A Dna Potentiometic Fet Sensor Based on the Direct Charge Accumulation

This paper reports a label-free field effect transistor (FET) sensor for the detection of DNA hybridization, which measures the surface potential on oligonucleotide modified electrodes using a direct charge accumulation method. The sensor directly and repeatedly transfers the charges that correspond to the surface potential induced by intrinsic negative charges in immobilized molecules, resulting in an improved signal-to-noise ratio (SNR) through the oversampling effect of accumulation and differential architecture. Our sensor offers a stable, robust and reproducible measurement, unlike the previous ion-sensitive field effect transistors (ISFETs). The proposed device is integrated with working electrodes, a reference electrode and readout circuits into one package via a 0.35 μm CMOS process. Our electrical biosensor has great potential as a bio analytical tool for point-of-care diagnoses.