Dual-mode, signal-amplified DNA biosensor for label-free, reliable assay of gestational diabetes mellitus-related miRNA (miR-135a)

Abstract

miR-135a is highly expressed in patients with gestational diabetes mellitus, and its target genes are also involved in insulin signaling pathway, so it is one biomarker for gestational diabetes mellitus. Herein we designed a dual-mode DNA biosensor for reliable assay of miR-135a based on the fluorescence and colorimetric signals. Several experiments were carried out to demonstrate the assay feasibility and mechanism for this dual-mode DNA biosensor. With optimum parameters, this proposed dual-mode biosensor has been realized sensitive and quantitative assay of miR-135a. For the fluorescence and colorimetric signals, the working ranges are 0.56–61 and 8.3–74 nM, while limits of detection are 0.18 and 3.7 nM respectively. This dual-mode strategy allows two independent signals for miR-135a assay, so it can verify each other to show more accurate results with good fidelity. Furthermore, there is a good selectivity in the biosensor for target miR-135a over other nucleotide variants, as well as good anti-interference ability in complex samples. This dual-mode DNA biosensor provides a new approach for miR-135a assay and miRNA expression profiling in gestational diabetes mellitus.