Highly sensitive microRNA quantification with zero background signal from silver nanoparticles

• An analytical method for microRNA assay using silver nanoparticles is established.
• Zero background signal is ascribed to ligation and denaturation procedures.
• Excellent selectivity for target microRNA is achieved.
• Determination of microRNA in human serum samples is studied.

MicroRNAs are a class of noncoding RNAs, which play vital roles in numerous cellular processes. Recent studies have confirmed their significance in the theranostics of various diseases. We herein fabricate an electrochemical approach for microRNA quantification. DNA/microRNA/DNA hybridization and electrochemical signals from silver nanoparticles (AgNPs) are employed in this work. DNA1 immobilized on a gold electrode interacts with target microRNA, along with amino group labeled DNA2, to form the sandwich hybrid. The adjacent DNA1 and DNA2 are then ligated, which can keep DNA2 on the electrode surface during the denaturation. Amino group modified at the 5′ end of DNA2 captures AgNPs on the electrode surface, which provide sharp stripping peaks for microRNA quantification. This electrochemical approach offers a simple and sensitive platform for the detection of microRNA, which shows great utility in biomedical research and clinical diagnosis.

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