Group 6 Piezoelectric Cupular Micro Transducer · on cupula Fills role of damaged hair cells...
Transcript of Group 6 Piezoelectric Cupular Micro Transducer · on cupula Fills role of damaged hair cells...
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Piezoelectric Cupular Micro Transducer Implant
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Vestibular Hair Cells
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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
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Healthy Hair Cells
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Microtransducer location
The Cupula
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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.
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● 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
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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
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● 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
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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
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● 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
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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