Electrogenerated chemiluminescence detection of mercury(II) ions based on DNA probe labeled with ruthenium complex

A novel mercury(II) ion (Hg(2+)) biosensor with electrogenerated chemiluminescence (ECL) detection using tris(2,2'-bipyridyl) ruthenium derivatives (ruthenium complex) as labeling was developed in the prescent work. One thymine (T)-rich single-strand DNA (ssDNA) labeled with a ruthenium complex was taken as an ECL probe. When the other T-rich capture ssDNA was self-assembled onto the surface of a gold electrode with a thiol group, and then hybridized with the ECL probe to form double-strand DNA (dsDNA) structures in the presence of Hg(2+), a strong ECL response was electrochemically generated. The ECL intensity was linearly related to the concentration of Hg(2+) in the range from 1.0 × 10(-6) to 1 × 10(-9) M with a detection limit of 3.0 × 10(-10) M. The relative standard deviation was 4.1% at 1.0 × 10(-7) M Hg(2+) (n = 5). This work demonstrates that the combination of the strongly binding T-rich DNA to Hg(2+) with the highly sensitive ECL technique to design an ECL Hg(2+) biosensor is a great promising approach for the determination of metal ions.