A microrheometric assay of matrix mechanics

基质力学的微流变测定

• 批准号: 7030750
• 负责人: Daniel J. Tschumperlin
• 金额: $ 20.5万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-25 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7030750
• 关键词: bioassay; bioengineering /biomedical engineering; biomagnetism measurement; collagen; extracellular matrix; immunomagnetic separation; iron compounds; magnetic field; method development; molecular dynamics; nanotechnology; nonblood rheology; tissue engineering; tissue support frame; viscosity

DESCRIPTION (provided by applicant): Cells synthesize, organize, and remodel the three-dimensional latticework of the extracellular matrix, altering its composition, structure, and ultimately its mechanical properties to fulfill the needs of individual tissues. Understanding (and eventually manipulating) cellular control of extracellular matrix mechanical properties will be essential to the engineering of improved tissue replacements, and will drive the development of new treatment strategies for disorders of the extracellular matrix. Current approaches for investigating cell- mediated control of matrix mechanics are limited by time and resource costs. The central goal of this proposal is to develop, validate, and employ a unique bioassay that enables rapid, cost-effective measurement of the mechanical properties of cell-populated extracellular matrices. The proposed approach, termed magnetic twisting microrheometry, uses micron-scale ferromagnetic beads embedded within cell- matrix constructs (fibroblast-seeded collagen type I gels). The embedded beads are magnetized and exposed to an oscillatory magnetic twisting field. Bead rotations are resisted by the surrounding matrix, to which the beads are firmly coupled. The resulting relationship between applied torque and observed rotation is used to characterize the viscoelastic behavior of the matrix. In the first aim the assay will be developed and optimized, and its output validated against a standard technique. In the second aim magnetic twisting microrheometry will be employed to measure cell-mediated modulation of matrix viscoelastic properties under the control of selected matrix-active and inflammatory mediators, alone and in combination. The proposed assay probes a complex, integrated cellular process on a time and size scale amenable to resource efficient screening of compounds, treatment strategies, and molecular perturbations. Successful completion of the proposed studies could provide a powerful new experimental paradigm by which cell- mediated matrix remodeling is evaluated, setting the stage for detailed investigations into the molecular and microstructural mechanisms by which cells establish and modify extracellular matrix mechanics. The central goal of this proposal is to develop a new technology enabling rapid and efficient dissection of the cellular processes controlling extracellular matrix mechanics. Understanding these processes will improve the engineering of replacement tissues, and the treatment of extracellular matrix diseases.

描述（由申请人提供）：细胞合成、组织和重塑细胞外基质的三维网格，改变其组成、结构，并最终改变其机械性能，以满足个体组织的需要。了解（并最终操纵）细胞外基质机械特性的细胞控制对于改进组织替代物的工程至关重要，并将推动细胞外基质疾病新治疗策略的开发。目前研究细胞介导的基质力学控制的方法受到时间和资源成本的限制。该提案的中心目标是开发、验证和采用一种独特的生物测定法，能够快速、经济有效地测量细胞填充的细胞外基质的机械特性。所提出的方法称为磁扭转微流变测量法，使用嵌入细胞基质结构（成纤维细胞接种的 I 型胶原蛋白凝胶）中的微米级铁磁珠。嵌入的珠子被磁化并暴露于振荡磁扭转场。珠子旋转受到周围基质的抵抗，珠子牢固地耦合到周围基质上。由此产生的施加扭矩和观察到的旋转之间的关系用于表征基体的粘弹性行为。第一个目标是开发和优化检测方法，并根据标准技术验证其输出。在第二个目标中，磁扭转微流变测量法将用于测量在选定的基质活性和炎症介质单独或组合的控制下细胞介导的基质粘弹性特性的调节。所提出的测定在时间和尺寸范围内探测复杂的、集成的细胞过程，适合对化合物、治疗策略和分子扰动进行资源有效的筛选。所提出的研究的成功完成可以提供一个强大的新实验范式，通过该范式评估细胞介导的基质重塑，为详细研究细胞建立和修改细胞外基质力学的分子和微观结构机制奠定基础。该提案的中心目标是开发一种新技术，能够快速有效地解剖控制细胞外基质力学的细胞过程。了解这些过程将改善替代组织的工程设计以及细胞外基质疾病的治疗。