CAREER: Microfluidic development of dual-gel culture matrices for studying effects of interstitial flow on cellular behaviors

非技术总结：该项目将开发和使用生物材料来研究间质流动对细胞行为的影响。在所有生物体中，活细胞的行为受到其周围组织环境中各种因素的影响。这些因素的例子包括细胞外缓慢的流体流动，邻近细胞或其他成分的限制，以及组织的刚性。该计划将设计和使用新的生物材料来揭示环境刺激对重要细胞特性的影响。为了理解细胞行为背后的机制，需要采用一个实验模型，提供一个模拟组织的环境，并允许独立控制相关因素，如孔径。这对于传统的生物材料细胞培养模型来说仍然是一个挑战，这些模型是由单一的水凝胶（如胶原蛋白）制成的。提出的研究将通过使用强大的微流体研究方法开发一种新的复杂的双组分“双凝胶”生物材料来解决这一未满足的挑战。还将开发一个用户友好的计算机程序，并与科学界共享，以促进这种双凝胶材料的应用。所提出的生物材料可以很容易地适应于研究各种细胞类型，从而潜在地有益于广泛的基础生物医学研究问题。最终，这些新的生物材料可以帮助研究人员了解组织如何生长和癌细胞如何扩散等问题。此外，该教育项目将为从高中到研究生阶段的学生提供研究机会和指导，包括研究和职业发展。外联活动包括为家庭举办科学讲习班和假日系列讲座，将科学和生物技术带到当地社区。技术概述：本项目将开发和使用生物材料来研究间质流动对细胞行为的影响。间质流动是发生在细胞外基质（ECM）间质空间的缓慢流体流动，与细胞外基质的渗透性有关，并通过剪切和正常应力向常驻细胞提供直接的机械信号。此外，间质流动与生物分子扩散耦合诱导趋化信号。该项目旨在通过设计生物材料来控制间质流体速度和ECM渗透率，而不影响其他因素，如刚度和物理限制，来研究细胞在间质流动下的迁移调节机制。在传统的基于水凝胶的培养模型中，实现这种独立控制仍然是一项艰巨的任务，因为水凝胶的各种性质之间不可避免地存在相关性。提出的研究将通过开发模拟组织的双凝胶3D细胞培养基质来克服这一挑战，该基质能够独立控制基质特性，包括刚度、渗透性、限制孔径、细胞结合基序和间质流体流动。此外，该项目将展示双凝胶基质在调节空间分布和细胞数量比例的情况下共培养多个细胞的能力。提出的双凝胶培养模型将通过两种微流体方法的结合来制造。本项目亦会以MATLAB开发GUI电脑程式，以模拟双孔隙度材料中流体流动与分子扩散之间的耦合。教育外展的目标是为从高中到研究生的学生提供研究机会和指导，包括研究和职业发展。外展计划还将为家庭举办科学研讨会和假日系列讲座，将软物质科学、运输现象和生物技术带到当地社区。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical summary: This project will develop and use biomaterials to investigate the effects of interstitial flow on cell behavior. The behavior of living cells in all organisms is influenced by a variety of factors in their surrounding tissue environment. Examples of these factors include the slow fluid flux outside cells, the confinement from neighbor cells or other components, and the rigidity of the tissue. This program will design and use new biomaterials to reveal the effects of environmental stimuli on important cell characteristics. To understand the mechanisms underlying cellular behavior, it is desired to employ an experimental model that provides a tissue-mimetic environment and allows for independent control of relevant contributing factors such as pore size. This remains a challenge for traditional biomaterial cell culture models which have been made of a single hydrogel, such as collagen. The proposed study will address this unmet challenge by developing a new and sophisticated two component “dual gel” biomaterial using powerful microfluidics research methods. A user-friendly computer program will also be developed and shared with the science community to facilitate applications of such dual-gel materials. The proposed biomaterials can be readily adapted to study various cell types and thus potentially benefit a broad range of fundamental biomedical research questions. Ultimately these new biomaterials could help researchers understand questions like how tissue grows and how cancer cells spread. Moreover, the educational program will provide research opportunities and mentoring to students from high school to graduate levels on both research and career development. The outreach activities include developing science workshops and holiday lecture series for families to bring science and biotechnology to the local community. Technical summary: This project will develop and use biomaterials to investigate the effects of interstitial flow on cell behavior. Interstitial flow, the slow flux of fluid occurring in the interstitial space of the extracellular matrix (ECM), is linked to ECM permeability and provides direct mechanical cues to the resident cells through shear and normal stress. Moreover, interstitial flow couples with biomolecular diffusion to induce chemotactic signals. This project seeks to investigate the mechanisms regulating cell migration under interstitial flow by designing biomaterials to manipulate interstitial fluid velocity and ECM permeability without affecting other contributing factors, such as stiffness and physical confinement. Achieving this independent control remains a daunting task in traditional hydrogel-based culture models due to the inevitable correlation among various properties of a hydrogel. The proposed research will overcome this challenge by developing tissue-mimetic, dual-gel 3D cell culture matrices that enable independent control of matrix properties, including stiffness, permeability, confining pore size, cell-binding motifs, and interstitial fluid flow. Moreover, the project will demonstrate the capability of the dual-gel matrix to co-culture multiple cells with regulated spatial distribution and cell number ratio. The proposed dual-gel culture models will be fabricated by a combination of two microfluidics approaches. The project will also develop a GUI computer program in MATLAB for numerical visualization of coupling between fluid flow and molecular diffusion in dual-porosity materials. The educational outreach targets on providing research opportunities and mentoring to students from high school to graduate levels in both research and career development. The outreach program will also develop science workshops and holiday lecture series for families to bring science of soft matter, transport phenomena, and biotechnology to the local community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.