OBJECTIVE: This work deals with studying and improving the insulation lifetime of polyimide-insulated thin film neural implants, or related polyimide-based medical implants. APPROACH: The evolution of the leak impedance of insulated conductors was investigated in saline water at 40 °C. The fabrication process as commonly found in literature for polyimide/platinum/polyimide microelectrode arrays was compared with three possible improvements: one based on lowering the curing temperature of the lower layer, one based on chemical activation and one based on an additional plasma activation step. MAIN RESULTS: The lower curing temperature process was found to yield a 7.5-fold improved lifetime compared with the state of the art process. Also, the leak impedances found after soak testing are an order of magnitude higher compared to the standard process. SIGNIFICANCE: By improving the lifetime and insulation impedance of polyimide insulation with one order of magnitude, this work increases the applicability of polyimide in chronic thin film neural implants considerably.
OBJECTIVE: This work deals with studying and improving the insulation lifetime of polyimide-insulated thin film neural implants, or related polyimide-based medical implants. APPROACH: The evolution of the leak impedance of insulated conductors was investigated in saline water at 40 °C. The fabrication process as commonly found in literature for polyimide/platinum/polyimide microelectrode arrays was compared with three possible improvements: one based on lowering the curing temperature of the lower layer, one based on chemical activation and one based on an additional plasma activation step. MAIN RESULTS: The lower curing temperature process was found to yield a 7.5-fold improved lifetime compared with the state of the art process. Also, the leak impedances found after soak testing are an order of magnitude higher compared to the standard process. SIGNIFICANCE: By improving the lifetime and insulation impedance of polyimide insulation with one order of magnitude, this work increases the applicability of polyimide in chronic thin film neural implants considerably.
Authors: Kunal Sahasrabuddhe; Aamir A Khan; Aditya P Singh; Tyler M Stern; Yeena Ng; Aleksandar Tadić; Peter Orel; Chris LaReau; Daniel Pouzzner; Kurtis Nishimura; Kevin M Boergens; Sashank Shivakumar; Matthew S Hopper; Bryan Kerr; Mina-Elraheb S Hanna; Robert J Edgington; Ingrid McNamara; Devin Fell; Peng Gao; Amir Babaie-Fishani; Sampsa Veijalainen; Alexander V Klekachev; Alison M Stuckey; Bert Luyssaert; Takashi D Y Kozai; Chong Xie; Vikash Gilja; Bart Dierickx; Yifan Kong; Malgorzata Straka; Harbaljit S Sohal; Matthew R Angle Journal: J Neural Eng Date: 2021-02-24 Impact factor: 5.379
Authors: Luke A Stangler; Abbas Kouzani; Kevin E Bennet; Ludovic Dumee; Michael Berk; Gregory A Worrell; Steven Steele; Terence C Burns; Charles L Howe Journal: Fluids Barriers CNS Date: 2021-12-01