Thermal method measures microscopic particles

The technique, developed at North Carolina State University, the University of North Carolina at Chapel Hill and Marquette University, is claimed to be less expensive than light-based techniques and can be used on a wider array of materials than electricity-based methods.

’We launched this study purely out of curiosity, but it’s developed into a technique that has significant advantages over existing methods for counting and measuring the size of microscopic objects,’ said Dr. Glenn Walker, senior author of a paper on the work and an associate professor in the joint biomedical engineering program at NC State and UNC-Chapel Hill.

Particle counters are used in a wide variety of industries; physicians use them to count and identify blood and cancer cells while ink manufacturers use them to ensure consistent toner quality. According to NCSU, the new thermal technique could also lead to new applications.

The researchers built a device in which an extremely narrow plastic tube rests on a silicon substrate. A wire is connected to a single point beneath the tube and an extremely small current is run through the wire, both generating heat that radiates into the tube and measuring the temperature of the tube and its contents.