Projet ANR-06-PCVI-0017 – e-bioprobs : New ultra-sensitive electrochemical biomolecular probes for real-time multi-detection of infectious diseases in complex media
Programme : Physique et Chimie du Vivant (PCV) (PCV) 2006
Année de financement : 2006
Coordinateur du projet : UNIVERSITE JOSEPH FOURIER GRENOBLE 1 (UNIVERSITE JOSEPH FOURIER GRENOBLE 1)
Partenaires : Centre national de la recherche scientifique; PME; Université Claude Bernard - Lyon 1; Université de Grenoble Alpes
Montant : 540000.0 euros
Date de début : 2006
Durée : 36 mois
Résumé : Intense research activities are carried out worldwide to develop rapid, simple, and sensitive detection tools for medical diagnostics and biomedical research applications. In the field of infectious diseases, immunoassay systems stay of great interest for pathogen diagnosis as it allows direct detection of proteins present in sera without specific treatment of samples. With this view, several techniques based on physical analyses of surface or on optical detections have been developed. However, the application of electrochemical methods to the sensing of biologically related species may provide very significant advantages. Specifically, the advantages of bioelectronic approaches include the speed, sensitivity, and low cost/mass/power requirements of electrochemical detection. The objectives of the project are to elaborate new types of redox capture biomolecules which can act as efficient signal transducers to perform real-time electrochemical detection of related peptide-protein interactions. We aim at performing sensitive serological tests in solution, by electrochemically detecting a conformational change of the capture biomolecule induced by the interaction with the protein target. Redox bio-receptor will be associated to an additional system allowing signal amplification, by the means of a sacrificial redox molecular system that could undergo electrocatalytic reaction in solution, allowing an increase of sensitivity limit, directly in human sera and without labelling of proteins. We plan to evaluate the sensitivity of our method on HIV-1 seropositive patients' sera, aiming at detecting the early stage of the human serological response. As the ultimate goal, we envision to electroaddress the capture biomolecules on a biochip device to achieve simultaneous HIV, HBV and HCV detection. The project aims at electrochemically sensing a protein-protein recognition event through conformational changes of a synthetic host upon complexation, inducing a disruption of the electrochemical communication processes between multiple redox probes bore by the bio-receptor. The first step of the project lies thus in the design of appropriate redox hosts combining redox subunits, in electrochemical interaction at the free state, and recognition sites, organized on a convenient structured platform. The induced modification of the electrochemical signature upon complexation and disruption of the communication are expected to allow an efficient redox sensing through the simultaneous shift and enhancement of the original electrochemical signal. In a second step, the search of a convenient redox amplifier will be carried out in order to achieve an electrocatalytic amplification of the electrochemical signal. Finally, we aim at electro-addressing the capture biomolecules on a biochip device to perform direct multi-detection. For this, two strategies of conjugate immobilization will be investigated, namely by the use of pyrrole electropolymerization, by the way of diazonium cations grafted through electrochemical reduction, or by the entrapment of the redox bio-receptor into an inactive matrix deposited onto the electrode surface. This novel approach relying on a promising biosensing concept open up new perspectives in molecular electrochemical recognition that aims at producing novel prototypes molecular sensory devices. During this project, it is expected the synthesis of redox bio-receptors combining recognition sites and multiple redox subunits in electrochemical interaction at the free state. The following key step deals with the observation of a conformational change upon complexation with a targeted protein, inducing a disruption of the initial electrochemical communication which, usually, results in a change of the electrochemical signature of the receptor. The selection of an appropriate redox amplifier playing the role of a 'sacrificial catalyst', and its suitable functionalization, will be then carried out with the view of amplification of