Fluid-Structure Interaction in Arthropod Mechanoreceptors with Application to Bio-Inspired Micro-Fluidic Sensors

在许多工程应用中，使用小型传感器(1 mm或更小)识别微流特性的能力正变得越来越重要。在生物医学工程中，需要测量血管中的局部流动特性，因为这些流体特性对血管壁的结构完整性有潜在的影响。在航空航天工程中，微型飞机正被开发用于许多应用，但由于难以防止沿机翼的流动分离和由此导致的失速，这些微型飞机的性能受到限制。在微型飞机飞行时测量这些特性被证明是一个巨大的挑战。虽然工程师们几十年来一直在努力设计微型流量传感器，但蟋蟀和其他节肢动物已经利用几百万年的进化开发出了微型流量传感器，这对威胁检测、躲避捕食者和交流至关重要。在普通的室内蟋蟀中，微型流量传感器是位于腹部后部的两个类似天线的附属物，称为Cerci。每个子宫颈覆盖着大约800根丝状机械感觉毛发，每一根毛发都连接到一个产生棘波的神经元。气流使头发偏转，会改变毛发根部相关感受器神经元的放电活动。结果表明，该系统具有极高的灵敏度，能够探测到热噪声引起的空气运动。这种灵敏度超出了目前人工微流量传感器的能力范围。我们的项目是基于这样一个假设，即对节肢动物微流量传感器的更好理解可以指导人工微流量传感器的发展和改进。我们将开发基于浸没边界技术的非定常Stokes方程的新的建模和计算工具，以研究蟋蟀体内的颈微传感器。这些模型将直接应用于人工微流量传感器。多年来，人们已经认识到，工程设计可以从对生物结构的了解中受益匪浅。进化为与检测和分析动物周围环境中非常微小的空气和流体运动有关的复杂问题提供了非常复杂的解决方案，这些生物解决方案的各个方面原则上应该直接适用于或可推广到工程系统中。一个由工程师、数学家和神经生物学家组成的跨学科团队将开发新的建模和计算工具，以研究蟋蟀颈部微流量传感器的性能特征。两个主要成果将直接适用于人工微流量传感器的设计。第一个成果将是一个计算技术和模型的集合，这些技术和模型明确地解决了流体运动对传感器的影响。第二个结果将是一套生物原理，这些原理是根据结构-流体相互作用的物理约束而演变出来的，可以指导人工流量传感器的发展。

The ability to identify micro-flow characteristics using small sensors (1 mm or less) is becoming increasingly important in many engineering applications. In biomedical engineering there is a need to measure local flow properties in blood vessels because these fluid properties have a potential impact on the structural integrity of the vessel wall. In aerospace engineering, micro-planes are being developed for a number of applications, but the performance of these micro-planes is limited due to the difficulties of preventing flow separation along the wings and the resulting stall. Measuring these characteristics while the micro-plane is in flight is proving to be a significant challenge. While engineers have been grappling with the design of micro-flow-sensors for a few decades, crickets and other arthropods have used a few million years of evolution to develop micro-flow-sensors that are essential for threat detection, predator avoidance, and communication. In the common house cricket the micro-flow-sensors are two antenna-like appendages, called cerci, at the rear of the abdomen. Each cercus is covered with approximately 800 filiform mechanosensory hairs, each of which is connected to a single spike-generating neuron. Deflection of a hair by air currents changes the spiking activity of the associated receptor neuron at the base of the hair. It has been shown that the cercal system is extraordinarily sensitive and capable of detection of air motion caused by thermal noise. This sensitivity is beyond the capability of current artificial micro-flow sensors. Our project is based on the hypothesis that a better understanding of the arthropod micro-flow-sensor can guide the development and improvement of artificial micro-flow-sensors. We will develop new modeling and computational tools for the unsteady Stokes equations based on immersed boundary techniques to study the cercal micro-sensor in crickets. These models will be directly applicable to artificial micro-flow sensors.It has been recognized for many years that engineering design can greatly benefit from the understanding of biological structures. Evolution has resulted in very sophisticated solutions for complex problems related to the detection and analysis of very small air and fluid movements in an animal's immediate environment, and aspects of those biological solutions should be directly applicable or generalizable, in principle, for engineered systems. An interdisciplinary team that combines an engineer, mathematician and a neurobiologist will develop new modeling and computational tools to study performance characteristics of the cercal micro-flow sensor in crickets. Two principal outcomes will be directly applicable to design of artificial micro-flow sensors. The first outcome will be a collection of computational techniques and models which explicitly address the effect of fluid motion on the sensors. The second outcome will be a set of biological principles that evolved in response to constrains posed by the physics of structure-fluid interactions, and that can guide the development of artificial flow sensors.