While microfluidic devices that can help detect disease biomarkers can get pretty small, they often require a microscope to read the results, negating the size advantage. Researchers at Georgia Tech have developed an electronic sensor that can detect cancer cells flowing through many channels of a microfluidic device simultaneously. The ability to use a single electronic signal to spot more than one cell at a time across the different channels was possible by borrowing data encoding techniques from CDMA, the data transmission alternative to GSM that’s used by Verizon and Sprint for cell phones on their networks in the U.S.
The sensor measures the change in the impedance as a cell passes through a channel covered by an electric field. This provides the ability to identify the size of the cell, as well as where it is on the sensor and how fast it’s moving.
The team was able to identify ovarian cancer cells to an accuracy of at least 90% using the prototype technology, potentially improving that much closer to 100%.
From the study abstract in journal Lab on a Chip:
In this paper, we introduce a scalable electronic sensor technology, called microfluidic CODES, that utilizes resistive pulse sensing to orthogonally detect particles in multiple microfluidic channels from a single electrical output. Combining the techniques from telecommunications and microfluidics, we route three coplanar electrodes on a glass substrate to create multiple Coulter counters producing distinct orthogonal digital codes when they detect particles. We specifically design a digital code set using the mathematical principles of Code Division Multiple Access (CDMA) telecommunication networks and can decode signals from different microfluidic channels with >90% accuracy through computation even if these signals overlap. As a proof of principle, we use this technology to detect human ovarian cancer cells in four different microfluidic channels fabricated using soft lithography.
Here’s a short Georgia Tech video report about the technology:
Study in Lab on a Chip: Microfluidic CODES: a scalable multiplexed electronic sensor for orthogonal detection of particles in microfluidic channels…
Via: Georgia Tech…