CaO-B2O3-SiO2 glass fibers for wound healing

Abstract

It was reported by Jung and Day in 2011 that a cotton-like glass fiber pad made of borate glass 13-93B3 demonstrated a remarkable wound healing effect. It was approved for sale as a novel wound dressing in the management of acute and chronic wounds in 2016. However, the detailed mechanism of its wound healing effect has not been reported. In the present study, glass fibers of different composition in the system CaO-B₂O₃-SiO₂ were prepared and their in vitro properties investigated to determine the role of the constituent components in wound healing. Fine glass fibers that were 0.6-2.0 μm in diameter were obtained by a melt blown method. However, these fibers were accompanied by small glass beads because of the low viscosity of the glass melts. 13-93B3 glass released an appreciable amount of borate and calcium ions into simulated body fluid (SBF). The amounts of these released ions decreased with partial replacement of the B₂O₃ in 13-93B3 with SiO₂. The addition of large amounts of the borate and calcium ions into the culture medium decreased the viability of the L929 fibroblasts. Partial replacement of the B₂O₃ in 13-93B3 with SiO₂ induced the formation of an apatite-like phase amenable to the adsorption of biological components on its surface in SBF. The wound healing effect of these glass fibers of different composition is worth examining in future animal experiments.

Fig. 1

Compositions of examined glasses, which were plotted in the compositional triangle CaO-B₂O₃-SiO₂

Fig. 2

Schematic representation of preparation of glass fibers

Fig. 3

SEM pictures of as-prepared glass fibers

Fig. 4

Powder XRD patterns of glasses fibers

Fig. 5

DTA profiles of glass fibers. ∇ Glass transition temperature ▼Crystallization temperature

Fig. 6

Thin-film XRD patterns of the surfaces of the glasses after soaking in SBF for 1 week. • Apatite, ∇ Silica gel, □ NaCl

Fig. 7

Effect of (a) pH and concentrations of (b) calcium, and (c) borate ions in the medium on cell viability of L929 cells

Fig. 8

Effect of low amount of calcium and borate ions on cell viability of L929 cells. *, **: statistical significant difference against control

Fig. 9

Effect of released ions extracted from 13-93B3 and S3 glass fibers on cell viability of L929 cells after culture periods of (a) 1 and (b) 3 days

Fig. 10

Concentrations of calcium, borate and silicate ions released from the glasses into SBF for 2 days as a function of (a) SiO₂ and (b) B₂O₃ contents of glasses