Crosslinkable cell scale fibers for large meniscus defect repair

摘要 半月板在健康的膝关节功能中起着至关重要的作用。然而，考虑到该组织在负载中的中心位置， 由于交通和苛刻的物理环境，受伤是常见的，成年人的愈合是有限的。的 目前缺乏用于膝半月板损伤的再生解决方案，部分原因是 该技术可用于修复半月板的致密和复杂的组织结构。特别 具有挑战性的是再生组织的不同的内部和外部区域，其具有不同的组成， 机械性能，以实现有效的承载。虽然模拟大体积几何形状的支架 半月板被引入临床以促进半月板的修复/再生，但这些支架不 提供微观的细胞尺度的线索，这些线索需要模拟细胞来形成与这些区域相匹配的组织， 具体属性。这种限制导致不成熟的类胰岛组织，缺乏承载能力。是 越来越好地理解结构特性（例如，形状和刚度）可以 影响细胞活性和直接基质形成。为了利用这些见解，我们的团队开发了 FiberGel系统，以产生基于生物聚合物的细胞级微纤维，其中单个纤维具有可调的 直径和刚度。这些微纤维可以被模塑和交联成各种形状以填充弯月面 缺陷，并且内部微纤维可以形成为随机或对齐的构型以模仿微纤维的结构。 天然半月板的不同区域。半月板细胞可以直接混合到FiberGel糊剂中， 交联以产生均匀的细胞化构建体。在这个提议中，我们优化了这种有前途的材料， 以确定促进内区和外区表型和结构形成的条件。我们将 确定FiberGel系统的可调参数-直径，刚度和对齐-如何影响 半月板细胞的生物合成活性，通过一系列旨在完善和优化基质的研究， 阵确定基于FiberGel的植入物如何对关节产生的机械力做出反应 运动时，我们还将使用定制的机械生物反应器，在其运动过程中向结构施加生理负荷。 成熟我们的中心假设是存在一组最佳的微纤维参数（直径， 刚度和对齐）用于再生半月板的内部和外部区域。成功完成 这项工作将产生可用于膝关节半月板的临床修复的FiberGel制剂。

Abstract The meniscus plays a vital role in healthy knee function. However, given the centrality of this tissue in load transfer and the demanding physical environment, injury is common and healing in adults is limited. The current lack of regenerative solutions for knee meniscus injury arises, in part, from the significant gap in technology that can be used to repair the dense and complex tissue structure of the meniscus. Particularly challenging is regenerating the distinct inner and outer zones of tissue, which have distinct composition and mechanical properties to enable effective load bearing. While scaffolds that mimic the bulk geometry of meniscus are being introduced clinically to promote the repair/regeneration of meniscus, these scaffolds do not provide the microscopic, cell-scale cues that are needed to simulate cells to form tissue matching these region- specific attributes. This limitation leads to immature meniscus-like tissue, lacking in load-bearing capacity. It is increasingly well understood that structural properties (e.g., shape and stiffness) of cell-scale structures can influence the cell activity and direct matrix formation. To harness these insights, our team developed the FiberGel system to generate biopolymer-based, cell-scale microfibers, in which individual fibers have a tunable diameter and stiffness. These microfibers can be molded and crosslinked into various shapes to fill meniscus defects, and the internal microfibers can be formed into a random or aligned configuration to mimic the different regions of the native meniscus. Meniscus cells can be directly mixed into the FiberGel paste before crosslinking to produce uniformly cellularized constructs. In this proposal, we optimize this promising material to define conditions that promote formation of inner and outer zone phenotypes and structures. We will determine how the tunable parameters of FiberGel system — diameter, stiffness and alignment — impact the biosynthetic activities of meniscus cells through a series of studies designed to refine and optimize matrix formation. To determine how FiberGel-based implants respond to mechanical forces that arise with joint motion, we will also use a custom mechanical bioreactor to apply physiologic load to constructs during their maturation. Our central hypothesis is that there exists an optimal set of microfibers parameters (diameter, stiffness and alignment) for regenerating the inner and outer regions of our meniscus. Successful completion of this work will generate FiberGel formulations that may be used for the clinical repair of the knee meniscus.