An electrochemical biosensor based on AuNPs/Ti3C2 MXene three-dimensional nanocomposite for microRNA-155 detection by exonuclease III-aided cascade target recycling

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2020-12, Vol.878, p.114669, Article 114669
• Main Authors: Yang, Xiao, Feng, Minghui, Xia, Jianfei, Zhang, Feifei, Wang, Zonghua
• Format: Article
• Language: English
• Subjects: Biosensors; Chemical bonds; Chemical sensors; Deoxyribonucleic acid; DNA; Electrical resistivity; Electrochemical biosensor; Exonuclease III; Gold; Methylene blue; MicroRNAs; MiRNA-155; MXene; MXenes; Nanocomposites; Nanoparticles; Recycling; Ribonucleic acid; RNA
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2020.114669

A novel electrochemical biosensor based on AuNPs/Ti3C2 MXene three-dimensional nanocomposite for sensitive miRNA-155 detection by exonuclease III (Exo III)-aided cascade target recycling is reported. Ti3C2 MXene is synthesized and used as a support to immobilize Au nanoparticles (AuNPs) due to its special layered structure and metallic properties. The three-dimensional (3D) structure of the AuNPs/Ti3C2 MXene nanocomposite for the biosensor platform leverages the integrated advantages of a large specific surface area, excellent electrical conductivity and electrocatalytic properties. AuNPs are used to immobilize capture DNA (C-DNA) by AuS chemical bonds. The C-DNA was modified with methylene blue (MB) at the 3′ end, resulting in an initial DPV electrochemical signal (Id). In the presence of target, miRNA-155 and C-DNA formed a double-stranded structure by complementary base pairing. Subsequently, Exo III digested the 3′ end of the C-DNA in the double-stranded structure and caused the electrochemical signal to “turn off” (the final signal denoted as Ih). By Exo III-aided cascade cleavage of the target, one miRNA-155 chain causes the release of several C-DNAs under certain conditions, which significantly amplifies the peak current difference on the fabricated biosensor (ΔI = Id﹣Ih). The electrochemical sensor achieved a detection limit of 0.35 fM (S/N = 3) with a linear range from 1.0 fM to 10 nM. This sensor also shows desirable stability, reproducibility and specificity. •A novel electrochemical sensor for detection of miRNA-155 was developed.•MXene/AuNPs 3D nanocomposite was served as nanocarrier for C-DNA probe and electron accelerator of methylene blue.•The exonuclease III-aided cascade target recycling was utilized for the signal amplification.