Every year in the United States, over 45,000 corneal transplants are performed. The success rate for this procedure is fairly high (90% after two years) and although current access to donor tissue is adequate, the quality of tissue varies significantly which influences surgical outcomes. In addition, the proliferation of LASIK procedures, which disqualifies a cornea for transplantation, threatens to reduce the availability of donor corneas in the near future. 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 into a collagen matrix. However, such constructs have only met with limited success because the stromal matrix, which provides the cornea with its unique (and critically important) mechanical and optical properties, has not been reproduced. Randomly oriented collagen gels, which represent the typical starting point for tissue-engineered corneas, are not likely to be strong enough or clear enough for clinical use. In addition, expecting a significant in vivo ? remodeling response to integrate a partially functioning artificial cornea is not acceptable. The artificial ? construct should be functional at the time of implantation. For these reasons, we propose a stromal-centric approach toward the generation of an artificial cornea. By combining engineering, biology, biomechanics and biochemistry, two different routes, both designed to produce biomimetic stromal lamellae (the building blocks for an artificial cornea) will be attempted. The first method employs microfluidics to influence the self-assembly of thin, aligned lamellar sheets comprising collagen and proteoglycans. This approach is acellular and is designed to produce a biomimetic stromal scaffold de novo. The second approach utilizes mechanical cues such as contact guidance (provided by the ? de novo lamellae) and strain to """"""""direct"""""""" the synthesis of matrix by ascorbic acid stimulated human corneal fibroblasts. An extensive characterization of the synthetic response to the imposed stimuli will be conducted to gain a fundamental understanding of synthesis, remodeling and homoeostasis of highly structured matrix. Completion of both parts of this proposal will provide insight critical to achieving our ultimate goal, which is the ex vivo generation of a functional, biomimetic artificial cornea from natural components. ? ? ? ?
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