EAGER: Development of Methods to Study Dynamical Mechanical Properties of the Pericellular Layer of Cells

细胞周层是细胞中一个重要但尚未得到充分研究的部分。它覆盖了所有哺乳动物细胞和大多数细菌的细胞体。这一层的变化与许多进行性疾病有关，包括心血管疾病、炎症和癌症。有证据表明它对衰老也很重要。正如最近发现的那样，这一层在细胞力学中起着重要作用。虽然该层的静态力学性能最近成为研究的主题，但该层的动态力学性能仍然完全未知。同时，这些特性应该定义了许多正常生理和病理生理过程中的细胞-细胞相互作用，包括血液流动、癌细胞侵袭和干细胞治疗期间的细胞运动。造成这种知识差距的主要原因是缺乏实验工具来测量细胞的细胞周层的动态力学特性。这项由早期概念探索性研究基金（EAGER）资助的研究将专注于开发这样一种变革性工具，它可以直接研究细胞周围层的动态力学特性。这项研究涉及硬件的进步和计算分析的进步，这是在纳米和亚微米水平上进行测量所必需的。将分析所得的实验数据，以概述细胞周围层的力学性质。首要的长期目标是利用这个新工具来研究细胞周层在癌症和衰老中的作用。研究成果将纳入教材和生物工程课程的模块中。本研究将开发一种基于原子力显微镜平台的动态机械分析仪，同时测量所有频率。这种模式被称为傅里叶变换纳米odma，或ft -纳米odma。一种新的反馈系统将允许对探针进行精确控制。样品相互作用测量细胞周围层的存储和损耗模量作为频率的函数。一个新的力学模型提取存储和损失从纳米压痕测量将开发使用Sneddon形式。该设备和模型将使用商用超软聚合物进行验证。在固定的哺乳动物细胞上获得细胞外膜动态力学性能的第一个实验数据，可以精确分离糖萼分子和细胞外膜的波纹对细胞外刷层动态响应的影响。这些数据将与现有的细胞生物力学力学模型进行比较。这些知识将有助于了解现有模型是否能够描述观测到的数据，或者是否必须开发新的模型。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。

The pericellular layer is an important but not fully studied part of cells. It covers the cell body of all mammalian cells and the majority of bacteria. Changes in this layer have been connected with many progressive diseases, including cardiovascular disorders, inflammation, and cancer. There is evidence that it is also important in aging. As has recently been discovered, this layer plays an important role in cell mechanics. Although static mechanical properties of this layer have recently become a subject of investigation, dynamical mechanical properties of this layer remain totally unknown. At the same time, these properties should define cell-cell interactions in many normal physiological and pathophysiological processes - including blood flow, invasion of cancer cells, and cell motion during stem cell therapy. The main reason for this gap in our knowledge is the lack of experimental tools to measure dynamical mechanical properties of the pericellular layer of cells. The research supported by this EArly-concept Grant for Exploratory Research (EAGER) award will focus on the development of such a transformative tool, which allows direct studying the dynamical mechanical properties of the pericellular layer of cells. This research involves both advances in hardware and advances in computational analysis necessary to make measurements at the nano and submicron level. The obtained experimental data will be analyzed to outline the mechanical nature of the pericellular layer. The overarching long-term goal is to use this new tool to study the role of the pericellular layer in cancer and aging. The research results will be incorporated into modules for teaching Materials and Bioengineering courses. This research will develop a dynamical mechanical analyzer, based on the atomic force microscopy platform, in which all frequencies are measured at the same time. The mode is called Fourier transform nanoDMA, or FT-NanoDMA. A novel feedback system will allow for precise controlling of the probe?sample interaction to measure storage and loss moduli of the pericellular layer as a function of frequency. A new mechanical model extracting the storage and loss from the nanoindentation measurements will be developed using Sneddon formalism . The device and the model will be verified using commercial ultrasoft polymers. The first experimental data of the dynamic mechanical properties of the pericellular coat will be obtained on fixed mammalian cells, which allow precise separation of the impact of the glyocalyx molecules and the corrugations of the pericellular membrane to the dynamic response of the pericellular brush layer. The data will be compared against existing mechanical models of cellular biomechanics. This knowledge will help to understand if the existing models can describe the observed data or if new models have to be developed.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.