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

摘要

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.