SiO2-CaO-P2O5 sol-gel-derived glass coating on porous β-tricalcium phosphate ceramics

Silicon species have been regarded to be one of the essential trace elements for healthy bone and reported to stimulate osteogenic cells to proliferate and mineralize. In the present work, porous scaffolds of beta-tricalcium phosphate (beta-TCP) were coated with sol-gel-derived bioactive glass or glass-ceramics of 55S (55 mol% SiO2, 41 mol% CaO, 4 mot% P2O5) composition. Skeletal surfaces of the beta-TCP scaffolds were coated with an apatitic compound containing numerous hydroxyl groups through a hydrothermal treatment in distilled water at 140 degrees C for 2 h. After the hydrothermal treatment, the scaffolds were soaked in the 55S sol and then heated at 700-1000 degrees C for 3 h. The 55S glasses with the size of 100 nm in thickness adhered on the skeletal surfaces via the apatitic compound layer. The scaffolds coated with the 55S glass formed hydroxyapatite (HA) layer on their surfaces in simulated body fluid in one day and released silicon species in a cell-culture medium for >= 2 w. The formed HA layer adhered strongly on the skeletal surfaces, since they remained on the surfaces after sonication in distilled water for 15 min. Amount of the silicon-species released from the scaffolds was controllable by changing the heat-treatment temperature on the preparation process of the 55S glass. These results indicate that the porous beta-TCP scaffolds coated with the 55S glass have high potential as materials for bone reconstruction and propose a useful method for preparing a new scaffold having functionalized surface using the sol-gel-derived glasses. (C)2009 The Ceramic society of Japan. All rights reserved.