(695g) Improved Interfacial Shear Strength In UHWMPE-PVA Hydrogel Composites Following Glutaraldehyde Grafting for Soft Tissue Applications

A fiber-reinforced hydrogel-based synthetic biomaterial allows tailoring of the mechanical properties to match the anisotropic property distribution of many soft fibrous tissues and molding of the implant to the size and shape of the tissue being replaced. The mechanical and swelling properties of this composite have been evaluated previously showing the ability of this material to be tailored across a wide range of properties matching that of many soft tissues. Poor adhesion between UHMWPE fibers and the hydrogel, however, has been an issue. Oxygen plasma and glutaraldehyde treatments were performed to increase adhesion at the fiber-matrix interface. The degree of adhesion was quantified by calculating interfacial shear strength at the fiber-hydrogel interface using single fiber pull-out tests. Scanning electron microscopy was used to show fiber morphology and grafted thickness for various treatment times. Titrimetric methods were used to determine grafting yield. Fiber surface treatments successfully increased fiber-matrix interfacial shear strength from 11.5 kPa without any treatment to above 200 kPa following chemical grafting. Fiber-Hydrogel interfacial adhesion was dependent upon both oxygen plasma treatment time and exposure to glutaraldehyde, indicative of control over both the number of sites available for grafting and grafting efficiency respectively. In some cases, calculated fiber stresses exceeded 2 GPa during debonding and sample failure occurred within the fiber phase showing successful utilization of fiber strength after fiber surface modification.