Effect of collagen‐glycosaminoglycan scaffold pore size on matrix mineralization and cellular behavior in different cell types

Abstract

We have previously examined osteoblast behavior 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 (325 μm). Scaffolds provide a framework for construct development; therefore, it is crucial to identify the optimal pore size for augmented tissue formation. Utilizing the same range of scaffolds (85 μm - 325 μm), this study aimed to examine the effects of mean pore size on subsequent osteoblast differentiation and matrix mineralization, and to understand the mechanism by which pore size influences behavior of different cell types. Consequently, primary mesenchymal stem cells (MSCs) were assessed and their behavior compared to osteoblasts. Results demonstrated that scaffolds with the largest pore size (325 μm) facilitated improved osteoblast infiltration, earlier expression of mature bone markers osteopontin (OPN) and osteocalcin (OCN), and increased mineralization. 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.

Collagen type I and hyaluronic acid based hybrid scaffolds for heart valve tissue engineering

“…and therefore the rate of proliferation is also low as shown in Figure 4C Cell response of a scaffold may also be affected by microstructural features such as pore size [62][63][64] which should be large enough to provide room for cell attachment. [65] CDCs attachment on the hybrid scaffolds decreases despite the fact that pore size is within the permissible range of 66-126 μm as shown in Figure 7B.…”

Osteogenesis and mineralization of mesenchymal stem cells in collagen type I‐based recombinant peptide scaffolds

“…The initial attachment of the cells, around 50%, is comparable to attachment on native collagen scaffolds, demonstrating the biocompatibility of the recombinant peptide. 23 The addition of osteogenic media reduced cell attachment on the scaffolds, probably due to an alteration in the cell membrane receptors, which differ between MSCs and osteoblasts 30 As measurements of attachment were taken after 24 h, it is not expected that different rates of proliferation played a significant role in the attachment. Over the course of 28 days, the cells were able to penetrate the entire scaffold volume and fill the pores, illustrating the effectiveness of the linear scaffold for promoting cell growth inside the structure, regardless of crosslinking.…”

Bioinspired Collagen Scaffolds in Cranial Bone Regeneration: From Bedside to Bench

“…[8] Murphy and O’Brien evaluated a range of pore sizes in collagen glycosaminoglycan scaffolds of identical composition, crosslinking, and synthesis methods. [13,101] They demonstrated that wide differences in adhesion, migration, and differentiation in a range of 85–325 μm in pore sizes, with the larger pore size demonstrating the best results. These studies highlight that minute changes can provoke significant differences in the success of regenerative materials.…”

“…[13,101,114,115] Termed the “sulfation code”, GAGs may function as an organizer of extracellular signals. Hortensius and Harley evaluated a panel of GAGs including hyaluronic acid, chondroitin sulfate, and heparan sulfate.…”