group 6 piezoelectric cupular micro transducer · on cupula fills role of damaged hair cells...
TRANSCRIPT
Piezoelectric Cupular Micro Transducer Implant
Vestibular Hair Cells
Vestibular Hair Cell Damage
Hair Cell Damage
Damage can cause hair cells to no longer stand up & reduce/diminish signal
sent to brain
Vestibular Ototoxicity
Balance Disorders
Our Solution: Device that replaces damaged hair cells & sense fluid flow in the vestibular
area to send signals to the brain to adjust balance
Healthy Hair Cells
Microtransducer location
The Cupula
Proposed Solution
● Thin film piezoelectric MEMS device implanted on cupula
● Fills role of damaged hair cells● Cantilever beams extend, transducing stress
into electrical signal to vestibular nerve
Large-scale model of proposed cantilever device lodged on cupula and exposed in endolymph.
● Converting mechanical stress to an electrical signal
● Direct piezoelectric effect○ Voltage generated across
material from tensile or compressive stress
○ Proportional via piezoelectric constant
Cantilever Mechanotransduction
Fabrication1. Construct “hair cell” cantilever beams as per Ilik et al.
a. Thin Film Piezoelectric Transducer (6 mask)
b. Patterned using RIE and cantilever formed with DRIE
2. Connect to single-supply micro-sized voltage-to-current
OpAmp
● Parylene C coating○ Flexible○ Biocompatible○ Protects electrical connections
● Cautions○ Silicon foreign body response shown in
cochlear implants○ Calcium Carbonate crystal interference
■ Symptom of Benign Paroxysmal Positional Vertigo (BPPV)
Biocompatibility
Pre-clinical:
● Animal testing: chinchillas○ Evaluate animals with vestibular hair cell
loss, control group and group with implanted device on balance pre- and post-implantation
TestingBenchtop:
● Affirm voltage sensitivity and accuracy as a function of cantilever displacement
● Biomimetic semicircular canal model: affirm correct signal transduction with additive effects of 3 semicircular canals
● Difficult to replace or remove a broken device ● Voltage-to-current transduction requires
uninterrupted battery supply● Sensitivity vs. size trade-off--higher number of
smaller cantilevers is more sensitive, but more difficult to manufacture
Limitations
Haybach, P., RN, MS. (2015, December 29). Ototoxicity. Retrieved from https://vestibular.org/ototoxicity
Anatomy and Physiology Chapter 8: The Nervous System - Hearing and Equilibrium. Lumen Learning. Retrieved from https://courses.lumenlearning.com/nemcc-ap/chapter/special-senses-hearing-audition-and-balance/
Angelaki, D. & Dickman, J. D.. “The vestibular system.” In R. Biswas-Diener & E. Diener (Eds), Noba textbook series: Psychology. 2019. Champaign, IL nobaproject.com
Ilik, B., Koyuncuoglu, A., Sardon-Sukas, O., Kulah, H. “Thin film piezoelectric acoustic transducer for fully implantable cochlear implants” Sensors and Actuators A: Physical. Sep. 2018. Vol. 280, pp. 38-46.
Della Santina, C., Migliaccio, A., Patel, A. “Electrical Stimulation to Restore Vestibular Function--Development of a 3D Vestibular Prosthesis.” Conf. Proc. IEEE Eng Med Biol Soc. Oct. 2009. Vol 7, pp. 7380-7385.
O'Malley, Jennifer T, et al. “Foreign Body Response to Silicone in Cochlear Implant Electrodes in the Human.” Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology
Society [and] European Academy of Otology and Neurotology, U.S. National Library of Medicine, Aug. 2017
References