A Disposable paper breathalyzer with an alcohol sensing organic electrochemical transistor.

UNLABELLED: Breathalyzers estimate Blood Alcohol Content (BAC) from the concentration of ethanol in the breath. Breathalyzers are easy to use but are limited either by their high price and by environmental concerns, or by a short lifetime and the need for continuous recalibration. Here, we demonstrate a proof-of-concept disposable breathalyzer using an organic electrochemical transistor (OECT) modified with alcohol dehydrogenase (ADH) as the sensor. The OECT is made with the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT: PSS), and is printed on paper. ADH and its cofactor nicotinamide adenine dinucleotide (NAD(+)) are immobilized onto the OECT with an electrolyte gel. When the OECT-breathalyzer is exposed to ethanol vapor, the enzymatic reaction of ADH and ethanol transforms NAD(+) into NADH, which causes a decrease in the OECT source drain current. In this fashion, the OECT-breathalyzer easily detects ethanol in the breath equivalent to BAC from 0.01% to 0.2%. The use of a printed OECT may contribute to the development of breathalyzers that are disposable, ecofriendly, and integrated with wearable devices for real-time BAC monitoring

Magnon Heat Transport in (Sr,La)_14Cu_24O_41

We have measured the thermal heat conductivity kappa of the compounds Sr_14Cu_24O_41 and Ca_9La_5Cu_24O_41 containing doped and undoped spin ladders, respectively. We find a huge anisotropy of both, the size and the temperature dependence of kappa which we interpret in terms of a very large heat conductivity due to the magnetic excitations of the one-dimensional spin ladders. This magnon heat conductivity decreases with increasing hole doping of the ladders. The magnon heat transport is analyzed theoretically using a simple kinetic model. From this analysis we determine the spin gap and the temperature dependent mean free path of the magnons which ranges by several thousand angstroms at low temperature. The relevance of several scattering channels for the magnon transport is discussed.Comment: 6 pages, 5 figures, submitted to Phys. Rev.

Ultra-conformal drawn-on-skin electronics for multifunctional motion artifact-free sensing and point-of-care treatment

An accurate extraction of physiological and physical signals from human skin is crucial for health monitoring, disease prevention, and treatment. Recent advances in wearable bioelectronics directly embedded to the epidermal surface are a promising solution for future epidermal sensing. However, the existing wearable bioelectronics are susceptible to motion artifacts as they lack proper adhesion and conformal interfacing with the skin during motion. Here, we present ultra-conformal, customizable, and deformable drawn-on-skin electronics, which is robust to motion due to strong adhesion and ultra-conformality of the electronic inks drawn directly on skin. Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors. Electrophysiological signal monitoring during motion shows drawn-on-skin electronics' immunity to motion artifacts. Additionally, electrical stimulation based on drawn-on-skin electronics demonstrates accelerated healing of skin wounds. Designing efficient wearable bioelectronics for health monitoring, disease prevention, and treatment, remains a challenge. Here, the authors demonstrate an ultra-conformal, customizable and deformable drawn-on-skin electronics which is robust to motion artifacts and resistant to physical damage

Ligne et Antenne MID réalisées par impression jet d'encre sur ABSPC

National audienceno abstrac

Fully printed all-polymer tattoo/textile electronics for electromyography

© 2018 IOP Publishing Ltd. Driven by the ever-growing need for developing low-cost, easy-to-use, noninvasive diagnostic tools, biomedical devices that can be integrated on human skin or textiles have begun to emerge. These 'wearable' devices should couple electronics directly to the human skin and detect a variety of biologically relevant signals such as neuromuscular activity. In this work, we develop a simple, low-cost and customizable device to perform electromyography measurements based on electronics fabricated on tattoo paper. The electrodes are based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) and inkjet-printed on the conformable tattoo paper. Addressing the integration challenge common to such flexible electronic devices, we connect the tattoo electrodes to the acquisition system through a textile in the form of a wristband comprising printed PEDOT:PSS contacts. While the textile wristband conforms around the 'tattooed' skin, it enables a reliable contact with the electrodes beneath. We show that this tattoo/textile electronics platform is able to monitor the biceps activity of the arm during muscle contractions lasting for a period of 7 h, with comparable performance to conventional biopotential electrodes and without the use of gels or expensive metallic materials. Combining the tattoo electronics with the electronic textile improves the communication of skin-like electrodes with external electronics, renders a reliable and versatile system for detecting biopotential signals critical for myoelectric prosthesis, muscle injury prevention and/or detection

All poly(3,4-ethylenedioxythiophene) organic electrochemical transistor to amplify amperometric signals

Organic Electrochemical Transistors (OECTs) are emerging devices that find applications as sensors because they offer amazing features such as intrinsic signal amplification, low energy consumption, low cost and easy adaptability to new and unconventional architectures. The signal transduction usually exploits a redox reaction as happens in a common amperometric sensor, but the channel of the transistor is able to amplify this signal. This paper aims to thoroughly investigate the amplification of Faradaic currents in OECT sensors that exploit PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate)) as semiconductor material in the channel and electrochemical transducer. The devices were fabricated with different geometries and thicknesses of PEDOT:PSS in order to find the best configuration. The amplification was studied in phosphate buffer solution as electrolyte by determining the OECT transconductance. A thick PEDOT:PSS layer and a high ratio between gate and channel areas ensure the best performance from an electrical point of view. The amplification was also studied while the OECTs work as chemical sensors for the detection of ascorbic acid. The highest gain was observed for the thickest PEDOT:PSS channel and the lowest ratio between the gate and the channel areas. Moreover, the gate voltage has an important effect on the transistor amplification, being the gain highest (of about 2 orders of magnitude) for the lowest gate voltage

Resistance variation of conductive ink applied by the screen printing technique on different substrates

This research study focuses on the application of conductive ink by the screen printing technique to evaluate the potential of creating printed electrodes and to investigate the effect of washing upon electrical resistance and flexibility. Two conductive inks were applied by a conventional screen printing method on four different textile substrates, 100% cotton, 50%/50% cotton/polyester, 100% polyester and 100% polyamide. The inks were also applied on a multifibre fabric. Atmospheric plasma treatment was applied to improve the adhesion to the samples, and the resistance values were compared with those of non-treated samples. The values were measured before and after cleaning and washing tests, which were performed to simulate domestic treatment for garments to predict the behaviour of the inks after normal usage of the fabrics. Comfort properties like stiffness of the fabrics were also evaluated after five and 10 washing cycles. It was observed that PE 825 ink forms a thicker film on the fabric surface, contributing to the loss of flexibility of the textile. However, PE 825 ink also produced the best results in terms of durability and lower values of resistance. Polyamide fabrics lost their conductive property after five washing cycles due to weak bonding between the ink and the fibres, whereas cotton fibres provided the best results.This work is financed by Project“Deus ex Machina”, NORTE-01-0145-FEDER-000026, funded by CCDRN, through Sistema de Apoio à Investigação Cientifica e Tecnológica (Projetos Estruturados I&D&I) of Programa Operacional Regional do Norte, from Portugal 2020 and by Project UID/CTM/00264/2019 of 2C2T –Centro de Ciência e Tecnologia Têxtil, funded by National Founds through FCT/MCTES.Derya Tama thanks FCT for fellowship 2C2T-BPD-08-2017