The effect of mean pore size on cell attachment, proliferation and migration in collagen–glycosaminoglycan scaffolds for bone tissue engineering

In the literature there are conflicting reports on the optimal scaffold mean pore size required for successful bone tissue engineering. This study set out to investigate the effect of mean pore size, in a series of collagen–glycosaminoglycan (CG) scaffolds with mean pore sizes ranging from 85 μm to 325 μm, on osteoblast adhesion and early stage proliferation up to 7 days post-seeding. The results show that cell number was highest in scaffolds with the largest pore size of 325 μm. However, an early additional peak in cell number was also seen in scaffolds with a mean pore size of 120 μm at time points up to 48 h post-seeding. This is consistent with previous studies from our laboratory which suggest that scaffold specific surface area plays an important role on initial cell adhesion. This early peak disappears following cell proliferation indicating that while specific surface area may be important for initial cell adhesion, improved cell migration provided by scaffolds with pores above 300 μm overcomes this effect. An added advantage of the larger pores is a reduction in cell aggregations that develop along the edges of the scaffolds. Ultimately scaffolds with a mean pore size of 325 μm were deemed optimal for bone tissue engineering.