Biomedical Implementation of Liquid Metal Ink as Drawable ECG Electrode and Skin Circuit

Abstract

BackgroundConventional ways of making bio-electrodes are generally complicated, expensive and unconformable. Here we describe for the first time the method of applying Ga-based liquid metal ink as drawable electrocardiogram (ECG) electrodes. Such material owns unique merits in both liquid phase conformability and high electrical conductivity, which provides flexible ways for making electrical circuits on skin surface and a prospective substitution of conventional rigid printed circuit boards (PCBs).MethodsFundamental measurements of impedance and polarization voltage of the liquid metal ink were carried out to evaluate its basic electrical properties. Conceptual experiments were performed to draw the alloy as bio-electrodes to acquire ECG signals from both rabbit and human via a wireless module developed on the mobile phone. Further, a typical electrical circuit was drawn in the palm with the ink to demonstrate its potential of implementing more sophisticated skin circuits.ResultsWith an oxide concentration of 0.34%, the resistivity of the liquid metal ink was measured as 44.1 µΩ·cm with quite low reactance in the form of straight line. Its peak polarization voltage with the physiological saline was detected as −0.73 V. The quality of ECG wave detected from the liquid metal electrodes was found as good as that of conventional electrodes, from both rabbit and human experiments. In addition, the circuit drawn with the liquid metal ink in the palm also runs efficiently. When the loop was switched on, all the light emitting diodes (LEDs) were lit and emitted colorful lights.ConclusionsThe liquid metal ink promises unique printable electrical properties as both bio-electrodes and electrical wires. The implemented ECG measurement on biological surface and the successfully run skin circuit demonstrated the conformability and attachment of the liquid metal. The present method is expected to innovate future physiological measurement and biological circuit manufacturing technique in a large extent.

Inkjet‐Printed Flexible Gold Electrode Arrays for Bioelectronic Interfaces

“…Gold is a high work function metal, hence it demonstrates superior stability and inertness when in contact with aqueous media, biological fl uids, or living tissues. To summarize, although bioelectronic electrodes can be fabricated in different ways by using conductive materials, [21][22][23][24] there is still a lack in the materials science literature of the description of robust and effi cient inkjetprinted electrode arrays with applications in the biomedical fi eld.…”

Electrophoretic Deposition of Gallium with High Deposition Rate

“…As previously mentioned, gallium and its compounds can find many applications in electronic devices and flexible electrodes. The EPD method reported herein can potentially offer a low-cost, less complex and scalable alternative to conventional vapor deposition processes and recently reported injecting and printing processes of delicate gallium patterning [28,29]. In order to verify its compatibility with micropatterning technology for such applications, several gallium micro patterns were obtained by masking the substrate during EPD.…”

Preparations, Characteristics and Applications of the Functional Liquid Metal Materials

“…Yu et al have used the EGaIn alloy as a physiological electrode for ECG detection and evaluated its performance [101] (Figure 10a). Yu et al have used the EGaIn alloy as a physiological electrode for ECG detection and evaluated its performance [101] (Figure 10a).…”

“…As shown in Figure 12a and b, the target vessels of the pig heart and kidney in vitro were significantly lightened in several orders after infused the liquid gallium. Deng et al have fabricated an ultrathin and stretchable radiation-shielding film with a thickness of 0.3 mm based on room temperature liquid [101] Copyright 2013, Yu et al c) GaIn based non-invasive ECG recording and Photos of drosophila invasive ECG recording. The minimum vessel diameter observed using this method is 30 mm, which is also limited by the precision of equipment.…”