Daisuke Kawagoe

In Vitro Osteogenic Activity of Rat Bone Marrow Derived Mesenchymal Stem Cells Cultured on Transparent Hydroxyapatite Ceramics

Direct observation of cultured cells on various materials has benef it for assessment of fundamental cellular functions including cell attachment, spreading, prol iferation and differentiation on the materials. For this purpose, we made transparent hydroxyapatite (tHA) ceramics, where cultured rat bone marrow-derived mesenchymal stem cells (rMSCs) could be visible by phase contrast microscopy immediately after plating. The seeded rMSCs adhered and proliferated on the tHA ceramics. Furtheremore, the cells cultured on the tHA ceram ics were able to differentiate into osteoblasts under osteogenic conditions and showed comparable osteogenic act ivity to the cells cultured on tissue culture polystyrene dishes. The results suggested tha cultured cells could be monitored in a time dependent manner using the tHA ceramics.

In Vitro Osteogenic Activity of Rat Mesenchymal Cells Cultured on Transparent β-Tricalcium Phosphate Ceramics

We have cultured mesenchymal cells (MSC) on various types of ceramic disks and used these tissue-engineered ceramics for hard tissue regeneration. In this approach, observation of cultured cell morphology is important even if culture substrata are calcium phosphate ceramics, which usually show bioactive nature. However, due to the opaque nature of the ceramics, cells observation is very difficult. Here, we demonstrate light microscopic observation of rat MSC cultured on transparent β-tricalcium phosphate ceramics (β-TCP). The culture was performed in osteogenic medium. Thus, the cell differentiated into bone-forming osteoblasts, which fabricated a mineralized matrix on the ceramic disks. Microscopic observation revealed that the cascade of osteogenic differentiation after attachment/proliferation of MSC on the ceramic disks was similar to that on a culture grade polystyrene dish. These results confirmed the excellent property of β-TCP for MSC culture leading to hard tissue regeneration.

Densification process of OH controlled hydroxyapatite ceramics by spark plasma sintering

Calcium hydroxyapatite, Ca10(PO4)6(OH)2:HA, is the inorganic principle component of natural bones and teeth. It has been already suggested that the amount of OH ion in the crystal structure of HA is closely related to the biocompatibility. The amount of OH ion in current HA, however, has not been controlled. In order to prepare more functional HA ceramics, the amount of OH ion must be controlled. In this study, HA ceramics with different OH amount were prepared from fine HA crystals by spark plasma sintering (SPS). In order to reveal the ideal sintering conditions for preparation of transparent ceramics, densification process on SPS was investigated. The samples were pressed uniaxialy under 60 MPa, and then they were heated by SPS at 800 °C, 900 °C and 1000 °C for 10 min with the heating rate of 25 °C⋅min−1. The quantity of OH ion in HA ceramics sintered by SPS was decreased with increasing temperature of sintering. Transparent HA ceramics were prepared by SPS at 900 °C and 1000 °C. In analysis of the den...

Effect of Hydrothermal Treatment on Sinterability of Hydroxyapatite

Calcium hydroxyapatite, Ca10(PO4)6(OH)2:HA, is the inorganic principle component of natural bones and teeth. It has been already suggested that the amount of OH ion in the crystal structure of HA is closely related to the biocompatibility. The amount of OH ion in current HA, however, has not been controlled. In order to prepare more functional HA ceramics, the amount of OH ion must be controlled. In this study, HA ceramics with different OH amount were prepared from fine HA crystals by spark plasma sintering (SPS). Fine powder of HA was treated hydrothermally at 200 °C for 24 h with pH 10 NH3 aqueous solution. The samples were pressed uniaxialy under 60 MPa, and then they were SPS at 800 °C, 900 °C and 1000 °C for 10 min with the heating rate of 25 °C⋅min−1. No phases other than HA were revealed by XRD for the starting samples after hydrothermal treatment and samples after sintering by SPS at 800 °C, 900 °C and 1000 °C for 10 min. The quantity of OH ion in HA ceramics sintered by SPS was decreased with in...