Putting a Spin on Parasites; July 1993; Scientific American Magazine; by Tim Beardsley; 1 Page(s)

Adrian Parton used to spend his days pondering molecular biology. Then, in 1991, he heard a talk given by biophysicist Ronald Pethig of the University College of Wales, in which he described how electric fields can be used to manipulate particles. That set Parton, who works for Scientific Generics, a technology consulting firm in Cambridge, England, thinking about rotating fields.

A rotating electric field--easily produced from four electrodes--creates a torque on small particles that can make them spin if the frequency is right. Parton has shown that the effect can function as the basis for an extremely sensitive assay to detect microscopic parasites and even single biological molecules. Co-inventors Parton and Pethig call it the electrorotation assay.