Conducting polymers on microelectronic devices as tools for biological analyses

In the field of biological analysis, the need for multiparametric analysis has prompted the development of supports bearing a series of biomolecules l inked to a support in a precise location (addressed). To reach a high infor mation density, miniaturization of this kind of support has to be carried o ut. We describe in this paper an approach involving the use of electro-cond ucting polymers such as polypyrrole. This technology is based on an electro -directed copolymerization of pyrrole and oligodeoxynucleotides (ODN) linke d to a pyrrole residue. The process allows the grafting of the selected ODN at the surface of the successively addressed microelectrodes. In this way, the syntheses are carried out on 50 mu m electrodes on passive chips or on active (multiplexed) chips bearing 48 or 128 gold microelectrodes, respect ively. The detection of biological targets recognized by the biochip is car ried out by using fluorescent tracers. This technology, involving prepurifi ed materials precisely addressed, allows better reproducibility of the bioc hip preparation and, then, an easy interpretation of the fluorescence resul ts. The versatility of this technology is illustrated by ODN or peptide cop olymerizations leading to DNA chips or peptide chips, respectively. This wo uld open the field for other biological interaction studies. (C) 1998 Elsev ier Science B.V. All rights reserved.