Abstract

3D-Printed Epidermal Microfluidic Systems

Tyler Ray, Assistant Professor, University of Hawaii at Manoa

An emerging class of wearable devices integrates microfluidic lab-on-chip designs with low-modulus materials, colorimetric assays, and electrochemical sensors to support the real-time, non-invasive analysis of sweat. Such skin-interfaced microfluidic systems offer powerful capabilities for personalized assessment of health, nutrition, and wellness through the non-invasive, real-time analysis of sweat. Initially simple systems of microfluidic channels, current devices comprise sophisticated networks channels, valves, and reservoirs with some embodiments employing multilayer design strategies. While these platforms exhibit powerful analytical capabilities, device fabrication requires time, labor, and resource-intensive cleanroom processing, which restricts the device design space (2D) and elongates the development time. Additive manufacturing processes, particularly stereolithography (SLA)-based printing, offer powerful pathways for overcoming these limitations 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’). 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.