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简便方法，但它们不利于同时递送细胞。 承受关节中发现的巨大力量（需要高模量）并促进干细胞分化 （需要低模量）。此外，支架和相邻支架之间的机械性能不匹配， 组织可能导致机械不稳定并最终导致周围关节组织的退化。这 指出需要一种能够承受正常关节载荷的机械坚固的脚手架。在骨软骨病中 在组织中，细胞驻留在它们自己的小生境中，并且在很大程度上受到细胞外基质的保护而不受大的力的影响。 组织工程的解决方案是模仿自然界解决这个复杂问题的方法。 具体来说，我们将解耦结构（即，承载）组件从我们的细胞龛内， 水凝胶设计。一个刚性和功能梯度，承重结构水凝胶组件将承受 较大的力并传递适当的应变（即，机械信号）到每个细胞小生境。独立地， 三个细胞龛将捕获适合于透明软骨、钙化 软骨和骨骼。当与动态载荷相结合时， 通过向每个细胞小生境添加干细胞组分，将实现干细胞介导的OC组织再生。我们的做法是 通过数字投影光刻和高度可调的photoclickable技术， 水凝胶因此，本研究的总体假设是：结构刚性和功能梯度 嵌入含有干细胞的软材料中的材料支持正常的关节负荷，最大限度地减少损伤 并促进OC组织再生。为了验证这一假设，我们概述了 三个具体目标。在具体目标#1中，我们将设计结构控制的3D OC模拟水凝胶 材料可支持类似于体内天然OC组织的应力，并将适当的应变转移到每层 OC模拟水凝胶。我们将测试无细胞和机械稳定的OC模拟水凝胶 以最大限度地减少对猪膝关节OC缺损周围组织的损伤。在具体目标#2中，我们将研究 MSC分化和OC组织再生，当MSC并入软细胞成分时 它的设计具有适合每个OC生态位的生化和机械线索，并在定制环境中培养， 模拟体内装载环境的生物反应器。在具体目标#3中，可降解和 含有自体MSC的机械刚性OC模拟水凝胶将植入猪OC膝关节缺损中， 12周，并评价工程OC组织和对缺损周围组织的损伤。后 完成该项目后，我们预计将展示一种机械刚性水凝胶， MSC能够（a）承受大的力，（B）促进干细胞介导的OC组织再生， (c)保持缺损周围组织的健康。从长远来看，我们正在开发一种小型化的 以及便携式打印技术，外科医生可以通过关节镜平台轻松使用。