CAREER: Liquid Crystallinity as a Tool to Probe Cell and Protein Behavior in Gel Biomaterials

组织的机械特性会影响单个细胞的行为。机械性能的变化往往是疾病的标志，对于损伤后的健康修复至关重要。然而，细胞如何在不同的长度尺度上感知这些特性，以及这些信息如何影响细胞功能，还没有被很好地理解。这项职业研究研究的是与人类细胞兼容的新聚合物，可以用来包围细胞，在三维(3D)凝胶中进行实验室培养。这种聚合物是液晶(LC)，这意味着它们可以按不同的长度尺度进行定制。这项研究将建立新的凝胶材料，并确定蛋白质在凝胶中的顺序。然后，这项工作将确定细胞感知机械特性的长度尺度如何影响细胞功能，以及研究基于材料的方法来调节蛋白质沉积/组织和细胞激活。从这个职业项目中获得的关于细胞行为的知识可以帮助发现和验证纤维化等疾病的治疗方法，这是一种以过度瘢痕为特征的病理，并可以为再生医学提供新的材料。该项目的教育目标是为那些在STEM中因自我效能降低而易受性别歧视影响的五年级和六年级学生提供练习复原力或“毅力”的机会，这是一种可衡量和可培训的技能。基于研究的活动将允许这些学生在本科生导师的支持下，在安全的环境中尝试挑战，面对和克服失败。综合教育和研究计划旨在1)向未得到充分服务的学生传授复原力技能，以提高对STEM自我效能的态度；2)培训本科生和研究生进行研究，并向不同受众交流研究成果；3)广泛传播研究成果，激发人们对STEM的兴趣。技术概述体外细胞培养分析产生细胞行为的知识，可以揭示治疗靶点，验证临床治疗，并为再生医学建立新的材料。哺乳动物细胞对具有不同弹性和粘弹性(粘弹性)的培养底物的反应会改变功能，但细胞如何感知粘弹性还不是很清楚。鉴于自然组织的异质性，澄清细胞在什么长度尺度(从微米到毫米)感知和/或响应粘弹性被假设为当前培养基质中未考虑到的关键设计变量。该项目将建立一种新的细胞兼容的三维(3D)液晶(LC)凝胶，使细胞能够在体外被包裹，并开创对局部3D环境的细胞/亚细胞反应的新见解。第一个目标是合成LC水凝胶，并建立控制LC聚合物顺序和材料特性的设计参数。这种水凝胶将与I型胶原和成纤维细胞结合，以确定LC聚合物的有序性如何影响重组和从头合成的胶原的组织。第二个目标将量化成纤维细胞的激活和蛋白质对不同长度尺度下局部3D环境粘弹性变化的反应。教育目标的核心是韧性或“坚韧”，作为STEM自我效能的关键，一种可测量的、可培训的技能。一种新的服务学习模式将把研究与教育结合起来，重点关注小学后期和中学早期水平上代表性不足的学生，这一时期STEM自我效能感的性别差异出现，并影响学生进入STEM学习和继续学习的速度。研究整合活动将允许5年级和6年级的学生在本科生导师的支持下，在安全的环境中尝试挑战，面对和克服失败。综合和可持续的教育和研究计划预计将1)向服务不足的学生传授复原力技能，2)培训本科生和研究生进行研究，并将研究成果与不同受众交流，3)广泛传播成果并激发人们对STEM研究的兴趣。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Mechanical properties of tissues can influence how individual cells behave. Changes in mechanical properties are often hallmarks of disease and are critical for healthy repair following injury. However, how the cells sense these properties at different length scales and how that information affects cell function are not well-understood. This CAREER research investigates new polymers that are compatible with human cells and can be used to surround cells for laboratory culture in three-dimensional (3D) gels. The polymers are liquid crystalline (LC), which means that they can be designed to order at different length scales. The research will establish new gel materials and determine how protein orders within the gels. The work will then determine how the length scales at which cells sense mechanical properties affect cell function, as well as investigate materials-based approaches to tune protein deposition/organization and cellular activation. The knowledge of cell behavior gained from this CAREER project can help discover and validate therapies for diseases such as fibrosis, a pathology characterized by excess scarring, and can contribute to new materials for regenerative medicine. The educational goal of this project is to provide fifth and sixth grade students, who are vulnerable along gendered lines to decreased self-efficacy in STEM, with opportunities to practice resilience or "grit", a measurable and trainable skill. Research-based activities will allow these students to attempt challenges and confront and overcome failure in a safe environment with support from undergraduate mentors. The integrated educational and research program aims to 1) teach resiliency skills to underserved students to increase attitudes of STEM self-efficacy, 2) train undergraduate and graduate students in research and to communicate research to diverse audiences, and 3) broadly distribute results of that research and generate interest in STEM. Part 2: Technical SummaryAnalysis of cell cultures in vitro generates knowledge of cell behavior and can reveal therapeutic targets, validate clinical therapies, and establish new materials for regenerative medicine. Mammalian cells alter function in response to culture substrates with different elastic and viscous (viscoelastic) properties, yet how cells sense viscoelasticity is not well understood. Given the heterogeneity of natural tissues, clarifying at what length scales (from microns to millimeters) cells sense and/or respond to viscoelasticity is hypothesized to be a critical design variable unaccounted for in current culture substrates. This project will establish a new class of cytocompatible, three-dimensional (3D) liquid crystalline (LC) gels, to enable encapsulation of cells in vitro and to pioneer new insight into cellular/subcellular responses to local 3D environments. The first objective will synthesize LC hydrogels and establish design parameters that control LC polymer order and material properties. The hydrogels will be combined with Type I collagen and fibroblasts to determine how LC polymer ordering affects the organization of reconstituted and de novo synthesized collagen. The second objective will quantify fibroblast activation and protein responses to changes in the viscoelasticity of the local 3D environment at varying length scales. The educational goal centers on resilience or "grit" as a measurable, trainable skill key to self-efficacy in STEM. A novel service learning model will integrate research with education, focusing on underrepresented students at the late elementary and early middle school level, a time when gender differences in STEM self-efficacy arise and affect both the rate at which students enter and continue with STEM studies. Research-integrated activities will allow 5th and 6th grade students to attempt challenges and confront and overcome failure in a safe environment with support from undergraduate student mentors. The integrated and sustainable educational and research program is expected to 1) teach resiliency skills to underserved students, 2) train undergraduate and graduate students in research and to communicate research to diverse audiences, and 3) broadly disseminate results and generate interest in STEM research.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.