Electrochemical Detection of Micro-RNAs As Potential Cancer Biomarker

Abstract

MicroRNAs (miRNAs) are single-stranded RNA transcripts, typically of 19–23 nucleotides in length. Recently, miRNAs have been identified as important biomarkers that hold promise in early cancer diagnosis. Accumulative evidences have proved that abnormal expression of miRNAs is closely related with the occurrence, diagnosis and treatment of cancer [1]. Conventional methods of miRNA detection have some intrinsic drawbacks including the need for tedious and complex procedures, requirement of large amount of samples, highly skilled experts and high-end equipment. To address these shortcomings as well as to provide multiplexing capability, different types of electrochemical cancer biosensors have been developed. Electrochemical biosensors have been widely paid attention due to their merits including high sensitivity, specificity, low-cost, and multiplexing [2]. Herein, a label-free and sensitive biosensor was developed for miRNA-21 detection at femtomolar concentrations. A glassy carbon electrode (GCE) was first modified with carbon nanotube (CNT) which serves as platform for immobilization of probe DNA as well as providing higher surface area. Capture DNA probes were immobilized onto the surface of CNT modified electrode using an established molecular tethering method [3,4]. Electrochemical analyses confirmed the surface modification, immobilization, and hybridization between probe DNA and the target miRNA. Besides, different variables such as probe concentration and hybridization time were investigated and optimized to find the optimal experimental conditions for miRNA detection. The obtained results demonstrated that the proposed biosensor exhibits excellent analytical properties including high sensitivity, low detection limit, selectivity, and reproducibility for miRNA detection. References Lan H, Lu H, Wang X, Jin H (2015) MicroRNAs as potential biomarkers in cancer: opportunities and challenges. BioMed research international 2015Kilic T, Erdem A, Ozsoz M, Carrara S (2018) MicroRNA biosensors: Opportunities and challenges among conventional and commercially available techniques. Biosensors and Bioelectronics 99:525-546Ramasamy RP, Luckarift HR, Ivnitski DM, Atanassov PB, Johnson GR (2010) High electrocatalytic activity of tethered multicopper oxidase–carbon nanotube conjugates. Chemical Communications 46 (33):6045-6047Zhou Y, Fang Y, Ramasamy RP (2019) Non-covalent functionalization of carbon nanotubes for electrochemical biosensor development. Sensors 19 (2):392