Investigation of Electrical Stability and Sensitivity of High Field Modulated Extended Gate FET Biosensors for miRNA Detection

Abstract

miRNAs have been proven to be highly potential biomarkers for a variety of cancers and cardiovascular diseases. Typically miRNA detection method uses polymerase chain reaction (PCR) to amplify the miRNA concentration. This method has the disadvantage of being time-consuming and unable to directly detect the original concentration. Therefore, this study intends to design a FET biosensor to detect miRNA. In order to design a stable and highly sensitive miRNA FET biosensor, this study used different metal deposition techniques to form sensing electrodes and observed sensor response in different temperatures and aqueous solutions to evaluate the fluctuation of the electrical signal, and found that the ions in the solution will follow the mechanism of Brownian motion. While the Brownian motion reduces, the stability of the electrical signal will be improved. Then we used different concentrations of ssDNA probe to functionalize the sensor chip to detect target miRNA concentration, to compare the dynamic range and sensitivity. The optimization can help us to make a miRNA FET biosensor with high sensitivity, high stability and large detection range. Finally, the target detection experiments with the mismatch sequence demonstrate the high selectivity of the sensor. Comparison of ELISA based fluorescent signals with FET signals shows that FET biosensors have better detection limits. These data proved that the miRNA FET biosensor can directly measure the original concentration of miRNA without amplifying the concentration by PCR, which can effectively solve the problems faced by miRNA detection in the present time. Figure 1