A self-assembled collagen scaffold suitable for use in soft and hard tissue replacement

Abstract Over a period of several million years, natural selection and evolution have optimized the morphological and mechanical properties of biological tissues. The biomaterials scientist can make use of these ‘natural’ design processes by mimicking the extracellular matrix, the primary natural scaffolding material. Previous studies have documented the propensity of acid soluble type I collagen to self-assemble in vitro and form microscopic collagen fibrils with D periodic banding analogous to native fibrils. Recently, our laboratory extended the in vitro fibrillogenesis process to self-assemble macroscopic fibers from solutions of acid extracted type I collagen. These fibers may serve as scaffolding material for a variety of soft and hard tissue replacements. Results of mechanical analyses demonstrated that the self-assembled collagen fibers, 60–120 μm in diameter, have dry tensile properties comparable with native, aligned fibrous tissue and wet tensile properties which are superior to similarly produced collagen fibers from insoluble type I collagen. Results of the birefringence analysis conducted in this study suggest that this technique is useful for correlating the degree of fibrillar alignment and packing with the mechanical properties of fibrous collagen scaffolds. Preliminary ultrastructural findings show that selfassembled collagen fibers contain aligned collagen fibrils with diameter distributions similar to native collagen fibers. Additionally, the uniaxial alignment of fibrils in collagen fibers self-assembled from soluble collagen was greater than similar fibrils observed in collagen fibers produced from disrupted, insoluble corium.