There is a definite interest to create lab-on-a-chip devices which are able to identify chemicals quickly, cheaply, and with small samples. Researchers across the planet are working towards these devices that will cut medical costs and save lives, and now researchers at MIT have developed a new approach that is quite innovative. Instead of relying on specific chemical reactions within microscope channels, this new technique looks at vibrating magnetic beads, which are already used in biomedicine.
This new method starts by coating the magnetic beads with a biomolecule that attaches to other molecules in a sample, but only a specific kind of molecule. As the molecules attach, the volume of the bead increases, which alters the friction on it as it moves through a fluid. The beads are then subjected to magnetic domain walls, which are essentially very powerful and localized magnetic fields that will isolate a single bead from another. By moving the field and watching the bead's movement, the researchers are able to determine how much of the targeted biomolecule is present in the sample.
There are several advantages to this approach over other methods, including its reusability. The device that creates the magnetic fields is separated from the sample and it is the beads which determine what biomolecule is detected. Instead of changing the entire device for a new test, the sample can simply be flushed out and new beads used.