Electropolymerization as a Versatile Route for Immobilizing Biological Species onto Surfaces

Abstract

Biosensors based on electronic conducting polymers appear particularly well suited to the requirements of modern biological analysis--multi-parametric 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 oligonucleotides bearing on their 5' end a pyrrole moiety. The resulting polymer film deposited on the addressed electrode consists of pyrrole chains bearing covalently linked oligonucleotides (ODN). An oligonucleotide array was constructed on a silicon device bearing a matrix of 48 addressable 50 x 50 microns gold microelectrodes. This technology was successfully applied to the genotyping of hepatitis C virus in blood samples. Fluorescence detection results show good sensitivity and a high degree of spatial resolution. In addition, gravimetric studies carried out by the quartz crystal microbalance technique provide quantitative data on the amount of surface-immobilized species. In the case of ODN, it allows discrimination between hybridization and nonspecific adsorption. The need for versatile processes for the immobilization of biological species on surfaces led us to extend our methodology. A biotinylated surface was obtained by coelectropolymerization of pyrrole and biotin-pyrrole monomers. The efficiency for recognition (and consequently immobilization) of R-phycoerythrin-avidin was demonstrated by fluorescence detection. Copolymerization of decreasing ratios of pyrrole-biotin over pyrrole allowed us to obtain a decreasing scale of fluorescence.

Development of Nanoprobe for the Determination of Blood Cholesterol

“…Conducting polymers are multifunctional materials that can be employed as receptors as well as transducers or immobilization matrices in electrochemical biosensing. They are characterized by an extended π -conjugation along the polymer backbone, which promotes an intrinsic conductivity, ranging between 1E−14 and 1E2 S/cm [17]. Their electrical conductivity results from the formation of charge carriers ("doping") upon oxidizing (p -doping) or reducing (n -doping) their conjugated backbone [18].…”

Effect of Immobilized Nerve Growth Factor on Conductive Polymers: Electrical Properties and Cellular Response

“…Conducting electroactive polymers, such as polypyrrole, polyaniline, and polythiophene, have been used to modify bioelectronics [1,[7][8][9][10][11][12][13][14][15] and biosensors by immobilizing a biological element, [16] for example enzymes, [17][18][19] antibodies, [20,21] or DNA. [22] This incorporation is also appropriate for the fabrication of multianalyte senThe use of biologically active dopants in conductive polymers allows the polymer to be tailored for specific applications. The incorporation of nerve growth factor (NGF) as a co-dopant in the electrochemical deposition of conductive polymers is evaluated for its ability to elicit specific biological interactions with neurons.…”

Electropolymerized Films of π‐Conjugated Polymers. A Tool for Surface Functionalization: A Brief Historical Evolution and Recent Trends

“…This class of polypyrrole-Ru complexes was investigated in detail for their electrocatalytic properties by Deronzier et al [165]. Various substituents, such as the ferrocene group [166], nitroxide functions [167] and anthraquinone groups [168], the camphor chiral unit [169], porphyrin [170], phenothiazine [171], enzyme [172], calixarene [173] and fluorene [174], biotine [152,153,175], and single-stranded DNA [176,177] were soon grafted at the nitrogen -there is no limitation to the substituents that can be used. The basic chemistry to perform N-substitution is counterbalanced by a loss in conductivity by 5-7 orders of magnitude.…”