Properties Of Hydroxyapatite Scaffolds Research Articles

Mechanical and Biological Properties of Magnesium- and Silicon-Substituted Hydroxyapatite Scaffolds.

Magnesium (Mg)- and silicon (Si)-substituted hydroxyapatite (HA) scaffolds were synthesized using the sponge replica method. The influence of Mg2+ and SiO44− ion substitution on the microstructural, mechanical and biological properties of HA scaffolds was evaluated. All synthesized scaffolds exhibited porosity >92%, with interconnected pores and pore sizes ranging between 200 and 800 μm. X-ray diffraction analysis showed that β-TCP was formed in the case of Mg substitution. X-ray fluorescence mapping showed a homogeneous distribution of Mg and Si ions in the respective scaffolds. Compared to the pure HA scaffold, a reduced grain size was observed in the Mg- and Si-substituted scaffolds, which greatly influenced the mechanical properties of the scaffolds. Mechanical tests revealed better performance in HA-Mg (0.44 ± 0.05 MPa), HA-Si (0.64 ± 0.02 MPa) and HA-MgSi (0.53 ± 0.01 MPa) samples compared to pure HA (0.2 ± 0.01 MPa). During biodegradability tests in Tris-HCl, slight weight loss and a substantial reduction in mechanical performances of the scaffolds were observed. Cell proliferation determined by the MTT assay using hBMSC showed that all scaffolds were biocompatible, and the HA-MgSi scaffold seemed the most effective for cell adhesion and proliferation. Furthermore, ALP activity and osteogenic marker expression analysis revealed the ability of HA-Si and HA-MgSi scaffolds to promote osteoblast differentiation.

Effect of alginate on the properties of hydroxyapatite scaffold and cell migration assay study

Abstract This study investigates the effect of alginate concentration and immersion time towards the mechanical properties of hydroxyapatite (HAp) scaffold. Sodium alginate was extracted via neutral extraction from local brown seaweed, Sargassum polycystum. HAp scaffolds were produced from polymer reticulate method and were sintered at 1250°C. HAp scaffolds were immersed in sodium alginate solution at 1%, 3% and 5% concentration under vacuum condition and immersion time of 1, 6, 12 and 24 hours respectively. FTIR spectra confirms the present of functional groups similar to commercially available sodium alginate. Compression test on the HAp scaffolds of different concentration and immersion time shows a significant increase in compression strength of the scaffold of 86.9 kPa for 24 hours of immersion time with 5% concentration of sodium alginate compared to 2.8 kPa of uncoated HAp scaffold. Morphology observation on the surface of HAp scaffolds reveal that the microcracks on the struts were covered by alginate and the coverage was improved as immersion time increased. The increased in compressive strength of scaffold is due to the filled microcrack and struts by sodium alginate. In vitro migration assay revealed that HAp coated alginate enhanced cell migration whereby the cells were able to migrate to fully close the wound however, no significant effect was observed for different alginate concentration used.

Structure control of hydroxyapatite ceramics via an electric field assisted freeze casting method

Using H2O2 aqueous solution as pore-forming agent, hydroxyapatite (HA) porous scaffolds with both lamellar and spherical pores were fabricated by a freeze casting method. The highest porosity was obtained in HA scaffolds prepared using 5vol% H2O2 aqueous solution. The relationship between the electric field intensity and the properties of HA scaffolds was investigated. Results showed that when the electric field intensity was increased from 0 to 90kV/m, the average diameters of lamellar and spherical pores of HA scaffold were increased from 460μm to 810μm, and from 320μm to 420μm, respectively. Vitro cellular assay indicated that HA scaffold with both the lamellar and the spherical pores has a better biocompatibility, compared with that with single pores.

OS0606 ハイドロキシアパタイトScaffoldの力学特性に及ぼす多孔質構造制御の影響

OS0606 ハイドロキシアパタイトScaffoldの力学特性に及ぼす多孔質構造制御の影響

Improvement of Compressive Properties of Porous HA Scaffold by Introducing PCL Secondary Phase

Continuous porous hydroxyapatite (HA) scaffold has been considered to be used in bone tissue engineering. However, the low fracture property of HA scaffold has been a problem to be solved. In the present study, polycaprolactone (PCL) was introduced as a secondary phase into the porous structure of HA scaffold to improve the low fracture property. HA scaffolds were firstly fabricated using the template method. The HA scaffolds were then coated with PCL by changing the solution concentration from 1 to 5 wt%. Compression tests and SEM were done to examine the mechanical properties and the morphology of the two-phase composite scaffolds. It was found that the compression strength and modulus increased with increasing PCL concentration. It is also noted that PCL coating can greatly improve the brittleness of pure HA scaffolds. XRD test was also done to study the phase stability of HA and the two-phase scaffolds. There was no chemical reaction between PCL and HA observed by the XRD results. On the overall, these results indicated that PCL coating can effectively improve the low fracture property of pure HA scaffold and the two-phase scaffold could be a potential candidate for bone regeneration.