par Doneux, Thomas 
;De Rache, Aurore ;Triffaux, Eleonore ;Meunier, Anne ;Steichen, Marc ;Buess Herman, Claudine
Référence ChemElectroChem (Weinheim), 1, 1, page (147-157)
Publication Publié, 2014
;De Rache, Aurore ;Triffaux, Eleonore ;Meunier, Anne ;Steichen, Marc ;Buess Herman, Claudine Référence ChemElectroChem (Weinheim), 1, 1, page (147-157)
Publication Publié, 2014
Article révisé par les pairs
| Résumé : | The analytical performances (selectivity, sensitivity, limit-of-detection) are ultimately connected to the interfacial architecture of the sensing surface which needs to be optimised. Self-assembly of a mixed monolayer of thiolated probes and diluent onto gold surfaces used in the design of biosensing platforms is nowadays commonly performed by a two step immobilisation procedure. In this work the merits of the one step co-adsorption procedure is emphasized and it is shown that the ionic strength is a very efficient tool for a fine control of the surface concentration of the immobilised probe. Probe densities have been obtained by ac voltammetry or fluorescence measurements depending on the type of labelling of the probes. With the non-labelled DNA sequences chroncoulometric measurements were performed in the presence of dissolved hexaammineruthenium(III) cations. The maximum probe density achievable at high ionic strength by the one step co-adsorption procedure is limited by steric constraints and depends on the structure of the sequence. Various thiolated DNA sequences (ssDNA and dsDNA, linear, hairpin, quadruplex) co-adsorbed with a common diluent, the 4-mercaptobutan-1-ol (MCB) have been used to discuss the structural factors affecting the maximum surface densities obtained for the different types of probe. Application of the one step co-adsorption procedure to the optimisation of the analytical performances of a protein aptasensor is illustrated by building a sensor for the detection of thrombin, based on the thrombin binding aptamer (TBA) sequence. |
