Design and Characterization of Biomimetic Artificial Hair Cells in an Artificial Cochlear Environment
Travis, Jeffrey Philip
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This research details the creation and characterization of a new biomimetic artificial inner hair cell sensor in an artificial cochlear environment. Designed to mimic the fluid flows around the inner hair cells of the human cochlea, the artificial cochlear environment produces controlled, linear sinusoidal fluid flows with frequencies between 25 and 400 Hz. The lipid bilayer-based artificial inner hair cell generates current through changes in the bilayer's capacitance. This capacitance change occurs as the sensor's artificial stereocilium transfers the force in the fluid flow to the bilayer. Frequency tuning tests are performed to characterize the artificial inner hair cell's response to a linear chirp signal from 1 to 400 Hz. The artificial inner hair cell's response peaks at a resonant frequency of approximately 83 Hz throughout most of the tests. Modelling the artificial stereocilium as a pinned free beam with a rotational spring at the pinned end yields a rotational spring stiffness of 177*10^-6 Nm/rad. Results with 0 mV potential applied across the bilayer indicate that current generation at 0 mV likely comes from other sources besides the bilayer. Increasing the voltage potential increases the broadband power output of the system, with an approximately linear relationship. A final test keeps the fluid flow frequency constant and varies the fluid velocity and applied voltage potential. Manipulation of the applied voltage potential results in a fluid velocity to RMS current relationship reminiscent of the variable sensitivity of the human cochlea.
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