Résumés disponibles (92) :

PALOMINO DURAND Carla Cynthia Ines (INSERM U1008 - Feng CHAI)
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@mail :  carla.palominodurand@univ-lille2.fr      tél. :  03 20 62 69 75

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Titre de la communication :
Chitosan/poly-cyclodextrin hydrogels and sponges for bone tissue engineering application
Auteurs (et leurs adresses) de la communication :
C. Palomino Durand1, A. Gauzit-Amiel1, M. Lopez2, F. Cazaux2, B. Martel2, N. Blanchemain1, F. Chai1 - 1 Univ. Lille, Inserm U1008, 2 Univ. Lille, CNRS, INRA, EENSCL UMR8207, UMET.
Résumé de la communication :
INTRODUCTION: Bone defect repair using the tissue engineering (TE) approach is viewed as an efficient alternative to the traditional use of bone grafts. Hydrogels, as well as sponges, can be used as TE scaffolds to mimic extracellular matrix topography and deliver bioactive agents that promote tissue regeneration. Chitosan (CS), a natural cationic polymer, is an excellent excipient to prepare hydrogels due to its non-toxicity, stability, good biodegradability, and capacity to form composite scaffolds with other polymers or inorganic materials. The preparation of a CS-hydrogel is either physically associated or chemically cross-linked. A physical CS-hydrogel preparation by non-covalent strategies avoids the use of cross-linkers, and consequently the cytotoxicity thereof. The aim of this study is to develop a physical hydrogel for bone TE, based on polyelectrolyte complex composed of CS and an anionic polymer of cyclodextrin (PCD).
EXPERIMENTAL METHODS: A CS, with a deacetylation degree of 74.6% and a molecular weight between 190-310 kDa, was selected for this research following a pilot study. Hydrogels were prepared by firstly co-milling the powder of CS and PCD in a Mixer Mill device to obtain a well dispersed and refined CS/PCD powder. Then this powder was mixed with a 1% lactic acid solution by two interconnected syringes. Different CS:PCD ratios, i.e. 3:3 and 3:5 w/w, were studied to obtain hydrogels with good cohesion in phosphate-buffered saline (PBS, pH 7.4) and desired rheological properties. Sponge samples were obtained by freeze-drying the hydrogels and further thermo-treated at 140°C for 1.5 h. The microstructure (scanning electron microscopy), the swelling behavior (weight gain) and degradation rate (weight loss) of sponges were evaluated. Finally, the cell response of pre-osteoblast cells (MC3T3-E1, ATCC) to the extract of hydrogels and sponges was assessed by AlamarBlue® assay, according to the ISO 10993-5 standard.
RESULTS: For both CS:PCD ratios tested, the hydrogels showed a good cohesion up to 1 h after injection in PBS and similar viscoelastic properties. In general, all of the sponges showed a high swelling rate in 1h (up to 3 times of its dry weight). The degradation study showed a similar profile for both ratios and reached a plateau (~13% weight loss) after 24h up to 5 days. All sponges presented a porous microstructure and good cytocompatibility (cell survival > 87%).
CONCLUSION: A satisfying CS/PCD hydrogel and sponge can be formed with both tested CS:PCD ratios. These promising materials could be applied as injectable hydrogel or sponge scaffolds for bone TE, respectively. Thus, further study will include the incorporation of hydroxyapatite in order to improve their mechanical properties and enhance their osseointegration.

PALOMINO DURAND Carla Cynthia Ines (INSERM U1008 - Feng CHAI)