Silver-Enhanced Colloidal Gold Electrochemical Stripping Detection of DNA Hybridization

Abstract

We report on a novel method for detecting DNA hybridization, based on the precipitation of silver on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved silver. Such coupling of a nanoparticle-promoted silver precipitation with the remarkable sensitivity of stripping metal analysis offers a dramatic enhancement of the hybridization response. An efficient magnetic isolation of the duplex is used for discriminating against nonhybridized DNA, including an excess of mismatched oligonucleotides. The new silver-enhanced colloidal gold stripping detection strategy holds great promise for the detection of DNA hybridization and represents an attractive alternative to indirect optical affinity assays of nucleic acids and other biomolecules.

Carbon and gold electrodes as electrochemical transducers for DNA hybridisation sensors

“…The bioanalytical assay was applied for the detection of short sequences related to breast-cancer BRCA1; a detection limit of 10 g/l was achieved. Analogous probe-modified beads have been used to detect DNA hybridisation in connection with the precipitation of silver onto gold nanoparticle tags and subsequent electrochemical stripping detection of the dissolved silver onto thick-film carbon electrodes (Wang et al, 2001b). The procedure consisted of hybridisation of probe-modified beads with biotinylated target, which were subsequently coupled with streptavidin-coated 20 nm colloidal gold.…”

Successively amplified electrochemical immunoassay based on biocatalytic deposition of silver nanoparticles and silver enhancement

“…Based on this principle, Mirkin's group has developed a scanometric DNA array (Taton et al, 2000), an electrical detection-based DNA array (Park et al, 2002) and Raman spectroscopic fingerprints for DNA and RNA detection (Cao et al, 2002). In these methods, the autocatalytic metal deposition procedure enlarges the size and darkens the color of nanoparticles, resulting in two to three orders of magnitude improvement in detection sensitivity of scanning electrochemical microscope , QCM (Su et al, 2001) or electrochemical stripping techniques (Wang et al, 2001;Cai et al, 2002;Liao and Huang, 2005;Chu et al, 2005). Anodic stripping voltammetry (ASV) has been proved to be a powerful approach for trace determination of metal ions (Jacobs, 1963;Dequaire et al, 2000).…”

Two‐Surface Strategy in Electrochemical DNA Hybridization Assays: Detection of Osmium‐Labeled Target DNA at Carbon Electrodes

“…Target DNA modified with Os, bipy can be easily detected at solid (graphite) electrodes with a good sensitivity, allowing to detect tens of femtomoles of both 71-mer oligonucleotide and 3-kilobase plasmid DNA. The sensitivity reached with short DNAs (due to a lack of published data, no comparison could be done for long target DNAs) appears to be remarkably better than label-free DNA detection based on guanine oxidation peak (picomole ODN amounts, concentration 160 pM [29]) but by one order of magnitude less favorable, as compared to those reached in enzyme-linked immunoassay of osmium-labeled DNA at the beads with electrochemical detection (3 fmol of a 67-mer ODN in 20 mL, concentration 150 fM [27]), or in silverenhanced electrochemical detection of colloidal gold nanoparticles captured at hybridized DNA via streptavidinbiotin linking (1.5 fmol of a 19-mer ODN in 50 mL, concentration 30 fM [30]). Direct detection of the osmium prelabeled DNA at graphite electrodes is inexpensive and rapid (except the hybridization, washing and dehybridization steps, no other manipulations with the samples are necessary; the detection step does not require oxygen removal and involves a fast-scan voltammetric technique).…”

“…Direct detection of the osmium prelabeled DNA at graphite electrodes is inexpensive and rapid (except the hybridization, washing and dehybridization steps, no other manipulations with the samples are necessary; the detection step does not require oxygen removal and involves a fast-scan voltammetric technique). Using mercury detection electrodes (allowing to measure the osmium catalytic signal [24]), sensitivity of the pre-labeling assay can be increased at least by an order of magnitude [M. Fojta et al, in preparation], thus approaching the sensitivity of the above mentioned techniques [27,30].…”