Electropolymerisable pyrrole-oligonucleotide: synthesis and analysis of ODN hybridisation by fluorescence and QCM.

Conducting polymer films, such as polypyrrole, appear particularly attractive for the immobilisation of biological molecules by entrapment or covalent grafting. We describe here a new pyrrole phosphorarnidite building block allowing the synthesis of oligonucleotide (ODN) bearing a pyrrole moiety. The electropolymerisable pyrrole moiety was then introduced on the 5' end of the oligonucleotide.

Introduction to Formal Graphs, a new approach to the classical formalism.

The creation of a purely graphic language called Formal Graphs for modelling many physical and physico-chemical systems is described. It represents an improvement over traditional equivalent circuits used for modelling systems made of individual components and over bond graphs used mainly in physico-chemistry. In contradistinction with these graphs, which represent graphically only mounting equations and maintain algebraic equations for describing components behaviour, a formal graph is an oriented graph incorporating all the information contained in a usual algebraic model.

Experimental and theoretical investigations on the adsorption of 2'-deoxyguanosine oxidation products at oxidized boron-doped diamond electrodes.

Electrochemical oxidation of 2'-deoxyguanosine has been performed on boron-doped diamond (BDD) electrodes, resulting in a strong adsorption of the formed oxidized products onto the BDD surface. The adsorption behavior has been investigated by studying the electrochemical behavior of a redox probe ([IrCl6]3-) using cyclic voltammetry. The most probable situations are the formation of (A) an insulating adsorbed film resulting in a partially blocked electrode behavior, (B) a porous film, or (C) an overall conductive film.

Nucleosides and ODN electrochemical detection onto boron doped diamond electrodes.

Boron doped diamond (BDD) is a promising material for electroanalytical chemistry due mainly to its chemical stability, its high electrical conductivity and to the large amplitude of its electroactive window in aqueous media. The latter feature allowed us to study the direct oxidation of the two electroactive nucleosides, guanosine and adenosine. The BDD electrode was first activated by applying high oxidizing potentials, allowing to increase anodically its working potential window through the oxidation of CH surface groups into hydroxyl and carbonyl terminations.

Study of DNA hybridization on polypyrrole grafted with oligonucleotides by photocurrent spectroscopy.

Recognition of DNA sequences by biochemical sensor is generally performed by analysis after completion of hybridization. Using a technique able to directly translate the biological event into an electrical signal allows the in situ monitoring of the hybridization kinetics. In this aim, the photoelectrochemical behavior of one electroactive polymeric sensor based on a copolymer of polypyrrole and polypyrrole-oligonucleotide has been investigated in aqueous solution.

Electropolymerization as a versatile route for immobilizing biological species onto surfaces. Application to DNA biochips.

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.

A combined electrochemical quartz-crystal microbalance probe beam deflection (EQCM-PBD) study of solvent and ion transfers at a poly.

The oxidative polymerisation of the complex2,3-dimethyl-N,N'-bis-(salicylidene)butane-2,3-diaminatonick-el(II), [Ni(saltMe)], was monitored by the electrochemical quartz microbalance (EQCM) and crystal impedance techniques. Polymerisation efficiency was maintained throughout deposition of a film, which behaved rigidly, on the electrode. A combined EQCM-PBD (probe beam deflection) study of the redox process of the film exposed to a monomer-free solution of 0.

Incorporation of sulphonated cyclodextrins into polypyrrole: an approach for the electro-controlled delivering of neutral drugs.

The electro-controlled delivery of drugs based on the doping-dedoping mechanism of Electro-Conducting Polymers is restricted to charged substances acting as dopants. In order to overcome this limitation, this study presents an approach where the trapping/delivering is based on host-guest interaction. As an example of a neutral guest, the molecule N-methylphenothiazine (NMP) is encapsulated in the host, heptasulphonated beta-cyclodextrin (beta-CDSO3-), which is tailor-made to dope PPy.