Wireless graphene-based electrocardiogram (ECG) sensor including multiple physiological measurement system
Year: 2017
Type: dissertation
Abstract: In this thesis, a novel graphene (GN) based electrocardiogram (ECG) sensor is designed, constructed and tested to validate the concept of coating GN, which is a highly electrically conductive material, on Ag substrates of conventional electrodes.The background theory, design, experiments and results for the proposed GN-based ECG sensor are also presented.Due to the attractive electrical and physical characteristics of graphene, a new ECG sensor was investigated by coating GN onto itself.The main focus of this project was to examine the effect of GN on ECG monitoring and to compare its performance with conventional methods.A thorough investigation into GN synthesis on Ag substrate was conducted, which was accompanied by extensive simulation and experimentation.A GN-enabled ECG electrode was characterised by Raman spectroscopy, scanning electron microscopy along with electrical resistivity and conductivity measurements.The results obtained from the GN characteristic experimentation on Raman spectroscopy, detected a 2D peak in the GN-coated electrode, which was not observed with the conventional Ag/AgCl electrode.SEM characterisation also revealed that a GN coating smooths the surface of the electrode and hence, improves the skin-to-electrode contact.Furthermore, a comparison regarding the electrical conductivity calculation was made between the proposed GNcoated electrodes and conventional Ag/AgCl ones.The resistance values obtained were 212.4 Ω and 28.3 Ω for bare and GN-coated electrodes, respectively.That indicates that the electrical conductivity of GN-based electrodes is superior and hence, it is concluded that skin-electrode contact impedance can be lowered by their usage.Additional COMSOL simulation was carried out to observe the effect of an electrical field and surface charge density using GN-coated and conventional Ag/AgCl electrodes on a simplified human skin model.The results demonstrated the effectiveness of the addition of electrical field and surface charge capabilities and hence, coating GN on Ag substrates was validated through this simulation.This novel ECG electrode was tested with various types of electrodes on ten different subjects in order to analyse the obtained ECG signals.The experimental results clearly showed that the proposed GN-based electrode exhibits the best performance in terms of ECG signal quality, detection of critical waves of ECG morphology (P-wave, QRS complex and T-wave), signal-tonoise ratio (SNR) with 27.0 dB and skin-electrode contact impedance (65.82 kΩ at 20 Hz) when compared to those obtained by conventional a Ag/AgCl electrode.Moreover, this proposed GN-based ECG sensor was integrated with core body temperature (CBT) sensor in an ear-based device, which was designed and printed using 3D technology.Subsequently,
Author: Numan Celik
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2765259979