Medical and Health Sciences
Carla C. I. Palomino Durand(1)*, Alice Gauzit-Amiel(1), Marco Lopez(2), Fréderic Cazaux(2), Bernard Martel(2), Nicolas Blanchemain(1), Feng Chai(1)
(1) Univ. Lille, Inserm, CHU Lille, U1008 – Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
(2) Univ. Lille, CNRS, INRA, ENSCL UMR8207, UMET – Unité Matériaux et Transformations, F-59000 Lille, France
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 to deliver bioactive agents. Chitosan (CS), a natural cationic polymer, is an excellent excipient to prepare hydrogels due to its non-toxicity, biodegradability, and capacity to form composite scaffolds with other polymers or inorganic materials. 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, based on polyelectrolyte complex of CS with an anionic polymer of cyclodextrin (PCD) that could be use for bone TE.
A CS with a deacetylation degree of 73.3% and a molecular weight of 150 kDa was used in this study. Hydrogels were prepared by firstly co-milling the powder of CS and PCD in a mixer mill (10 Hz, 3 min) to obtain a CS/PCD powder. Then the collected 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 used. The obtained hydrogels were characterized by assessing their cohesion in phosphate-buffered saline (PBS, pH 7.4) and their rheological properties. Sponges were obtained by freeze-drying the hydrogels and thermo-treated at 140°C for 1.5 h. The microstructure, the swelling behavior and the degradation rate of sponges were evaluated. Response of pre-osteoblast cells (MC3T3-E1, ATCC) to the extract of sponges and to the sponges was evaluated via AlamarBlue® assay and scanning electronic microscope.
For both CS:PCD ratios, hydrogels showed a good cohesion in PBS till 1 h after injection in PBS, and rheological analysis indicates similar viscoelastic properties. In general, all sponges showed a high swelling rate (up to 3 times of its dry weight). The degradation study showed a similar profile for both ratios and reached a plateau after 24 h up to 5 days (~13% weight loss). All sponges presented a porous microstructure, good cytocompatibility (cell survival >95%) and cell adhesion inside the sponge was also demonstrated.
To conclude, CS/PCD hydrogels were developed and the ratios studied showed very similar characteristics both in hydrogels and in sponges. These promising materials could be injected into bony void or transformed into 3D sponge scaffolds for bone TE, respectively. Incorporation of hydroxyapatite into hydrogel will be studied for further improving their properties.
This work was developed thanks to the financing of Cienciactiva (CONCYTEC-PERU).