3D-Printed Epidermal Microfluidic Systems: Opportunities to Expand Access to Personalized Health Monitoring

Persistent disparities exist in access to state-of-the-art healthcare and disproportionately affect underserved and vulnerable populations. Advances in wearable sensors enabled by additive manufacturing (AM) offer new opportunities to address such disparities and enhance equitable access to 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. Here, we present 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.