Collagen density significantly affects the functional properties of an engineered provisional scaffold

The formation of a provisional scaffold is essential in wound healing. However, for tissues inside of joints, this process is impeded by the synovial fluid environment and wound healing is significantly impaired as a result. Therefore, development of substitute provisional scaffolds which are effective in the intra-articular environment is of great interest. Collagen-platelet hydrogels have recently been found useful as substitute provisional scaffolding materials. In this study, our hypothesis was that increasing the collagen density in the hydrogel would result in physiologic changes that would be likely to affect their function as provisional scaffold substitutes. The primary functional outcome measures were modulus of the hydrogel, platelet activation, fibroblast proliferation, and scaffold retraction. Increased collagen density resulted in collagen-platelet hydrogels with a higher storage modulus. Platelet activation was not found to be dependent on the collagen density within the range tested. Increasing the collagen density had a suppressive effect on both fibroblast proliferation and scaffold retraction. These studies suggest that the collagen density may be able to significantly influence the function of collagen-platelet hydrogels used as substitute provisional scaffolds.