Carbon Nanotube AFM tips for biotechnology (BIONANOTIP)

The aim of the BIONANOTIP project (Funding : ANR-2010-P2N) is to perform reproducible characterization of a biofunctionalized surface to analyze the distribution of single proteins and evaluate their biological activity. This project will focus on critical steps to determine the optimum surface density to ensure the native conformation of single-molecules leading to the measure of functionally-relevant interactions between complementary molecule.
To develop an accurate and sensitive biosensor, it is critical to be able to characterize qualitatively and quantitatively the biological surface of the biosensor. The project will focus on the covalent grafting of biological receptors on self-assembled monolayers deposited on a glass/silicon surface. The project will use Atomic Force Microscopy (AFM) to characterize this grafting. To probe the surface at a single molecule level, the BIONANOTIP project will also functionalized carbon nanotubes with various ligands, and the ligand-receptor interaction will be measured by Dynamic Force Spectroscopy (DFS).

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Partners : ISM, Univ. Bordeaux/CBMN, Univ. Bordeaux/LIRM, CEA Marcoule.

Detection of E. coli bacteria (BIOALERT)

The efficiency of monomolecular epoxysilane films grafted with specific antibodies on an acoustic wave sensor to detect whole E. coli bacteria was demonstrated. With a short-chain molecular monolayer, i.e. (3-glycidylpropyl)trimethoxysilane, anti-E. coli antibodies did not lead to a significant bacteria immobilization.
This was partially attributed to the intrinsic roughness of the SiO2 sensor surface. An innovative method has been developed to overcome this difficulty. It consists in bonding goat anti-mouse antibodies (GAM) onto the sensor surface in a first step, and introducing E. coli bacteria incubated with anti-E. coli antibodies onto the sensor in a second step. This method enables us to keep the specificity of the antibody/antigen interaction and provides significant results in less than 1 h. It leads to a detection threshold of 106 bacteria/mL in a 500-µL chamber.

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Individual E. coli trapped on modified silica wave-guide via a long-chain glycidyl-terminated SAM and specific anti-E. coli antibodies

An autonomous, real-time and in situ water quality monitoring system was developed and the method to detect E. coli bacteria in seawater and fresh water was patented by AGUR. Interestingly, anti-E. coli antibodies grafted on a long-chain (C22) glydidyl-terminated SAM allowed the direct detection of whole E. coli.
Partners : ISM, Univ. Bordeaux/IMS, Univ. Bordeaux/LIP, Univ. Bordeaux

Detection of Circulating Tumoral Cells (CAPCELL)

We designed a new immunosensor and demonstrated its analytic performances to capture efficiently, under laminar flow, circulating tumour cells from blood samples (Funding ANR EMPB 2006). The surface floor of the laminar flow chamber was bonded with an amino-terminated long alkyl chain silylated spacer (21-aminohenicosyltrichlorosilane, AHTS). Properties of the AHTS- and antibody-grafted surface floor were compared to that of surface floors coated with the commercially available short alkyl spacers such as (3-glycidylpropyl)tri-methoxysilane or (3-aminopropyl)-triethoxysilane. In order to calculate the cell flow trajectories, a theoretical model was constructed according to the geometry of the flow chamber. Cell capture experiments demonstrated that cells immobilization was optimized throughout the whole flow chamber. Highest cell capture was obtained with the AHTS-modified surface. This new microfluidic device and its use in capturing CTC or foetal cells were patented and a biotech startup (CyToCap) was created.
Partners : ISM, Univ. Bordeaux/Satie, ENS Cachan.


La synthèse organique bordelaise à l’honneur !
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Publication d’un article dans Nature Chemistry - Groupe COMEX
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