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Photografted Zwitterionic Hydrogel Coating Durability for Reduced Foreign Body Response to Cochlear Implants
Adreann Peel1, Douglas Bennion2, Ryan Horne1
1Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, United States.
ACS Applied Bio Materials
|April 8, 2024
Summary
Photografted zwitterionic hydrogel coatings significantly enhance cochlear implant lubricity, reducing insertion forces and trauma. These durable antifouling surfaces maintain function even after drying and rehydration, proving viable for long-term use.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Medical Device Engineering
Background:
- Cochlear implants require biomaterials with antifouling properties to minimize tissue trauma and scarring.
- Zwitterionic hydrogels offer excellent biocompatibility and antifouling characteristics.
- The durability of these coatings during surgical insertion and long-term implantation is critical for clinical success.
Purpose of the Study:
- To evaluate the durability and antifouling performance of photografted zwitterionic hydrogel coatings on cochlear implant biomaterials.
- To assess the impact of coating hydration, applied force, and time on lubricity and mechanical integrity.
- To determine the effectiveness of these coatings in reducing insertion forces during cochlear implantation.
Main Methods:
- Tribometry was employed to measure the coefficient of friction under varying hydration levels, applied forces, and time.
- Mandrel bending was used to assess the flexural resistance of the hydrogel films.
- Ex vivo testing involved measuring friction between tissues and coated surfaces.
- Cochlear implantation forces were quantified using cadaveric human cochleae.
Main Results:
- Hydrated zwitterionic hydrogel coatings reduced frictional resistance by approximately 20-fold compared to uncoated PDMS.
- Coated cochlear implants experienced significantly lower insertion forces than uncoated systems.
- Zwitterionic films demonstrated resistance to desiccation for up to 60 minutes and maintained lubricity for 20 hours under continuous hydrated force.
- Coatings showed no degradation and retained lubricity before and after implantation, with improved performance in loosely cross-linked systems, even after rehydration.
Conclusions:
- Photografted zwitterionic hydrogel coatings are durable and maintain antifouling viability for cochlear implant applications.
- The enhanced lubricity and mechanical properties are preserved under various conditions, including drying and rehydration.
- These coatings significantly decrease insertion forces, potentially reducing surgical trauma and improving patient outcomes.
