Force Clamp Systems for Evaluation of Mechanotransduction

这项工作提出了一个完全集成的方法来研究机械-电转导的意义 的触摸，并专注于开发一种新的基于微系统的工具，即一种力夹， 使用适当比例的压阻式杠杆作为直接力传感器（PR力钳）。该提案 包括充分描述第一代设备的能力，设计和建造第二代设备， 能够在更高带宽下操作的生成设备，并使用这些设备来分析和建模 生物力学通过模型机械感受器细胞提供自由传递和机械-电转换， 支配秀丽隐杆线虫体壁的触觉感受器神经元。C. elegans 是一个很好的生物平台，用于开发所提出的工具，这些工具可能会在 在包括脊椎动物毛细胞在内的其他机械感觉细胞中的机械-电转导的研究， 背根神经节一组只有六个触觉感受器神经元负责对 触摸C。（与脊椎动物中的数万种相比），这种反应是由 通过施加到体壁的力激活MEC-4通道复合物。原型力夹系统 使用PR力钳和压电致动器与可编程控制器应用校准的纳米到 微牛顿点负载曲线，带宽> 1 kHz。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整合，用于同步力-位移- 生理记录这项技术将首次直接测量 在机械-电转换过程中可能发生的组织硬度并引起适应。 与公共卫生的相关性。触觉会因遗传和后天疾病而退化， 包括艾滋病和糖尿病，以及化疗药物。此类外周并发症 估计感觉神经病每年花费超过40亿美元的卫生保健费用。尽管如此， 触觉及其在疾病中的退化仍然知之甚少。开发的研究工具 在这项工作的过程中，有可能大大推进我们的理解。

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 toolnamely, 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.