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Sensitive detection of chloramphenicol based on Ag-DNAzyme-mediated signal amplification modulated by DNA/metal ion interaction

Huang, Yue, Zheng, Ji, Wang, Lei, Duan, Xuguo, Wang, Yaosong, Xiang, Yang, Li, Genxi
Biosensors & bioelectronics 2019 v.127 pp. 45-49
DNA, antibiotics, biosensors, chloramphenicol, cost effectiveness, electrochemistry, electrodes, food safety, oligonucleotides, silver
We here report a novel method for antibiotic detection by making use of DNA/metal ion interaction coupled with Ag-DNAzyme cleavage-mediated signal amplification. Taking the analysis of chloramphenicol (CAP) as an example, upon the specific recognition between the antibiotic CAP and its aptamer, the secondary structure of the DNA aptamer shaped by C-Ag+-C base mismatches will be altered, liberating the pre-captured Ag+. Subsequently, the free Ag+ provided as a cofactor can activate the Ag-DNAzyme, which behaves recycled cleavage of substrate DNA on the electrode surface for signal amplification. The more CAP is present, the more Ag+ is released, thus more Ag-DNAzyme can be activated to achieve a higher electrochemical signal. Therefore, the target-responsive variation of electrochemical signal enables the sensitive detection of CAP. The proposed method is cost-effective only with plain metal ion as modulator. It has also been challenged with real food samples, indicating the potential to be a promising tool for food safety detection.