Results

The sponge-like plugs of prototype Col-HA composites were successfully fabricated with different collagen and HA ratios. The macroscopic and SEM views of the prototype type I collagen without HA and 3 different ratios of collagen-HA (20%Col-80%HA; 50%Col-50%HA; 80%Col-20%HA) composites are shown in Figure 1. The SEM views show the inside microstructures of the prototype pure type I collagen without HA and 3 different ratios of collagen-HA composites (Figure 1). Pure type I collagen and the 80%Col-20%HA composite showed more porosities and less densities.

Following 1, 3, 5, and 7 days of culturing mouse MSCs with Adi-GFP transfection (C₃H₁₀T_1/2 + Adi-GFP), we found that the 80%Col-20%HA and 50%Col-50%HA composites possessed the best biocompatibility and supported the attachment and proliferation of mouse MSCs (Figure 2). CollaPlug and the high HA (20%Col-80%HA) composite had unfavorable cell morphologies and quantities in comparison with 80%Col-20%HA and 50%Col-50%HA composites. These results suggested that an appropriate HA proportion in the composites facilitated cell attachment, proliferation, and differentiation.

As the 50%Col-50%HA composite appeared to promote attachment and proliferation of mouse MSCs and have favorable mechanical properties in comparison to 20%Col-80%HA and pure type I collagen-based scaffolds, we used it for further testing. The hPDSCs biocompatibility assays showed that the 50%Col-50%HA composites have the same cell growth and proliferation properties as pure type I collagen materials (CollaPlug, Foundation, and a prototype collagen without HA) (P > .05, ANOVA; Figure 3).