Morphologies, dynamics & functions of assemblies of amphiphiles |
Dr. Reiko OdaResearch director (DR2), CNRS This e-mail address is being protected from spambots. You need JavaScript enabled to view it Tel: +33(0)540002229  BioReiko Oda, after obtaining a bachelor degree in physics at the University of Tokyo in 1988, got her PhD in Physics at the Massachusetts Institute of Technology in 1994 under the supervision of Pr. D. Litster. She then had four years of postdoctoral position in the laboratory of S. J. Candau at University Louis Pasteur (Strasbourg). She joined the IECB on 1998 as a group leader. Her research deals with the structural study and design of aggregates of amphiphilic molecules and their interactions with biological polyions, as well as functionalization of such aggregates. Keywords / Expertise / Techniquesamphiphilic molecules, surfactant, lipid, gel, molecular recognition, functional molecular assemblies, self-assembled fibrillar network, micelles, vesicle / x-ray, neutron, light scat- tering, electron microscopy, optical microscopy, IR, CD, spectroscopy  SummaryThe team is interested in understanding the mechanism of formation of molecular assemblies in order to design and build new nanometric molecular assembly systems of amphiphilic molecules, the morphologies and functions of which can be finely tuned. This requires first of all understanding the role of different parameters (molecular architecture and various physico-chemical parameters) upon such molecular assemblies. Once the control of the assembly formation at the molecular level is achieved, their functionalization can be envisaged. The assemblies can therefore serve as the support for the biomolecular structure formation or the induction of interaction between the aggregates via molecular recognition.  Activity reportOur activities are divided in several subjects as shown below:
We combine experimental and computational approach to rationalize the century old problem: ion specific effect on the balance of forces controlling aggregates structure. We investigate the aggregation behaviors of cationic amphiphilic molecules in the presence of various counterions such as Halide anions, alkyl carboxylates and aromatic carboxylates in order to elucidate the complex effects of ion properties (ionic volume, pKa, nucleophilicity, polarizability, etc.) on the properties of molecular self-assemblies from the molecular level to the bulk solution. ( J. Phys. Chem. B 2008, Langmuir 2010) We have obtained an international collaborative grant ANR-blanc International for a collaborative work between Michel Laguerre (IECB, molecular dynamics), Dario Bassani (ISM, Photochemist), and colleagues from Rutgers University : Larry Romsted (physical organic chemist: chemical trapping technique), Ronald Sauers (DFT calculation), David Case (MD/DFT approach) in order to elucidate the interface properties of amphiphilic assemblies in terms of counterion and water concentration. We are interested in the mechanism of formation of chiral mesoscopic molecular assemblies. We have shown that when complexed with tartrate anions, cationic surfactants form chiral ribbon which express supramolecular chirality of the order of 10 nm to microns. The morphologies of these chiral assemblies can be controlled with a number of parameters (Nature 1999, JACS 2007). The detailed study of these systems allowed us to better understand the mechanism of the chirality transfer from chiral counterions to achiral membranes from molecular level up to mesoscopic level. (JACS 2002, J. Phys. Chem. A 2004, JACS 2008, Chirality 2009). When the same cationic surfactants are complexed with peptides or nucleotides, they form simplified model systems which mimic the lipid-protein interaction, or lipid-nucleotide interaction (Figure 1). (ChemCommun 2007, Chem. Eur. J. 2011) Remarkably, the chirality of peptides and nucleotides also lead to the expression of supramolecular chirality of the assemblies. Such reciprocal and cooperative effects between membranes and counterions, seem to be general in the case of the systems studied here. Figure 1. Chiral ribbons induced by complex cationic surfactant-anionic peptides; confined peptides form ß sheet
We have developed a method to synthesize well controlled chiral inorganic nanostructures based on the sol-gel transcription of organic self-assemblies. These inorganic structures can then be functionalized to serve as templates for confining nanoparticles (see figure 2). (Nanoletters 2008, ANR Blanc grant 2010.) Â Figure 2. (left) organic nanotubules are used as template to form silica nanohelices . (right) Silica nanohelices are functionalized and their use in catalysis, cell-adhesion or NEMS are investigated Self assembled nanocatalysts As of January 2011, Sylvain Nlate, an associate professor (Mdc) specialised in dendrimers and catalysis has joined the group. We started a totally new project concerning the design of new catalysis systems for asymmetric oxidation reactions using tunable nanometrical chiral molecular assemblies.
 Selected publications
 Research team
The team is part of the unit "Chimie et Biologie des Membranes et Nanoobjets" (CBMN), CNRS/Université bordeaux 1/IPB (UMR 5248) |