Andrews found inspiration in a burgeoning technology: sensors based on field-effect transistors. Scientists had begun modifying field-effect transistors with protein receptors that could bind small biological molecules. When the receptor snares a target, the electric field around the transistor shifts, which can be read out as a change in current through the device. Unfortunately, the approach is limited in biological environments like the brain by something called the Debye length—the farthest away a molecule can be from the transistor and still be detected. The greater a solution’s ionic strength, the shorter the Debye length because ions obscure the field effects created when the molecule binds to a receptor.
by Erika Gebel Berg |
September 06, 2018