MODIFICATION OF CORNEAL TISSUE ENGINEERED SCAFFOLDS TO PROMOTE EPITHELIALIZATION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。用合成材料增强和替代角膜的尝试取得了有限的成功，主要是因为这些设备无法支持和维持正常的分层上皮。最根本的问题是，宿主上皮细胞将聚合物表面识别为基质或“自身”以外的东西，因此，在植入物的整个生命周期中都存在一定程度的异物反应。虽然天然材料通常具有良好的生物相容性，但它们缺乏支持组织再生的强度和承受自然伤口重塑过程的能力。因此，考虑组合策略以利用合成材料和天然材料在组织工程应用中的优势是有利的。对于角膜材料的构建，至少需要2层微结构支架来分离上皮层和间质细胞层。支架材料的中心部分必须支持基质细胞的浸润和生长，而支架的外表面必须允许上皮层的粘附和维持。细胞外基质蛋白（ECMPs）和多肽共价拴在支架表面也需要促进细胞生长。我们建议整合新的化学，微/纳米制造和细胞生物学方法，首先了解并控制角膜上皮和基质细胞-材料的相互作用，作为设计有效的角膜替代/增强材料的方法。我们的具体目标如下：具体目标1：开发和表征硅水凝胶、胶原蛋白和壳聚糖（和/或其共聚物）的三维支架，作为最佳角膜替代/增强材料的框架。特定目标二：通过使用新型微/纳米制造技术，用拴系的ECMPs和肽修饰聚合物支架材料的表面，增加对聚合物支架材料的最佳细胞反应。特异性目的三：利用原代兔上皮细胞和角质细胞培养以及角膜器官培养，定量分析细胞对聚合物支架的反应。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Attempts to augment and replace the cornea with synthetic materials have met with limited succeass, primarily because these devices have been unable to support and maintain a normal stratified epithelium. The fundamental problem is that the host epithelial cells recognize the polymer surface as other than stroma or "self" and, therefore, a degree of foreign body response is present throughout the life of the implant. Although natural materials often have good biocompatibility, they lack the strength to support tissue regeneration and the ability to withstand the natural wound remodeling process. It is advantageous, therefore, to consider combination strategies for leveraging the advantages of synthetic and natural materials for tissue engineering applications. For corneal material construction, a minimum 2-layer microstructured scaffold is specifically required to separate the epithelial layer from the stromal cell layer. The central part of the scaffold material must support infiltration and growth of stromal cells, whereas the outer surface of the scaffold must allow the adhesion and maintenance of the epithelial layer. Extracellular matrix proteins (ECMPs) and peptides covalently tethered to the scaffold surfaces are also needed to enhance cell growth. We propose to integrate novel chemistry, micro/nanofabrication, and cell biology methods to first understand and then control corneal both epithelial and stromal cell-material interactions as a method to engineer an effective corneal replacement/augmentation material. Our specific aims are as follows: Specific Aim I: To develop and characterize 3-dimensional scaffolds of silicone hydrogels, collagen, and chitosan (and/or copolymers thereof), as the framework for an optimal corneal replacement/augmentation material. Specific Aim II: To increase optimal cellular response to the developed polymer scaffold materials by modifying their surfaces with tethered ECMPs and peptides using novel micro/nanofabrication techniques. Specific Aim III: To quantify and analyze the cellular response to the developed polymer scaffolds using primary rabbit epithelial and keratocyte cell culture and corneal organ culture.