Assessment of polyglycolic acid mesh and bioactive glass for soft-tissue engineering scaffolds

Sufficient neovascularization of neotissue is currently a limiting factor for the engineering of large tissue constructs. 45S5 Bioglass® has been investigated extensively in bone tissue engineering but there has been relatively little previous research on its application to soft-tissue engineering. The objectives of this study were to investigate the use of 45S5 Bioglass® in soft-tissue engineering scaffolds using in vitro and in vivo models. A fibroblast cell line (208F) was used for in vitro evaluation of surfaces coated with 45S5 Bioglass®. Increased proliferation of fibroblasts was observed after growth on polystyrene surfaces coated with low concentrations (0.01–0.2% wt/vol) of 45S5 Bioglass® for 24 h in vitro, determined as a change in total cell number by measuring lactate dehydrogenase. At higher concentrations of 45S5 Bioglass® and longer periods of incubation (48 and 72 h) on coated surfaces, cell proliferation was reduced. Light microscopy revealed that the morphology of fibroblasts grown on 45S5 Bioglass®-coated surfaces was not altered at low concentrations, but at higher concentrations fibroblasts became vacuolated. Enzyme-linked immunosorbent assay of conditioned culture medium collected from fibroblasts grown for 24 h on surfaces coated with low concentrations of 45S5 Bioglass® (0.01% wt/vol) was found to contain significantly higher concentrations of vascular endothelial growth factor. Histological examination of polyglycolic acid (PGA)/45S5 Bioglass® composite scaffolds that had been implanted subcutaneously into rats revealed that 45S5 Bioglass®-coated meshes were well tolerated. Light microscopy revealed that neovascularization into 45S5 Bioglass®-coated meshes was significantly increased at 28 and 42 days. Electron microscopy revealed fibroblasts adhering closely to the PGA mesh but not to 45S5 Bioglass® particles. The apparent ability of 45S5 Bioglass® incorporated into scaffolds to increase neovascularization would be extremely beneficial during the engineering of larger soft-tissue constructs.