Synthesis of layered, graded bioscaffolds

Abstract

Layered, multi-compartment structures are an important class of biomaterials currently under development; their aim is to more accurately recapitulate the heterogeneity of the native extracellular matrix found in many tissues and organs. This chapter describes the synthesis and characterization of two groups of layered, graded collagen-glycosaminoglycan (CG) scaffolds. The first is a multi-compartment material for osteochondral repair. This material contains distinct cartilagenous and osseous compartments joined via a continuous interface that mimics elements of the native articular cartilage-bone interface (tidemark). Techniques to evaluate the chemical composition, mineral phase and distribution, pore size and shape, mechanics, and permeability in spatially selective manners are also introduced. The second class of material discussed in this chapter is a core-shell composite scaffold for tendon and ligament regeneration. Here, the design strategy was inspired by mechanically efficient core-shell structures in nature such as plant stems. Composites were fabricated from a high-density CG membrane integrated into a highly porous (low-density) anisotropic CG core to enhance construct mechanical competence without sacrificing scaffold porosity. Throughout, cellular solids modeling techniques are used as a framework to understand observed trends in scaffold microstructure and mechanics. Overall, the work described here presents two platform technologies for developing heterogeneously structured materials for complex tissue engineering applications.