Bioinspired Ionic Biogels for Conformal On-Skin Wearable Bioelectronics

Clinical Snapshot

Key Findings

• P Value: Not reported

• Effect Size: Not reported quantitatively in abstract; described qualitatively as 'low modulus', 'high stretchability', 'strong adhesion', and 'good environmental stability'

• Primary Outcome: IBG43 formulation demonstrated mechanical compliance, skin adhesion, water retention, ionic conductivity, stable strain sensing, and electrophysiological signal acquisition (ECG, EMG, EEG) in proof-of-concept demonstrations

• Nnt Or Sensitivity: Not applicable at this developmental stage; no diagnostic accuracy, therapeutic efficacy, or prognostic metrics reported. Signal-to-noise ratio and electrode impedance values — the relevant functional metrics — are not quantified in the abstract.

• Confidence Interval: Not reported

Clinical Application

Clinical feasibility is highly premature. Key barriers include: absence of ISO 10993 biocompatibility data for the ionic liquid component; undefined gelation temperature control requirements in clinical settings; unknown shelf-life and storage requirements; no manufacturing scale-up data; undefined regulatory classification. The in situ application concept, while innovative, introduces procedural complexity compared to peel-and-apply commercial electrodes. In Australia, this device class would require TGA registration as a medical device (likely Class IIa or IIb under the Therapeutic Goods (Medical Devices) Regulations 2002) before any clinical use. The ionic liquid component (1-ethyl-3-methylimidazolium ethyl sulfate) would require assessment under the Industrial Chemicals Act 2019 if manufactured domestically. RACGP and CSANZ guidelines for ambulatory cardiac monitoring currently specify validated commercial electrode systems; this technology is not near guideline inclusion. PBS reimbursement pathways for novel electrode materials do not currently exist. Australian tropical climate conditions (high ambient temperature, humidity) may affect gelation kinetics and require specific formulation adaptation. Research collaboration with Australian institutions (e.g., through ARC Linkage grants) would be required for local validation. Theoretically applicable to any patient population requiring continuous non-invasive electrophysiological monitoring (cardiac monitoring, neurological assessment, rehabilitation medicine, sports medicine). Particularly relevant for patients with irregular skin topography, excessive movement artefact, or poor electrode adhesion with conventional systems.

Abstract

Conductive gels are promising materials for on-skin wearable bioelectronics owing to their softness, ionic conductivity, and tissue-like interfacial characteristics. However, conventional preformed conductive gels often cannot fully accommodate complex and dynamically deforming skin surfaces, thereby limiting their interfacial adhesion and signal-transmission performance. Inspired by the reversible mechanical switching behavior of sea cucumbers, we developed a thermoresponsive ionic biogel (IBG) composed of gelatin, water, and 1-ethyl-3-methylimidazolium ethyl sulfate. In this system, gelatin forms a physical network with reversible sol-gel transition behavior, while the ionic liquid modulates the network through hydrogen bonding and electrostatic interactions and provides mobile ions for charge transport. This design integrates mechanical compliance, skin adhesion, water retention, and electrical functionality. The IBG can be directly coated onto skin in a flowable state and subsequently undergo mild in situ gelation, forming a soft, adaptive, and ion-conductive bioelectronic interface. The optimized IBG43 exhibits a low modulus, high stretchability, strong adhesion, and good environmental stability, together with stable strain sensing, reliable electrophysiological signal acquisition, and potential for self-powered sensing. This work presents a simple and effective strategy for constructing in situ formable skin-interfaced bioelectronic materials.

References

1. 1.Zou, X., Gou, M., Zhang, X., & Wang, L. (2026). Bioinspired ionic biogels for conformal on-skin wearable bioelectronics. ACS Applied Materials & Interfaces. Advance online publication. https://doi.org/10.1021/acsami.6c06889