A Digital Microfluidic Biosensor for Multianalyte Detection

A microfluidic lab-on-chip (LoC) for measuring the concentration of human body metabolites, using submicroliter droplets as reaction chambers, is presented in this paper. The device is based on the manipulation of droplets using the principle of electrowetting and is integrated with an optical absorbance measurement system for detection. We have demonstrated the detection of glucose using a colorimetric enzyme-kinetic assay in less than 40 seconds. The sensor response is linear in the range of 25mg/dl to 300mg/dl, with less than 5% deviation from linearity at the upper limit. In addition to glucose, we have also demonstrated the feasibility of lactate, glutamate, and pyruvate assays using our system.