A novel conductive nanocomposite-based biosensor for ultrasensitive detection of microRNA-21 in serum, using methylene blue as mediator
Résumé
MicroRNA-21 (miRNA-21) is a common biomarker with high expression in breast tumors. Therefore, sensitive
detection of miRNA-21 is of great significance for clinical breast tumor diagnosis. A TH/rGO/CMK-3/AuNPs
nanocomposite is composed of thionine (TH), reduced graphene oxide (rGO), ordered mesoporous carbon
(CMK-3), and gold nanoparticles (AuNPs), which help to increase the specific surface area of a glassy carbon
electrode (GCE) and to amplify the DPV signal. Meanwhile, methylene blue (MB) was combined with the capture
probe guanine and absorbed by the composite material to mediate the differential pulse voltammetry (DPV) of
the obtained miRNA biosensor. The current response decreased with increasing miRNA-21 concentration under
optimal conditions. The biosensor responds to miRNA-21 in the 0.1fM-1 pM concentration range, and the
detection limit (LOD) was 0.046 fM. Moreover, human serum samples were effectively detected utilizing the
miRNA-21 biosensor with satisfactory results.