MEMS Acoustic Tweezers for Micromanipulation of Living Cells

摘要 本研究旨在发展一种以菲涅尔透镜为基础的超音波镊子， 根据需要在三维（3D）空间中的组织，非常像光学镊子，但是具有几个数量级的 对于给定的温度上升，机械捕获力更强。由校长领导的实验室 研究者（PI）最近证明了液体中微粒（直径70 - 400 µm）的超声捕获 一个多焦点菲涅尔传感器（MFT）。捕获的微粒按需移动， 在3D中移动MFT本身。在此成功的基础上，该提案将推动传感器技术， 单个MFT可以根据需要用电信号捕获和移动3D中的颗粒或细胞，而无需 需要移动传感器。这将有利于广泛的生物研究人员，包括那些在 分子、发育和细胞生物学。 生物测试实验将用于聚焦和验证技术开发。我们的第一个具体 超声波镊子的应用将是捕获和保持对于激光捕获来说太大的活体样本（例如， 斑马鱼胚胎和癌症衍生的球状体）。这些被困的多细胞结构将被 保持不受机械接触，用于延时显微镜，并将被声镊扭曲， 测试改变的物理力对胚胎和类器官发育的影响。这些实验需要 捕获和镊子的力量足够大，以改变胚胎的形状（远远大于力 可能使用光学镊子）。 我们将开发三维空间中捕获位置的电气可控性，以便捕获的标本 可以是：（1）从一个位置移动到另一个位置，（2）拉伸或压缩，以表征 细胞的弹性，（3）与其他细胞或含有基因的脂质体接触。这些都将得到 在电指令下执行，而不需要机械地移动超声镊子。 为了优化超声镊子作为生物实验工具的发展，两个 生物实验室（由共同研究者领导）将从一开始就参与研究。他们将获得 在4年期间的第6、18、30和42个月末， 研究期间，并将使用它们进行转基因胚胎，细胞 球状体和非粘附循环细胞。拟议中的生物实验需要操纵活的 细胞在液体环境中，而没有任何由保持装置引起的损坏。这种无接触的操作 如果没有提议的镊子，这将是极其困难的，如果不是不可能的话。两个生物实验室将 积极参与镊子的协同进步，进行生物实验， 提供及时的反馈，指导PI的实验室创造最有用的设计。 由于MFT将声能集中在一个非常小的点上，并且能够通过 作为一种中间固体，它可以被结合到各种微流体平台中用于细胞的管理， 液体、颗粒和蛋白质。MFT对捕获位置和方向的电可控性 力，结合MFT形成阵列的顺从性，将允许创建复杂的 生物化学测定和/或生物医学处理。MFT前所未有的能力， 微粒/细胞（直径为数十-数百微米）的3D捕获和按需操作将 在细胞研究、基因转染、并置和操作方面开辟了许多新的可能性。

Abstract This research is to develop Fresnel-lens-based ultrasonic tweezers that can capture and manipulate living tissue in three dimensional (3D) space on demand, very much like optical tweezers but with several orders of magnitude stronger mechanical trapping force for a given temperature rise. The lab led by the Principal Investigator (PI) recently demonstrated ultrasonic capture of microparticles (70 - 400 µm in diameter) in liquid with a single Multi-foci Fresnel Transducer (MFT). The captured microparticle was moved on demand by moving the MFT itself in 3D. Building on this success, this proposal will advance the transducer technology so that a single MFT can capture and move particles or cells in 3D on demand with an electrical signal without the need to move the transducer. This will benefit a wide range of biological researchers including those in molecular, developmental and cellular biology. Biological test experiments will be used to focus and validate the technology development. Our first specific application of the ultrasonic tweezers will be to trap and hold living specimens too large for laser-trapping (e.g., zebrafish embryos and cancer-derived spheroids) using a MFT. These trapped multi-cellular structures will be held free from mechanical contact for time-lapse microscopy, and will be distorted by the acoustic tweezers to test the effects of altered physical forces on embryo and organoid development. These experiments require trapping and tweezing forces large enough to change the shape of the embryo (far greater than the forces possible with optical tweezers). We will develop electrical controllability of the trapping location in 3D space so that the captured specimens may be: (1) moved from one location to another, (2) stretched or compressed for the characterization of the cell's elastic properties, (3) brought into contact with other cells or gene-containing liposomes. These will all be performed under electrical command without the need to move the ultrasonic tweezers mechanically. To optimize the development of ultrasonic tweezers as an enabling tool for biological experiments, two biological labs (led by the co-Investigators) will participate in the research from the start. They will receive successive versions of acoustic tweezers at the ends of the 6th, 18th, 30th, and 42nd month during the 4-year research period, and will use them to conduct the proposed experiments with transgenic embryos, cell spheroids and non-adherent circulating cells. The proposed biological experiments require manipulation of live cells in a liquid environment without any damage caused by the holding device. Such contact-free manipulation would be extremely difficult, if not impossible, without the proposed tweezers. The two biology labs will participate actively in a synergistic advancement of the tweezers, performing the biological experiments, and providing timely feedbacks, directing the PI's lab towards creating the most useful designs. Since MFT focuses acoustic energy on a very small spot and is capable of delivering acoustic energy through an intermediate solid, it can be incorporated into various microfluidic platforms for the management of cells, liquids, particles and proteins. The MFT's electrical controllability on the location and direction of the trapping force, combined with amenability of MFT being formed into an array, will allow the creation of complex biochemical assays and/or biomedical treatments at high throughput. The MFT's unprecedented capability of 3D capture and on-demand manipulation of microparticles/cells (of tens - hundreds of microns in diameter) will open up many new possibilities in cell study, gene transfection, juxtaposition and manipulation.