Plant-inspired soft actuators powered by water

Abstract

Unlike animals, plants lack motion-generating systems such as a central nervous system or muscles, but they have successfully developed mechanisms to sense and respond to environmental changes, ensuring their survival. Most of their movements rely on the movement of water into and out of their cells or tissues, which are intrinsically soft and porous. Understanding and harnessing these natural processes can lead to the development of environmentally friendly and biocompatible soft actuator systems. This article explains the strategies employed by plants to generate movement through water transportation, categorizing them into osmosis-driven and hygroscopic swelling-driven mechanisms. Additionally, we discuss the latest trends in soft actuators that replicate plant water-utilizing movements, suggest directions for further development, and provide a review of practical applications.