Force Clamp Systems for Evaluation of Mechanotransduction

描述（由申请人提供）：这项工作提出了一种完全集成的方法来研究触觉中的机电转导，并专注于开发一种新的基于微系统的工具，即使用适当比例的压阻悬臂作为直接力传感器的力钳（PR力钳）。该提案包括充分表征第一代设备的功能，设计和构建能够在更高带宽下运行的第二代设备，并使用这些设备通过模型机械受体细胞（支配秀丽隐杆线虫体壁的触觉受体神经元）分析和模拟生物力学传递和机电转导。秀丽隐杆线虫是开发上述工具的良好生物平台，这些工具可能在其他机械感觉细胞（包括脊椎动物毛细胞和背根神经节）的机电转导研究中得到应用。在秀丽隐杆线虫中，只有6个触觉受体神经元负责对触摸的行为反应（相比之下，脊椎动物中有数万个），这些反应是通过施加在体壁上的力激活MEC-4通道复合物而启动的。原型力夹系统使用PR力夹和带有可编程控制器的压电致动器来应用校准的纳米到微牛顿点负载配置文件，带宽为> 1kHz。这项工作的一个关键和创新方面是PR力钳与膜片钳电生理学的集成，用于同步力-位移-生理记录。这项技术将首次能够直接测量组织刚度的动态变化，这种变化可能发生在机电转导过程中，并产生适应性。与公共卫生有关。触觉可因遗传和获得性疾病（包括艾滋病和糖尿病）以及化疗药物而退化。据估计，这种周围感觉神经病变的并发症每年在医疗保健方面的花费超过40亿美元。尽管如此，人们对触觉及其在疾病中的退化仍然知之甚少。在这项工作过程中开发的研究工具有可能大大促进我们的理解。

DESCRIPTION (provided by applicant): This work proposes a fully integrated approach to the study of mechano-electrical transduction in the sense of touch and focuses on the development of a novel microsystems-based tool-namely, a force clamp that uses appropriately-scaled piezeoresistive cantilevers as direct force sensors (PR force clamp). The proposal includes work to fully characterize the capabilities of a first-generation device, to design and build a second- generation device capable of operating at higher bandwidth, and to use these devices to analyze and model the biomechanics offeree transfer and mechano-electrical transduction by a model mechahoreceptor cell, the touch receptor neurons that innervate the body wall of the nematode Caenorhabditis elegans. C. elegans is an excellent biological platform for developing the proposed tools, which are likely to find application in the study of mechano-electrical transduction in other mechanosensory cells including vertebrate hair cells and dorsal root ganglion. A set of only six touch receptor neurons is responsible for behavioral responses to touch in C. elegans (compared to tens of thousands in vertebrates) and such responses are initiated by activation of the MEC-4 channel complex by forces applied to the body wall. Prototype force clamp systems use PR force clamps and piezoelectric actuators with programmable controllers to apply calibrated nano- to micro-Newton point load profiles with > 1kHz bandwidth. A critical and innovative aspect of this work is the integration of the PR force clamp with patch-clamp electrophysiology for synchronous force-displacement- physiological recordings. This technology will enable the first direct measurement of dynamic changes in tissue stiffness that may occur during mechano-electrical transduction and give rise to adaptation. Relevance to public health. The sense of touch can be degraded by both inherited and acquired disease, including AIDS and diabetes, as well as by chemotherapeutic drugs. Complications from such peripheral sensory neuropathies are estimated to cost more than $4 billion annual in health care costs. Despite this, the sense of touch and its degradation in disease remain poorly understood. The research tools developed in the course of this work have the potential to significantly advance our understanding.