An electrogenerated polyterthiophene for binding and sensing polyadenosine-functionalised oligonucleotides

The isolation of mRNA from other cellular RNA is a key step in isolating genetic information. Since most mRNA has a polythymine ‘tail’ at the 3′ end, this is usually done by hybridisation with polyadenosine oligonucleotides anchored to magnetic particles. In this paper, we describe an electrochemical method for binding and reporting mRNA. A terthiophene bearing an activated ester-terminated side-chain has been electrochemically polymerised using a 2 mm diameter disk electrode, and to this polymer has been grafted an aminoalkyl-terminated polyadenosine oligonucleotide. The cyclic voltammogram of the polymer showed distinctive changes upon the binding of polythymine. Attempts to adopt the method for microelectrodes to boost sensitivity are also described.