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A highly sensitive and colorimetric biosensor based on magnetic nano‐DNAzyme for detection of lead (II) ion in real water samples
Author(s) -
Rong Mingge,
Li Jun,
Hu Jiahui,
Chen Aolong,
Wu Wenhe,
Lyu Jianxin
Publication year - 2018
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5684
Subject(s) - deoxyribozyme , detection limit , chemistry , metal ions in aqueous solution , biosensor , nano , selectivity , nanotechnology , nanosensor , substrate (aquarium) , colloidal gold , nanoparticle , analytical chemistry (journal) , ion , chromatography , materials science , biochemistry , catalysis , organic chemistry , oceanography , geology , composite material
BACKGROUND Colorimetric biosensors based on DNAzyme provide convenient and selective means for the detection of lead ion (Pb 2+ ), which are critically important to prevent lead exposure and poisoning. However, they still remain challenging because of their limitation of sensitivity (only nmol L ‐1 level) and practical application. Herein, we design a highly sensitive, selective, simple, and quantitative platform for direct Pb 2+ detection based on the magnetic nano‐DNAzyme in real water samples. RESULTS Magnetic beads were modified with enzyme strand of DNAzyme to work as solid phase carriers and hybridized with DNAzyme's substrate strand/horseradish peroxidase molecules double‐codified gold nanoparticles to form a stable magnetic nano‐DNAzyme complex. Under the optimized reaction conditions, the magnetic nano‐DNAzyme had a quantitative detection range from 10 2 to 10 8 pmol L ‐1 , a limit of detection of 32 pmol L ‐1 and high selectivity for Pb 2+ over other metal ions with an assay time less than 1 h. In addition, this method showed enhanced pH stability and long service life, and had a potential to detect other metal ions only by changing corresponding DNAzyme specific to them. Finally, the magnetic nano‐DNAzyme platform was demonstrated to work well in direct Pb 2+ detection in real water samples. CONCLUSION The magnetic nano‐DNAzyme system for colorimetric detection of Pb 2+ showed high sensitivity and selectivity, simple, enhanced pH stability with long service life in practical application. © 2018 Society of Chemical Industry