Asynchronous Magnetic Bead Rotation In Microfluidic Droplets for Monitoring Cell Growth

The rapid identification and characterization of bacterial pathogens is an important goal for point-of-care diagnostics. Droplet-based lab-on-a-chip systems decrease analysis time and allow for higher levels of throughput because each droplet acts as an isolated reaction chamber. We demonstrate an asynchronous magnetic bead rotation (AMBR) droplet system for single cell and colony growth studies. By monitoring a magnetic bead’s asynchronous frequency response to a rotating magnetic field, the continuous growth and division of individual bacterium and the growth of a small bacterial colony can be observed. The sensitivity of the combined AMBR droplet microfluidics system reduces minimum inhibitory concentration (MIC) measurement time from days to minutes. This technology provides a single cell, as well as a colony analysis platform, that can be used for rapid, high-throughput characterization of individual bacteria or bacterial colonies.