Highly Stable and Integrable Graphene/Molybdenum Disulfide Heterojunction Field-Effect Transistor-Based miRNA Biosensor

MicroRNAs (miRNAs) are important noncoding RNA molecules that participate in gene regulation and are widely associated with the occurrence and development of various cancers. Developing rapid, highly sensitive, low-cost, and highly stable miRNA detection methods is of great significance for clinical diagnosis. Field-effect transistors (FETs) based on two-dimensional (2D) materials have been proven to have great potential in the field of miRNA detection due to their label-free, rapid, highly sensitive, low-power, and portable features. However, biosensors based on 2D material FETs require the application of an external gate voltage in solution, which seriously hinders the integration, miniaturization, and signal stability of the devices. This study proposes a graphene-molybdenum disulfide heterojunction (G/MoS2) FET biosensing platform to detect miRNA-21 and miRNA-155 without the need for an external gate voltage. The results demonstrate a detection time of approximately 30 min, a linear response range spanning from 10 fM to 10 nM, and limits of detection of 6.06 fM for miRNA-21 and 2.59 fM for miRNA-155. Through comparative experiments, the biosensor shows excellent selectivity and can distinguish target miRNAs from nontarget miRNAs. The G/MoS2 FET biosensor developed in this study provides a technical platform for miRNA detection and has a broad application prospect, especially in the early diagnosis of diseases and the screening of biomarkers.