Three-Way Electrochemical Sensing of Ultra-Low MicroRNA Levels

TL;DR

This paper introduces a highly sensitive three-way electrochemical sensor capable of detecting ultra-low microRNA levels in biological samples, with potential applications in cancer diagnostics.

Contribution

The study presents a novel three-mode electrochemical sensor that detects microRNAs without PCR, offering high sensitivity, specificity, and multiplexing capabilities.

Findings

Detects as low as 5 aM of microRNA without PCR

Operates over a dynamic range from 10 aM to 1 μM

Successfully profiles multiple microRNAs in human serum

Abstract

MicroRNAs (miRNAs) are an emerging class of biomarkers that are frequently deregulated in cancer cells and have shown a great promise for cancer classification and prognosis. In this work, we developed a three-way electrochemical sensor for detection and quantitation of ultra-low amounts of miRNAs in a wide dynamic range of measured concentrations. The sensor facilitates three detection modes based on hybridization (H-SENS), p19 protein binding (P-SENS) and protein displacement (D-SENS). The combined HPD sensor (HPD-SENS) identifies as low as 5 aM or 90 molecules of miRNA per 30\muL of sample without PCR amplification, and can be operated within the dynamic range from 10 aM to 1 \muM. The HPD senor is made on a commercially-available gold nanoparticles-modified electrode and suitable for analysing multiple miRNAs on a single electrode. This three-way sensor exhibits high selectivity and specificity and was successfully used for sequential analysis of miR-32 and miR-122 on one electrode. Furthermore, the P-SENS was employed for profiling of three endogenous microRNAs (miR-21, miR-32 and miR-122) in human blood serum.