Ultrasensitive electrochemical DNAzyme sensor for lead ion based on cleavage-induced template-independent polymerization and alkaline phosphatase amplification.
In this article, a simple, highly sensitive and selective electrochemical DNAzyme sensor for Pb(2+) was developed on the basis of a 8-17 DNAzyme cleavage-induced template-independent polymerization and alkaline phosphatase amplification strategy. The hairpin-like substrate strand (HP DNA) of 8-17 DNAzyme was firstly immobilized onto the electrode. In the presence of Pb(2+) and the catalytic strand of 8-17 DNAzyme, the HP DNA could be cleaved to expose the free 3'-OH terminal, which could be then utilized for the cascade operation by terminal deoxynucleotidyl transferase (TdTase) for the base extension to incorporate biotinylated dUTP (dUTP-biotin). The further conjugated streptavidin-labeled alkaline phosphatase (SA-ALP) then catalyzed conversion of electrochemically inactive 1-naphthyl phosphate (1-NP) for the generation of electrochemical response signal. The currently fabricated Pb(2+) sensor effectively combines triply cascade amplification effects including cyclic Pb(2+)-dependent DNAzyme cleavage, TdTase-mediated base extension and enzymatic catalysis of ALP. An impressive detection limit of 0.043nM toward Pb(2+) with an excellent selectivity could be ultimately obtained, which was superior than most of the electrochemical methods. Thus, the developed amplification strategy opens a promising avenue for the detection of metal ions and may extend for the detection of other nucleic acid-related analytes.
Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China. Electronic address: sliu@qust.edu.cn.
Shufeng
S
Liu
Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
Wenji
W
Wei
Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
Xinya
X
Sun
Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, No.53, Rd. Zhengzhou, Qingdao, Shandong 266042, China.
Li
L
Wang
D000469:Alkaline Phosphatase / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D021881:DNA, Catalytic / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D057230:Limit of Detection; D058105:Polymerization; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
D021881:DNA, Catalytic; D061925:Immobilized Nucleic Acids; D014874:Water Pollutants, Chemical; D014867:Water; D007854:Lead; D000469:Alkaline Phosphatase
DNAzyme; Electrochemical sensor; Pb(2+) detection; Terminal deoxynucleotidyl transferase