric Sensor (LAPS) using two different types of magnetic beads

Two types of commercially available, streptavidin-coated magnetic beads (SAMB) were labeled with the same biotinylated anti E. coli O157 antibodies. Labeled SAMB and other necessary antibody derivatives needed for Light-addressable Potentiometric Sensor (LAPS) detection were used to capture E. coli O157:H7 in solution. The LAPS signal intensity was then used to determine the overall bacterial capture efficiency. The static and hydrodynamic properties of the beads were then used to correlate with determined efficiencies. It was found that the capture increased as the total mass of SAMB increased. Also, greater capture with SAMB of a higher. density was observed with the same bead mass. In addition, the SAMB of higher density also required less time of rocking to reach a maximum capture. These observations are in agreement with the predictions from the hydrodynamic properties of tested SAMB.