51. Ultrasensitive electrochemical detection of Pb2+ based on DNAzyme coupling with exonuclease III –Assisted target recycling
- Author
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Huali Jin, Lina Wu, Di Zhang, Xin Yu, and Min Wei
- Subjects
Exonuclease III ,Detection limit ,Exonuclease ,biology ,General Chemical Engineering ,Deoxyribozyme ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Cleavage (embryo) ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Electrochemistry ,biology.protein ,0210 nano-technology ,Biosensor ,Methylene blue ,DNA - Abstract
A sensitive and selective electrochemical Pb2+ sensor was developed based on GR-5 DNAzyme and exonuclease III-assisted target recycling amplification. When target Pb2+ existed, GR-5 DNAzyme was cleaved into two free DNA fragments. One of the fragments could open the hairpin DNA (HP1) modified on the electrode to form DNA duplex with blunt end at the 3′-terminus and triggered Exo III cleavage process. A large amount of residual part of HP1 were obtained by the Exo III-aided recycling which could hybridized with another hairpin DNA labeled with methylene blue, resulting in the dramatic increase of current. The electrochemical signal of methylene blue positive correlated with the Pb2+ concentration. The proposed sensor has the concentration ranging from 10−11 to 8×10−6 mol/L with a detection limit of 2.74 p mol/L. Moreover, the analysis of Pb2+ concentration in real water revealed that the proposed biosensor has a promising application in environment monitoring.
- Published
- 2021