Hydrogels and Carbon Nanotubes: Composite Electrode Materials for Long-Term Electrocardiography Monitoring.

This paper presents methods for developing high-performance interface electrode materials designed to enhance signal collection efficacy during long-term (over 24 h) electrocardiography (ECG) monitoring. The electrode materials are fabricated by integrating commercial ECG liquid hydrogels with carbon nanotubes (CNTs), which are widely utilized in dry-electrode technologies and extensively discussed in the current scientific literature. The composite materials are either prepared by dispersing CNTs within the commercial liquid hydrogel matrix or by encasing the hydrogels in macroscopic CNT films. Both approaches ensure the optimal wetting of the epidermis via the hydrogels, while the CNTs reduce material impedance and stabilize the drying process. The resulting electrode materials maintain their softness, allowing for micro-conformal skin attachment, and are biocompatible. Empirical testing confirms that the ECG electrodes employing these hybrid hydrogels adhere to relevant standards for durations exceeding 24 h. These innovative hybrid solutions merge the benefits of both wet and dry ECG electrode technologies, potentially facilitating the extended monitoring of ECG signals and thus advancing the diagnosis and treatment of various cardiac conditions.

Assessment of a new KoMaWo electrode-patch configuration accuracy and review of the literature.

INTRODUCTION: Standard 12­lead electrocardiogram (ECG) is a basic element of routine everyday clinical practice. Traditional cardiac monitoring devices are associated with considerable limitations. Adhesive patches, novel digital solutions, may become a useful diagnostic tool for several cardiovascular diseases. MATERIALS AND METHODS: We propose a new variation of ECG electrodes positioning called KoMaWo. 15 consecutive patients presenting with ST segment deviations due to coronary artery disease were enrolled. The accuracy and utility of the new configuration was assessed and compared with the Mason-Likar configuration, as well as with a standard 12­lead ECG recording. The scans were blinded and interpreted by two independent cardiologists. RESULTS: There were no statistically significant differences in morphology, as well as in the duration of individual waves, complexes, segments, and intervals between the scans obtained using all three methods. In a subgroup analysis, with regard to age, body mass and left ventricle ejection fraction (LVEF), KoMaWo was non-inferior to standard ECG with a 0.2 mm margin. DISCUSSION: The role of traditional cardiac monitoring devices is recognized as the gold standard of patient management. However, certain limitations should be considered. Adhesive patches are light-weight, well-tolerated and do not interfere with daily activities of patients. These novel devices allow for extended monitoring, facilitating increased diagnostic accuracy, regarding cardiac arrhythmias. CONCLUSIONS: The KoMaWo configuration is not inferior to standard electrode placement, nor to Mason-Likar configuration, including its ability to capture ST segment deviations. Adhesive patches may become a valid alternative for traditional cardiac monitoring methods.

Enriching WPCs and NFPCs with Carbon Nanotubes and Graphene.

Carbon nanotubes (CNTs) and graphene, with their unique mechanical, electrical, thermal, optical, and wettability properties, are very effective fillers for many types of composites. Recently, a number of studies have shown that CNTs and graphene may be integrated into wood-plastic composites (WPCs) and natural-fibre-reinforced polymer composites (NFPCs) to improve the existing performance of the WPCs/NFPCs as well as enabling their use in completely new areas of engineering. The following review analyses the results of the studies presented to date, from which it can be seen that that inclusion of CNTs/graphene may indeed improve the mechanical properties of the WPCs/NFPCs, while increasing their thermal conductivity, making them electroconductive, more photostable, less sensitive to water absorption, less flammable, and more thermally stable. This study indicates that the composition and methods of manufacturing of hybrid WPCs/NFPCs vary significantly between the samples, with a consequent impact on the level of improvement of specific properties. This review also shows that the incorporation of CNTs/graphene may enable new applications of WPCs/NFPCs, such as solar thermal energy storage devices, electromagnetic shielding, antistatic packaging, sensors, and heaters. Finally, this paper recognises key challenges in the study area, and proposes future work.

Screen-printed resistive pressure sensors containing graphene nanoplatelets and carbon nanotubes.

Polymer composites with nanomaterials such as graphene nanoplatelets and carbon nanotubes are a new group of materials with high application possibilities in printed and flexible electronics. In this study such carbon nanomaterials were used as a conductive phase in polymer composites. Pastes with dispersed nanomaterials in PMMA and PVDF vehicles were screen printed on flexible substrates, and used as an active layer in pressure sensors, exploiting contact resistance phenomena. The relationship between resistance and pressure is nearly linear on a logarithmic scale for selected types of samples, and their response is several times higher than for similar sensors with graphite layers. The use of surfactants allowed us to fabricate evenly dispersed nanomaterials with different amount of nanoplatelets and nanotubes in the composites. The samples contained from 1.25 wt.% to 2 wt.% of graphene and 1 wt.% to 0.5 wt.% of nanotubes and exhibited diverse sheet resistivity. Experiments revealed the relationship between morphology and loading of functional phase in the polymer matrix and the sensors' sensitivity.