Co-culture data

The objective of this research is to establish the ideal conditions for co-culturing cells on both two-dimensional (2D) collagen films and three-dimensional (3D) collagen scaffolds that are cross-linked using the EDC/NHS method. This study evaluated how different seeding densities and cell ratios affect the metabolic activity and growth of primary human osteoblasts (hOBs) and human dermal microvascular endothelial cells (HDMECs). A systematic analysis of various hOB to HDMEC ratios indicated that a 70:30 ratio was most effective for forming microvessels on 2D films, while a 50:50 ratio was ideal for 3D scaffolds. However, the vascularization of these collagen-based materials was still found to be suboptimal. Further investigation on 2D films identified that the detachment of osteoblasts was a significant barrier to vessel development. To overcome this, pre-treating the materials with a 5 μg/mL fibronectin solution created favorable conditions for a stable layer of osteoblasts, which in turn facilitated the growth of a rich network of vessels on the collagen. In summary, collagen scaffolds coated with fibronectin and seeded with an equal ratio of hOBs and HDMECs led to the formation of a dense microvascular network, featuring extensive branching and lumens, without the need for externally supplied VEGF.