Composite membranes of poly(ϵ-caprolactone) with bisphosphonate-loaded bioactive glasses for potential bone tissue engineering applications

Abstract

Poly(ϵ-caprolactone) (PCL) is a bioresorbable synthetic polyester with numerous biomedical applications. PCL membranes show great potential in guided tissue regeneration because they are biocompatible, occlusive and space maintaining, but lack osteoconductivity. Therefore, two different types of mesoporous bioactive glasses (SiO2-CaO-P2O5 and SiO2-SrO-P2O5) were synthesized and incorporated in PCL thin membranes by spin coating. To enhance the osteogenic effect of resulting membranes, the bioglasses were loaded with the bisphosphonate drug ibandronate prior to their incorporation in the polymeric matrix. The effect of the composition of the bioglasses as well as the presence of absorbed ibandronate on the physicochemical, cell attachment and differentiation properties of the PCL membranes was evaluated. Both fillers led to a decrease of the crystallinity of PCL, along with an increase in its hydrophilicity and a noticeable increase in its bioactivity. Bioactivity was further increased in the presence of a Sr substituted bioglass loaded with ibandronate. The membranes exhibited excellent biocompatibility upon estimation of their cytotoxicity on Wharton's Jelly Mesenchymal Stromal Cells (WJ-SCs), while they presented higher osteogenic potential in comparison with neat PCL after WJ-SCs induced differentiation towards bone cells, which was enhanced by a possible synergistic effect of Sr and ibandronate.