Suchergebnisse

We present a CMOS compatible technique for fabrication a sensor system based on field-effect transistors
with a nanowire channel with an integrated thermoregulation elements. 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 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 occurs most efficiently allows increasing specificity and avoiding false
positive results, as well as reducing analysis time. The possibility of heating up to 85–90∘C allows you to
reuse such devices.

In this work we present an automatic thermoregulation system for biosensors based on field-effect transistors with a nanowire channel, which provides full control on the required temperature regime in bioanalytical analises. The system elements, including field-effect transistors with a nanowire channel, temperature sensors and heaters, were fabricated on a single silicon cristal using electron beam lithography, reactive ion etching and high-vacuum deposition techniques. Unicue electronics have been developed to control and maintain temperature. The dependence of thermometer readout on heating power was measured, which is in good agreement with the results of numerical simulation. A demonstration of a thermoregulation system with PID-feedback was carried out, ensuring the establishment of a desiered temperature in the range of 30-70◦ C in 18 s in liquid. A demonstration of a thermoregulation system for detecting nucleic acids was carried out using synthetic single-stranded DNA, which is a gene fragment from the bacterium Escherichia coli. The minimal detectable response was observed for a sample with a concentration of 3 fM.