Detection of Pb 2+ in aqueous solution by using a DNA-modified microcantilever

Abstract

We developed a novel Pb 2+ -sensor based on a microcantilever that was modified with a specific Pb 2+ -dependent DNAzyme molecule. This microcantilever sensor could detect Pb 2+ sensitively and selectively in an aqueous solution. Upon complexation with Pb 2+ , the DNAzyme duplex unwinded and formed a G-quadruplex conformation, which led to an increase of repulsion between the DNAzyme molecules and a subsequent bending of the microcantilever. This microcantilever sensor could be regenerated, flowing through a strong Pb 2+ chelator, 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid. The detection limit of the microcantilever sensor for Pb 2+ ions is as low as 10 -8 M. The microcantilever sensor also exhibited a high selectivity to Pb 2+ over other metal ions such as Mg 2+ , Fe3+, Zn 2+ , Ca 2+ , and Cd 2+ . 2016