Ultraconformable, Self‐Adhering Surface Electrodes for Measuring Electrical Signals in Plants

Abstract

The electrical signals in plant's physiological processes are of great interest in biology, biohybrid robotics, and sensors for interfacing the living organisms with an electronic readout and control. This paper reports on the application of conformable, self‐adhering surface electrodes for the measurement and bidirectional stimulation of electrical signals in plants. The inkjet‐printed poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate based electrodes are <3 µm thick, light‐weight, soft and flexible, and can be easily and non‐invasively transferred onto plant's outer organs for surface potential recordings due to their realization on tattoo transfer paper. The devices prove to be extremely versatile for analyzing electrical signals in Dionaea muscipula, Arabidopsis thaliana, and Codariocalyx motorius and for stimulating mechanical responses in D. muscipula. A benefit over traditional electrodes is the van der Waals self‐adherence of the thin electrodes, their intrinsic flexibility and adaptation also on small leaves while providing excellent readout. The same electrode allows long‐term multicycle measurements over at least 10 days and, moreover, straightforward recordings on fast‐moving organs such as snapping fly traps and endogenously oscillating leaflets. The results confirm that self‐adhering soft organic electronics are particularly suitable for plant electrical signal analysis when easy‐application, self‐adaptation, and long‐term performance are required in plant science, biohybrid robotics, and biohybrid sensors. Soft, organic electronics that adapt perfectly to multiple surfaces provide new opportunities in interfacing, recording, and bidirectionally stimulating electrical signals in plants. The conformable electrodes applied to measure plant's electrical signals in this paper contribute a novel interface for plant‐hybrid robots and new sensors for biology and agriculture.