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Paper on Capacitive Coupling of Conducting Polymer Tattoo Electrodes with the Skin

“Capacitive Coupling of Conducting Polymer Tattoo Electrodes with the Skin”

The skin and the electrode interface. a) Schematization of the skin layers. The epidermis, with the stratum corneum as top layer and the electrodes adopted in the study: tattoo and Ag/AgCl electrodes. The dermis, with sweat glands, nerve ending and blood vessels. The subcutaneous tissue, composed by the hypodermis and the muscle layer. On the top-right, the equivalent circuit is adopted to model the skin. b) The electrode/skin interface through Ag/AgCl (top) and tattoo electrode (down). The equivalent circuits are represented together with the physical mechanism leading to the biosignal transduction.

Laura M. Ferrari, Usein Ismailov, Francesco Greco, Esma Ismailova
Publication Date: July 10, 2021
https://onlinelibrary.wiley.com/doi/10.1002/admi.202100352

 

Abstract

Tattoo electronics is one of the emerging technologies in skin compliant biosensing. The growing interest in their large application in health monitoring raises several interrogations on how these sensors interface with the skin. In this paper, the bioimpedance at the interface of the skin and ultra-conformable tattoo electrodes made of conducting polymers are focused on. The electrochemical characteristics of these electrodes differ from traditional gelled Ag/AgCl electrodes. The modeling of equivalent circuits in different skin-electrode configurations proposes the explanation of the biopotentials transduction mechanism. The strong agreement between the circuit model and experimental values reveals the capacitive coupling of conducting polymer tattoo electrodes where circuit’s values reflect the electrodes’ and skin physical characteristics. Additional studies underline an enhanced signal stability in inter/intra-subject evaluations using dry tattoos beneficial for broad long-term recordings. This study provides a comprehensive explanation of the skin/tattoo electrode interface model. The understanding of this interface is essential when designing next generation wearable biomonitoring devices using imperceptible interfaces.

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Paper on Printed Tattoo Organic Photodiode in ACS Applied Electronic Materials + Journal Front Cover

Temporary Tattoo Approach for a Transferable Printed Organic Photodiode

Tattoo Photodiode_ToC

Bernhard Burtscher, Günther Leising, Francesco Greco
Publication Date: June 10, 2021
https://doi.org/10.1021/acsaelm.1c00249

Abstract

Generation of ultrathin, transferable, and imperceptible electronic devices [e.g., organic photodiode (OPD)] for multiple applications, such as personalized health monitors and wearables, is emerging due to the continuous development of materials and manufacturing processes. For such devices, the choice of a suitable substrate is of utmost importance. A water decal transfer from a temporary tattoo paper is adopted here as a substrate for ultrathin and conformable organic components because of easy and reliable transfer of a ≈600 nm robust and transparent polymer nanofilm of ethyl cellulose. Strategies for the fabrication of a transferable OPD on a temporary tattoo are investigated. A device with an overall thickness <1 μm and its performance after transfer are demonstrated. Then, efforts are put into fabricating an OPD by inkjet printing with a water-soluble active layer consisting of polythiophene and fullerene derivatives to aid cost- and material-efficient, large-scale production possibilities. Additionally, a second semitransparent electrode made of printed aluminum-doped zinc oxide and silver nanowires is used to allow usage from both sides to enhance the application potential. Both OPD examples presented here need improvement of the device performance but permitted us to highlight the versatility and application potential of temporary tattoos for transferable components. Target surfaces for the final application after transfer include artificial (flat and smooth, e.g., glass, or even complex and rough, e.g., concrete, paper, and so forth) as well as natural ones.

Featured in Journal Front COVER of June 2021 Issue

Front cover_ACS Appl Electron Mater June 21_Tattoo photodiode
A temporary tattoo printed organic photodiode (OPD) transferred onto a maple leaf. With an overall device thickness <1 μm, the tattoo OPD is able to achieve stable conformal adhesion on a variety of uneven target surfaces.
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Smart tattoos are keeping tabs on our health – chemistryworld.com

Francesco Greco, Head of LAMPSe, recently was interviewed by Nina Notman for a feature article on smart tattoos for the UK Royal Society of Chemistry’s Chemistry World magazine www.chemistryworld.com.

