Degradable Bone Graft Substitute for Effective Delivery of Multiple Growth Factors in the Treatment of Nonunion Fractures.

摘要

During this reporting period, a more general set of hydrogel synthesis steps were defined which enables the incorporation of chitosan from multiple sources and suppliers and still produce a consistent material. Functional behavior of the hydrogel was confirmed with a new source of chitosan, inducing tissue ingrowth into a subcutaneously injected scaffold loaded with the composite xylan/chitosan hydrogel. Delivery of new hydrogel treatment for tibia fractures was accomplished with the xylan/chitosan composite showing bioactivity even in the absence of therapeutic proteins. Fractures treated with the xylan/chitosan composite showed accelerated remodeling of the fracture callus to normal bone compared to a hydrogel without the xylan component. No mineralization in response to treatment with BMP-4 has been observed in subcutaneous models, therefore activity is being tested with positive controls. Demonstration of non-union defect in rodent femur has been accomplished. Femoral fracture study in rats is now underway.