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Updated: Sep 22, 2026
Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Electrochemiluminescence Biosensor for Ascorbic Acid Based on Target Transformation of Cell-Free RNA Transcription
Ming Chen1, Hongfu Zeng2, Fang Luo1
1Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Abstract:
A cell-free RNA transcription system had been coupled with electrochemiluminescence (ECL) detection technology for the first time to develop an ascorbic acid (AA, acting as a model target) biosensor. The biosensor is composed of single-stranded DNA (ssDNA) sequences modified with alkynyl and azido groups, respectively, alongside an incomplete gene circuit framework. The addition of target AA and copper ions will cause the linkage of the two ssDNA sequences through a click chemistry reaction. This results in the subsequent reconstruction of a complete gene circuit. The reconstituted gene circuit, in conjunction with the T7 RNA polymerase, drives the transcription of substantial quantities of RNA. ssDNA labeled with ferrocene (Fc) (Fc-DNA) had been immobilized on a tris(2,2'-bipyridyl) ruthenium(II) chloride hexahydrate-doped SiO2 nanoparticle (Ru@SiO2 NPs) modified electrode first. The quenching effect of Fc on Ru@SiO2 causes the low ECL detected. The transcribed RNA sequence assisted double-stranded specific nuclease (DSN) to cut the ssDNA-Fc and the ECL of the system was enhanced. Optimal experimental conditions reveal that the ECL signal exhibits a linear correlation with the logarithmic concentration of AA, spanning a detection range from 100 nM to 1 mM, with a detection limit of 45 nM. This innovative methodology expands the utility of a cell-free RNA transcription system within the realm of biosensing applications.
