Nanoscale Biosensor with Integrated Temperature Controller for DNA Diagnostics

A CMOS compatible technique for fabricating a sensor system based on field-effect transistors with a nanowire channel with an integrated thermoregulation elements is presented. The proposed system provides the necessary temperature regimes for many bioanalytical studies. Field-effect transistors with a nanowire channel were fabricated using of reactive-ion etching of the upper layer of a silicon on insulator wafer through a mask formed by electron beam lithography. Titanium thermoresistive strips for temperature control were located on the surface of the chip nearby to the nanowire transistors. Their fabrication is carried out simultaneously with the formation of contact pads to the transistor electrodes, which made it possible to avoid additional technological steps. A demonstration of a system with a built-in temperature controller for the determination of nucleic acids was carried out on model oligonucleotides. Increasing the operating temperature of the device to the ranges at which DNA hybridization allows increasing specificity and avoiding false positive results, as well as reducing the analysis time. The possibility of heating up to 85-90 degrees C allows such devices to be reused.