Biosensors based on electronic conducting polymers (ECPs) appear particular
ly well suited to the requirements of modern biological analysis: multipara
metric assays, high information density and miniaturization. We describe a
new methodology for the preparation of addressed DNA matrices. The process
includes an electrochemically directed copolymerization of pyrrole and olig
onucleotides bearing on their 5(2) end a pyrrole moiety. The resulting poly
mer film deposited on the addressed electrode consists of pyrrole chains be
aring covalently linked oligonucleotides. An oligonucleotide array was cons
tructed on a silicon device bearing a matrix of 48 addressable 50 mu m x 50
mu m gold microelectrodes. This technology was successfully applied to the
genotyping of Hepatitis C Virus in blood samples. Fluorescence detection r
esults show good sensivity and a high degree of dimensional resolution. The
need for versatile processes for the immobilization of biological species
on surface led us to extend our methodology. A biotinylated surface was obt
ained by co-electropolymerization of pyrrole and biotin-pyrrole monomers. T
he efficiency for recognition (and consequently immobilization) of R-phycoe
rythrin-avidin was demonstrated by fluorescence detection. Copolymerization
of decreasing ratios of pyrrole-biotin over pyrrole allowed us to obtain a
decreasing scale of fluorescence.