Getting results from a blood test can take anywhere from one day to a week, depending on what a test is targeting. The same goes for tests of water pollution and food contamination. And in most cases, the wait time has to do with time-consuming steps in sample processing and analysis.
Now, MIT engineers have identified a new optical signature in a widely used class of magnetic beads, which could be used to quickly detect contaminants in a variety of diagnostic tests. For example, the team showed the signature could be used to detect signs of the food contaminant Salmonella.
The so-called Dynabeads are microscopic magnetic beads that can be coated with antibodies that bind to target molecules, such as a specific pathogen. Dynabeads are typically used in experiments in which they are mixed into solutions to capture molecules of interest. But from there, scientists have to take additional, time-consuming steps to confirm that the molecules are indeed present and bound to the beads.
The MIT team found a faster way to confirm the presence of Dynabead-bound pathogens, using optics, specifically, Raman spectroscopy. This optical technique identifies specific molecules based on their “Raman signature,” or the unique way in which a molecule scatters light.
Read more at Massachusetts Institute of Technology
Image: Caption: Dynabeads, which are antibody-coated superparamagnetic beads, served as a strong Raman reporter for the simultaneous capture and detection of pathogenic bacterium such as Salmonella. This image shows the Dynabeads (grey spheres) interacting with Salmonella bacterium (in green). The inset shows the Y-shaped antibodies coating the Dynabeads. Credits: Image: Courtesy of the researchers