Label-free electrical detection of antigens based on micro-channel gating

Current microbiological techniques used for multi-analyte detection, necessary for medical diagnostics, involve expensive and time consuming methods based on sandwich immunoassays. Described below is the design, fabrication, and testing of a rapid and inexpensive sensor, involving the use of microelectrodes in a micro-channel, which can be used to detect target antigens electrically (label-free format) in real-time. As a proof of principle, we have successfully demonstrated real-time detection of target antigens by measuring instantaneous changes in ionic impedance. We have also demonstrated the selectivity of our sensors in responding to target antigens while remaining irresponsive to non-target antigens. Using this technique, an array of these sensors can be multiplexed onto a biochip and used to detect the various biomarkers present in a complex mixture.