A Hybridization Chain Reaction-Based Electrochemical Biosensor for Highly Sensitive and Selective Detection of miR-378

In recent years, microRNAs have been used as cancer markers in clinical testing. In this study, an electrochemical biosensor was developed based on nanomaterials and the hybridization chain reaction (HCR) for highly sensitive and selective detection of the target miR-378 using K₃Fe(CN)₆/K₄Fe(CN)₆ as a redox indicator. MiR-378 is located on human chromosome 5q32 and serves as an important gene regulatory locus. Recent studies have found that aberrant expression of miR-378 is associated with cervical cancer, breast cancer, lung cancer, and other diseases. HCR is a simple and efficient isothermal amplification technique that does not require enzyme mediation and can be performed at room temperature. Evaluations of the specificity, stability, and sensitivity of the developed sensor revealed its ability to rapidly and specifically detect miR-378 in two hours with a detection limit as low as 100 cells in a volume of 400 µL, thereby indicating that this device could provide a novel approach for clinical diagnosis.