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

Montana State University, Bozeman MT

Investigators

Abstract

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.