The in vitro response of osteoblasts to bioactive glass.

Osteoblasts from neonate rat calvaria migrated in culture from the endocranial surface of parietal bones onto fragments of bone-bonding 45S5 glass or non-bone-bonding quartz glass. These organ culture units were maintained for up to 4 wk. No significant production of extracellular matrix (ECM) was seen on the quartz glass samples. However, osteoblasts colonized the 45S5 samples in multilayers and produced abundant ECM as seen by light (LM), scanning electron (SEM) and transmission electron (TEM) microscopy. The interface developed on 45S5 glass was designated as either Type I (non-collagen-bonding) or Type II (showing direct interdigitation of collagen with the calcium phosphate-rich glass surface). It was concluded that, since this in vitro method is capable of reproducing some aspects of the known in vivo behaviour of 45S5, such techniques may be developed as a means of batch-testing bioactive biomaterials and investigating bone cell/biomaterial interactions.