A bioinspired, self-powered, flytrap-based sensor and actuator enabled by voltage triggered hydrogel electrodes

Because of its adaptive interfacial property, soft sensors/actuators can be used to perform more delicate tasks than their rigid counterparts. However, plant epidermis with a waxy cuticle layer challenges stable and high-fidelity non-invasive electrophysiology since the conventional electrodes are invasive, easily detached from plants, and require complicated setup procedures. Here, we report a bioinspired sensor and actuator created by using a conformable electrode interface as an electrical modulation unit on a Venus flytrap. Our conformable electrode, by employing an adhesive hydrogel layer, can achieve the merits of low impedance, stretchable, biocompatible, reusable, and transparent enough for normal chlorophyll activity to occur. Owing to the high sensitivity of a flytrap to a triggering mechanical stimulation, a plant sensor matrix based on flytraps has been demonstrated by capturing the stimulated action potential (AP) signals from upper epidermis, which can orient honeybee colonies by their touch during collecting nectar. Moreover, via frequency-dependent AP modulation, an autonomous on-demand actuation on a flytrap is realized. The flytrap actuator can be controlled to responsively grasp tiny objects by the modulated signals triggered by a triboelectric nanogenerator (TENG). This work paves a way of developing autonomous plant-based sensors and actuators toward smart agriculture and intelligent robots.