Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.

Most research aimed at measuring biomarkers on the skin is only concerned with sensing chemicals in sweat using electrical signals, but these methods are not truly non-invasive nor non-intrusive because they require substantial amounts of sweat to get a reading. This project aims to create a truly n...

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Main Authors: Anthony Annerino, Michael Faltas, Manoj Srinivasan, Pelagia-Irene Gouma
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0267311
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author Anthony Annerino
Michael Faltas
Manoj Srinivasan
Pelagia-Irene Gouma
author_facet Anthony Annerino
Michael Faltas
Manoj Srinivasan
Pelagia-Irene Gouma
author_sort Anthony Annerino
collection DOAJ
description Most research aimed at measuring biomarkers on the skin is only concerned with sensing chemicals in sweat using electrical signals, but these methods are not truly non-invasive nor non-intrusive because they require substantial amounts of sweat to get a reading. This project aims to create a truly non-invasive wearable sensor that continuously detects the gaseous acetone (a biomarker related to metabolic disorders) that ambiently comes out of the skin. Composite films of polyaniline and cellulose acetate, exhibiting chemo-mechanical actuation upon exposure to gaseous acetone, were tested in the headspaces above multiple solutions containing acetone, ethanol, and water to gauge response sensitivity, selectivity, and repeatability. The bending of the films in response to exposures to these environments was tracked by an automatic video processing code, which was found to out-perform an off-the-shelf deep neural network-based tracker. Using principal component analysis, we showed that the film bending is low dimensional with over 90% of the shape changes being captured with just two parameters. We constructed forward models to predict shape changes from the known exposure history and found that a linear model can explain 40% of the observed variance in film tip angle changes. We constructed inverse models, going from third order fits of shape changes to acetone concentrations where about 45% of the acetone variation and about 30% of ethanol variation are captured by linear models, and non-linear models did not perform substantially better. This suggests there is sufficient sensitivity and inherent selectivity of the films. These models, however, provide evidence for substantial hysteretic or long-time-scale responses of the PANI films, seemingly due to the presence of water. Further experiments will allow more accurate discrimination of unknown exposure environments. Nevertheless, the sensor will operate with high selectivity in low sweat body locations, like behind the ear or on the nails.
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spelling doaj.art-24a9c4e3112a4ef392c4c4641e8822332022-12-22T02:38:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-01174e026731110.1371/journal.pone.0267311Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.Anthony AnnerinoMichael FaltasManoj SrinivasanPelagia-Irene GoumaMost research aimed at measuring biomarkers on the skin is only concerned with sensing chemicals in sweat using electrical signals, but these methods are not truly non-invasive nor non-intrusive because they require substantial amounts of sweat to get a reading. This project aims to create a truly non-invasive wearable sensor that continuously detects the gaseous acetone (a biomarker related to metabolic disorders) that ambiently comes out of the skin. Composite films of polyaniline and cellulose acetate, exhibiting chemo-mechanical actuation upon exposure to gaseous acetone, were tested in the headspaces above multiple solutions containing acetone, ethanol, and water to gauge response sensitivity, selectivity, and repeatability. The bending of the films in response to exposures to these environments was tracked by an automatic video processing code, which was found to out-perform an off-the-shelf deep neural network-based tracker. Using principal component analysis, we showed that the film bending is low dimensional with over 90% of the shape changes being captured with just two parameters. We constructed forward models to predict shape changes from the known exposure history and found that a linear model can explain 40% of the observed variance in film tip angle changes. We constructed inverse models, going from third order fits of shape changes to acetone concentrations where about 45% of the acetone variation and about 30% of ethanol variation are captured by linear models, and non-linear models did not perform substantially better. This suggests there is sufficient sensitivity and inherent selectivity of the films. These models, however, provide evidence for substantial hysteretic or long-time-scale responses of the PANI films, seemingly due to the presence of water. Further experiments will allow more accurate discrimination of unknown exposure environments. Nevertheless, the sensor will operate with high selectivity in low sweat body locations, like behind the ear or on the nails.https://doi.org/10.1371/journal.pone.0267311
spellingShingle Anthony Annerino
Michael Faltas
Manoj Srinivasan
Pelagia-Irene Gouma
Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
PLoS ONE
title Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
title_full Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
title_fullStr Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
title_full_unstemmed Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
title_short Towards skin-acetone monitors with selective sensitivity: Dynamics of PANI-CA films.
title_sort towards skin acetone monitors with selective sensitivity dynamics of pani ca films
url https://doi.org/10.1371/journal.pone.0267311
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