Integrated flexible/stretchable electrode and interconnect systems for next generation neural interfaces

This PhD research relates to design, fabrication, and characterization of integrated flexible electrodes and packaging systems for neural interfaces. MEMS (micro-electro-mechanical-system) neural electrodes have the potential to improve the quality of life for people with neurological diseases and to enhance our understanding of nervous system. My research described here consists of five main sections. The first section discusses a Stretchable PDMS Electrode Arrays (SPEA) for dynamic neural recording. The stretchable electrode can be utilized in studying cellular behavior central to several important pathologies such as traumatic brain injury, cardiomyopathy, and vascular disorders. The second part is focused on designing a composite system of PDMS-Parylene electrodes for subdural cortical recording and stimulation. The composite system provides an enhanced flexible platform for wireless monitoring of epilepsy patients. The third part we developed a new scheme for transmitting parallel neural data using a free space optical link. The neural activities are wireless recorded with an optical microsystem consisting Integrated Biopotential Amplifiers (IBA), low power LEDs, and CCD Camera. The fourth section describes a semi-flexible hydrogel-parylene neural electrode. The parylene electrodes with selectively patterned hydrogel provide stiff mechanical properties for easy penetration into the brain tissues and subsequent flexibility after insertion upon swelling of the hydrogel. The final part discusses an advanced packaging system with using a composite inorganic parylene combination. Atomic layer deposited alumina-zirconia (Al2O3–ZrO2) composite layer can provide a conformal and nano-laminated coating on parylene surface in neural packaging systems in order to improve the hermeticity for long term implantations