Characterization of Depth-Dependent Mechanical Properties in Bio-Titanium Hybrid Osteochondral Tissue Engineered Constructs

Abstract

With cartilage autografts and allografts in short supply, tissue engineered osteochondral (OC) grafts offer an alternative [1]. These constructs are comprised of a chondrocyte-seeded hydrogel region and a porous, bone-like base. Our laboratory has shown growth of more robust osteochondral constructs on clinically-relevant metal substrates (eg. tantalum) as opposed to devitalized bone, and these constructs have been evaluated in vivo [1,2]. Due to the presence of the base, it is expected that transport of nutrients and chemical factors in OC constructs will differ from transport in chondral-only constructs (Fig. 1, bottom-left). Depth-dependent mechanical properties of chondral-only constructs have been measured, yielding a “U-shaped” strain profile, in which the construct is stiffest on the edges and softest in the center. However, depth-dependent properties have not been measured in tissue engineered OC grafts [3].