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Updated: Mar 15, 2026
Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
Electrochemical detection of glutathione by using thymine-rich DNA-gated switch functionalized mesoporous silica
Yonghong Wang1, Lun Jiang2, Lei Chu2
1College of Life Science and Technology, Forestry Biotechnology Hunan Key Laboratories, Central South University of Forestry and Technology, Changsha, 410004 China; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 China.
Abstract:
A novel electrochemical sensor for highly sensitive and selective detection of glutathione (GSH) was developed coupled thymine-Hg2+-thymine (T-Hg2+-T) coordination with mesoporous silica nanoparticles (MSN). Hg2+ ions could specifically interact with thymine bases to form strong and stable T-Hg2+-T complexes. And the electroactive molecules-methylene blue (MB) was sealed in the inner pores of MSN with a unique sequential thymine (T)-rich DNA in the presence of Hg2+. After the target was added, the formed duplex DNA T-Hg2+-T complex could deform into single-stranded DNA by a competitive displacement reaction, leading to the release of MB entrapped in the MSN. Thus the target-dependent amount of released MB could be conveniently monitored with an n-dodecanethiol modified screen-printed gold electrode. Using GSH as a model target, the proposed assay showed a wide detection ranging from 1.0nM to 1.0μM with a detection limit of 0.6nM. This strategy was simple and universal for various analytes with different competitive displacement ligands, possessing a great potential for convenient biotools testing and commercial application.
