Self-Assembled Biosensors on a Solid Interface for Rapid Detection and Growth Monitoring of Bacteria

Developing rapid methods for pathogen detection and growth monitoring at low cell and analyte concentrations is an important goal, which numerous technologies are working towards solving. Rapid biosensors have already made a dramatic impact on improving patient outcomes and with continued development, these technologies may also help limit the emergence of antimicrobial resistance and reduce the ever expanding risk of foodborne illnesses. One technology that is being developed with these goals in mind is asynchronous magnetic bead rotation (AMBR) biosensors. Self-assembled AMBR biosensors have been demonstrated at water/air and water/oil interfaces, and here, for the first time, we report on self-assembled AMBR biosensors used at a solid interface. The solid interface configuration was used to measure the growth of Escherichia coli with two distinct phenomena at low cell concentrations: firstly, the AMBR rotational period decreased and secondly, the rotational period increased after several division times. Taking advantage of this low cell concentration behavior, a 20% signal change from the growth of E. coli O157:H7 was detected in 91 \pm 4 minutes, with a starting concentration of 5 x 103 CFU/mL. Such a rapid cell growth sensor could dramatically improve the detection time and sensitivity in applications requiring phenotypic testing of target cells.