Monitoring plant health and how it changes in response to the environment is one way scientists can work to protect and preserve important species and vital crops. The challenge is designing monitoring tools that can be easily attached to plants without damaging them and that won’t have a negative impact on the environment themselves. Researchers at the Instituto Italiano di Tecnologia (ITT) have now created a new 3D-printed biodegradable microhook adhesive that can be used to both attach sensors to leaves and deliver beneficial substances to them in a minimally invasive manner.
The new design is inspired by the climbing plant Galium aparine, also known as “catchweed,” which has microhooks on its leaves that allow it to parasitically latch onto other plants for physical support. The researchers used a high-resolution 3D printer to create artificial replicas of the catchweed microhooks, using the soluble, biodegradable material isomalt and a flexible photosensitive resin. The microhooks cause the printed isomalt or resin components to adhere to plant leaves similarly to Velcro, achieving a strong grip while also being lightweight and causing minimal damage.
The isomalt materials can be attached to the leaves and then dissolve in order to locally deliver useful substances such as drugs and pesticides. This could prevent excessive pesticide use overall compared to spraying methods. The photosensitive resin materials can be made into clips and attached to sensing devices that can help researchers monitor environmental conditions such as temperature, humidity and light, said first author Isabella Fiorello. The researchers even designed a microrobotic system called MiniBot, with microhooks on its “feet” that can move it forward over the surface of leaves in a ratchet motion with the help of an actuator. This study was published in Communications Materials.
“Our studies always begin by observing nature, seeking to replicate the strategies employed by living creatures through low-environmental-impact robotic technologies,” said Barbara Mazzolai, head of the ITT Bioinspired Soft Robotics Lab and corresponding author on the paper. “With this latest research project, we have further demonstrated that it is possible to create innovative solutions that not only have the aim of monitoring the health of our planet, in particular of plants, but of doing so without altering it.”
The researchers have filed a patent application for their technology and hope to design more advanced microrobotic systems with microhooks and electronic components that could change their movement direction and resist external perturbations such as wind.