Every year in the United States, over 45000 corneal transplants are performed. The success rate for this procedure, owing to the relatively modest immune response in corneal tissue, is fairly high (90% after two years). Currently, access to donor tissue is adequate, however, the quality of donor tissue varies significantly, affecting surgical outcomes. In addition, the proliferation of LASIK procedures, which disqualifies a cornea for transplantation purposes, threatens to reduce the availability of donor corneas in the future. Finally, access to donor tissue elsewhere in the world, where there are over six million cases of corneal blindness, is severely limited. ? In recent years, laudable attempts have been made to produce corneal equivalents by tissue engineering. These constructs have proven the concept that three layers of cells, resembling the epithelium, keratocytes and endothelium may be cultured onto and within a collagen matrix for extended periods. However, such constructs cannot be used in the clinic primarily because the stromal matrix, which provides the cornea with mechanical strength and transparency cannot be reproduced, ? This proposal takes a stromal centric approach to generation of an artificial corneal construct. The corneal stroma comprises multiple layers (lamellae) of aligned 35 nm collagen fibrils stacked one upon another with fiber orientation rotating 90 degrees in each successive lamella. Recently, using microfluidics methods, artificial de novo """"""""lamellae"""""""" have been generated by self-assembling collagen fibrils on a surface over which there is an extremely thin flowing film of collagen monomers. Using this technique alone or as a template for tissue engineering, the generation of a suitable stromal scaffolding for use in corneal repair or replacement, will be attempted. ? The first approach proposes to generate a stromal scaffolding by stacking many artificially generated, de novo """"""""lamellae"""""""" orthogonally to one another to produce a thick stromal construct. The second approach uses a few of these de novo lamellae to influence, through contact guidance, the structure of matrix produced by ascorbic acid stimulated corneal fibroblasts. Following generation of thick stromal scaffolds by each method, epithelium and endothelium will be cultured on to the engineered stroma to produce an artificial cornea. The two constructs will be tested to determine their potential utility as corneal replacements. ? ?
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