Traditional bacterial cultures often take days to analyze, and the amount of detail of the results is usually limited by the power of an optical microscope, about 250 nanometers. However, a new biosensor developed at the University of Michigan is able to measure the growth of a single bacterium over just a few minutes.
The device, called an asynchronous magnetic bead rotation (AMBR), uses the laws of circular motion as the basis for detection. The sensor uses a spherical, magnetic bead that asynchronously spins in a magnetic field. Anything attached to the bead will affect the way it spins by creating drag, and slows its rate of rotation. According to the researchers, simply attaching one bacterium causes the bead to slow by a factor of four, and any growth greater than 80 nanometers causes the bead to slow even more.
Such technology could have great implications not only on the study of bacteria, but also antibiotic activity on bacteria, as well as monitoring the growth of yeast, cancer, and other cells.
Article @ University of Michigan: See how they grow: Monitoring single bacteria without a microscope…
Abstract in Biosensors and Bioelectronics: Monitoring the growth and drug susceptibility of individual bacteria using asynchronous magnetic bead rotation sensors