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Bio-based polymer hydrogels to control adhesion

Laboratoire Sciences et Ingénierie de la Matière Molle, (SIMM)

Adresse:ESPCI, 10 Rue Vauquelin 75005 Paris

Directeur du laboratoire : Christian Frétigny

Responsables du stage : Yvette Tran, Francisco Cedano, Dominique Hourdet, Costantino Creton

Contact : Yvette Tran

   

Projet scientifique :
 
How does bioadhesion work ? How can we control bioadhesion  ? The wide interest in bioadhesion research is due to its relevance for the development of new biomaterials, therapies and technological products… An understanding of the fundamental mechanisms that govern bioadhesion is essential for the improvement and optimization of biomaterials. While significant experimental and theoretical advances have been made on adhesion of synthetic materials, there is still a clear lack of knowledge on bioadhesion processes. It can be overcome with a systematic control of bio-based adhesives in terms of surface topography, chemically active interactions and viscoelastic properties.

The objective is to go beyond synthetic model systems by using more realistic bio-polymers or bio-based polymer hydrogels . This project is inherently interdisciplinary and bridges polymer surface chemistry with mechanics of soft materials and biomimetics.

Design of bio-based hydrogel surfaces with well-controlled chemistry and topography . We will synthesize biomimetic surfaces with a well-controlled chemistry and topography by adjusting the successful strategy we have developed for synthetic hydrogel films to design bio-based hydrogel surfaces. We plan to fabricate surfaces grafted with hydrogels of gelatins or polysaccharides. Type A and B gelatins will be used as they present different (positive/negative) ionic charges depending on the pH. We will also focus on polysaccharides such as hyaluronic acid, alginic acid and chitosan. The bioadhesive surfaces will need to be well-defined in terms of chemistry (cross-linking density, water content, electrostatic charges and hydrogen bonds available for adhesion) and topography (shape, size and thickness of hydrogel patterns).

Design of biopolymer soft adhesives with a well-defined deformability . We will use the same kind of biopolymers as for the design of surfaces. Special care will be also taken to control systematically the bulk mechanical properties of adhesives as there is a strong coupling between interfacial and viscoelastic properties in adhesion processes. The biopolymer adhesive material should be sufficiently stiff in order not to be damaged during (strong) adhesion tests and not be too soft to be sensitive to the surface topography/roughness on adhesion properties. The viscoelastic properties of the adhesive can be adjusted with the chemical cross-linking.

Adhesion tests in real-life conditions . The underwater adhesion tests are performed using a home-made probe-tack device. The advantage of these tests is to be close to “real-life” conditions that may be encountered in bioadhesion or mucoadhesion. Adhesion tests in physiological buffer conditions and also in various physico-chemistry conditions (pH, salt concentration…) are planned. The underwater adhesion properties will be investigated by varying the viscoelastic properties of the biopolymer adhesive as well as the interfacial (chemical) interactions between the adhesive and the surfaces.

Techniques utilisées : Bio-polymers functionalization ; Bio-polymers cross-linking ; 1H NMR Spectroscopy ; Spin-coating ; Ellipsometry ; Rheology tests ; Underwater probe-tack adhesion tests
 
Références

Evan A. Dubiel, E. A. ; Martin, Y. ; Vermette, P. Bridging the gap between physicochemistry and interpretation prevalent in cell-surface interactions. Chem. Rev. 2011, 111, 2900–2936.
Sudre, G. ; Olanier, L. ; Tran, Y. ; Hourdet, D. ; Creton, C. Reversible adhesion between a hydrogel and a polymer brush. Soft Matter, 2012, 8, 8184-8193.
Li, M. ; Bresson, B. ; Fretigny, C. ; Cousin, F. ; Tran, Y. Submicrometric films of surface-attached polymer networks : temperature-responsive properties. Langmuir, 2015, 31, 11516-11524.
Chollet, B. ; Li, M. ; Martwong, E. ; Bresson, B. ; Fretigny, C. ; Tabeling, P. ; Tran, Y. Multiscale surface-attached hydrogel thin films with tailored architecture. ACS Appl. Mat. Interfaces, 2016, 8, 11729-11738.
 
Qualités du candidat requises : goût pour l’expérience, goût pour la physico-chimie

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