Polyimide-Based Flexible Multi-Electrode Arrays: Synthesis, Microfabrication, andin-vivoValidation

Abstract

Thin film neural microelectrodes are popularly being used in brain-computer interfaces and tools for neurosurgical interventions. Among the various thin films used, polyimide stands out as an excellent material for substrate passivation due to its chemical inertness, biocompatibility, mechanical flexibility, and superior dielectric properties. While polyimide is extensively used as a substrate in thin film neural interfaces, the lack of availability of a clinical-grade polyimide limits their use in human clinical applications. This paper presents a comprehensive solution by developing an ISO-10993-11-approved polyamic acid for fabricating thin-film polyimide microelectrodes. Benchtop tests and in-vivo experiments in anesthetized mice demonstrate the potential of this synthesized polyamic acid and microfabrication processes for commercialization in clinical settings, particularly for brain-computer interfaces and invasive neural microelectrodes.