MSC differentiation on two-photon polymerized, stiffness and BMP2 modified biological copolymers.

Introduction: Bone tissue regeneration requires a three-dimensional biological setting. An ideal scaffold should enable cell proliferation and differentiation by mimicking structure and mechanical properties of the compromised defect as well as carrying growth factors. Two-photon polymerization (2PP) allows the preparation of 3D structures with a micrometric resolution.

Methods: In this study, 2PP was applied to design scaffolds made from biocompatible methacrylated D,L-lactide-co-ε-caprolactone copolymers (LC) with a controlled porous architecture. Proliferation and differentiation of bone marrow mesenchymal stromal cells on LC was analyzed and compared to a standard inorganic urethane-dimethacrylate (UDMA) matrix. To functionalize LC and UDMA surfaces we analyzed a biomimetic, layer-by-layer coating, which could be modified in stiffness and integration of bone morphogenetic protein 2 (BMP2) and evaluated its effect on osteogenic differentiation.

Results: On LC surfaces, BMSC demonstrated an optimal proliferation within pore sizes of 60-100 μm and showed a continuous expression of Vimentin. On the polyelectrolyte multilayer coating a significant increase in BMSC proliferation and differentiation as marked by Osteonectin expression was achieved using stiffness modification and BMP2 functionalization.

Conclusion: Combining 3D-Design with biofunctionalization, LC offers a promising approach for future regenerative applications in osteogenic differentiation of BMSCs.