Nanostructured Porous Silicon / Polymer Composites as Ophthalmic Implants

描述（由申请人提供）：该项目的长期目标是开发新型多孔硅基眼科植入物作为自体细胞转移到眼睛的支架，用于治疗人类眼表疾病。所提出的这种植入物的基本成分是微粒形式的纳米结构多孔硅。多孔硅是一种相对无毒、完全可生物降解的材料，易于制备和改性，可以有效负载生物活性物质，表现出优异的生物相容性并支持哺乳动物眼细胞的生长。在结构中添加可再吸收的有机聚合物组分增加了机械灵活性、易于处理，并减少了基于多孔硅微粒形状的任何可能的有害影响。将使用临床相关的眼表疾病大鼠模型。该提案解决了两个具体目标：（1）制造新型多孔硅/可吸收聚合物复合材料，对其表面进行功能化，并加载生物活性物质，为将大鼠口腔粘膜来源的干细胞群体转移到眼表面提供支持，并提供人工干细胞生态位； (2) 探索这些携带自体细胞的植入物在转移至大鼠体内眼睛后调节眼表疾病的潜力。 研究设计和方法：（1）将制造多孔硅微粒和电纺聚（己内酯）或其他可吸收聚合物的复合材料，进行表面衍生化、表征，并负载生物活性物质，例如可溶性生长因子。这些复合材料的性能将通过复合材料结构以及所存在的多孔硅微粒的性能来调节。多孔硅组分的孔隙率的变化将改变硅的降解速率和基质的寿命。改变表面化学不仅会影响多孔硅降解动力学，而且明智地选择吸附在多孔硅上的适当生物分子将改善上皮细胞的附着、存活和生长。 (2)将大鼠口腔粘膜上皮细胞在复合材料上扩增，并通过表型特异性标记物染色检查细胞的分化状态。含有推定成体干细胞和瞬时扩增细胞的离体扩增群体或外植体将被 移植到大鼠眼表，以测试其修复受损眼表的能力。中央角膜印迹细胞学检查和聚合酶链式反应将用于检测眼表面供体细胞基因组 DNA，细胞追踪染料将用于可视化供体细胞的迁移。细胞供体和受体大鼠属于同一近交系，因此不会发生免疫排斥反应。

DESCRIPTION (provided by applicant): The long-term objective of this project is to develop novel porous silicon-based ophthalmic implants as scaffolds for autologous cell transfer to the eye, for the treatment of human ocular surface disease. The proposed base component for such implants is nanostructured porous silicon in the form of microparticles. Porous silicon is a relatively non-toxic, completely biodegradable material that is easily prepared and modified, can be loaded efficiently with bioactives, shows excellent biocompatibility and supports the growth of mammalian ocular cells. The addition of a resorbable organic polymer component to the structure adds mechanical flexibility, ease of handling, and reduction of any possible deleterious effects based on shape of the porous silicon microparticles. Clinically relevant rat models of ocular surface disease will be used. This proposal addresses two specific aims: (1) to fabricate novel porous silicon/resorbable polymer composites, functionalize their surfaces, and load them with bioactive species, to generate supports for the transfer of expanded populations of rat oral mucosa-derived stem cells to the ocular surface, and to provide an artificial stem cell niche; and (2) to explore the potential of these implants carrying autologous cells to modulate ocular surface disease, following transfer to the eye of the rat in vivo. Research Design and Methods: (1) Composites of porous silicon microparticles and electrospun poly(¿-caprolactone) or other resorbable polymers will be fabricated, surface-derivatized, characterized, and loaded with bioactives such as soluble growth factors. The properties of these composite will be tuned by the composite structure but also by the properties of the porous silicon microparticles present. Variation of the porosity of the porous silicon component will alter the rate of silicon degradatio and lifetime of the matrix. Altering the surface chemistry will not only affect porous silicon degradation kinetics, but with judicious selection of appropriate biomolecules adsorbed on to the porous silicon will improve the attachment, survival and growth of epithelial cells. (2) Rat oral mucosal epithelial cells will be expanded on the composite materials and the differentiation status of cells examined by staining for phenotype specific markers. Ex vivo expanded populations or explants containing putative adult stem cells and transient amplifying cells will be transplanted to the rat ocular surface, to test their ability to repair a damaged ocular surface. Impression cytology of the central cornea followed by polymerase chain reaction will be used to detect donor cell genomic DNA on the ocular surface, and cell tracker dyes will be used to visualize migration of donor cells. The cell donors and recipient rats will be of the same inbred strain, so that no immunological rejection will occur.