Osteoblast Behavior at the Surface of CO3Ap-Collagen Sponges
Carbonate apatite (CO3Ap) was synthesized at 60+1°C and pH 7.4+0.2, to develop a new biodegradable scaffold biomaterial. The synthetic CO3Ap was mixed with a neutralized collagen gel and the CO3Ap-collagen mixtures with different kinds of CO3Ap contents and porosity were frozen and dried in lyophilized into the sponges. CO3Ap-collagen mixtures were also lyophilized into sponges in a HAp frame ring with 0.5 mm pores. To examine the degree of cell invasion, mouse MC3T3-E1 cells were grown in αMEM with 10% heat-inactivated FBS in 96-well plates containing the CO3Ap-collagen sponges at 37°C in a 5% humidified atmosphere. Under pentobarbital anesthesia, samples of UV-irradiated CO3Ap-collagen sponges with frames were surgically implanted beneath the periosteum cranii of rats. SEM observation of CO3Ap-collagen sponges showed favorable pores for cell invasion. Approximately 50~300 µm size pores seemed to continue into the deep bottom. X-ray high-resolution microtomography revealed a clear image of 3D structure of the sponges. 70 wt% CO3Ap-collagen sponge seemed to be most favorable biomaterial from the viewpoint of the natural bone properties. Then, to avoid the shrinkage of the sponges, we successfully made a hybridized CO3Ap-collagen sponge with a frame. When these sponge-frame complexes were implanted beneath the periosteum cranii of rats, newly created bone was observed toward the inner core of the complex from the surface of the periosteum cranii.
Takashi Nakamura, Kimihiro Yamashita and Masashi Neo
M. Okazaki et al., "Osteoblast Behavior at the Surface of CO3Ap-Collagen Sponges", Key Engineering Materials, Vols. 309-311, pp. 989-992, 2006