The article features the newest developments on smart tattoos, discussing blood-analysing patches, sweat sensors, color changing – UV detecting tattoos and electrophysiological sensing tattoos, like the ones developed at LAMPSe.

picture of a tattoo electrode

Here the link to the article available on chemistryworld.com:

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Optimized connections for tattoo skin-contact electrodes toward real use in health monitoring: new publication in Sensors

A new open access paper by S. Taccola et al. about skin-contact Temporary Tattoo Electrodes (TTEs). The study is part of a collaboration of our former group at CMBR IIT – Italian Institute of Technology, Pontedera (Italy) with the company MEDEL Gmbh, Innsbruck (Austria). The study investigates skin-contact tattoo electrodes in various bio-electric signals recording applications, such as bioimpedance for respiration monitoring. Novel methods for realizing  a repositionable, long-term stable and robust interconnection of TTEs with external “docking” devices are presented. A further step forward toward the real use of our tattoo interfaces in health monitoring!

Publication  in Sensors MDPI:

Toward the Use of Temporary Tattoo Electrodes for Impedancemetric Respiration Monitoring and Other Electrophysiological Recordings on Skin

Silvia Taccola, Aliria Poliziani,  Daniele Santonocito, Alessio Mondini, Christian Denk, Alessandro Noriaki Ide, Markus Oberparleiter, Francesco Greco, Virgilio Mattoli

Sensors, 21(4), 1197 (2021).

DOI: 10.3390/s21041197
https://www.mdpi.com/1424-8220/21/4/1197

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Tattooable OLEDs: new publication in Advanced Electronic Materials

OLED tattoo cross section & transfer on bottle

A new paper by Jonathan Barsotti et al. about Organic Light Emitting Diodes (OLEDs) on temporary tattoo. The study is a collaboration with groups of Dr. Virgilio Mattoli (CMBR IIT, Italy) and Prof. Franco Cacialli (UCL, London, UK). Ultrathin tattooable OLEDS are presented which can be transferred onto various target surfaces maintaining their functionality.

Publication  in Advanced Electronic Materials:

Ultrathin, Ultra‐Conformable, and Free‐Standing Tattooable Organic Light‐Emitting Diodes

Jonathan Barsotti, Alexandros G. Rapidis, Ikue Hirata, Francesco Greco, Franco Cacialli, Virgilio Mattoli

Advanced Electronic Materials, 2001145 (2021).

DOI: 10.1002/aelm.202001145
https://onlinelibrary.wiley.com/doi/full/10.1002/aelm.202001145

UPDATE:
The publication on the tattooable OLED got mentioned in the BBC article “Could electric tattoos be the next step in body art?”.

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LAMPSe and Tattoo Electrodes on Ö1 Radio – DIGITAL.LEBEN

In Summer LAMPSe was interviewed by Ö1, one of Austria’s public radio stations. The interview was broadcasted on October 21st and can now be accessed online. Listen to Alexander Dallinger and Francesco Greco talking about the innovative tattoo electrodes.

picture of a tattoo electrode

Here the link to the interview available on Ö1 – DIGITAL.LEBEN:

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Tattoo for Brain recordings on IEEEBrain Braininsight newsletter

We published an highlight on our tattoo for brain recordings in the latest issue of Braininsight, the newsletter of IEEE Brain dedicated to neuroscience and neurotechnology community.

IEEE Brain Braininsight
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LAMPSe and Tattoo electrodes on ORF2 TV News

Our tattoo electrodes and the activities of LAMPSe group TUGraz have been highlighted by ORF, the Austrian National Broadcasting Corporation, on ORF2 News “Steiermark Heute”.

Tattoo on skin_ORF

Here the link to the video available on the YouTube channel of TU Graz:

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Press Release: Brain signals recording with printed tattoo electrodes

New press release by TUGraz showcasing our tattoo electrodes for brain signals recordings, a study by Laura Ferrari (former PhD student, now postdoc in France) and made in collaboration with Esma Ismailova and her group at Bioelectronics Dept., École Nationale Supérieure des Mines de Saint-Étienne, France . Here the links to the full text of the press release and to press coverage.

Tattoo electrode_EEG recording on scalp
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Temporary Tattoo Electrodes for EEG – Brain recordings: new publication in npj Flexible Electronics

A new paper by Laura Ferrari et al. about temporary tattoo electrodes for on-skin electrophysiological recordings, in collaboration with group of Prof. Esma Ismailova (BEL EMSE, France). Electroencephalographic (EEG) signals are recorded in a clinical environment.

Publication (Open Access) in npj Flexible Electronics:
Conducting polymer tattoo electrodes in clinical electro- and magneto-encephalography

Laura M. Ferrari, Usein Ismailov, Jean-Michel Badier, Francesco Greco & Esma Ismailova

npj Flex Electron 4, 4 (2020).

DOI: 10.1038/s41528-020-0067-z
https://www.nature.com/articles/s41528-020-0067-z