We have previously examined osteoblast behaviour on porous collagen-glycosaminoglycan (CG) scaffolds with a range of mean pore sizes demonstrating superior cell attachment and migration in scaffolds with the largest pores (325μm). Scaffolds provide a framework for construct development; therefore, it is crucial to identify the optimal pore size for augmented tissue formation. Utilising the same range of scaffolds (85μm - 325μm), this study aimed to examine the effects of mean pore size on subsequent osteoblast differentiation and matrix mineralisation, and to understand the mechanism by which pore size influences behaviour of different cell types. Consequently, primary mesenchymal stem cells (MSCs) were assessed and their behaviour compared to osteoblasts. Results demonstrated that scaffolds with the largest pore size (325μm) facilitated improved osteoblast infiltration, earlier expression of mature bone markers osteopontin (OPN) and osteocalcin (OCN), and increased mineralisation. MSCs responded similarly to osteoblasts whereby cell attachment and scaffold infiltration improved with increasing pore size. However, MSCs showed reduced cell motility, proliferation, and scaffold infiltration compared to osteoblasts. This was associated with differences in the profile of integrin subunits (α2) and collagen receptors (CD44), indicating that osteoblasts have a stronger affinity for CG scaffolds compared to MSCs. In summary, these results reveal how larger pores promote improved cell infiltration, essential for construct development, however the optimal scaffold pore size can be cell type specific. As such, this study highlights a necessity to tailor both scaffold micro-architecture and cell-type when designing constructs for successful bone tissue engineering applications. This article is protected by copyright. All rights reserved.
Royal College of Surgeons in Ireland ->