Journal of the American Ceramic Society, Vol.97, No.11, 3501-3509, 2014
In Vitro Degradation and Conversion of Melt-Derived Microfibrous Borate (13-93B3) Bioactive Glass Doped with Metal Ions
Microfibrous melt-derived bioactive glasses based on a borate 13-93B3 composition are showing a considerable capacity to heal chronic soft tissue wounds in humans and animals. Metal ion dopants in borate 13-93B3 microfibers can be beneficial for healing soft tissue wounds and bone defects but their role and delivery have received little attention. In this study, the effect of selected metal ion dopants on the degradation and conversion of 13-93B3 microfibers in simulated body fluid at 37 degrees C was investigated. Two groups of microfibers (diameter = 0.2-3m) composed of 13-93B3 glass (composition 6 Na2O, 12 K2O, 5 MgO, 20 CaO, 4 P2O5, 53 B2O3, wt%) doped with (1) CuO (0.4 wt%) + ZnO (1.0 wt%); and (2) CuO (0.4 wt%) + ZnO (1.0 wt%) + Fe2O3 (0.4 wt%) + SrO (2.0 wt%) were studied. The metal ion dopants had little effect on the degradation of the parent 13-93B3 glass microfibers and their conversion to an amorphous calcium phosphate (ACP) product but they inhibited the crystallization of the ACP to HA. The release of Cu and Sr ions from the glass into the medium was considerably higher than Zn and Fe ions which were retained mainly in the ACP or HA product. These results are pertinent to the design of borate bioactive glasses for optimum healing of soft tissue wounds and bone.