Thermoregulation System for Biosensors Based on Field-Effect Transistors with a Nanowire Channel

In this work, an automatic thermoregulation system for biosensors based on field-effect transistors with a nanowire channel is demonstrated, providing full control and maintenance of the required temperature regime in bioanalytical analyses. The system elements, including field-effect transistors with a nanowire channel, temperature sensors, and heaters, were fabricated on a single silicon crystal using electron beam lithography, reactive ion etching, and high-vacuum deposition techniques. Unique electronics for temperature control and maintenance were developed. 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, ensuring the establishment of a desired temperature in the range from 30 to 70 degrees C within 18 s in a liquid medium, was carried out. A demonstration of a thermoregulation system for detecting nucleic acids was performed using synthetic single-stranded DNA, representing a gene fragment from the bacterium Escherichia coli. The minimum detectable response was observed for a sample with a concentration of 3 fM.