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Gardanne, France

Roberts T.,Aix - Marseille University | De Graaf J.B.,Aix - Marseille University | Nicol C.,Aix - Marseille University | Herve T.,Microvitae Technologies | And 2 more authors.
Advanced Healthcare Materials | Year: 2016

Flexible Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive-polymer multielectrode arrays (MEAs) are fabricated without etching or aggressive lift-off processes, only by additive solution processes. Inkjet printing technology has several advantages, such as a customized design and a rapid realization time, adaptability to different patients and to different applications. In particular, inkjet printing technology, as additive and “contactless” technology, can be easily inserted into various technological fabrication steps on different substrates at low cost. In vivo electrochemical impedance spectroscopy measurements show the time stability of such MEAs. An equivalent circuit model is established for such flexible cutaneous MEAs. It is shown that the charge transfer resistance remains the same, even two months after fabrication. Surface electromyography and electrocardiography measurements show that the PEDOT:PSS MEAs record electrophysiological activity signals that are comparable to those obtained with unitary Ag/AgCl commercial electrodes. Additionally, such MEAs offer parallel and simultaneous recordings on multiple locations at high surface density. It also proves its suitability to reconstruct an innervation zone map and opens new perspectives for a better control of amputee's myoelectric prostheses. The employment of additive technologies such as inkjet printing suggests that the integration of multifunctional sensors can improve the performances of ultraflexible brain-computer interfaces. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Khodagholy D.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Gurfinkel M.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Stavrinidou E.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Leleux P.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | And 4 more authors.
Applied Physics Letters | Year: 2011

A generic lithographic process is presented that allows the fabrication of high density organic electrochemical transistor arrays meant to interface with aqueous electrolytes. The channels of the transistors, which were 6 m long, were made of the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) and were in direct contact with phosphate buffered saline. Source and drain electrodes and interconnects were insulated by parylene C, a biocompatible material. The transistors operated at low voltages and showed a response time of the order of 100 s. © 2011 American Institute of Physics.

Khodagholy D.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Rivnay J.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Sessolo M.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Gurfinkel M.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | And 8 more authors.
Nature Communications | Year: 2013

The development of transistors with high gain is essential for applications ranging from switching elements and drivers to transducers for chemical and biological sensing. Organic transistors have become well-established based on their distinct advantages, including ease of fabrication, synthetic freedom for chemical functionalization, and the ability to take on unique form factors. These devices, however, are largely viewed as belonging to the low-end of the performance spectrum. Here we present organic electrochemical transistors with a transconductance in the mS range, outperforming transistors from both traditional and emerging semiconductors. The transconductance of these devices remains fairly constant from DC up to a frequency of the order of 1 kHz, a value determined by the process of ion transport between the electrolyte and the channel. These devices, which continue to work even after being crumpled, are predicted to be highly relevant as transducers in biosensing applications. © 2013 Macmillan Publishers Limited. All rights reserved.

Isik M.,University of the Basque Country | Lonjaret T.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Sardon H.,University of the Basque Country | Marcilla R.,IMDEA Madrid Institute for Advanced Studies | And 5 more authors.
Journal of Materials Chemistry C | Year: 2015

Cholinium-based bio-ion gels were prepared by photopolymerization of poly(cholinium lactate methacrylate) network within cholinium lactate ionic liquid. The rheological and thermal properties as well as ionic conductivity of ion gels of different compositions were measured. As indicated by rheological measurements, the ion gels show the properties of gel materials which become soft by increasing the amount of free ionic liquid. Cholinium ion gels with various composition of free ionic liquid vs. methacrylic network show glass transitions between -40° and -70 °C and thermal stability up to 200 °C. The ionic conductivity of these gels increases from 10-8 to 10-3 S cm-1 at 20 °C by varying the amount of free ionic liquid between 0 and 60 wt%, respectively. Low glass transition temperature and enhanced ionic conductivity make the cholinium-based ion gels good candidates to be used as a solid electrolytic interface between the skin and an electrode. The ion gels decrease the impedance with the human skin to levels that are similar to commercial Ag/AgCl electrodes. Accurate physiologic signals such as electrocardiography (ECG) were recorded with ion gels assisted electrodes for a long period of time (up to 72 h) with a remarkable stability. The low toxicity and superior ambient stability of cholinium ionic liquids and ion gels make these materials highly attractive for long-term cutaneous electrophysiology and other biomedical applications. This journal is © The Royal Society of Chemistry 2015.

Ramuz M.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Margita K.,Newberry College | Hama A.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Leleux P.,Microvitae Technologies | And 3 more authors.
ChemPhysChem | Year: 2015

The organic electrochemical transistor (OECT) is a unique device that shows great promise for sensing in biomedical applications such as monitoring of the integrity of epithelial tissue. It is a label-free sensor that is amenable to low-cost production by roll-to-roll or other printing technologies. Herein, the optimization of a planar OECT for the characterization of barrier tissue is presented. Evaluation of surface coating, gate biocompatibility and performance, and optimization of the geometry of the transistor are highlighted. The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), which is used as the active material in the transistor, has the added advantage of allowing significant light transmission compared to traditional electrode materials and thus permits high-quality optical microscopy. The combination of optical and electronic monitoring of cells shown herein provides the opportunity to couple two very complementary techniques to yield a low-cost method for in vitro cell sensing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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