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Background: In the process of bone defective reparation and engineered bone tissue construction, osteoblasts are adhered to the surface of the scaffold materials and impart the external mechanical load to the osteoblasts. So, the dynamic mechanical property of the scaffolds play an important role in the bone tissue repair and it is valuable to research. Material type and the architectural design of scaffolds are also important to facilitate cell and tissue growth. The aim of this study was to prepare a kind of material with good pore connectivity and analyze its dynamic mechanical property.Methods: Fabrication and characterization of micro-hydroxyapatite(m-HA)/chitosan(CS) polymer composite scaffolds with well interconnected spherical pore architectures were reports. Micro-HA was prepared by being calcined and ball milled. Paraffin spheres in the range of 160-330 µm were fabricated with a dispersion method and used as the porogen in the fabrication of the scaffolds. Polymer scaffolds were fabricated by the technique of compression molding and particulate leaching method. The effects of the porogen content on the properties of the scaffolds were studied.Results: With the increase of porogen, the pore of the scaffolds increased and became interconnected. Cyclic loading of three scaffolds were tested with 10 % strain under four levels of loading frequency, 0.1, 0.5, 1 and 1.5 Hz. The porous composite scaffolds exhibited a viscosity-elastic behaviour with a maximum stress of 3-4 kPa. At each frequency, modulus value is decreased with the paraffin microspheres content, but there was no significance difference in the peak stress of the three samples. All the samples tested displayed clear hysteresis loops. There was no significance difference in the peak hysteresis of the three samples, and the hysteresis difference values between the sixth compression cycle and the initial cycle for three samples was similar, with no statistically significant differences.Conclusions: Micro-HA/CS composite scaffolds with interconnected spherical macropores were fabricated using pherical paraffin as porogen. The porous composite scaffolds exhibited a viscosity-elastic behaviour with good repeatability. It is benefit to study the influence of the mechanical load on the cell of the scaffold. [ABSTRACT FROM AUTHOR]

The property of collagen–chitosan porous scaffold varies according to cross-linking density and scaffold composition. This study was designed to compare the properties of collagen–chitosan porous scaffolds cross-linked with γ-irradiation and carbodiimide (CAR) for the first time. Eleven sets of collagen–chitosan scaffolds containing different concentrations of chitosan at a 5% increasing gradient were fabricated. Fourier transform infrared spectroscopy was performed to confirm the success of cross-linking in the scaffolds. The scaffold morphology was evaluated under scanning electron microscope (SEM). SEM revealed that chitosan was an indispensable material for the fabrication of γ-ray irradiation scaffold. The microstructure of γ-ray irradiation scaffold was less stable than those of alternative scaffolds. Based upon swelling ratio, porosity factor, and collagenase degradation, γ-ray irradiation scaffold was less stable than CAR and 25% proportion of chitosan scaffolds. Mechanical property determines the orientation in γ-irradiation and CAR scaffold.In vitrodegradation test indicated that γ-irradiation and CAR cross-linking can elevate the scaffold biocompatibility. Compared with γ-ray irradiation, CAR cross-linked scaffold containing 25% chitosan can more significantly enhance the bio-stability and biocompatibility of collagen–chitosan scaffolds. CAR cross-linked scaffold may be the best choice for future tissue engineering. [ABSTRACT FROM PUBLISHER]