Journal
BIOSENSORS & BIOELECTRONICS
Volume 78, Issue -, Pages 236-243Publisher
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2015.11.055
Keywords
Electrochemical biosensor; Lead ion; Bimetallic nanoparticles; DNAzyme
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Funding
- National Natural Science Foundation of China [41176079, 21475025]
- National Science Foundation of Fujian Province [2014J07001]
- Key Science Project (Type A) of the Fujian Provincial Department of Education, China [JA12021]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT1116]
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In this work, a sensitive and specific electrochemical biosensor for lead ion (Pb2+) detection was developed by coupling with synergetic catalysis of porous Au-Pd bimetallic nanoparticles and hemin/G-quadruplex-based DNAzyme. In the presence of target Pb2+, the substrate strand was cleaved and the enzyme strand was released. Subsequently, G-rich DNA-labeled Au-Pd bimetallic nanoparticle was linked with the released enzyme strand through the helper DNA. Upon addition of hemin, a large number of hemin/G-quadruplex-based DNAzyme molecules were formed on the electrode to serve as nicotinamide adenine dinucleotide hydrogen (NADH) oxidase and peroxidase mimics. DNAzyme could catalyzed the reduction of H2O2, generated from NADH in the presence of O-2, to produce an electrochemical signal when using thionine as the electron mediator. Introduction of porors Au-Pd bimetallic nanoparticles could enhance the detectable signal and cause the increase in the sensitivity. Experimental results showed that the variations (Delta I) in the cathodic peak currents of the biosensor were linearly dependent on target Pb2+ concentrations from 1.0 pM to 100 nM with a detection limit (LOD) of 0.34 pM. The excellent performance of the sensing platform indicated its promising prospect as a valuable tool for simple and cost-effective Pb2+ detection in practical application. (C) 2015 Elsevier B.V. All rights reserved.
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