An intracochlear lead-zirconate-titanate (PZT) microactuator integrated with a cochlear implant electrode array could be a feasible strategy to implement combined electric and acoustic stimulation inside the cochlea. The purpose of this paper is to characterize in vitro a prototype PZT microactuator for intracochlear applications, including service life, failure mechanisms, and lead leaching. PZT microactuators were driven sinusoidally to failure in air and in artificial perilymph. Frequency response functions (FRFs) and electrical impedance were monitored. After the PZT microactuators failed, the amount of leached lead was measured via inductive coupled plasma mass spectrometry (ICP-MS). Two failure mechanisms are identified: electrical breakdown and structural failure. The electrical breakdown, possibly from loss of parylene encapsulation, is evidenced by a sudden and significant drop of the actuators' electrical resistance. The structural failure, possibly from electrode delamination, is evidenced by a sudden and significant drop of FRFs. The amount of lead leached from the PZT microactuator is well below published safety guidelines from federal agencies.
A Study on Long-Term In Vitro Reliability of Intracochlear Lead-Zirconate-Titanate Microactuators
Manuscript received March 11, 2018; final manuscript received April 27, 2018; published online May 28, 2018. Assoc. Editor: Xiaoning Jiang.
- Views Icon Views
- Share Icon Share
- Search Site
Liu, Y., Luo, C., Cao, G. Z., Hume, C. R., and Shen, I. Y. (May 28, 2018). "A Study on Long-Term In Vitro Reliability of Intracochlear Lead-Zirconate-Titanate Microactuators." ASME. ASME J of Medical Diagnostics. August 2018; 1(3): 031005. https://doi.org/10.1115/1.4040103
Download citation file: