A Morphable Ionic Electrode Based on Thermogel for Non‐Invasive Hairy Plant Electrophysiology

Abstract

Plant electrophysiology lays the foundation for smart plant interrogation and intervention. However, plant trichomes with hair‐like morphologies present topographical features that challenge stable and high‐fidelity non‐invasive electrophysiology, due to the inadequate dynamic shape adaptability of conventional electrodes. Here, this issue is overcome using a morphable ionic electrode based on a thermogel, which gradually transforms from a viscous liquid to a viscoelastic gel. This transformation enables the morphable electrode to lock into the abrupt hairy surface irregularities and establish a conformal and adhesive interface. It achieves down to one tenth of the impedance and 4–5 times the adhesive strengths of conventional hydrogel electrodes on hairy leaves. As a result of the improved electrical and mechanical robustness, the morphable electrode can record more than one order of magnitude higher signal‐to‐noise ratio on hairy plants and maintains high‐fidelity recording despite plant movements, achieving superior performance to conventional hydrogel electrodes. The reported morphable electrode is a promising tool for hairy plant electrophysiology and may be applied to diversely textured plants for advanced sensing and modulation.

Non-destructive Technologies for Plant Health Diagnosis

“…Conductive agar gels, connected to metal wires, can be employed as electrodes to capture the temporal profile of electrical signals elicited upon wounding in Arabidopsis thaliana (Mousavi et al, 2013 ; Nguyen et al, 2018 ). Recently, the conformability of such hydrogel-based approach was improved by using thermogels as morphable electrodes (Luo et al, 2021 ). The thermogel solution can undergo in situ gelation on hairy leaf surfaces at room temperature to provide higher adhesiveness and improved signal-to-noise ratio for plant electrophysiology ( Figure 2A ).…”

“… (A) Thermogel application to monitor electrical potential signals from plants with hairy stems (Luo et al, 2021 ). (B) Printed conductive polymers enabled impedance spectroscopy to detect ozone damage (Kim et al, 2020 ).…”

Flexible Wearables for Plants

“…Luo et al. [ 120 ] have innovatively designed a deformable ionic electrode based on thermo‐gel to address this problem. The gel can be gradually converted from viscous liquid to viscoelastic gel for the electrophysiological detection of hairy plants.…”

“…Reproduced with permission. [ 120 ] Copyright 2021, Wiley‐VCH. a) Schematic diagram of wound plants used in the experiment.…”

A Facile Liquid Alloy Wetting Enhancing Strategy on Super‐Hydrophobic Lotus Leaves for Plant‐Hybrid System Implementation

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Recently, quite a few strategies have been discovered to implement such planthybrid systems. [10][11][12][13][14][15][16][17][18] Here just list a few of them. Information on plant growth, physiology, microclimate, humidity, and chemicals can be obtained by plant wearable sensors.

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