Air-gap-free epidermal bioelectronics via ethanol-triggered interfacial reconstruction for high-quality electrophysiological monitoring

Abstract

Stable and high-fidelity electrophysiological monitoring with dry epidermal electrodes remains limited by interfacial air gaps and mechanical mismatch, which induce dynamic impedance fluctuations and severe motion artifacts during skin deformation. Here, we introduce an ethanol-triggered interfacial reconstruction strategy that directly fabricates a ~5 µm-thick conductive nanomesh onto the epidermis, seamlessly conforming to complex skin micro-textures. This interfacial reconstruction effectively eliminates trapped air gaps, reduces mechanical mismatch, and establishes a stable low-impedance bioelectronic interface (37.8 kΩ at 100 Hz). Thus, it enables high-quality electrophysiological recordings with higher signal-to-noise ratio compared to commercial gel electrodes. The resulting nanomesh electrode exhibits high breathability and conformality, robust resistance to sweat, and on-demand ethanol-assisted removability. Hence, it allows long-term, irritation-free monitoring of electrophysiological signals under dynamic deformation and wet conditions. This thin epidermal electrode provides a new pathway toward reliable acquisition of electrophysiological signals, offering broad potential for personalized health monitoring, early disease diagnosis, and next-generation brain-computer interfaces.

Keywords

Air-gap-free interface / conformal electrode / low-motion artifact / electrophysiological recording

References

[1] Wu H,Zhu K.Materials, devices, and systems of on-skin electrodes for electrophysiological monitoring and human-machine interfaces.Adv Sci2021;8:2001938 PMCID:PMC7816724

[2] Wang C,Li J.Conformal electrodes for on-skin digitalization.SmartMat2021;2:252-62

[3] Wang J,Zhang J.Stretchable, breathable and skin-conformal nanofilm-based epidermal dry electrodes for electrophysiological and motion monitoring.Adv Funct Mater2026;36:e24980

[4] Zhu M,Li S.Flexible electrodes for in vivo and in vitro electrophysiological signal recording.Adv Healthc Mater2021;10:e2100646

[5] Yan W,Wang Y.Conformal, substrate-free liquid metal electrode for continuous health monitoring.ACS Sens2025;10:3450-60

[6] Gogurla N,Cho S,Kim S.Multifunctional and ultrathin electronic tattoo for on-skin diagnostic and therapeutic applications.Adv Mater2021;33:e2008308

[7] Zhao Y,Yu T.Ultra-conformal skin electrodes with synergistically enhanced conductivity for long-time and low-motion artifact epidermal electrophysiology.Nat Commun2021;12:4880 PMCID:PMC8361161

[8] Rauf S,Li J,Ahmad AN.Fully screen-printed and gentle-to-skin wet ECG electrodes with compact wireless readout for cardiac diagnosis and remote monitoring.ACS Nano2024;18:10074-87 PMCID:PMC11022287

[9] Yang S.Nanoscale strategies for enhancing the performance of adhesive dry electrodes for the skin.ACS Nano2024;18:27107-25

[10] Zheng B,Wang Z.Fishing net-inspired mutiscale ionic organohydrogels with outstanding mechanical robustness for flexible electronic devices.Adv Funct Mater2023;33:2213501

[11] Ye H,Sun S.Self-compliant ionic skin by leveraging hierarchical hydrogen bond association.Nat Commun2024;15:885 PMCID:PMC10825218

[12] Ma J,Sa Z.High-precision electrohydrodynamic printing of EGaIn-AgNPs biphasic conductive ink for conformal and lightweight bioelectrodes.Soft Sci2025;5:50

[13] Yin J,Tat T.Motion artefact management for soft bioelectronics.Nat Rev Bioeng2024;2:541-58 PMCID:PMC13012649

[14] Dong J,Lim T.Viscoelastic adhesive, super-conformable, and semi-flowable liquid metal eutectogels for high-fidelity electrophysiological monitoring.ACS Appl Mater Interfaces2024;16:34732-42

[15] Yu W,Zhang G.Autonomous in situ biointerfacing platform for real-time electrophysiological monitoring and advanced wound management.ACS Nano2026;20:5764-80 PMCID:PMC12947733

[16] Zhang Z,Wang H.A 10-micrometer-thick nanomesh-reinforced gas-permeable hydrogel skin sensor for long-term electrophysiological monitoring.Sci Adv2024;10:eadj5389 PMCID:PMC10781413

[17] Wang Y,Zhang Y.A 2.7-μm-thick robust, permeable, and antifreezing hydrogel electrode for long-term ambulatory health monitoring.Sci Adv2025;11:eadt2286 PMCID:PMC12442859

[18] Cheng S,Zhang L.Ultrathin hydrogel films toward breathable skin-integrated electronics.Adv Mater2023;35:e2206793

[19] Wang C,Wang B.On-skin paintable biogel for long-term high-fidelity electroencephalogram recording.Sci Adv2022;8:eabo1396 PMCID:PMC9122322

