DOI: 10.5061/dryad.95x69p8v0
title: Soft, wearable, microfluidic system for fluorometric analysis of loss of amino acids through eccrine sweat

description: Amino acids are essential for protein synthesis and metabolic processes in
 support of homeostatic balance and healthy body functions. This study
 quantitatively investigates eccrine sweat as a significant channel for
 loss of amino acids during exercise, to improve an understanding of amino
 acid turnover and to provide feedback to users on the need for supplement
 intake. The measurement platform consists of a soft, skin-interfaced
 microfluidic system for real-time analysis of amino acid content in
 eccrine sweat. This system relies on integrated fluorometric assays and
 smartphone-based imaging techniques for quantitative analysis, as a
 simple, cost-effective approach that does not require electrochemical
 sensors, electronics or batteries.  Human subject studies reveal
 substantial amino acid losses in sweat from working muscle regions during
 prolonged physical activities, thereby motivating the need for dietary
 supplementation. The findings suggest potential applications in
 healthcare, particularly in athletic and clinical settings, where
 maintaining amino acid balance is critical for ensuring proper
 homeostasis.
description: # Soft, wearable, microfluidic system for fluorometric analysis of loss of
 amino acids through eccrine sweat [Access this dataset on
 Dryad](https://doi.org/10.5061/dryad.95x69p8v0.) ## Description of the
 data and file structure Data is structured as the title of the plot,
 headings including units, and data. Detailed descriptions for
 abbreviations and units can be found in the manuscript. Data are organized
 based on the figure they appear in, in the manuscript: Soft, wearable,
 microfluidic system for fluorometric analysis of loss of amino acids
 through eccrine sweat * Fig.2: Fluorometric analysis of amino acid
 concentrations in sweat based on enzymatic assays. Fluorescence images and
 standard curves for total amino acid, alanine, and lysine show
 fluorescence as a function of concentration. Fluorometric results and
 those obtained by NMR for total amino acid, alanine, and lysine. -
 Fig.3d-f: Time-dynamic analysis of total amino acid, alanine, and lysine
 in sweat before, during, and after exercise. * Fig.3g-i: Concentrations of
 total amino acid, alanine, and lysine in sweat for male and female
 subjects after exercise from non-working regions and working regions. -
 Fig.3j: Concentration of L-amino acid in sweat after exercise and warm
 water shower from five regions of the body. * Fig.4c: Correlation of total
 amino acid loss and total sweat loss after exercise from working and
 non-working regions. - Fig.4d-e: Estimated whole-body amino acid loss from
 exercise and a warm water shower. * Fig.4f-h: Sweat amino acid levels from
 a working regions and non-working region during two consecutive exercise
 sessions comparing the same to recovery methods mentioned previously, for
 total amino acid, alanine, and lysine. - Fig.S1: PDMS absorption tests.
 Analysis of sweat samples before and after transport through PDMS
 microfluidic channels for total amino acid, alanine, and lysine. * Fig.S6:
 Fluorometric results from each enzymatic assay targeting total amino acid,
 alanine, and lysine, when exposed to potential interferents (10 mM urea,
 10mM lactate, 0.5 mM Ca2+, 0.5 mM Mg2+, 10 mM uric acid, and 10 mM
 glucose) and target amino acids (10 mM total amino acid, 2 mM alanine, and
 2 mM lysine). - Fig.S7: Cross-reactivity between amino acids. Fluorometric
 results from each enzymatic assay targeting total amino acid, alanine, and
 lysine, when exposed to various amino acids (1 mM histidine, 1 mM serine,
 1 mM ornithine, 1 mM glycine, 1 mM lysine, 1 mM alanine, 0.5 mM leucine,
 0.5 mM valine, 0.5 mM glutamic acid, and 0.5 mM aspartic acid). * Fig.S8:
 Fluorometric results for the enzymatic assays as a function of reaction
 time for total amino acid, alanine, and lysine. - Fig.S9: Fluorometric
 results for the enzymatic assays at various pH for total amino acid,
 alanine, and lysine. * Fig.S10: Temperature dependency of enzymatic
 assays. Fluorometric results from enzymatic assays for total amino acid,
 alanine, and lysine of various concentrations and temperatures (28-50 °C).
 Fluorometric results for 20 mM total amino acid, 2 mM alanine, and 1 mM
 lysine at various temperatures (28-50 °C). - Fig.S11: Skin temperature
 measured pre-exercise, during a 60 min exercise on stationary bike, and
 post-exercise recovery * Fig.S12: Fluorometric results for the enzymatic
 assays as a function of storage time at temperatures 25 °C and -18 °C for
 total amino acid, alanine, and lysine. - Fig.S13: Correlation between
 amino acid concentrations from blood and sweat. Analysis of blood and
 sweat samples taken during rest, after 30 min exercise on a stationary
 bike, and comparison results for total amino acid, alanine, and lysine. *
 Fig.S14: Time-dynamic analysis of total amino acid in sweat induced by
 warm water shower and iontophoresis from the thigh and forearm. - Fig.S17:
 Whole body sweat loss estimates for exercise and warm water shower. ##
 Sharing/Access information All data presented in the manuscript can be
 found in the dataset, with the exception of human subject data which are
 not publicly available to protect the identity of participants according
 to the Northwestern University Institutional Review Board (IRB). ##
 Code/Software Calibration of the fluorometric system was based on
 fluorescence measured by the Azure SapphireTM Biomolecular Imager and NMR
 measured by the X500 Bruker Avance III HD system. Data analysis were
 performed using ImageJ 1.54d, MATLAB 2024, and Origin 2019.