PITA Fiscal Year 2015 Projects

Lifetime Projection for Next-Generation Medical Implants

Lead University: Carnegie Mellon University
PI: Shawn Kelly, ICES

We propose to develop and build a prototype electronic system to test and characterize thin-film coatings used as packaging for next-generation implantable medical devices, such as neural prostheses or retinal prostheses. Existing titanium and ceramic packages use helium leakage rates as a standard method to project the lifetime of the device after implantation, and the FDA strongly favors this type of characterization for every device. Titanium and ceramic packages have reached their technological limitations in terms of feedthrough density and package size, and microfabrication methods are being explored to create packages for next-generation, highchannel- count devices. However, a method of testing these microfabricated coatings is needed. Research has shown that the impedance of interdigitated electrodes embedded in the package coatings will change as water vapor begins to penetrate the package, and we believe that this impedance shift can be use to predict the failure of the device, and its useful lifetime. Using the standard techniques of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), we will calculate charge capacity and impedance of the interdigitated electrodes to test various coatings and characterize the lifetime of a device using these coatings. A CMU faculty member and CMU graduate students will perform this work. We will collaborate with a small company that plans to build a design center in Pittsburgh, a major eye hospital, and the Department of Veterans Affairs. This team from academia, industry, and government will create the test and characterization system, potentially creating a spinoff company to license the technology.