Engineered μ-bimodal poly(ε-caprolactone) porous scaffold for enhanced hMSC colonization and proliferation

The use of scaffold-based strategies in the regeneration of biological tissues requires that the design of the microarchitecture of the scaffold satisfy key microstructural and biological requirements. Here, we examined the ability of a porous poly(ε-caprolactone) (PCL) scaffold with novel bimodal-micron scale (μ-bimodal) porous architecture to promote and guide the in vitro adhesion, proliferation and three-dimensional (3-D) colonization of human mesenchymal stem cells (hMSCs). The μ-bimodal PCL scaffold was prepared by a combination of gas foaming (GF) and selective polymer extraction (PE) from co-continuous blends. The microarchitectural properties of the scaffold, in particular its morphology, porosity distribution and mechanical compression properties, were analyzed and correlated with the results of the in vitro cell–scaffold interaction study, carried out for 21 days under static conditions. Alamar Blue assay, scanning electron microscopy, confocal laser scanning microscopy and histological analyses were performed to assess hMSC adhesion, proliferation and 3-D colonization. The results showed that the combined GF–PE technique allowed the preparation of PCL scaffold with a unique multiscaled and highly interconnected microarchitecture that was characterized by mechanical properties suitable for load-bearing applications. Study of the cell–scaffold interaction also demonstrated the ability of the scaffold to support hMSC adhesion and proliferation, as well as the possibility to promote and guide 3-D cell colonization by appropriately designing the microarchitectural features of the scaffold.