Reliable chronic electrophysiological recordings remain elusive due to persistent biological failure affecting the electrode-tissue interface. While large scale recordings (>100 channels) have been demonstrated using microwire and silicon-based intracortical electrodes, the rigidity of such construction risks further damage to soft neural tissue that elicits chronic immune response and the associated glial encapsulation. Soft polymer construction reduces the mechanical mismatch by two orders of magnitude, however, polymer neural probe technology has lagged behind that of silicon in electrode density per shank and integration with microelectronic circuitry. Through advances in polymer micromachining, we demonstrated multi-electrode probes and probe arrays comprising thin shanks of poly(para-chloro-xylylene) (Parylene C) integrated with a high density of platinum recording sites. These devices were successfully deployed for deep brain recordings in the hippocampus with minimal immune response owing to the thin, flexible substrate, and a novel insertion method that obviates the need for bulky insertion shuttles or stiffening agents. Overall, these technical advances seek to achieve large-scale, high-density arrays of polymer-based neural probes for chronic large scale recording of neural activity.
Ellis Meng is Professor of biomedical and electrical engineering in the Viterbi School of Engineering at the University of Southern California where she has been since 2004. She is also Dwight C. and Hildagarde E. Baum Chair of the Department of Biomedical Engineering and inaugural holder of a Gabilan Distinguished Professorship in Science and Engineering. She received the B.S. degree in engineering and applied science and the M.S. and Ph.D. degrees in electrical engineering from the California Institute of Technology (Caltech), Pasadena, in 1997, 1998, and 2003, respectively. Her research interests include biomedical microelectromechanical systems (bioMEMS), implantable biomedical microdevices, microfluidics, multimodality integrated microsystems, microsensors and actuators, biocompatible polymer microfabrication, and packaging. Dr. Meng is a member of Tau Beta Pi, the Biomedical Engineering Society, American Society of Mechanical Engineers, and the American Society for Engineering Education. Her honors include the NSF CAREER award, Wallace H. Coulter Foundation Early Career Award, 2009 TR35 Young Innovator Under 35, Viterbi Early Career Chair, and ASEE Curtis W. McGraw Research Award. She is a fellow of IEEE, ASME, BMES, and AIMBE. She is on the editorial board of the Journal of Micromechanics and Microengineering and Frontiers in Mechanical Engineering, Micro- and Nano-mechanical Systems. She was co-chair of the 2017 IEEE MEMS conference. She is also an active educator and authored a textbook on bioMEMS.