Highly sensitive electrogenerated chemiluminescence biosensor based on hybridization chain reaction and amplification of gold nanoparticles for DNA detection

A one-target-triggered hybridization chain reaction (HCR) strategy was designed for high sensitive electrogenerated chemiluminescence (ECL) detection of DNA. The sensor was constructed by immobilizing a capture probe (CP) on a gold electrode via an Au-S bond. When target DNA (tDNA) was introduced, its 5 terminus hybridized with the CP and the 3' terminus hybridized with a concatamer. Then the long DNA concatamer, self-assembled by numerous biotinylated probes (auxiliary 1 and auxiliary 2), was firmly immobilized on the gold electrode via tDNA and CP. At last a large number of gold nanoparticles-streptavidin assembling on the DNA sensor surface by biotin-streptavidin system, which generates a magnificently amplified ECL signal in carbonate buffer solution (CBS) contains luminol. With the use of Human Immunodeficiency Virus type 1 (HIV-1) as a proof-of-principle analyte, this newly designed protocol provides highly sensitive ECL detection of HIV-1 with a limit of detection down to 5.0 fM, and also exhibit good selectivity in complex matrixes. Therefore, the proposed ECL-based method should have wide applications in diagnosis of genetic diseases due to its simplicity, low cost, and high sensitivity at extremely low concentrations. (C) 2015 Elsevier B.V. All rights reserved.