Electrochemical detection of DNA hybridization based on silver-enhanced gold nanoparticle label

摘要

An electrochemical detection method for analyzing sequence-specific DNA using gold nanoparticle DNA probes and subsequent signal amplification step by silver enhancement is described. The assay relies on the electrostatic adsorption of starget oligonucleotides onto the sensing surface of the glass carbon electrode (GCE) and its hybridization to the gold nanoparticle-labeled oligonucleotides DNA probe. After silver deposition onto gold nanoparticles, binding events between probe and target were monitored by he differential pulse voltammetry (DPV) signal of the larger number of silver atoms anchored on the hybrids at the electrode surface. The signal intensity difference permits to distinguish between the match of two perfectly matched DNA strands and the near-perfect match where just one base pair was wrong. Coupled with this 'babioartucke-promoted' reduction of silver signal amplification method, the sensitivity of this electrochemical DNA biosensor has been increased by approximately two orders of magnitude and a detection limit of 50 pM of complementary oligonucleotides was obtained.