Mechanical and Electrical Characterization of Piezoelectric Artificial Cochlear Device and Biocompatible Packaging

Abstract

This paper presents the development of a piezoelectric artificial cochlea (PAC) device capable of analyzing vibratory signal inputs and converting them into electrical signal outputs without an external power source by mimicking the function of human cochlea within an audible frequency range. The PAC consists of an artificial basilar membrane (ABM) part and an implantable packaged part. The packaged part provides a liquid environment through which incoming vibrations are transmitted to the membrane part. The membrane part responds to the transmitted signal, and the local area of the ABM part vibrates differently depending on its local resonant frequency. The membrane was designed to have a logarithmically varying width from 0.97 mm to 8.0 mm along the 28 mm length. By incorporating a micro-actuator in an experimental platform for the package part that mimics the function of a stapes bone in the middle ear, we created a similar experimental environment to cochlea where the human basilar membrane vibrates. The mechanical and electrical responses of fabricated PAC were measured with a laser Doppler vibrometer and a data acquisition system, and were compared with simulation results. Finally, the fabricated PAC in a biocompatible package was developed and its mechanical and electrical characteristics were measured. The experimental results shows successful frequency separation of incoming mechanical signal from micro-actuator into frequency bandwidth within the 0.4 kHz–5 kHz range.

Biomimetic Artificial Basilar Membranes for Next‐Generation Cochlear Implants

“…Given that the purpose of the ABM is to operate sustainably in the human body, the piezoelectric and triboelectric effects that can create self‐powered devices are now being actively studied. Various types of piezoelectric material, such as PZT, AlN, PVDF, and P(VDF‐TrFE), are used as the active materials for different types of ABM. The advantages of each piezoelectric material are well reflected in the characteristics of the ABMs.…”

“…Due to their excellent chemical stability, mechanical flexibility, and biocompatibility, both PVDF and P(VDF‐TrFE) are widely used for piezoelectric sensors and actuators . In particular, PVDF has been used in ABMs due to its flexibility and piezoelectric properties …”

“…Recently, the piezoelectric and triboelectric effect have been actively used to implement self‐powered ABMs without an external power source. Piezoelectric ABMs have been fabricated using various piezoelectric materials, such as lead zirconate titanate (PZT), aluminum nitride (AlN), polyvinylidene fluoride (PVDF), and PVDF fluoride trifluoroethylene [P(VDF‐TrFE))] …”

Implantable microphones as an alternative to external microphones for cochlear implants

“…Zhang et al designed a piezoelectric sensor which is placed in perilymph to pick up pressure waves within (Zhang, Seligman, Klein, & Cowan, 2009). Jung et al (2015) designed an artificial basilar membrane with an integrated piezoelectric sheet allowing detection of fluid movement within an artificial cochlear chamber. The design was capable of frequency separation between 450 Hz and 5 kHz (Y. Jung, Kwak, Kang, Kim, & Hur, 2015).…”

Sensor Devices Inspired by the Five Senses: A Review

“…On the other side, the Esteem is a total implantable device. It is invisible, which is cosmetically desirable, and allows usage of the device while swimming and improves the comfort and hygiene . Despite some imperfections, the cochlear implants have improved over the last few years and there is a massive industry behind them.…”