A Magnetic Micromanipulation System for Intra-Cellular and Intra-Tissue Mechanics

为了揭示细胞内结构和细胞器的力学和功能，需要对细胞内部进行直接的力学测量。与从细胞外进行的常规细胞力学相比，细胞内力学测量是探索不足的。类似地，几乎没有尝试测量大块组织内的力学（相对于组织表面）。众所周知，细胞在体外向基质的刚性区域迁移，这一过程称为硬旋转。然而，组织内硬旋转的实验测量仍然缺乏。该RTI应用要求磁性微操作仪器具有在单细胞内或组织内部深处移动磁性微珠的独特能力，以获得用于细胞内和组织内力学表征的精确力变形数据。磁微操作仪器包含放置在不同平面上的八个磁性线圈，以产生3D磁场。它有两种操作模式：（1）使用八个磁性线圈中的六个来产生强磁场梯度，用于移动微米尺寸的磁珠并施加高达200 pN的力，这将用于我们提出的细胞内力学工作;（2）使用八个磁性线圈来产生均匀的磁场梯度，以在工作空间内的所有磁珠上施加相同的力，其将用于我们提出的组织内力学工作。在实验中，磁性微珠和细胞结构将被荧光标记，并且它们的位移/变形将通过荧光显微镜成像来测量。** 我们的HQP将使用所要求的设备在单个细胞内进行力学测量，机械加载细胞内结构以诱导机械转导反应，并实现组织深处的力学测量。这些设备将用于培训大量博士后和研究生，他们将获得细胞和组织力学，细胞机械转导，发育生物学，显微成像以及精密仪器控制和测量方面的技能。

To reveal the mechanics and functions of intracellular structures and organelles demands direct mechanical measurement inside a cell. Compared to conventional cell mechanics performed from outside the cell, intracellular mechanical measurement is underexplored. Similarly, few attempts have been made to measure the mechanics within bulk tissue (vs. on tissue surface). It is well recognized that cells in vitro migrate towards the stiff region of a substrate, a process termed durotaxis. However, experimental measurement of durotaxis inside tissue remains lacking.******This RTI application requests a magnetic micromanipulation instrument with unique capabilities of moving magnetic microbeads inside single cells or deep inside a tissue to obtain accurate force-deformation data for intracellular and intra-tissue mechanics characterization. The magnetic micromanipulation instrument contains eight magnetic coils placed on different planes to generate 3D magnetic fields. It has two operation modes: (1) the use of six of the eight magnetic coils to generate a strong magnetic field gradient for moving a micrometer-sized magnetic bead and applying forces up to 200 pN, which will be used for our proposed intracellular mechanics work; (2) the use of the eight magnetic coils to generate uniform magnetic field gradient for applying the same force on all the magnetic beads within the workspace, which will be used for our proposed intra-tissue mechanics work. In experiments, magnetic microbeads and cellular structures will be fluorescently labelled, and their displacement/deformation will be measured by fluorescence microscopy imaging. ******Our HQP will use the requested equipment to perform mechanical measurement inside individual cells, mechanically load intracellular structures to induce mechanotransduction responses, and achieve mechanical measurement deep within tissue. The equipment will be used to train a high number of postdocs and graduate students who will gain skills in cell and tissue mechanics, cell mechanotransduction, development biology, microscopy imaging, and precision instrument control and measurement.