Effect of bioactive glass particles on osteogenic differentiation of adipose-derived mesenchymal stem cells seeded on lactide and caprolactone based scaffolds.

Incorporation of bioactive glass (BG) particles to synthetic polymer scaffolds is a promising strategy to improve the bioactivity of bioinert materials and to stimulate specific cell responses. In this study, the influence of incorporating BG particles to lactide and caprolactone based porous scaffolds on osteogenic differentiation of adipose-derived stem cells (ASCs) was analyzed. Accordingly, ASCs were seeded on poly(L-lactide) (PLLA), poly(ε-caprolactone) (PCL), or poly(L-lactide-co-ε-caprolactone) (PLCL) scaffolds containing 15 vol % of BG particles in two culture conditions: standard versus osteogenic culture medium. In standard culture medium, incorporation of BG to a PLLA scaffold increased the ALP activity with respect to its unfilled counterpart (ca. 1.2- and a 1.6-fold increase over 7 and 14 days, respectively). Moreover, in all the studied polymers the incorporation of BG induced a slightly higher production of mineralized matrix by ASCs, but the differences observed were not statistically significant. In the osteogenic medium, the effect of BG was masked by the effect of osteogenic supplements in the long-term. However, in the short-term (day 7), BG particles induced an early ALP activity of predifferentiated osteoblasts on PLLA and PCL scaffolds and higher matrix mineralization on PCL scaffolds. In summary, the addition of BG particles to PLLA and PCL scaffolds sustains ASC osteogenic differentiation, facilitates mineralization and induces the formation of a hydroxyapatite layer on the surface of the polymer scaffolds.