Fabrication Of HA Porous Scaffold By Freeze-Drying

A new porous ceramic preparing method, freeze-drying has been developed in recent years. It provides lamellar pores by removing the liquid from frozen body. The character of lamellar pores can be controlled by freeze-drying parameter and sintering temperature. In this paper, the porous hydroxyapatite (HA) scaffolds with lamellar pores structure were fabricated by freeze-drying. The properties including pores morphology, size, and distribution were investigated; the mechanical properties were tested by Instron5565 material testing. The results show that the scaffolds have an open, unidirectional and interconnected lamellar structure with a porosity between 45～85%, and with pore size between 50～400μm, The volume fraction of HA powder played an important role preparing of the scaffolds. The volume fraction of HA powder between 30～35% could fabricate lamellar scaffold, while slurry with HA powder 30%vol could obtain scaffold with porosity between 60～65%. The pore size of HA scaffold were controlled by freeze temperature, when the temperature were -10℃,-30℃and -196℃respectively, the pore size were 350～400μm,200～250μm,50～100μm.The results of compressive have a great relationship with porosity and pore size distribution; the compressive strength decrease gradually with the increasing of porosity and pore size. When sintered temperature and time was 1250℃, 2～6h, the compressive strength of 7.9MPa was obtained at porosity 65%, and pore size 200～250μm.The porous scaffold was proved to have a good compatible by vitro cellular assay. The osteoblast-like cells were attached and spread well throughout the porous scaffold, while the pore size and the porosity were 200～250μm and 65%, the absorbance of HA scaffold was 0.26 Arbit.unit.