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Simultaneous fluorescent detection of multiple metal ions based on the DNAzymes and graphene oxide

Yun, Wen, Wu, Hong, Liu, Xingyan, Fu, Min, Jiang, Jiaolai, Du, Yunfeng, Yang, Lizhu, Huang, Yu
Analytica chimica acta 2017
DNA, analytical chemistry, blood serum, copper, detection limit, fluorescence, fluorescent dyes, graphene oxide, humans, lead, magnesium, metal ions, nucleotide sequences
A novel fluorescent detection strategy for simultaneous detection of Cu2+, Pb2+ and Mg2+ based on DNAzyme branched junction structure with three kinds of DNAzymes and graphene oxide (GO) was presented. Three fluorophores labeled DNA sequences consisted with enzyme-strand (E-DNA) and substrate strand (S-DNA) were annealed to form DNAzyme branched junction structure. In the presence of target metal ion, the DNAzyme was activated to cleave the fluorophore labeled S-DNA. The S-DNA fragments were released and adsorbed onto GO surface to quench the fluorescent signal. The detection limit was calculated to be 1 nM for Cu2+, 200 nM for Mg2+, and 0.3 nM for Pb2+, respectively. This strategy was successfully used for simultaneous detection of Cu2+, Mg2+ and Pb2+ in human serum. Moreover, it had potential application for simultaneous detection of multiple metal ions in environmental and biological samples.