Optical Chopsticks for Multidimensional Cellular Mechanics Study

项目编号：1403257单位：伍斯特理工学院题目：用于多维细胞力学研究的光学筷子机械力在细胞形态、运动、增殖和生理方面起着重要作用。尽管它们很重要，但目前关于机械力在细胞生物学中的作用的知识仍然有限，特别是对于三维（3D）环境中的细胞，其行为与二维（2D）基质上的细胞非常不同。其中一个原因是缺乏合适的技术和工具来非侵入性地应用表征良好的力来精确测量3D环境中细胞的机械反应。拟议的研究旨在开发和使用一种名为？光学筷子吗?这将使在非线性异构3D环境中同时施加力和细胞响应测量成为可能，打破了现有技术的限制。开发的光学筷子将是便携式的，易于使用，并由广泛的商用光纤组件支持。本研究结果不仅将对细胞生物物理学、机械生物学、生物光子学等多个领域产生重大影响，而且将进一步阐明其病理机制和诊断。该研究项目将为从高中到研究生院的广大学生提供跨学科的培训和教育。细胞力学已经用不同的方法进行了定量研究，包括基于荧光成像的牵引力显微镜、原子力显微镜（AFM）和光学镊子。然而，到目前为止，还没有工作显示在3D环境中应用和测量3D力，这更接近于体内环境。AFM受侧向力测量分辨率的限制，而传统的光学镊子由于工作距离有限，不适合测量三维矩阵中的细胞。提出的光学筷子是基于光纤镊子，它可以创建3D光学陷阱，用于非接触力的施加和测量。只要介质是透明的，光纤镊子就可以到达介质内部的任何地方，这对于嵌入在3D矩阵中的细胞的力测量尤其重要。此外，将实施光纤调制和检测系统，以促进三维矩阵中具有所需波形的光力的动态控制。有了这些能力，光学筷子将与荧光成像技术相结合，用于二维基质上细胞骨架中力传播的时空表征。更重要的是，光学筷子将用于精确测量非线性非均匀三维矩阵中的细胞力。同时，将方向和大小可控的三维力施加于细胞，研究细胞在外界机械刺激下的迁移。提出了四个具体目标。1)发展光学光学。2)实现光学筷子，建立光学力生成模型。3)在二维基底上进行细胞力学研究。4)在三维矩阵中进行细胞力学研究。该研究结果有望在细胞生物物理学、机械生物学、生物光子学等多个领域产生重大影响，并进一步阐明其病理机制和诊断。

PI: Liu, Yuxiang Proposal Number: 1403257Institution: Worcester Polytechnic InstituteTitle: Optical Chopsticks for Multidimensional Cellular Mechanics StudyMechanical forces play an important role in cell morphology, motility, proliferation, and physiology. Despite their importance, the current knowledge on the role of mechanical forces on cell biology is still limited, especially for cells in a three-dimensional (3D) environment, which behave very differently compared with those on two-dimensional (2D) substrates. One of the reasons is lack of suitable techniques and tools to non-invasively apply well characterized forces to and precisely measure mechanical response from cells in 3D environments. The proposed studies aim to develop and use a novel tool entitled ?optical chopsticks,? which would enable simultaneous force application and cell response measurements in a nonlinear heterogeneous 3D environment, breaking the limitation of existing techniques. The developed optical chopsticks will be portable, easy to work with, and supported by a broad spectrum of commercialized fiber optic components. The outcome of this research will not only have a significant impact to multiple areas such as cellular biophysics, mechanobiology, and biophotonics, but also shed further light on pathological mechanisms and diagnosis. The research project will provide interdisciplinary training and education for a broad audience of students ranging from high school to graduate school.Cell mechanics have been quantitatively investigated with different methods, including fluorescence imaging-based traction force microscopy, atomic force microscopy (AFM), and optical tweezers. However, no work has been shown so far to both apply and measure 3D forces in a 3D environment, which is much closer to the in vivo environment. AFM is limited by the resolution of lateral force measurements, while conventional optical tweezers are not suitable for measurements on cells in a 3D matrix due to limited working distances. The proposed optical chopsticks are based on fiber optical tweezers that can create 3D optical traps for non-contact force exertion and measurements. Fiber optical tweezers can reach anywhere inside the medium as long as the medium is transparent, which is especially important for force measurements on cells embedded in a 3D matrix. Moreover, a fiber optic modulation and detection system will be implemented to facilitate dynamic control of optical forces with desired waveforms on cells in a 3D matrix. With these capabilities, optical chopsticks will be integrated with fluorescence imaging techniques for spatiotemporal characterization of force propagation in cytoskeletons of cells on 2D substrates. More importantly, optical chopsticks will be used to precisely measure cell forces in a nonlinear heterogeneous 3D matrix. In the meantime, 3D forces with controllable directions and magnitudes will be applied to cells to study cell migration under external mechanical stimuli. Four specific aims are proposed. 1) To develop the optical chopstics. 2) To implement the optical chopsticks and model the optical force generation. 3) To perform cell mechanics studies on 2D substrates. 4) To perform cell mechanics studies in 3D matrices. The outcome of this research is expected to have a significant impact on multiple areas, including cellular biophysics, mechanobiology, and biophotonics, and also shed further light on pathological mechanisms and diagnosis.