Session: 03-07-01: Material Processing of Flexible/Emerging Electronics, Sensors, and Devices I

Paper Number: 100082

100082 - Advanced Thin-Film Materials and Electronics for High-Resolution and Chronically Stable Neural Interfaces 

The human body, such as the brain, produces a wide range of biophysical and biochemical signals that contain important information about the health condition and the progression of various diseases. There are critical challenges, however, to efficiently capture the signals due to the rigid characteristics of conventional medical systems. To address this issue, the design of thin, soft and flexible electronics forms the basis of novel wearable and implantable biomedical devices for the diagnostics and treatment of brain injuries and other chronic neurodegenerative diseases with improved outcomes and reduced costs.

This talk will focus on the science and engineering of thin-film materials for recording and stimulation in the nervous system to extend the frontier of human healthcare. This talk will first introduce the design and innovation of Si nanomembrane as interface to the brain for flexible micro-electrocorticographic (μECoG) arrays with multidecade lifetimes under physiological conditions. The technology enables flexible, actively multiplexed μECoG electrodes for recording and stimulation in nervous systems with chronic stability, high sensitivity, and unprecedented level of spatiotemporal resolution. Beyond applications in electrophysiology, coupling the waterproof transistors with various ion-selective membranes through the gate electrode allows for sensitive and selective detection of multiple ions as biomarkers for traumatic brain injury. By using ion-selective nanomembranes (ISMs) for H⁺, Na⁺, K⁺, and Ca²⁺ as examples, the study establishes the proof-of-concept and develops calibration standards based on the cross-sensitivity between different ions and ISMs. Systematic studies investigate failure mechanisms of ISMs during immersion tests associated with the leaching of functional components under physiological conditions. The study also demonstrates a similar encapsulation structure which enables the design of waterproof amperometric sensors based on this materials strategy and integration scheme. The results may create new opportunities for understanding the body's dynamic chemistry over extended periods during biomedical research and clinical practices. Integration of different bio-recognition elements can expand the device concept for efficient detection of various biomarkers using potentiometry and/or amperometry. Stable but ultimately bioresorbable active systems are also possible by replacing metals and polymers used here with transient counterparts (e.g., Zn, Mg).

Together, these materials and electronics provide a realistic pathway to biomedical devices with biocompatibility, bioconformality and biostability for the applications in closed-loop neuromodulation and neuroscience research. Future directions include the development of waterproof, high-resolution, and fully integrated chemical sensor arrays with local active components for mapping the spatiotemporal distribution of neuronal compounds, as well as multifunctional neural interfaces with integrated, miniaturized biochemical sensors and neural electrodes for dual-mode recording.

Presenting Author: Jinghua Li The Ohio State University

Presenting Author Biography: Dr. Jinghua Li is an assistant professor of materials science and engineering, beginning in September 2019. Prior to joining Ohio State, she worked as a postdoctoral fellow with Professor John A. Rogers in the Department of Materials Science and Engineering at Northwestern University. Dr. Li graduated from Duke University in May 2016 with a Ph.D. in Chemistry. Her two focus areas are: 1) fundamental understandings on synthesis chemistry and interfacial properties of thin-film materials as bio-interfaces; and 2) engineering efforts on application of these materials for the next generation wearable/implantable biomedical devices to bridge the gap between rigid machine and soft biology. Her faculty position is funded, in part, by the Discovery Themes Initiative in the area of Chronic Brain Injury, which has promoted faculty hires and support of critical materials needs in the areas of imaging, diagnosis, and treatment of brain injury. Dr. Li supports the Center for Design and Manufacturing Excellence, Nanotech West, and the Center for Electron Microscopy and Analysis with her expertise in the function of biomaterials.

Authors:

Jinghua Li The Ohio State University