Microarchitectural and mechanical characterization of chitosan/hydroxyapatite/demineralized bone matrix composite scaffold

Porous degradable scaffolds are used extensively in bone tissue engineering. As well as material type, the architectural and mechanical characterizations of scaffolds are important to facilitate cell and tissue growth. Matrices composed of hydroxyapatite (HA), chitosan (CS) and demineralized bone matrix (DBM) may create an appropriate environment for the regeneration of bones. In this study, CS/HA/DBM scaffolds with sufficient structural integrity and high interconnected porosity were produced using different combinations of CS, HA and DBM. Both mechanical and biological properties of porous scaffolds were determined by local microarchitecture whose parameters were quantified based on micro computed tomography (Micro-CT) analysis. Within porosity range of 48-65%, the ranges of average compressive modulus and ultimate strength of the scaffolds were 3 +/- 1-6 +/- 1 kPa and 11 +/- 2-24 +/- 2 kPa, respectively. With the increase of HA concentration at the equal weight of DBM, the average trabecular thickness and trabecular separation increased and bone surface/volume ratio decreased, resulting in higher volume fraction and lower total porosity. In vitro, MC3T3-E1 preosteoblast cells were used to investigate cell attachment, spreading and proliferation on the scaffolds via hematoxyline and eosin (HE), scanning electron microscopy (SEM) and MTS assay. The results showed that MC3T3-E1 cells adhered to the surface of composite scaffolds, cell number increased with culture time. Cell viability increased with the HA particles decreased, changed little with the DBM increased. Consideration of the microarchitectural and mechanical characterization and biocompatibility of the scaffolds, 3:3:1.5 and 3:5:1.5 groups were believed to be the best in our study.