Researchers from Cornell University, Manisa Celal Bayar University, and the Boyce Thompson Institute have come up with a soft robotic gripper that can give the most fragile of plants a gentle caress — while injecting even tough subjects with bacterial sensors or water-stress monitoring gel.
“Plants, like people, have different responses to the environment, and precision agriculture is an effort to move closer and closer to single-plant-level intervention – and the soil surrounding it,” Explains senior author Robert F. Shepherd of the team’s work. “Soft grippers to inject physical or biological probes unlock new and incredible capabilities. The immediate use of our system would likely be in greenhouses, where a robot would persistently inject and monitor individual plants to infer how much water they need.”
Researchers have developed a new robot gripper (A) capable of injecting various substances into leaves (B) with less damage than existing systems (C). (📷: Ilman et al)
That system takes the form of a soft robotic gripper, attached to an off-the-shelf robot arm, which is designed to incur minimum damage to a plant — even when injecting foreign material into its leaves. A sponge tip is designed to hold the deliverable, which could be anything from nanoparticles to genetic probes, and is connected to an actuator designed through repeated simulation and 3D printed to tailor it a multitude of leaf types.
“Its low stiffness allows it to warp the gripper’s shape to adapt to the orientation and surface of the leaf with little health implications to the leaf,” Shepherd explains. “The shape of the extending actuator allowed for a large displacement and ability to adjust orientation without bulky or complex motor control. New nanoparticles will also eventually be created that will inform us about many other health aspects of the plant. With this information, plants will yield more, and we will waste less. Once translated out of greenhouses, the implications will be larger. I am particularly interested in limiting the waste streams into lakes to prevent harmful algal blooms.”
“AquaDust allowed us to ‘see’ the water stress inside a leaf,” says first author Mehemt Mert Ilman of one of the device’s payloads, referring to a gel-like material which fluoresces in response to water stress, “and similarly, by injecting a bacterium that transforms the injection region with RUBY reporter genes, we were able to ‘see’ that this part of the leaf experienced a genetic transformation.”
The material to be delivered is added to a sponge held in a gasket on top of a linear actuator, and stamps each leave multiple times. (📷: Ilman et al)
Tested on sunflower and cotton leaves — chosen, perhaps surprisingly, for their toughness, with leaves which are easily damaged by the sheer force required to infiltrate using traditional syringe-based delivery methods — the gripper achieved over a 91 percent success rate in delivery, expanded the effective infiltration area by more than 12 times, and caused less damage than existing approaches.
The team’s work has been published in the journal Science Robotics under open-access terms.
Main article image courtesy of Savan DeSouza/Cornell University.