Mechanically Stiff Hydrogels for Osteochondral Tissue Engineering

用于骨软骨组织工程的机械刚性水凝胶

• 批准号: 9321175
• 负责人: Stephanie J Bryant
• 金额: $ 34.16万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-25 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9321175
• 关键词: 3D Print; Alpha Cell; Animal Model; Architecture; Autologous; Biochemical; Biomechanics; Biomimetics; Bioreactors; Calcified; Cartilage; Cell Differentiation process; Cells; Chemistry; Complex; Cues; Custom; Defect; Deposition; Development; Disease; Encapsulated; Engineering; Environment; Extracellular Matrix; Family suidae; Gene Expression; Health; Hyaline Cartilage; Hydrogels; Implant; In Situ; In Vitro; Inferior; Injury; Joints; Knee; Lead; Left; Lesion; Mechanics; Mediating; Mesenchymal Stem Cells; Methods; Modeling; Musculoskeletal; Natural regeneration; Nature; Optics; Orthopedics; Outcome; Pattern; Phenotype; Physiological; Printing; Proteins; Research; Signal Transduction; Sports Medicine; Stem cells; Stress; Structure; Supporting Cell; Surgeon; Technology; Testing; Time; Tissue Engineering; Tissues; Virginia; Weight-Bearing state; articular cartilage; base; bone; bone cell; calcification; cartilage cell; design; digital; healing; improved; in vivo; injured; joint loading; mechanical force; mechanical properties; mimetics; miniaturize; osteochondral tissue; portability; repaired; scaffold; stem cell differentiation; tissue degeneration; tissue regeneration; tissue repair

While hydrogels offer a facile method for in situ delivery of cells, they are not conducive to simultaneously withstanding the large forces found in joints (requiring high moduli) and promoting stem cell differentiation (requiring low moduli). Moreover, a mismatch in mechanical properties between scaffold and the adjacent tissue can lead to mechanical destabilization and eventually degeneration in the surrounding joint tissue. This points to the need for a mechanically robust scaffold that can withstand normal joint loads. In osteochondral tissues, cells reside in their own niche and are largely protected from large forces by the extracellular matrix. The proposed tissue engineering solution lies in mimicking nature's solution to this complex problem. Specifically, we will decouple the structural (i.e., load-bearing) component from the cellular niche within our hydrogel design. A stiff and functionally graded, load-bearing structural hydrogel component will withstand large forces and transfer appropriate strains (i.e., mechanical signals) to each cellular niche. Independently, three cellular niches will capture chemistries and degradation appropriate to hyaline cartilage, calcified cartilage and bone. When combined with dynamic loading that transfers mechanical cues from the structural component to each cellular niche, stem cell mediated OC tissue regeneration will be achieved. Our approach is possible by the enabling technologies of digital projection photolithography and highly tunable photoclickable hydrogels. Thus the overarching hypothesis for this research is: a structurally stiff and functionally graded material embedded within a soft material containing stem cells supports normal joint loads, minimizes damage to the surrounding tissue, and promotes OC tissue regeneration. To test this hypothesis, we have outlined three specific aims. In specific aim #1, we will design architecturally-controlled 3D OC mimetic hydrogel materials to support stresses similar to native OC tissue in vivo and transfer appropriate strains to each layer of the OC mimetic hydrogel. We will test the ability of an acellular and mechanically stable OC mimetic hydrogel to minimize damage to tissue surrounding an OC defect in swine knees. In specific aim #2, we will investigate MSC differentiation and OC tissue regeneration when MSCs are incorporated in the soft cellular component that is designed with biochemical and mechanical cues appropriate to each OC niche and cultured in custom bioreactors that mimic aspects of the in vivo loading environment. In specific aim #3, degradable and mechanically stiff OC mimetic hydrogels with autologous MSCs will be implanted in a swine OC knee defect for 12 weeks and evaluated for engineered OC tissue and damage to tissues surrounding the defect. Upon completion of this project, we expect to have demonstrated a mechanically stiff hydrogel with encapsulated MSCs is capable of (a) withstanding large forces, (b) promoting stem cell mediated OC tissue regeneration and (c) maintaining the health of the tissue surrounding the defect. Long-term, we are developing a miniaturized and portable printing technology that will be easily accessible to surgeons via an arthroscopic platform.

虽然水凝胶提供了一种用于原位递送细胞的轻松方法，但它们不利于同时供电 承受在关节中发现的大力量（需要高模量）并促进干细胞分化 （需要低模量）。此外，支架与相邻之间的机械性能不匹配 组织会导致机械不稳定，并最终在周围的关节组织中变性。这 指出需要机械强大的脚手架，该支架可以承受正常的关节载荷。在骨软骨中 组织，细胞居住在自己的利基市场中，并在很大程度上受到细胞外基质的保护。 提出的组织工程解决方案在于模仿自然解决这一复杂问题的解决方案。 具体而言，我们将从我们的细胞小众中解脱结构（即承重）成分 水凝胶设计。刚性且功能分级的承载结构水凝胶组件将承受 大力并将适当的菌株（即机械信号）转移到每个细胞生态位。独立， 三个细胞壁细分市场将捕获适合透明软骨的化学和降解，钙化 软骨和骨头。与动态载荷结合起来，从结构转移机械线索 将实现每个细胞生态位，干细胞介导的OC组织再生的成分。我们的方法是 通过数字投影光刻学和高度可调光智能的能力技术可能 水凝胶。因此，这项研究的总体假设是：结构上的僵硬且功能分级 嵌入包含干细胞的软材料中的材料支持正常的关节载荷，最大程度地减少损害 到周围的组织，并促进OC组织再生。为了检验这一假设，我们概述了 三个具体目标。在特定的目标＃1中，我们将设计建筑控制的3D OC模拟水凝胶 支撑应力的材料类似于体内的天然OC组织，并将适当的菌株转移到每一层 OC模拟水凝胶。我们将测试细胞和机械稳定的OC模拟水凝胶的能力 为了最大程度地减少猪膝盖上OC缺陷周围组织的损害。在特定的目标＃2中，我们将调查 当MSC纳入软细胞成分时，MSC分化和OC组织再生 它采用适合每个OC的生化和机械提示设计，并按照习惯进行培养 模仿体内装载环境的生物反应器。在特定的目标＃3中，可降解和 与自体MSC的机械僵硬的OC模拟水凝胶将植入猪膝关节缺陷中 12周，评估了工程的OC组织和对缺陷周围组织的损害。之上 该项目的完成，我们希望已经证明了一个机械僵硬的水凝胶，并包含 MSC能够（a）承受大力，（b）促进干细胞介导的OC组织再生和 （c）维持缺陷周围组织的健康。长期，我们正在开发一个小型化 和便携式打印技术，可以通过关节镜平台轻松地使用外科医生。