[20] Li L,Ji Z.Paintable, fast gelation, highly adhesive hydrogels for high-fidelity electrophysiological monitoring wirelessly.Small2025;21:e2407996

[21] Lim C,Kang H.Highly conductive and stretchable hydrogel nanocomposite using whiskered gold nanosheets for soft bioelectronics.Adv Mater2024;36:e2407931

[22] Ma N,Wang L.Ag/AgCl@agar/P(AM-co-HEAA) hydrogel with ultra-stretchability, fatigue resistance, and freezing tolerance for human motion and electrophysiological signal monitoring.Int J Biol Macromol2025;331:148239

[23] Chen Y,Chen N.Skin-inspired MXene-based polyvinyl alcohol/gelatin organic hydrogel with good anti-drying, anti-swelling properties and high sensitivity.Sens Actuators A Phys2025;383:116231

[24] Alsharif AA,Mishra RB.3D printed dry electrodes for electrophysiological signal monitoring: a review.Adv Mater Technol2023;8:2201677

[25] Jeon MS,Hong S.All-dry self-adhesive soft electrodes with subsurface pores for long-term skin recording.Small2025;21:e07416

[26] He K,Ji S.An antidehydration hydrogel based on zwitterionic oligomers for bioelectronic interfacing.Adv Mater2024;36:e2311255

[27] Ding L,Yang S.In situ deposition of skin-adhesive liquid metal particles with robust wear resistance for epidermal electronics.Nano Lett2022;22:4482-90

[28] Liu X,Liu J.Liquid metal-based dynamic conformal electrodes.Soft Sci2025;5:34

[29] Qiu J,Zhang W.A bioinspired, durable, and nondisposable transparent graphene skin electrode for electrophysiological signal detection.ACS Materials Lett2020;2:999-1007

[30] Du X,Shi X.Ultrathin bioelectrode array with improved electrochemical performance for electrophysiological sensing and modulation.ACS Nano2024;18:34971-85

[31] Wang J,Wang A.Sponge inspired flexible, antibacterial aerogel electrode with long-term high-quality electrophysiological signal recording for human-machine interface.Adv Funct Mater2024;34:2309704

[32] Fan L,Xu L.Electrochemically enhanced low-impedance Ti₃C₂T_x MXene epidermal electrodes for accurate electrophysiological monitoring.Nanomicro Lett2026;18:297 PMCID:PMC13004779

[33] Zhang L,He H.Fully organic compliant dry electrodes self-adhesive to skin for long-term motion-robust epidermal biopotential monitoring.Nat Commun2020;11:4683 PMCID:PMC7499260

[34] Hwang C,Pang C,Park S.Skin-conformal Ag flake-decorated PEDOT:PSS sensor arrays for spatially resolved body temperature monitoring.Small2025;21:e2412675 PMCID:PMC12366251

[35] Hou S,Jin T,Han Y.A highly conductive, stretchable, and healable sensing electrode consisting of PEDOT conductive pathway and semi-interpenetrating network.Adv Funct Mater2026;36:e19643

[36] Yu J,Tian F.3D printing of robust high-performance conducting polymer hydrogel-based electrical bioadhesive interface for soft bioelectronics.Small2024;20:e2308778

[37] Shin JH,June K,Kim TI.Polymeric conductive adhesive-based ultrathin epidermal electrodes for long-term monitoring of electrophysiological signals.Adv Mater2024;36:e2313157

[38] Ma C,Yu W.Compliant and breathable electrospun epidermal electrode towards artifact-free electrophysiological monitoring.Chem Eng J2024;490:151118

[39] Tian Q,Wang X.Hairy-skin-adaptive viscoelastic dry electrodes for long-term electrophysiological monitoring.Adv Mater2023;35:e2211236

[40] Gao Y,Zhang L.Ultraconformal skin-interfaced sensing platform for motion artifact-free monitoring.ACS Appl Mater Interfaces2024;16:27952-60

[41] Kim J,Jeon J.Robust skin-conformal nano-electrodes for sustainable health and performance monitoring.ACS Nano2025;19:30322-37 PMCID:PMC12392733

[42] Zheng Y,Zhao Y.Ultrathin and highly breathable electronic tattoo for sensing multiple signals imperceptibly on the skin.Nano Energy2023;107:108092

[43] Mimuro M,Liang X.Breathable nanomesh electrodes with improved water resistance and stretchability for skin impedance monitoring.npj Flex Electron2026;10:542

[44] Liu T,Li Y.Eutectogel skin electrodes with superior adhesion, sweat resistance, and long-term stability for electrophysiological signal monitoring.Adv Funct Mater2025;35:e03568

[45] Zheng S,Miao W.2D prior spreading inspired from Chinese Xuan Papers.Adv Funct Mater2018;28:1800832

[46] Lin S,Huang K.Advanced electrode technologies for noninvasive brain-computer interfaces.ACS Nano2023;17:24487-513