Porous Magnetic Nanoparticles‐Based Electrochemical Biosensor for Determination of Mercury in the Aquatic Environment.

Fabrication of sensitive and convenient methods for the detection of heavy metal ions is an important task due to their high toxicity to environment and human health. Divalent mercury ions (Hg2+) are a kind of significant public health hazard, which generate harmful toxic effects. In this work, a novel self‐powered biosensor for the quantification of Hg2+ in aqueous solutions is developed. Porous magnetic nanoparticles are synthesized to load electrochemical species and a Hg2+ responsive single‐stranded DNA probe is used to seal them. After specific interaction with target ions, the DNA probe forms a rigid duplex, which can no longer block the pores of the magnetic nanoparticles. The leakage of electrochemical species can then increase the electrochemical response, which is used to indicate the initial concentration of Hg2+. This method shows high sensitivity and selectivity, and can be applied in real water samples with excellent recoveries. Therefore, a novel approach is provided for ultrasensitive and reliable detection of Hg2+ in practical applications. [ABSTRACT FROM AUTHOR]