Nanoparticles as a vehicle for delivering drugs precisely where they are needed promise to be a major revolution in medical science. Unfortunately, retrieving those particles from the body for detailed study is a long and involved process. But that may soon change with a team of engineers at the University of California, San Diego developing a technique that uses an oscillating electric field to separate nanoparticles from blood plasma in a way that may one day make it a routine procedure.

At a scale hundreds of times smaller than the width of a human hair, nanoparticles are so small and of such low density that separating them from blood plasma currently relies on some fairly brute force methods. Usually, this involves adding a chemical tag to the particles or diluting the plasma while adding a high concentration sugar solution, then spinning the mixture in a centrifuge.