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Published on: September 27, 2013
Characterization of parylene C as an encapsulation material for implanted neural prostheses
Christina Hassler1, Rene P von Metzen, Patrick Ruther
1Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, Freiburg, Germany. hassler@imtek.de
Summary
Parylene C shows promise for neural prostheses, with Silane A-174 improving adhesion on key substrates. Careful material selection and process optimization are crucial for effective encapsulation and device longevity.
Area of Science:
- Biomaterials Science
- Neuroengineering
- Materials Science
Background:
- Implanted neural prostheses require robust encapsulation materials to ensure device longevity and biocompatibility.
- Parylene C is a potential candidate for such applications due to its favorable electrical and mechanical properties.
Purpose of the Study:
- To characterize and optimize the use of parylene C as an encapsulation material for neural prostheses.
- To evaluate adhesion promotion methods and the effects of thermal treatment on parylene C films.
- To assess the protective capabilities of parylene C against corrosion.
Main Methods:
- Adhesion testing on various substrates (Si3N4, platinum, parylene C, gold, polyimide) using Silane A-174.
- Tensile testing and crystallinity measurements on parylene C films after thermal treatment (steam sterilization, annealing).
- Electrochemical impedance spectroscopy to evaluate corrosion protection of metallic structures.
Main Results:
- Satisfactory adhesion of parylene C was achieved on Si3N4, platinum, and parylene C using Silane A-174, withstanding steam sterilization.
- Adhesion to gold and polyimide remained insufficient with tested methods.
- Thermal treatment increased film brittleness and stiffness due to enhanced crystallinity.
- Silane A-174 treatment was necessary for parylene C to provide effective corrosion protection to metallic structures.
Conclusions:
- Silane A-174 is effective for promoting parylene C adhesion on specific neural prosthesis substrates.
- Material compatibility and process parameter optimization are critical for achieving optimal parylene C encapsulation performance.
- Further research may be needed to improve parylene C adhesion on challenging substrates like gold and polyimide.
