Abstract
Vertically-ordered mesoporous silica film (VMSF), with large amount of small pores and abundant negative charges, had been modified on the surface of indium tin oxide electrodes and applied to develop an electrochemiluminescence (ECL) biosensor for acute myeloid leukemia biomarker hsa-miR-10a-5p (chosen as a model target). The small ECL indicator (Ru(phen)32+) can be enriched in the pores through electrostatic adsorption and then diffuse to the electrode surface to produce strong ECL signals. The presence of target can trigger hyperbranched rolling circle amplification (HRCA) and produce a large amount of double-stranded DNA (dsDNA). Ru(phen)32+ can embed into the groove structure of dsDNA and forms negatively charged large-sized complexes, which cannot pass through the narrow pores of VMSF to reach the electrode. This led to a significant decrease of ECL signal of the system. The change of the ECL intensity of the system had a linear relationship with logarithm of target concentration within the range of 1 fM–1 nM. The limit of detection was 1.23 fM. The developed biosensor had been applied to determine the target substance in serum samples with satisfied results without complicated sample pretreatment. The introduction of VMSF endows the biosensor with superior anti-interference capability and simpler operational steps, promising applications in the diagnosis of acute myeloid leukemia and potential extension to the analysis of other target molecules through primer design.
Published Version
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