MiR-29b detection in serum using an electrochemical biosensor for the early diagnosis of gestational diabetes

Gestational diabetes mellitus (GDM) is a severe perinatal condition with serious consequences for the growth and development of the mother and baby. MicroRNA-29b (miR-29b) is essential to the pathogenesis of GDM and can be used as a molecular biomarker for diagnosis. Given the limitations of current GDM screening technologies, there is a pressing need for a sensitive detection approach to evaluate serum miR-29b in GDM patients, thus aiding in disease treatment. In this study, an electrochemical biosensor Co₇Fe₃-CN nanoparticles (NPs) was developed. Using a duplex-specific nuclease (DSN) signal amplification strategy with a linear range of 1-10⁴ pM and a low detection limit of 0.79 pM, the ultra-sensitive detection and quantification of miR-29b were accomplished. The dependability and applicability of the developed biosensor were validated by the standard method of qRT-PCR, and the content of serum miR-29b in GDM patients was shown to be significantly lower than that in the control group (P = 0.03). Specifically, miR-29b concentrations could be detected from 2.0 to 7.5 and 2.4 to 7.3 pM using qRT-PCR and the biosensor, respectively. These similar results indicated that a biosensor based on miR-29b detection has the potential to be used in the point-of-care testing of GDM patients in clinical practice.