Abstract
This report describes methods for fabricating substrates with anisotropic order from a single solution of high concentration collagen. By exploiting the intrinsic property of collagen to behave as a cholesteric liquid crystal, we demonstrate first the production of dense collagen films containing anisotropic fibers by simple dialysis and polymerization in ammonia vapor. We then utilized shear driven alignment of collagen using viscous extrusion to produce aligned collagen fibers. Next we describe an evaporation technique to observe crystalline growth into the collagen, which serves to template the substrate prior to fibrillogenesis. The ordered substrates supported osteogenic differentiation of hMSCs and also oriented growth of hMSCs. We also demonstrate using Raman spectroscopy that the local protein concentration in the substrates influenced the molecular orientation of collagen, Finally, we compare the resultant textures in the substrates with section of native cornea and tendon using polarized light microscopy, which showed remarkable similarities in terms of both anisotropy and second order chiral structure. These rapid, cost-effective methods could potentially serve a range of different applications in tissue engineering.
