Highly Sensitive Electrochemiluminescence Detection of Mercury(II) Ions Based on DNA-Linked Luminol-Au NPs Superstructure

A novel highly sensitive electrochemiluminescence (ECL) detection protocol for mercury(II) ions was developed. Based on the strong and stable thyminethymine mismatches complexes coordination chemistry, mercury(II) ions can specifically bind to a designed DNA strand, leading to the release of the complimentary DNA strand. The released DNA strand was then captured by magnetic beads modified with specific DNA, and then through the formation of DNA-linked luminol-Au nanoparticles (NPs) superstructure, a specific ECL system for mercury(II) ions was developed. Using 3-aminopropyl-triethoxysilane as an effective enhancer, the ECL system can detect Hg2+ ion within a linear range from 2.0x10(-10)molL(-1) to 2.0x10(-8)M, with a detection limit as low as 1.05x10(-10)M (3 sigma). Moreover, this ECL system is highly specific for Hg2+, without interference from other commonly coexisted metal ions, and it can be used for the analysis of real samples.