Phosphorous pentoxide-free bioactive glass exhibits dose-dependent angiogenic and osteogenic capacities which are retained in glass polymeric composite scaffolds

Abstract

Bioactive glasses (BGs) are attractive materials for bone tissue engineering because of their bioactivity and</p><p>osteoinductivity. In this study, we report the synthesis of a novel phosphorous pentoxide-free, silicatebased</p><p>bioactive glass (52S-BG) composed of 52.1% SiO2, 23.2% Na2O and 22.6% CaO (wt%). The glass</p><p>was thoroughly characterized. The biocompatibility and osteogenic properties of 52S-BG particles were</p><p>analyzed in vitro with human adipose-derived mesenchymal stem cells (AdMSCs) and human osteoblasts.</p><p>52S-BG particles were biocompatible and induced mineralized matrix deposition and the expression of</p><p>osteogenic markers (RunX2, alkaline phosphatase, osteocalcin, osteopontin, collagen I) and the angiogenic</p><p>marker vascular endothelial growth factor (VEGF). Angiogenic properties were additionally</p><p>confirmed in a zebrafish embryo model. 52S-BG was added to poly-ε-caprolactone (PCL) to obtain a</p><p>composite with 10 wt% glass content. Composite PCL/52S-BG scaffolds were fabricated by additive manufacturing</p><p>and displayed high porosity (76%) and pore interconnectivity. The incorporation of 52S-BG particles</p><p>increased the Young’s modulus of PCL scaffolds from 180 to 230 MPa. AdMSC seeding efficiency</p><p>and proliferation were higher in PCL/52S-BG compared to PCL scaffolds, indicating improved biocompatibility.</p><p>Finally, 52S-BG incorporation improved the scaffolds’ osteogenic and angiogenic properties by</p><p>increasing mineral deposition and inducing relevant gene expression and VEGF protein secretion. Overall,</p><p>52S-BG particles and PCL/52S-BG composites may be attractive for diverse bone engineering applications</p><p>requiring concomitant angiogenic properties.