Reduced Graphene Oxide-Based Field Effect Transistor Biosensors for High-Sensitivity miRNA21 Detection

Breast cancer has been ranked the first malignant tumor in women, and with the incidence of it increasing all over the world, early screening can effectively reduce mortality and improve the cure rate. MiRNAs, as potential biomarkers, play an important role in the early diagnosis and prognosis monitoring of breast cancer. However, since miRNAs, with low concentration, are the matrix in serum or plasma, accurately detecting miRNAs without a label in serum or plasma is challenging. Herein, we proposed a biosensor combination of nanomaterial for reduced graphene oxide (RGO) and field effect transistors (FETs). The biosensor used a few layers of RGO by the chemical reduction method as a semiconductor to detect the miRNA21 in human plasma with high sensitivity (LOD: 1 fM). It can not only distinguish between perfectly matched, single-base mismatched, and completely mismatched sequences, but it can also correctly respond to clinically complex matrix samples without the process of miRNA21 extraction, amplification, and labeling. The area under the receiver operating characteristic (ROC) curve was 0.9253, which means that the biosensor can distinguish between the breast cancer patients and healthy controls and can assist in clinical diagnosis and provide new ideas for the development of clinical testing.