Direct electrical detection of target cells on a microfluidic biochip

Pathogenic bacterial cell detection is currently performed using techniques such as culture enrichment and various plating methods, which are expensive and can take up to several days. In this study, we describe the design, fabrication, and testing of a rapid and inexpensive sensor for detection of target cells electrically in real-time. The sensor operates with the use of microelectrodes integrated in a micro-channel. As a proof of principle, we have successfully demonstrated real-time detection of target yeast cells with a concentration of 107 cells/ml. We have also demonstrated the selectivity of our sensors in responding to target cells while remaining irresponsive to non-target cells. We also perform theoretical modeling in order to determine the ultimate detection limit of the sensor. Based on our modeling results, proper optimization of the sensor can yield detection limits approaching the single cell level.