Electrochemiluminescence DNA biosensor based on the use of gold nanoparticle modified graphite-like carbon nitride.

The authors describe an electrochemiluminescent (ECL) DNA biosensor that is based on the use of gold nanoparticles (AuNPs) modified with graphite-like carbon nitride nanosheets (g-CN NSs) and carrying a DNA probe. In parallel, nanoparticles prepared from gold-platinum (Au/Pt) alloy and carbon nanotubes (CNTs) were placed on a glassy carbon electrode (GCE). Once the g-CN NHs hybridize with DNA-modified AuNPs, they exhibit strong and stable cathodic ECL activity. The Au/Pt-CNTs were prepared by electrochemical deposition of Au/Pt on the surface of the CNTs in order to warrant good electrical conductivity. On hybridization of immobilized capture probe (S), target DNA (S) and labeled signal probe (S), a sandwich-type DNA complex is formed that produces a stable ECL emission at a typical applied voltage of −1.18 V and in the presence of peroxodisulfate. Under optimized conditions, the method has a response to target DNA that is linearly related to the logarithm of its concentration in the range between 0.04 f. and 50 pM, with a 0.018 f. detection limit. [ABSTRACT FROM AUTHOR]