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Single‐gap Microelectrode Functionalized with Single‐walled Carbon Nanotubes and Pbzyme for the Determination of Pb 2+
Author(s) -
Wang Hui,
Yin Yuan,
Gang Liu
Publication year - 2019
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201900016
Subject(s) - carbon nanotube , biosensor , detection limit , microelectrode , metal , nanotechnology , conductivity , linear range , materials science , cleave , analytical chemistry (journal) , chemistry , dna , electrode , environmental chemistry , chromatography , biochemistry , metallurgy
Lead is a highly toxic metal, which can persist in the natural environment and enrich in biological bodies. It can cause many severe diseases in the human body even at extremely low concentration. Here, we developed a new biosensor using single‐walled carbon nanotubes (SWNTs) modified with a specific Pbzyme (Pbzyme/SWNTs/FET) to detect lead ion (Pb 2+ ), which can monitor the lead pollution. This biosensor used 3‐aminopropyltriethoxysilane to immobilize SWNTs on the area between the source and the drain of single‐gap microelectrode (FET), and the duplex DNA (Pbzyme) consisted of DNAzyme (GR‐5) and complementary DNA (CS‐DNA) was functionalized with the SWNTs’ surface through a peptide bond. The use of GR‐5 DANzyme and Pb 2+ to form a stable complex structure to cleave the CS‐DNA can change radically the Pbzyme's structure on the SWNTs’ surface, which will further affect the number of carriers in SNWTs and the conductivity of the Pbzyme/SWNTs/FET. The change in conductivity can be used to evaluate the Pb 2+ concentration. Under the optimal conditions, the relative resistances presented a positive correlation with the Pb 2+ concentrations, showing a good linear relationship in the range of 10 pM to 50 nM, where the linear regression equation was y =10.104 log [ C Pb ]+5.8656, and the detection limit was 7.4 pM. Finally, the biosensor was applied to measure the Pb 2+ contents in the soil collected from the forest grass green belt and paint, and the results were compared with the results of atomic fluorescence spectrometry.