Anisotropic mechanical properties of collagen hydrogels induced by uniaxial-flow for ocular applications.

Engineering of well-organized tissue constructs is active in the field of material science for biomedical applications. Here, we propose a method for orienting collagen in transparent high-density collagen hydrogels using a simple rolling method. Structural organization and mechanical function were adjusted by regulating the thickness of the construct and the cross-linking reagent. Directionality of collagen alignment on the microscopic scale was achieved parallel to the extensional flow. The preferential alignment of collagen significantly affected the mechanical properties of the construct, with strong tensile strength in the direction parallel to the collagen, and high elastic strain in the perpendicular direction. The tensile strength in the parallel direction was effectively increased by 67% by increasing the cross-linking reagents by 33%, without affecting transparency which remained at 70-80% to visible light. The constructs exhibit good bio-compatibility for as a substrate for the expansion of corneal epithelial cells isolated from human donor cornea, indicating the potential for tissue engineering and biomedical applications, particularly for ocular treatments. (C) Koninklijke Brill NV, Leiden, 2011