A Method for Electrochemical Detection of microRNAs

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Introduction: Micro RNAs (miRNAs) are small non-coding RNA molecules with typically 19-25 nucleotides. Accumulating evidence demonstrates that different miRNAs are dysregulated to different levels in different cancers and other diseases. Since a stable population of miRNAs exists in circulation, there has been extensive interest in employing circulating miRNAs as biomarkers for disease diagnosis, and potentially as a feedback system as a part of treatment. The global miRNA market is expected to witness robust growth at a CAGR of 7.9% over the next couple of years with a projected value of $666.7 million by 2025. Currently, quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the primary technique to profile microRNAs. There is no sensor available for point-of-care (POC) type detection. Also, existing detection sensors/methods require time-consuming and labor-intensive sample pretreatments and involve complicated multi-step analysis procedures. Therefore, there is a need to develop new methods and technologies that offer fast, low-cost quantitative analysis of microRNA signatures with suitable sensitivity and selectivity. Technology: Georgia State University researchers have developed a new one-step analytical sensor platform for simultaneous detection/quantitation of multiple microRNAs as disease biomarkers. The systems comprise different sensing units, each of which includes a sequence-specific nucleic acid and a redox current reporter. The sensing units are bound to an electroconductive substrate and exposed to a solution including chemical reactants that function as either reductants or oxidants. By amplifying the current flowing between the redox current reporter and the substrate, this easy-to-use method allows one-step label-free detection of target nucleic acids within minutes, even when those nucleic acids are present at very low levels in a sample. This technology can potentially be a platform for the development of high-throughput diagnostic tools recognizing disease biomarkers and even miRNA signatures to complement other existing techniques such as qRT-PCR.