Observing the Responses of the Interface Between New Bioactive Glasses and Human Osteoblast Cells (HOCs) by TEM

The purpose of this study was to investigate differences in the interface between new bioactive glasses (RKKP, RBP1, RBP2) and mirror-polished titanium alloys in the evaluation of human osteoblast cells (HOCs) by TEM. Mirror-polished titanium alloy (MTi), bioactive glass (RKKP, RBP1, RBP2), and plastic culture dishes (Falcon [F]; used as a control) were used in this study. 1.0×105 HOCs were plated on each of the materials and cultured for 1 week. For TEM, HOCs were fixed in 2.5% glutaraldehyde, post-fixed in 1% osmium tetroxide, dehydrated, and embedded in Epon 812. After polymerization for 48 hours, the sample was removed with liquid nitrogen, and the specimen was re-embedded in Epon 812, sliced into 200-nm-thick semithin sections, and stained with a mixture of 1% toluidine blue, 1% Azur II, and 1% borax. After confirming the presence of cells, the specimens were sliced at a thickness of approximately 78 nm, double-stained with uranyl acetate and lead citrate, and examined under a TEM. As results, In Falcon, we found an extremer on the material side, focal contact, and close contact in parts of the plate. In M-Ti, we observed a non-structured homogeneous layer. In RBP1 and RBP2, an intervening layer with a gel like condition of approximately 100 nm in thickness was observed. In RKKP the collagen fibers bonded directly, indicating the presence of a bone matrix of HOCs at all sites. In conclusion, the interface between the different bioactive materials and the bio-inactive material showed completely different phenomena. Furthermore, even the same bioactive materials showed different patterns because of their different composition. From these results, we concluded that RKKP might be the best biomaterial because it bonded directly to human osteoblast cells without an intervening layer