The first automated synthesis of ferrocene-labelled phosphorothioate DNA probe: a new potential tool for the fabrication of DNA microarrays.

We report the synthesis and the characterisation of the first electroactive ferrocene-labelled oligonucleotide phosphorothioate (ODN-Fc-Ps) probe obtained by automated synthesis. The grafting of ODN-Fc-Ps probe on gold electrode resulted in the appearance of the ferrocene redox couple in cyclic voltammetry confirming the effectiveness of the ODN grafting. The electrochemical response of the modified electrode was analysed in aqueous media before and after hybridisation with ODN target. The hybridisation with ODN target induces a large conformational change in the surface-confined DNA structure monitored by cyclic voltammetry of the ferrocene marker which confirms the potential of ferrocene-labelled oligonucleotide phosphorothioate to develop electrochemical DNA chips.