Novel chitosan-coralline composite biomatrices for bone tissue engineering applications : microarchitectural features and in vitro mesenchymal stem cell responses
Notice bibliographique
Résumé
The purpose of this work was to develop novel 3D coralline-chitosan macroporous composite scaffolds for in vitro bone tissue engineering and investigate cellular responses to these scaffolds. In these composites, coral skeletal material, which is made of calcium carbonate (CaCO3), was simultaneously used as particulate reinforcing phase and gas-forming agent to obtain a structure with large pores and improved mechanical and biological properties. The reaction between the coralline material and the acidic chitosan polymer solvent, which produces carbon dioxide (CO2), was rapidly stopped by the subsequent thermally induced phase separation step, leaving coral particulates in the polymeric structure. Scaffolds containing 5 different proportions of coralline material (0, 25, 50, 75, and 100 wt%) were developed and studied under two different aspects. In a first part, the coralline:chitosan weight ratio parameter was studied for its effects on the physical properties of the scaffolds with a combination of scanning electron microscope (SEM), micro-CT imaging, and compression testing. In a second part, the scaffolds were cultured with mice MSCs. Cellular morphology, DNA content, as well as expression of osteogenic markers alkaline phosphatase (ALP) activity and osteocalcin release were evaluated. The effect of cell culture medium supplementation with beta-glycerophosphate and dexamethasone was studied. The results showed that higher coralline concentration increased the pore wall thickness and favoured large pore formation. Varying the coralline powder to chitosan polymer ratio from 0 to 75 wt% increased the observed pore sizes from 80 microm to 400 microm in average and decreased the porosity from 91% to 78%. The equilibrium compressive modulus was improved proportionally with the coral content, and the 75 wt% composites had a significantly higher modulus than all the other chitosan-based scaffolds. The coralline scaffolds showed by far the highest evaluation of cell number and ALP activity over all the other chitosan-based scaffolds. They were the only materials on which the osteocalcin protein was release throughout the study and generally at a high level. Nevertheless, the coralline:chitosan composite scaffolds containing high coralline ratios generally showed higher results than the pure chitosan scaffolds. Of all the chitosan-based scaffolds, the cells cultured on the 75:25 coralline:chitosan scaffolds obtained the highest peak of ALP activity and generally obtained the highest cell number. While the presence of osteogenic supplements had no obvious effect on cell behaviour and osteogenic differentiation, distinct cell morphology and osteoblastic phenotype expression were observed depending on the coralline to chitosan ratios composing the scaffolds. The results strongly suggest that coralline:chitosan composites, especially those having a high coralline content, may enhance adhesion proliferation and osteogenic differentiation of MSCs in comparison with pure chitosan. In conclusion, composite scaffolds with improved mechanical and biological properties concomitant with large pores were achieved by increasing the coralline:chitosan weight ratio. These composites possess therefore many advantages over coralline and chitosan scaffolds, suggesting that they have an excellent potential as biomatrices for tissue engineering.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».