A Carbon Nanotube-Based Impedimetric Biosensor for Detection of Micro-RNA

Abstract

MicroRNAs (miRNAs) have been recently regarded as clinically important biomarkers for early cancer diagnostic. Accumulative evidences have proved that dysregulated expression of miRNAs is closely related with the occurrence, diagnosis and treatment of cancer [1]. Conventional methods of miRNA detection have some limitations like requiring large amount of sample input, expensive instrumentation, and long analysis time. To address these shortcomings as well as providing multiplexing capability, selectivity, and real-time measurement different types of cancer biosensors have been developed. Among them electrochemical biosensors have shown great promise for this application due to their high sensitivity, specificity, cost-effectiveness, and compatibility with the miniaturization [2]. A label-free and ultrasensitive impedimetric biosensor for miRNA detection is reported in this study. We utilized a glassy carbon electrode (GCE) modified with multi-wall carbon nanotube (MWCNT) as a biosensor platform. Incorporation of nanomaterials such as MWCNT offers unique advantages including enhanced electronic properties, higher surface area, and rapid electrode kinetics which leads to higher sensitivities and lower limit of detection [3]. Capture DNA probes were immobilized onto the surface of MWCNT modified electrode using a novel molecular tethering agent. All surface modification, immobilization, and hybridization between probe DNA and the target miRNA were investigated by electrochemical analyses. Besides, different variables such as probe concentration, pH, ionic strength, and hybridization time were investigated and optimized to get 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 99:525-546Oliveira T, Morais S (2018) New Generation of Electrochemical Sensors Based on Multi-Walled Carbon Nanotubes. Applied Sciences 8 (10):1925 Figure 1