Covalent immobilization of oligonucleotides on electrodes

Electrocatalytic activity of DNA on electrodes as an indication of hybridisation

“…Since hybridisation occurs in the bulk phase, typical difficulties caused by the hybridisation on the surface are overcome. We anticipate that further optimisations of hybridisation conditions, of surface functionalizations [36], as well as measurements with a differential configuration or/and in non-equilibrium conditions [37], will improve the specificity as well as sensitivity of this approach.…”

Sensitive and Label-Free Detection of DNA by Surface Plasmon Resonance

“…With the development of organic and biological conjugation reactions, DNA immobilization can be realized. Amine-, thiol-, and aldehyde-coupling reactions and biotinstreptavidin complexation are just a few popular schemes employed for this purpose [17,41,42].…”

“…Three general approaches have been pursued to further enhance the sensitivity or to lower the detection level. The first involves the formation of a matrix of a high volume-to-surface ratio for immobilization of sensing molecules [41,73,74]. Heaton et al used an externally applied electric field to control the electrostatic forces on a surface-bound ODN monolayer [48] to alter the orientation of the immobilized ODN probes for a more favorable DNA hybridization reaction.…”

Improved DNA microarray detection sensitivity through immobilization of preformed in solution streptavidin/biotinylated oligonucleotide conjugates

“…The immobilization of ssDNA on glass and silicon substrates is usually performed on surfaces functionalized with silanes, e.g., epoxy-or amine-terminated silane, on which ssDNA can be covalently coupled either directly or by employing appropriate cross-linkers [6][7][8][9][10][11][12]. Concerning other types of substrates such as gold electrode surfaces, ssDNA probes are usually immobilized either through direct bonding of thiol-modified oligonucleotides [13,14], or via bonding of 5 -end modified ssDNA using bifunctional reagents (e.g., sulfosuccinimidyl-4-(Nmaleimidomethyl)cyclohexane-1-carboxylate or N-succinimidyl-S-acetylthiopropionate) [15]. More sophisticated approaches have been employed for DNA immobilization on polymer surfaces involving for example layer-by-layer polyelectrolyte assembly [16,17] or activation of the polymer surface through plasma polymerization [18][19][20].…”