Chongqing University of Technology

About: Chongqing University of Technology is a education organization based out in Chongqing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 5199 authors who have published 4205 publications receiving 35954 citations. The organization is also known as: Chongqing Institute of Technology.

A dual functional electrochemical “on–off” switch sensor for the detection of mercury(II) and melamine

Abstract: In this work, the development of a dual functional electrochemical switch sensor with the capability to detect Hg2+ and melamine is described. The thiol-modified, methylene blue (MB)-labeled and thymine (T)-rich SH-MB-DNA probes are self-assembled on the gold sensing electrode. The addition of Hg2+ to the sensor folds the SH-MB-DNA and brings the MB labels close to the electrode surface due to the specific T-Hg2+-T base pairing, resulting in an enhanced current response (electrochemical “on” state). While, subsequent incubation of the Hg2+-folded SH-MB-DNA with melamine releases Hg2+ and unfolds the probes because of the formation of more stable Hg2+–melamine multi-nitrogen heterocyclic ring special structures, causing a decrease in the current response (electrochemical “off” state). Such electrochemical “on–off” change of the sensor enables the detection of Hg2+ and melamine down to the low nanomolar levels. Besides, the developed sensor is also selective toward the corresponding target analytes. Based on the proposed dual functional sensing strategy, the detection of multiple targets (e.g., Ag+, cysteine and biothiols) can thus be expected by using appropriate DNA probes.