MiRNA-155 Biosensors Based on AlGaN/GaN Heterojunction Field Effect Transistors With an Au-SH-RNA Probe Gate

AlGaN/gallium nitride (GaN) heterojunction field effect transistors (HFETs) have been researched widely in the fields of gas detection and ions detection. In this article, we develop a biosensor based on AlGaN/GaN HFETs to detect the tumor biomarker miRNA-155 directly. By fixing the specific sulfhydryl modified ribonucleic acid (SH-RNA) probe on the Au-gate surface of the AlGaN/GaN HFET to fabricate an RNA-Au-AlGaN/GaN HFET biosensor, this biosensor can conveniently and rapidly detect miRNA-155. The experimental results show that this biosensor has an excellent detection limit of 1.81 fM and a high sensitivity of $77\,\mu \text{A}$ /log concentration with a linear range (2 fM–2 nM). The limit of detection is the lowest among the reported AlGaN/GaN HFET RNA biosensors. Meanwhile, this biosensor shows a high specific recognition capacity but is weak sensitive to the mismatched miRNA.