Engineering biomimetic corneal constructs

工程仿生角膜结构

• 批准号: 7012251
• 负责人: Jeffrey W Ruberti
• 金额: $ 43.53万
• 依托单位: NORTHEASTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7012251
• 关键词: ascorbate; bioengineering /biomedical engineering; biomechanics; biomimetics; clinical research; collagen; corneal stroma; extracellular matrix; fibroblasts; human tissue; immunocytochemistry; mass tissue /cell culture; microfluidics; tissue engineering

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：在美国，每年进行超过45，000例角膜移植。该手术的成功率相当高（两年后为90%），尽管目前供体组织的获取是足够的，但组织的质量差异很大，这会影响手术结果。此外，LASIK手术的激增使角膜不符合移植的条件，在不久的将来有可能减少供体角膜的可用性。近年来，通过组织工程学方法制备角膜替代物的尝试值得称赞。这些构建体已经证明了可以将类似于上皮、角膜细胞和内皮的三层细胞培养到胶原基质中的概念。然而，这样的构建物只取得了有限的成功，因为为角膜提供其独特的（并且至关重要的）机械和光学性质的基质基质还没有被复制。 随机取向的胶原蛋白凝胶，代表了组织工程角膜的典型起点，不太可能足够强或足够清晰，用于临床使用。此外，预期在体内 整合部分功能的人工角膜的重塑反应是不可接受的。人工 结构在植入时应具有功能。 基于这些原因，我们提出了一种以基质为中心的方法来产生人工角膜。 通过结合工程学、生物学、生物力学和生物化学，将尝试两种不同的路线，这两种路线都旨在生产仿生基质层（人工角膜的构建块）。第一种方法采用微流体来影响包含胶原蛋白和蛋白聚糖的薄的、对齐的层状片材的自组装。这种方法是无细胞的，旨在从头产生仿生基质支架。第二种方法利用机械提示，诸如接触引导（由 de novo Laminosa）和菌株来“指导”抗坏血酸刺激的人角膜成纤维细胞合成基质。 将进行对施加刺激的合成反应的广泛表征，以获得对高度结构化基质的合成、重塑和体内平衡的基本理解。 完成这两个部分的建议将提供关键的洞察力，以实现我们的最终目标，这是离体生成的功能，仿生人工角膜的天然成分。