A Disposable paper breathalyzer with an alcohol sensing organic electrochemical transistor

Abstract

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.

Organic transistors on paper: a brief review

“…There are more than a hundred publications in which operating voltages of 1 V or less have been reported for organic transistors fabricated on glass, silicon or plastic substrates, 49 while for organic transistors on paper, only one such report exists. 17 This may reflect the difficulty of minimizing the gate-dielectric thickness without introducing prohibitively large gate leakage on substrates with significant surface roughness, but this must be considered a solvable problem. Another interesting challenge will be the fabrication of organic permeable-base transistors 50 on paper.…”

“…1). 15 The general simplicity of the OECT fabrication process, the insensitivity of the performance to the substrate roughness, the low operating voltages and their potentially very large transconductance 16 make OECTs particularly useful for applications in sensing 17 and biological interfacing. 6 Fundamental drawbacks of OECTs are their relatively small on/off current ratio (typically smaller than 10 6 ) and their relatively small transit frequency (usually a few tens of kilohertz).…”

Wearable Organic Electrochemical Transistor Patch for Multiplexed Sensing of Calcium and Ammonium Ions from Human Perspiration

“…Electrochemical sensing is particularly convenient because it is able to directly translate chemical signals to electrical signals without the use of labels . Electrochemical sensing has been successful in sensing of biochemicals including blood‐alcohol level in the breath, glucose levels in saliva, and blood . Strategies to transduce chemical signals include transistors, amperometric and voltammetric sensors .…”

A fully inkjet-printed disposable glucose sensor on paper

“…[15][16][17][18] Recent advances in the development of organic electronic materials (e.g., conducting polymers) foster the use of printing techniques. The high conductivity and compatibility with screen printing [19][20][21] and inkjet-printing, 18,22,23 render poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) the benchmark conducting polymer of printed electronics. 24 Inkjet-printed PEDOT:PSS based devices have been used as biosensors, for instance, for acquiring cutaneous recordings of electrophysiological activity, [25][26][27][28] as well as for enzymatic sensing of gases, 22 and of glucose.…”

“…The high conductivity and compatibility with screen printing [19][20][21] and inkjet-printing, 18,22,23 render poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) the benchmark conducting polymer of printed electronics. 24 Inkjet-printed PEDOT:PSS based devices have been used as biosensors, for instance, for acquiring cutaneous recordings of electrophysiological activity, [25][26][27][28] as well as for enzymatic sensing of gases, 22 and of glucose. 18 Due to its soft nature, PEDOT:PSS can also be printed on recyclable, cheap and eco-friendly paper substrates which substitute rather expensive glass and plastics, promising for the realization of disposable in vitro diagnostic tools.…”