Related Experiment Video
Updated: Apr 12, 2026
Author Spotlight: Advancements in DNA Nanosensors – Addressing Sensitivity and Selectivity Challenges in Molecular Detection
Published on: February 9, 2024
Signal-off Electrochemiluminescence Biosensor Based on Phi29 DNA Polymerase Mediated Strand Displacement
Anyi Chen1, Guo-Feng Gui1, Ying Zhuo1
1Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Abstract:
A target induced cycling strand displacement amplification (SDA) mediated by phi29 DNA polymerase (phi29) was first investigated and applied in a signal-off electrochemiluminescence (ECL) biosensor for microRNA (miRNA) detection. Herein, the target miRNA triggered the phi29-mediated SDA which could produce amounts of single-stranded DNA (assistant probe) with accurate and comprehensive nucleotide sequence. Then, the assistant probe hybridized with the capture probe and the ferrocene-labeled probe (Fc-probe) to form a ternary "Y" structure for ECL signal quenching by ferrocene. Therefore, the ECL intensity would decrease with increasing concentration of the target miRNA, and the sensitivity of biosensor would be promoted on account of the efficient signal amplification of the target induced cycling reaction. Besides, a self-enhanced Ru(II) ECL system was designed to obtain a stable and strong initial signal to further improve the sensitivity. The ECL assay for miRNA-21 detection is developed with excellent sensitivity of a concentration variation from 10 aM to 1.0 pM and limit of detection down to 3.3 aM.
