Session: 04-17-01: Functional Soft Composites - Design, Mechanics, and Manufacturing

Paper Number: 172332

Chemistry-Centered Flexible Sensing and Actuation Systems for Advanced Human-Machine Interfaces 

Sensors and actuators are fundamental building blocks of next-generation human-machine interfaces. This talk presents our recent efforts to establish closed-loop, bidirectional communication and feedback within living systems, with an emphasis on the chemical dimension.

The first part of the talk presents a novel class of flexible, miniaturized probes inspired by biofuel cells for monitoring synaptically released glutamate in the nervous system. The resulting sensors, with dimensions as low as 50 by 50 μm, can detect real-time changes in glutamate within the biologically relevant concentration range. Experiments exploiting the hippocampal circuit in mice models demonstrate the capability of the sensors in monitoring glutamate release via electrical stimulation using acute brain slices. These advances could aid in basic neuroscience studies and translational engineering, as the sensors provide a diagnostic tool for neurological disorders. Additionally, adapting the biofuel cell design to other neurotransmitters can potentially enable the detailed study of the effect of neurotransmitter dysregulation on neuronal cell signaling pathways and revolutionize neuroscience. Additional efforts will focus on further reducing the overall size of the electrode for improved spatial resolution, enhancing the sensitivity, and minimizing the overall variation in sensitivity between devices. Furthermore, incorporating other wireless components, such as a Bluetooth or NFC chip, could improve the device's implantability and enable potential in vivo testing. This device could have potential applications in glutamate concentration mapping with high spatial and temporal resolution. A multiplexed system that incorporates an array of miniaturized anodes connected to a common cathode could enable the mapping of glutamate concentration across various brain regions simultaneously. Disease state models of TBI could be utilized to investigate the extent to which glutamate concentration increases in distinct brain regions and their correlation with elevated neuronal firing activity. Therefore, a multiplexed device could have diagnostic potential for detecting the onset and progression of brain injury by enabling the real-time monitoring of glutamate concentrations across multiple brain regions. Additionally, to enhance the diagnostic accuracy of the device, it would be valuable to increase the detection speed of the sensor, enabling it to recognize rising levels of glutamate concentration within a few milliseconds. This improvement would allow the device to detect increases in glutamate concentration resulting from each individual action potential, making it a useful tool for mapping out glutamate cell signaling pathways in both healthy and diseased states. This technology could be particularly beneficial to healthcare professionals by aiding in the early detection of diseases like stroke, epilepsy, and schizophrenia that can be caused by elevated levels of glutamate.

The second part of the talk presents a bio-integrated gustatory interface, “e-Taste,” to address the underrepresented chemical dimension in current VR/AR technologies. This system facilitates remote perception and replication of taste sensations through the coupling of physically separated sensors and actuators with wireless communication modules. By using chemicals representing five basic tastes, systematic codesign of key functional components yields reliable performance including tunability, versatility, safety, and mechanical robustness. Field testing involving human subjects focusing on user perception confirms its proficiency in digitally simulating a range of taste intensities and combinations. Overall, this investigation pioneers a chemical dimension in AR/VR technology, paving the way for users to transcend visual and auditory virtual engagements by integrating the taste sensation into virtual environment for enhanced digital experiences.

Presenting Author: Jinghua Li The Ohio State University

Presenting Author Biography: Jinghua Li received her B.S. degree in Biological Sciences from Shandong University, China, in 2011. She earned her Ph.D. from Duke University, United States, in chemistry in 2016. She spent 2016–2019 as a postdoctoral fellow at Northwestern University before joining the Department of Materials Science and Engineering at The Ohio State University as an assistant professor in 2019. 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