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.

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

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.

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

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

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?”.

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

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

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