Session: 04-26-01: Advanced Material Innovations in Wearable Biomedical Devices and Structures

Paper Number: 148677

148677 - Emerging Advanced Manufacturing Technologies for Wearable Sensors 

Persistent disparities exist in access to state-of-the-art healthcare disproportionately affecting underserved and vulnerable populations. Advances in wearable sensors enabled by additive manufacturing (AM) offer new opportunities to address such disparities and enhance equitable access advanced diagnostic technologies. Additive manufacturing processes, particularly stereolithography (SLA)-based printing, offer powerful pathways for circumventing existing barriers to innovation for resource-limited settings by providing significant reductions in prototype development cost and cycle time while substantially expanding device capabilities with fully 3D device designs. In this talk, we will present our recent efforts concentrated on developing (A) 3D-printing technologies for fabricating high-resolution flexible electronics and (B) new modalities for wearable microfluidic sensing platforms.

The additive manufacture of production-grade flexible, large area electronics is of intense interest to rapidly design, prototype, and fabricate electronics without reliance upon traditional electronics fabrication pathways. Such additive processes enable the direct integration of electronics on arbitrary, non-planar surfaces, expanding the potential form-factors and application spaces. Of particular interest is Aerosol Jet Printing (AJP) owing to the capacity to fabricate high-resolution printed interconnects with design geometries not possible via other additive manufacturing technologies. AJP is a process by which the controlled deposition of an aerosolized, liquid ink enables the conformal printing of electronic traces. However, several key challenges, such as overspray and process drift, which restrict broad deployment of AJP and limits the feature resolution of printed interconnects. To address these challenges, we report a new type of AJP print process to control and architect aerosolized ink. Termed acoustic focusing aerosol jet printing (AF-AJP), we utilize acoustic forces (AF) to control the width of printed material by focusing the jetted material to a narrower region than what would be possible with a physical orifice alone. As the acoustic focusing effect is dependent on the ink droplet size, the utilization of acoustic focusing provides a means to “refine” the jet (especially if not material rich) such that the deposited material has a smaller line width and exhibits a reduction in the typically observed particle overspray. We report a typical 30% reduction in trace width, sharp reduction in overspray, and an overall enhancement in print quality via this novel printing technique.

We also will present our work developing a simplified 3D-printing prototyping process to fabricate flexible, stretchable, epidermal microfluidic devices (‘3D-epifluidics’) suitable for direct on-body interfacing. These wearable sweat sensors integrate microfluidic channel networks with biochemical sensors and flexible electronics to enable the noninvasive, real-time monitoring of sweat-based biochemical signals associated with health and wellness. By reducing fabrication time to [O]min, this approach enables the integration of spatially-engineered features including 3D-structured passive capillary valves, monolithic channels, and reservoirs with spatially-graded geometries. With geometric features comparable to established epifluidic devices (channels >50 μm), benchtop and on-body testing validate the performance of 3D-epifluidic devices. We utilize these platforms to showcase how these devices hold the potential for addressing some of the formidable obstacles to delivering comprehensive medical care in under-resourced settings, especially in remote or geographically isolated areas.

Presenting Author: Tyler Ray University of Hawaii at Manoa

Presenting Author Biography: Tyler R. Ray is an Assistant Professor of Mechanical Engineering at the University of Hawaii at Manoa. He received a B.S. (2008) and M.S. (2010) in Mechanical Engineering from the University of South Carolina, and a Ph.D. (2015) in Mechanical Engineering from the University of California, Santa Barbara. His research interests are at the intersection of 3D printing functional materials, lab-on-chip diagnostics, and wearable sensing.

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