Abstract
AbstractBACKGROUNDColorimetric biosensors based on DNAzyme provide convenient and selective means for the detection of lead ion (Pb2+), 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 Pb2+ detection based on the magnetic nano‐DNAzyme in real water samples.RESULTSMagnetic 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 102 to 108 pmol L‐1, a limit of detection of 32 pmol L‐1 and high selectivity for Pb2+ 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 Pb2+ detection in real water samples.CONCLUSIONThe magnetic nano‐DNAzyme system for colorimetric detection of Pb2+ showed high sensitivity and selectivity, simple, enhanced pH stability with long service life in practical application. © 2018 Society of Chemical Industry
Published Version
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