1. Skin-interfaced soft microfluidic systems with modular and reusable electronics for in situ capacitive sensing of sweat loss, rate and conductivity
- Author
-
Blake V. Parsons, Weihua Li, Sung Bong Kim, John A. Rogers, Milan Raj, Roozbeh Ghaffari, Kun Hyuck Lee, Stephanie Schon, Amay J. Bandodkar, Yiwei Gao, Jungil Choi, Kelsey B. Fields, Ha Uk Chung, Tyler R. Ray, Raudel Avila, Yeguang Xue, Stephen P. Lee, Yonggang Huang, Jong Yoon Lee, Aurélie Hourlier-Fargette, Claire Liu, Philipp Gutruf, Jeffrey B. Model, Michael E. Johnson, Alexander J. Aranyosi, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA, Northwestern University [Evanston], Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical and Process Engineering ETH Zurich, CH-8092 Zurich, Switzerland, Epicore Biosystems, Inc. Cambridge, MA 02139, USA, Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, Sibel Inc, Evanston, IL 60201, USA, Departments of Biomedical Engineering, Electrical and Computer Engineering, Bio5 Institute, Neuroscience GIDP, The University of Arizona, Tucson, 85721, School of Mechanical Engineering, Kookmin University, Seoul 02707, South Korea, Department of Mechanical Engineering, University of Hawai’i at Mānoa, Honolulu, HI 96822, USA, and Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Subjects
sweat conductivity ,Computer science ,capacitive measurements ,Capacitive sensing ,Microfluidics ,microfluidics ,Biomedical Engineering ,Bioengineering ,02 engineering and technology ,Conductivity ,01 natural sciences ,Biochemistry ,epidermal ,sweat rate ,Sampling (signal processing) ,Hardware_INTEGRATEDCIRCUITS ,Wireless ,Electronics ,[PHYS]Physics [physics] ,business.industry ,010401 analytical chemistry ,General Chemistry ,Modular design ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,sweat ,wearables ,[SDV.IB]Life Sciences [q-bio]/Bioengineering ,0210 nano-technology ,business ,Computer hardware ,Loss rate - Abstract
Important insights into human health can be obtained through the non-invasive collection and detailed analysis of sweat, a biofluid that contains a wide range of essential biomarkers. Skin-interfaced microfluidic platforms, characterized by soft materials and thin geometries, offer a collection of capabilities for in situ capture, storage, and analysis of sweat and its constituents. In ambulatory uses cases, the ability to provide real-time feedback on sweat loss, rate and content, without visual inspection of the device, can be important. This paper introduces a low-profile skin-interfaced system that couples disposable microfluidic sampling devices with reusable 'stick-on' electrodes and wireless readout electronics that remain isolated from the sweat. An ultra-thin capping layer on the microfluidic platform permits high-sensitivity, contactless capacitive measurements of both sweat loss and sweat conductivity. This architecture avoids the potential for corrosion of the sensing components and eliminates the need for cleaning/sterilizing the electronics, thereby resulting in a cost-effective platform that is simple to use. Optimized electrode designs follow from a combination of extensive benchtop testing, analytical calculations and FEA simulations for two sensing configurations: (1) sweat rate and loss, and (2) sweat conductivity, which contains information about electrolyte content. Both configurations couple to a flexible, wireless electronics platform that digitizes and transmits information to Bluetooth-enabled devices. On-body field testing during physical exercise validates the performance of the system in scenarios of practical relevance to human health and performance.
- Published
- 2020