Abstract
Background
The gradient structure of osteochondral tissue, with bone, calcified and cartilage regions, challenges the design of biomaterials for defect repair. A novel biomimetic tri-layered collagen-based scaffold, designed to replicate these 3 anatomical layers, has been developed within our group and has shown success as an off-the-shelf product in treatment of focal defects in several animal models by recruiting host cells and directing them to form bone and cartilage in the requisite layers. This study aimed to elucidate the mechanism by which the extracellular matrix macromolecules in the scaffold directed stem cell differentiation in each layer.
Methods
Tri-layered scaffolds were divided into their three constituent layers. Each layer was individually seeded with rat mesenchymal stem cells (MSCs). Cell infiltration and proliferation, calcium production and sGAG formation were assessed up to 28 days.
Results
The scaffold allowed cell infiltration and proliferation through all layers. The collagen hydroxyapatite layer was found to be inherently osteogenic due to the hydroxyapatite. The collagen I/hyaluronic acid layer did not encourage osteogenesis and the collagen I/II layer demonstrated chondrogenesis even without the presence of chondrogenic supplements.
Conclusion
The biomaterial and microstructural properties within this tri-layered material thus show an ability to direct the response of native stem cells. The mechanisms demonstrated here explain the positive results previously observed in in vivo studies.
Level of Evidence
IIb
The senior author on this abstract serves on the Scientific and Medical Advisory Board and holds stock in SurgaColl Technologies for which he receives an honorarium
