Rapid-prototyped collagen scaffolds reinforced with PCL/β-TCP nanofibres to obtain high cell seeding efficiency and enhanced mechanical properties for bone tissue regeneration

In this study, hierarchical collagen scaffolds consisting of micro-strut collagen and electrospun poly(ε-caprolactone) (PCL)/β-tricalcium phosphate (TCP) nanofibres were fabricated to enhance cell seeding efficiency and mechanical properties compared to pure rapid-prototyped collagen scaffolds. To control the network of nanofibres, various deposition times (2, 5, 10, 20 s) of electrospun fibres were used to form one layer consisting of collagen struts. The tensile modulus of the hierarchical scaffolds, which have fibre networks electrospun for 20 s, was sevenfold higher than that of pure collagen scaffolds. Osteoblast-like cells (MG63) were seeded in the scaffolds to investigate cell seeding efficiency and various cellular activities. Cell seeding efficiency was measured; the efficiency increased from 55% for pure collagen scaffolds to 78% for hierarchical scaffolds (fibre deposition time: 20 s). In particular, even though for the low deposition time of fibres, 2 s, the seeding efficiency was about 64%. The hierarchical scaffold in which electrospun fibres were deposited for 10 s provided the highest proliferation rate of viable cells because the pores (11.6 ± 0.8 μm) of the fibre layer can effectively allow migration and proliferation of the injected cells. To observe the effect of bone tissue regeneration, the cellular activities including cell viability, ALP activity and calcium deposition were also evaluated. The results indicated that the activities were greatly enhanced due to the PCL/β-TCP nanofibres embedded in the collagen struts relative to pure collagen scaffolds.