Nano polythionine-based electrochemiluminescence biosensor for detection of the p16INK4a gene using RuAg@AuNPs core-shell nanocomposites as DNA labels

In this work, a nano polythionine (NPTh)-based universal sandwich-type electrochemiluminescence (ECL) biosensor for sensitive and specific detection of the p16INK4a gene using core-shell luminescent nanocomposites as excellent DNA labels was constructed. The NPTh electrode was prepared by in situ electropolymerization technique, which had a large surface area and was served as effective biosensing substrates for ssDNA1 immobilization by charge desorption. Meanwhile, tri(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+)/silver nanoparticles (AgNPs) doped gold (Au) core-shell nanocomposites (RuAg@AuNPs) were utilized as excellent ssDNA2 labels. The construction of dsDNA was fabricated through a hybridization reaction of ssDNA1, p16INK4a gene and RuAg@Au-ssDNA2. The change of ECL intensity on the NPTh electrode was found to have a linear relationship in respect to the logarithm of the p16INK4a gene concentrations in the wide range of 1.0 × 10-13~1.0 × 10−1 M, with a detection limit of 0.05 p.M. (S/N = 3). The presented biosensing strategy may provide great potential in the assay of other clinically biomarkers.