DOI: 10.5061/dryad.bk3j9kdp7
title: A non-contact wearable device for monitoring epidermal molecular flux

description: All existing wearable technologies rely on physical coupling to the body
 to establish optical, fluidic, thermal, and/or
 mechanical measurement interfaces. Here, we present a class of
 wearable device platform that relies instead on physical decoupling, to
 define an enclosed chamber immediately adjacent to the surface of the
 skin. Streams of vaporised molecular substances that pass out of or into
 the skin alter the properties of the microclimate defined within this
 chamber in ways that can be precisely quantified using an integrated
 collection of wireless sensors. A programmable, bistable valve dynamically
 controls access to the surrounding ambient, thereby creating a transient
 response that can be quantitatively related to the inward and outward flux
 of targeted species through analysis of the time dependent readings from
 the sensors. The systems reported here offer unique capabilities in
 measuring the flux of water vapour, volatile organic compounds (VOCs), and
 carbon dioxide from various locations on the body, each with distinct
 relevance to clinical care and/or exposure to hazardous vapours. Studies
 of healing processes associated with dermal wounds in normal and diabetic
 animal models and of responses in infected wound models reveal
 characteristic variations in flux that provide important insights, as use
 cases where the non-contact operation of the devices avoids potential
 damage to fragile tissues.
description: # A non-contact wearable device for monitoring epidermal molecular flux
 [Access this dataset on Dryad](https://doi.org/10.5061/dryad.bk3j9kdp7)
 **Description of the data and file structure** File names correspond to
 figures in the manuscript titled A non-contact wearable device for
 monitoring epidermal molecular flux. 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, some of the
 abbreviations are VOC: volatile organic compounds; RH: relative
 humidity; 8-OHdG: 8-hydroxy-2'-deoxyguanosine * esf_fig1ebottom: Time
 series data from gas sensors as the valve opens and closes through
 multiple cycles, showing effects from influx (atmospheric ethanol vapour).
 - esf_fig1etop1f: Time series data from gas sensors as the valve opens and
 closes through multiple cycles, showing effects from outflux (biogenic
 water vapour). * esf_fig2c: Computational analysis results indicating skin
 diffusive water resistance. - esf_fig2d: Exponential decrease in skin
 impedance following from different levels of perspiration. *
 esf_fig3bbottom: Example of inward epidermal VOC flux. - esf_fig3btop:
 Example of outward epidermal VOC flux. * esf_fig3e: Time series data
 associated with outward flux of CO2, corresponding to higher and lower
 diffusive resistance. - esf_fig3i: Epidermal outward flux of VOCs in
 response to UV irradiation on mouse skin. * esf_fig3istatistics:
 Statistical analysis of epidermal outward flux VOC in response to UV
 irradiation. - esf_fig3j: Cellular oxidative stress marker (8-OHdG)
 activity in response to UV irradiation. * esf_fig3jstatistics: Statistical
 analysis of cellular oxidative stress marker (8-OHdG) activity in response
 to UV irradiation. - esf_fig4b-1: Transitions of water vapour flux values
 throughout the wound healing process for normal mouse. * esf_fig4b-2:
 Transitions of VOC flux values throughout the wound healing process for
 normal mouse. - esf_fig4c4g: Normalised recovery parameters (WC for wound
 closure, BR for barrier restoration) and VOC flux changes for normal and
 type-2 diabetic mice. Early increasesin the VOC flux indicating normal and
 anomalous inflammatory phase. * esf_fig4e: Comparison of normal and
 diabetic wound healing pathways by water vapour flux analysis. -
 esf_fig4f: Immunofluorescence analysis delayed keratinocyte terminal
 differentiation of diabetic group. Post-closure Filaggrin activity
 increase compared to WC and BR changes. * esf_fig4h: Wound infection
 monitoring capability of the EFS. Onset and exponential increase of VOC
 emission from in vivo infected mouse wounds. - esf_woundclosure: Wound
 closure data from normal and diabetic mice. ## Sharing/Access information
 Custom analysis code and data presented in this study, with the exception
 of human subject data, are available in the public repository. Human
 subject data including protected health information constitutes a limited
 data set defined by HIPPA (Health Insurance Portability and
 Accountability). Completely de-identified human subject data can be
 provided upon request with a detailed description of the intended use at
 large to advance science and health. Requests sent to the corresponding
 author (Prof. John A. Rogers) via email
 ([jrogers@northwestern.edu](mailto:jrogers@northwestern.edu)) will be
 subject to executing a data use agreement with Northwestern University,
 which can take one month or less. ## Code/Software A secured data
 management server mediated the upload, archiving, and downloading of raw
 measurement data from EFS devices connected to the server via a custom
 smartphone application. Custom Python (ver. 3.11.0) and Microsoft Visual
 Basic for Application (ver. 7.1) codes implementing the analysis
 principles subsequently processed the downloaded raw data in the form of
 Jason files to derive the measurement results. Supplementary Note 2 covers
 the analysis principles in detail. The raw data in the form of csv or
 jason files were initially processed using custom Python 3.11.0 and
 Microsoft Visual Basic for Application 7.1 codes. All data
 ([https://doi.org/10.5061/dryad.bk3j9kdp7](https://doi.org/10.5061/dryad.bk3j9kdp7)) and custom analysis code ([https://doi.org/10.5281/zenodo.14884409](https://doi.org/10.5281/zenodo.14884409)) are available in the public repository. Additional software involved in data analysis include ImageJ 1.54m, SPSS 24, and Microsoft Excel 16.94.