Characterization of CO3Ap-collagen sponges using x-ray high-resolution microtomography

For reconstruction and regeneration of hard tissues, scaffold biomaterials with large size pores and high porosity are important, in addition to their roles as supporting frames. To develop a new biodegradable scaffold biomaterial, CO(3)Ap, which has crystallinity and a chemical composition similar to bone, was synthesized at pH 7.4 and 60degreesC. Then, the CO(3)Ap was mixed with a neutralized collagen gel and the CO(3)Ap-collagen mixtures with different kinds Of CO(3)Ap contents and porosity were lyophilized into sponges. Scanning electron micrography (SEM) observation Of CO(3)Ap-collagen sponges showed favorable pores for cell invasion. Approximately 50-300 mum size pores appeared to continue through the bulk. Higher magnification of the sponge showed a better adhesion between CO(3)Ap crystals and collagen. X-ray high-resolution microtomography revealed a clear image of the 3D structure of the sponges. The porosity of 0, 70 and 90%(w/w) CO(3)Ap-collagen sponges was 79.2 +/- 2.8%, 72.6 +/- 2.4% and 48.9 +/- 6.1%, respectively. The 70%(w/w) CO(3)Ap-collagen sponge appeared to be the most favorable biomaterial from the viewpoint of natural bone properties. Mouse osteoblast MC3T3-E1 cells were cultured in alphaMEM with 10% FCS for 2 weeks. Hematoxylin-eosin staining confirmed osteoblast cells invaded well into the CO(3)Ap-collagen sponge. These sponges are expected to be used as hard tissue scaffold biornaterials for therapeutic uses. (C) 2003 Elsevier Ltd. All rights reserved.