Portable and sensitive detection of copper(II) ion based on personal glucose meters and a ligation DNAzyme releasing strategy

Using a Cu2+-dependent DNA ligation DNAzyme, a portable and sensitive biosensor for Cu2+ detection based on personal glucose meters (PGMs) has been developed. In the presence of Cu2+, the DNAzyme catalyzed the ligation of nucleophilic attack of the phosphorus center of DNA1 by the hydroxyl group on DNA2 and forming a phosphodiseter bond. By introducing DNA-invertase conjugates and capture-DNA modified magnetic beads (MBs), the ligation product can hybridize with them and form invertase-functionalized MBs, which can be separated easily. The presence of invertase can convert sucrose to glucose and can be read out by the PGMs. With this method, a detection limit of 1 nM could be achieved. Moreover, the method exhibited excellent metal ion selectivity and there was almost no effect of biological complex to the detection performance, which suggested our method can be successfully applied to in biological process researches, drug discovery, and clinic diagnostics. (C) 2016 Elsevier B.V. All rights reserved.