Measurement of 3D Cell Dynamics: Forces and Vibrations

细胞的机械行为会因各种疾病而改变，如癌症、关节炎和心血管疾病。特别是，动态机械行为为诊断疾病和识别恶性细胞提供了关键，因为它揭示了细胞的新陈代谢状态和转移能力。具体地说，细胞迁移动力学和细胞壁振动的研究形成了一个具有相当大潜力的工程研究计划。拟议的研究计划将开发方法来调查这些动态活动并获得对它们的基本了解，目的是确定它们之间的相互作用，这将形成用于识别转移疾病的综合诊断工具的基础。 第一个目标是开发一种3D细胞牵引力显微镜技术来表征和量化3D细胞迁移引起的3D力和能量，作为我当前NSERC发现计划的扩展。在组织中迁移的过程中，细胞必须向周围的细胞外基质(ECM)施加力，称为细胞牵引力(CTF)。由于CTF与细胞的转移潜能密切相关，因此CTF的定量特征对于诊断转移性疾病至关重要。3D CTF和细胞诱导的能量将通过将当前Discovery计划中开发的数字体积相关(DVC)应用于受3D细胞迁移影响的ECM的3D图像来确定，作为细胞转移特性的衡量标准。 第二个目标是开发工程技术来测量细胞壁振动(CWV)，从而提供对细胞代谢状态的直接了解。最近，人们发现细胞膜在千赫兹范围内振动，这是由细胞代谢和运动蛋白引起的。由于代谢直接代表细胞的健康状态和转移潜能，CWV可作为诊断细胞疾病和异常的新指标。然而，这种方法只适用于植物细胞，而不适用于哺乳动物细胞。将这种方法推广到哺乳动物细胞将面临许多关键的工程挑战。我的团队最近在使用液体细胞原子力显微镜方面取得了一些初步成功，并准备好应对这些挑战。 CTF测量的转移潜能将通过CWV与细胞代谢相关，这是该工程研究计划的长期意图。人们希望最终能够确定细胞动力学行为和转移特性之间的相互作用，并将开发出综合的力学-生物物理模型。 这一研究计划的结果对于理解与癌症转移相关的细胞动力学至关重要，因此将有助于最终开发出一种有效的转移癌症诊断工具，并设计抑制转移癌症的治疗策略。

The mechanical behaviour of cells is altered by various diseases such as cancer, arthritis and cardiovascular disease. In particular, dynamic mechanical behaviour provides a key to diagnosing diseases and identifying malignant cells, as it reveals the metabolic state and metastatic ability of a cell. Specifically, the study of the dynamics of cell migration and cell wall vibration form an engineering research program of considerable potential. The proposed research program will develop methods to investigate these dynamic activities and obtain a fundamental understanding of them, with the intent to determine the interplay between them, which will form the basis for integrated diagnostic tools used to identify metastatic diseases. The first objective is to develop a 3D cell traction force microscopy technology to characterize and quantify the 3D forces and energies induced by 3D cell migration, as an extension of my current NSERC Discovery program. During migration through tissue, the cells must apply forces, known as cell traction forces (CTF), to the surrounding extracellular matrix (ECM). Since CTF is closely related to the metastatic potential of the cells, the quantitative characterization of CTF is essential to diagnosing metastatic diseases. Both 3D CTF and energies induced by cells will be determined by applying digital volume correlation (DVC), developed in the current Discovery program, to the 3D images of ECM affected by 3D cell migration, as a measure of the cell’s metastatic properties. The second objective is to develop the engineering technology to measure the cell wall vibration (CWV) that provides direct insight into a cell’s metabolic state. Recently, it was found that cell membranes vibrate in the kilohertz range, which is caused by the cellular metabolism and motor proteins. Since metabolism directly represents the state of health of the cell and metastatic potential, CWV can be adopted as a new measure for the diagnoses of diseases and abnormalities of the cell. However, this method has been applied only to plant cells and not mammalian cells. Extension of this method to mammalian cells will face many critical engineering challenges. My group has had some recent preliminary success with using liquid-cell AFM and is ready to tackle these challenges. The metastatic potential measured by the CTF will be related to cell metabolism via CWV, which is the long-term intent of this engineering research program. It is hoped that eventually the interplay between cell dynamic behaviour and metastatic properties can be determined and the integrative mechano-biophysical model will be developed. The outcomes of this research program are crucial to understanding the cellular dynamics involving cancer metastasis, and will thus help eventually develop an efficient diagnostic tool of metastatic cancers and design therapeutic strategies for their suppression.