Inexpensive and flexible nanographene-based electrodes for ubiquitous electrocardiogram monitoring

Francisco J Romero,Diego P Morales,Noel Rodriguez,Almudena Rivadeneyra,Alejandro Toral-Lopez,Francisco G Ruiz,Encarnacion Castillo,Markus Becherer

doi:10.1038/s41528-019-0056-2

Francisco J Romero, Diego P Morales + Show 6 more

Open Access

https://doi.org/10.1038/s41528-019-0056-2

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Abstract

Flexible electronics is one of the fundamental technologies for the development of electronic skin, implant wearables, or ubiquitous biosensing. In this context, graphene-derived materials have attracted great interest due to their unique properties to fulfill the demands of these applications. Here we report a simple one-step method for the fabrication of electrophysical electrodes based on the photothermal production of porous nanographene structures on the surface of flexible polyimide substrates. This approach constitutes an inexpensive alternative to the commercial medical electrodes, leading to a lower and much more stable skin–electrode contact resistance and providing comparable signal transduction. This technology has been framed inside the IoT paradigm through the development of a denoising and signal classification clustering algorithm suitable for its implementation in wearable devices. The experiments have shown promising achievements regarding noise reduction, increasing the crest factor ~3.7 dB, as well as for the over 90% heart rate-monitoring accuracy.

Highlights

Cardiovascular diseases (CVDs) are the most common cause of death in the world.[1]
Celik et al presented an electrode fabricated by chemical vapor deposition coating of graphene on top of a Agbased electrode;[15] chemically reduced graphene oxide on polyethylene terephthalate (PET) and porous textile substrates have been studied by Lou et al and Karim et al, respectively.[16,17]
We propose the use of a low-power laser diode to produce a foam of porous graphene (PG) on a flexible substrate; this structure is applied to the fabrication of electrodes for the continuous and ubiquitous monitoring of ECG signals

Summary

Introduction

Cardiovascular diseases (CVDs) are the most common cause of death in the world.[1]. This has led to assign great efforts to their early diagnosis, prevention, and treatment. According to the European Heart Network (EHN), overall CVDs are estimated to cost the EU economy 210 billion a year, of which around 53% (111 billion) are intended to the health costs.[2,3] Electrocardiography (ECG) is the most common method to diagnose abnormalities in the cardiac activity and to extract the information that might reveal CVDs in advance.[4] So far, this technique was traditionally limited to the hospital environment; the emergence of new technological paradigms, such as the Internet of Things (IoT), flexible electronic devices and electronic textiles (e-textiles) is shifting the “in-hospital care” towards the ubiquitous healthmonitoring.[5,6,7] Metals such as silver (Ag) or copper (Cu) are currently the most used materials for the biosignal transduction.[8,9,10] There is no doubt that these materials have offered high performance in this kind of applications and have contributed to the process of medical diagnosis. It is necessary to ensure a compromise between both the raw biosignal quality and the optimization of the processing algorithms to obtain accurate results

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