Multiplexed label-free biosensor chip based on nanoscale electrical double layer capacitance sensing

Abstract

We report the design, fabrication and testing of a microchip that exploits a capacitive detection scheme for multiplexed label-free biomolecular assays. The detection scheme is based on the nanoscale gap parallel-plate capacitor formed by the electrical double layer at the interface of a metal electrode and an ionic solution, which is sensitive to biological reactions at the electrode surface. Since the nanogap is obtained by electrical and chemical control, no nano-patterning techniques are needed and the simple device structure facilitates sensor readout, multiplexing, and packaging. Finally, this sensing technique is universal and can be applied to detection of diverse biological entities such as proteins and cells. Copyright © 2004 by ASME.