Abstract
In here, we have devised a portable biosensor system to detect protein-based biomarkers from a single drop of whole blood, in 5 minutes, without any additional sample pre-processing or extra reagents. The sensing methodology is based on electrical double layer (EDL) gated field effect transistor (FET) biosensor, in which an array of gold electrodes designed as extended gate structures, transduce immunological interaction of target protein to readable electrical signal. High electric field modulation of transistor drain current enables very high sensitivity, selectivity and wide dynamic range, in whole blood. Single drop of blood is dropped on the device and blood cells are gravitationally separated from blood plasma during 5 mins of incubation period, by rotating the device orientation to face downwards. A portable sensor measurement unit is designed to record the electrical characteristics of the sensor and display the test results in interfaced personal computer. We have demonstrated the detection of cardiac troponin I (cTnl) and brain natriuretic peptide (BNP) in IX PBS and whole blood samples. The sensor methodology has been developed to considerably reduce cost and assay complexity, with minimal user protocols. This whole blood assay can be performed at the convenience of homes, offices and hospitals, by anyone without prior training, in 5 minutes.