Force Clamp Systems for Evaluation of Mechanotransduction

这项工作提出了一种在一定意义上研究机电转换的完全集成的方法。 并专注于开发一种基于微系统的新型工具，即力夹具，它 使用适当比例的压阻悬臂梁作为直接力传感器(PR力钳)。这项建议 包括充分描述第一代设备能力的工作，设计和制造第二代设备- 能够在更高带宽下运行的生成设备，并使用这些设备进行分析和建模 模型机械感受器细胞传递和机电转导的生物力学， 线虫体壁上的触觉感受器神经元。线虫 是开发所建议的工具的极好的生物平台，这些工具很可能在 包括脊椎动物毛细胞在内的其他机械感觉细胞的力电转导研究 背根神经节。一组只有六个触摸感受器神经元负责对 在线虫中触摸(与脊椎动物中的数万)相比，这种反应是由 通过施加于体壁的力激活MEC-4通道复合体。原型力夹具系统 使用PR力夹和带有可编程控制器的压电致动器将校准后的纳米级应用于 具有&gt；1 kHz带宽的微牛顿点载荷分布。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相结合实现同步力-位移电生理-- 生理记录。这项技术将使人们能够首次直接测量 在机械-电转换过程中可能出现的组织僵硬，并引起适应。 与公共卫生的相关性。无论是遗传疾病还是后天疾病，触觉都会退化， 包括艾滋病和糖尿病，以及化疗药物。由这种外围设备引起的并发症 据估计，感觉神经疾病每年的医疗费用超过40亿美元。尽管如此， 人们对触觉及其在疾病中的退化仍知之甚少。开发的研究工具 在这项工作过程中，有可能极大地促进我们的理解。

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.