Characterization and in vivo biological performance of biosilicate

Abstract

After an introduction showing the growing interest in glasses and glass-ceramics as biomaterials used for bone healing, we describe a new biomaterial named Biosilicate. Biosilicate is the designation of a group of fully crystallized glass-ceramics of the Na₂O-CaO-SiO₂-P₂O₅ system. Several in vitro tests have shown that Biosilicate is a very active biomaterial and that the HCA layer is formed in less than 24 hours of exposure to "simulated body fluid" (SBF) solution. Also, in vitro studies with osteoblastic cells have shown that Biosilicate disks supported significantly larger areas of calcified matrix compared to 45S5 Bioglass, indicating that this bioactive glass-ceramic may promote enhancement of in vitro bone-like tissue formation in osteogenic cell cultures. Finally, due to its special characteristics, Biosilicate has also been successfully tested in several in vivo studies. These studies revealed that the material is biocompatible, presents excellent bioactive properties, and is effective to stimulate the deposition of newly formed bone in animal models. All these data highlight the huge potential of Biosilicate to be used in bone regeneration applications.

Figure 1

Evolution of the number of patents related to ceramic and glasses used for bone healing.

Figure 2

Illustration of the mechanism of hydroxycarbonate apatite (HCA) formation on the surface of a bioactive glass in contact with body fluids.

Figure 3

Simplified scheme showing the adhesion of cells to the HCA layer formed in the glass surface (extracted from [8]).

Figure 4

Scheme of the in vitro bioactivity test.

Figure 5

DSC curves of the compositions L1 and K1 [11].

Figure 6

FTIR spectra of Biosilicate nonexposed and exposed to SBF-K9 solution for 24 h, showing the formation of HCA on its surface [11].

Figure 7

SEM micrographs showing the dentin microchannels before the treatment (a) and after treatment with Biosilicate powder (b) (extracted from [16]).