A Self-Contained, Nano-Gap Biomolecule Impedance Sensor with Fluidic Control System

摘要

A sub-50nm biomolecular direct electrical-detection structure integrated with micro- and nano-fluidic systems has been constructed. These devices are composed of integrated microfluidic channels in PDMS and nanofluidic channels in silicon oxide. These in turn are all integrated with a nano-gap sensing structure which has metallic electrodes. The microfluidic channel in PDMS provides access to the nanofluidic channel feeding the nano-gap sensing structure. We provide a demonstration of the bio-molecular sensing capabilities of our device by using the carboxyl-amino group interaction and a nano-gap structure with gold electrodes. First, probe molecules with amino groups are infused through the fluidic system to the nano-gap and are self-assembled onto the gold electrodes via thiolate bonding. Then target molecules with terminating carboxyl groups are infused to bind with the probe molecules. Impedance changes are measured electrically at each infusing and binding step using an Agilent 4284A impedance analyzer thereby detecting the appearance of each molecule type as it passes through the system. We are able to detect about 15% impedance changes with the carboxyl-amino binding occurrence.