Skin-interfaced microfluidic systems with spatially engineered 3D fluidics for sweat capture and analysis

Abstract

Skin-interfaced wearable systems with integrated microfluidic structures and sensing capabilities offer powerful platforms for monitoring the signals arising from natural physiological processes. This paper introduces a set of strategies, processing approaches, and microfluidic designs that harness recent advances in additive manufacturing [three-dimensional (3D) printing] to establish a unique class of epidermal microfluidic (“epifluidic”) devices. A 3D printed epifluidic platform, called a “sweatainer,” demonstrates the potential of a true 3D design space for microfluidics through the fabrication of fluidic components with previously inaccessible complex architectures. These concepts support integration of colorimetric assays to facilitate in situ biomarker analysis operating in a mode analogous to traditional epifluidic systems. The sweatainer system enables a new mode of sweat collection, termed multidraw, which facilitates the collection of multiple, independent sweat samples for either on-body or external analysis. Field studies of the sweatainer system demonstrate the practical potential of these concepts.

Dermal-fluid-enabled detection platforms for non-invasive ambulatory monitoring

“…Concurrent initiatives to ensure data security and the implementation of high-throughput fabrication technologies such as 3D printing or roll-to-roll manufacturing are essential for easy translation of dermal fluid-enabled devices from laboratory- to clinical-grade products. 17,86 Age, sex, comorbidities, geographic region, medicine, lifestyle, time, and genetic variation affecting diagnostic accuracy can all have a significant impact on the clinical interpretation of biomarker data. A better understanding of the correlation between the various biomarkers and certain diseases utilizing advanced machine/deep learning (ML/DL) and artificial intelligence (AI) can assist in the clinical implementation of these biosensors.…”

“…84,85 Numerous soft microfluidic platforms based on PDMS have been introduced recently for this purpose. 86,87 These systems drive the flow of sweat by capillary forces, osmosis, or evaporation pumps to deliver the sweat to the detection chamber without external devices. 79 Microfluidic sampling devices based on capillary forces are the simplest.…”

Recent Advances in Skin-Interfaced Wearable Sweat Sensors: Opportunities for Equitable Personalized Medicine and Global Health Diagnostics

“…(D) 3D-printed epifluidic platform, called a “sweatainer,” that enables collection of multiple, independent sweat samples. Adapted with permission from ref . Copyright 2023 American Association for the Advancement of Science.…”

“…By constructing structurally complex objects from a digital computer-aided design (CAD) file, 3D printing enables rapid, cost-effective fabrication of microfluidic devices either directly or through production of soft lithographic templates, albeit at the expense of printer resolution (>200 μm). A recent report 180 details the first 3D-printed epifluidic device with true microfluidic dimensions (∼50 μm) using a standard, commercial resin-based 3D printer, highlighting the feasibility of leveraging AM for rapid prototyping and localized production. This novel 3D-printed epifluidic platform ("sweatainer") allows for a new mode of sweat collection that facilitates the acquisition of multiple, independent sweat samples via a channel architecture uniquely achievable through AM (Figure 4D pathways for successful production of affordable, real-time sweat sensors.…”

3D-printed epidermal sweat microfluidic systems with integrated microcuvettes for precise spectroscopic and fluorometric biochemical assays

“…Drawbacks of this method include contamination from oils and other substances on the skin or in the pads, as well as unavoidable sample loss via evaporation and manual manipulation. 6 Recently developed alternative approaches rely on wearable flexible electronic devices and/or microfluidic systems integrated with potentiometric, 7–11 colorimetric 12–16 or fluorometric 17–20 sensors. Systems for electrochemical detection and wireless data communication support capabilities for in situ analysis and continuous monitoring but they require power sources and they are susceptible to biofouling and other effects that can reduce robustness and reliability.…”