Mechanical modeling of mimicking stereocilia’s nonlinear amplifying mechanism

Abstract

Stereocilium, the basic sensory units of nature’s inertia sensor has high sensitivity over broad dynamic range which is a design conflict in conventional engineering sensor design. In this study, we propose a mechanical model mimicking hair bundle’s two amplifying mechanisms to resolve limitation of existing sensors. Negative stiffness mechanism, operated by ion-channel’s gating of nano-structure protein called tip-link, is mimicked using magnet’s repulsive force. Adaptation mechanism, worked by active motor, is mimicked by using horizontally moving magnet connected to stepping motor. we verify that this model represent the negative stiffness and adaptation mechanism through displacement-clamping experiment and also observe the spontaneous oscillation which appears combining two mechanisms using motion capture camera and optical maker. This result can be applying to engineering design problem such as nano-piezo actuator needed maximum amplification with bearable stiffness.