Force Clamp Systems for Evaluation of Mechanotransduction

描述(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摸意义上的机电转换，并专注于开发一种基于微系统的新型工具-即使用适当比例的压阻悬臂作为直接力传感器的力夹具(PR力钳)。该提案包括充分描述第一代设备的能力，设计和建造能够在更高带宽下工作的第二代设备，并使用这些设备来分析和模拟模型机械感受器细胞提供的生物力学传递和机械-电子转导，模型机械感受器细胞是支配线虫体壁的触摸感受器神经元。线虫是开发所提出的工具的一个很好的生物平台，很可能在包括脊椎动物毛细胞和背根神经节在内的其他机械感觉细胞的机电转换研究中得到应用。在线虫中，只有六个触摸感受器神经元负责对触摸的行为反应(与脊椎动物的数万个相比)，这种反应是由施加在身体壁上的力激活MEC-4通道复合体而启动的。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来应用经过校准的纳微牛顿点载荷分布，带宽为&gt；1 kHz。这项工作的一个关键和创新方面是将PR力钳与膜片钳电生理学相结合，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-电气转换过程中可能发生的组织硬度的动态变化，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，包括艾滋病和糖尿病，以及化疗药物，触觉都会退化。据估计，这种外周感觉神经病的并发症每年要花费超过40亿美元的医疗费用。尽管如此，人们对触觉及其在疾病中的退化仍然知之甚少。在这项工作中开发的研究工具有可能极大地促进我们的理解。

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.