Highly-sensitive graphene field effect transistor biosensor using PNA and DNA probes for RNA detection

DNA probe-based biosensors have been widely developed for detecting a range of analytes. However, the DNA probe-based sensors suffer from many problems, such as long hybridization time, background electrical noise, and relatively poor specificity. In this paper, we report the ultrasensitive detection for RNA by graphene field effect transistor (G-FET) biosensor using PNA and DNA probes. The limit of detection (LOD) of the PNA probe modified G-FET sensor is down to 0.1 aM, which is three orders of magnitude lower than that of DNA probe modified G-FET sensor. We demonstrate that both PNA and DNA probe-modified G-FET have great potential in quantitative detection of RNA. A good linear electrical response to RNA concentrations is obtained in a broad range from 0.1 aM to 1 pM for PNA probe-modified G-FET and from 100 aM to 1 pM for DNA probe-modified GFET, respectively. The PNA probe-modified G-FET sensors significantly reduce the detection time compared to DNA probe-modified G-FET sensors. Moreover, the electrical response of PNA probe-modified G-FET biosensor to non-complementary RNA is negligible, showing high specificity for RNA detection. What's more, the G-FET sensor was also used to detect RNA in human serum, making it a promising way for future detection of RNA in biomedical research and early clinical diagnosis.