Self-Adherent Biodegradable Gelatin-Based Hydrogel Electrodes for Electrocardiography Monitoring

Abstract

Patch-type hydrogel electrodes have received increasing attention in biomedical applications due to their high biocompatibility and conformal adherence. However, their poor mechanical properties and non-uniform electrical performance in a large area of the hydrogel electrode should be improved for use in wearable devices for biosignal monitoring. Here, we developed self-adherent, biocompatible hydrogel electrodes composed of biodegradable gelatin and conductive polymers for electrocardiography (ECG) measurement. After incorporating conductive poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) into gelatin hydrogels crosslinked by natural crosslinkers (genipin), the mechanical properties and electrical conductivity of the hydrogel electrodes were improved and additionally optimized by adjusting the amounts of crosslinker and PEDOT:PSS, respectively. Furthermore, the effect of dimethyl sulfoxide, as a dopant, on the conductivity of hydrogels was investigated. The gelatin-based, conductive hydrogel patch displayed self-adherence to human skin with an adhesive strength of 0.85 N and achieved conformal contact with less skin irritation compared to conventional electrodes with a chemical adhesive layer. Eyelet-type hydrogel electrodes, which were compatible with conventional ECG measurement instruments, exhibited a comparable performance in 12-lead human ECG measurement with commercial ECG clinical electrodes (3M Red Dot). These self-adherent, biocompatible, gelatin-based hydrogel electrodes could be used for monitoring various biosignals, such as in electromyography and electroencephalography.

Electroconductive Photo-Curable PEGDA-Gelatin/PEDOT:PSS Hydrogels for Prospective Cardiac Tissue Engineering Application

“…The P1G1P0.5 formulation showed a photo-gelation kinetic comparable to that of the other doped formulations, but with a higher starting G' (Figure 1B). This difference was probably a consequence of the more pronounced molecular interactions between the anionic sulfonic groups of PEDOT:PSS and the cationic amino acids, such as arginine or lysine, present on the gelatin backbone (Spencer et al, 2018;Lee et al, 2020).…”

“…Electroconductive hydrogels (ECHs) are a class of smart biomaterials that merge the electrical properties of intrinsically conductive components with highly hydrophilic and biocompatible hydrogel networks (Guiseppi-Elie, 2010). ECHs are currently studied for several biomedical applications, including biosensors (Ren et al, 2019;Lee et al, 2020), drug release (Qu et al, 2018;Chen et al, 2021) and tissue engineering (Roshanbinfar et al, 2018;Heo et al, 2019). Several types of conductive dopants have been combined with hydrogels networks to tune their electrical properties while showing biomimetic characteristics respect to the target tissue (Min et al, 2018).…”

High-Adhesive Flexible Electrodes and Their Manufacture: A Review

“…In addition to the extensive research value of conductive hydrogels on intrinsic stretchable conductors, researchers have also studied their adhesion [84]. Lee et al reacted a gelatin hydrogel mixed with the natural crosslinking agent PEDOT:PSS to obtain an adhesive patch-type hydrogel electrode that can be used in wearable devices to detect EP signals [117]. In their ECG signal detection experiment, the adhesiveness of the electrode patch to human skin was 0.85 N, the patch achieved conformal contact with human skin, and the measured signal quality was comparable with commercial ECG clinical electrodes [117].…”

“…Lee et al reacted a gelatin hydrogel mixed with the natural crosslinking agent PEDOT:PSS to obtain an adhesive patch-type hydrogel electrode that can be used in wearable devices to detect EP signals [117]. In their ECG signal detection experiment, the adhesiveness of the electrode patch to human skin was 0.85 N, the patch achieved conformal contact with human skin, and the measured signal quality was comparable with commercial ECG clinical electrodes [117]. Yang et al used in situ polymerization to prepare a highly adhesive electrode (CAPE) based on conductive hydrogel that is not affected by sweat [109].…”

Biomimetic Synthesized Conductive Copolymer EDOT-Pyrrole Electrodes for Electrocardiogram Recording in Humans

“…Mihara et al fabricated PEDOT:PSS/poly (styrene-butadiene-styrene) (SBS) waterproof bilayer nanosheet films for a comfortable waterproof bioelectrode [11]. Lee et al developed biocompatible, selfadhesive hydrogel electrodes for ECG measurements prepared from gelatin crosslinked with genipin, as a natural water-soluble crosslinking agent with less toxicity [12]. Trindade et al fabricated in situ PEDOT textile electrodes for continuous monitoring ECG [13].…”