Getting blood test results can take anywhere from a 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.

 …