The first 3D-printed biodegradable seed robot, able to change shape in response to humidity (w/video)

(Nanowerk News) In the pursuit of innovative solutions that harmoniously blend with the natural world, researchers at the Istituto Italiano di Tecnologia (IIT) in Genoa have developed the first 3D-printed seed-robot, known as I-Seed. Inspired by the shape of a seed and capable of navigating through soil based on humidity changes, this remarkable creation is fashioned from biodegradable materials and functions autonomously without the need for batteries or external energy sources. The pioneering Bioinspired Soft Robotics (BSR) Lab, led by Barbara Mazzolai, collaborated with the University of Trento in this groundbreaking endeavor.
The I-Seed is a versatile artificial seed with the potential for applications ranging from environmental monitoring to reforestation. Its prototype has been featured in a research paper published in Advanced Science ("4D Printing of Humidity-Driven Seed Inspired Soft Robots"), as well as gracing the journal's cover. The I-Seed project, which began in January 2021, is a European initiative coordinated by IIT, with the primary objective of developing innovative robots modeled after plant seeds that can serve as sensors for monitoring soil quality parameters and air metrics, such as CO2 levels, temperature, and humidity.
3D-printed seed-robot
The seeds of the South African geranium inspired the realization of the prototype. (Image: IIT)
The Pelargonium appendiculatum, a South African geranium, served as the inspiration for the I-Seed's hygromorphic structure, which allows it to change shape in response to variations in humidity in its environment. Barbara Mazzolai, Associate Director for Robotics at IIT and coordinator of the EU-funded I-Seed project, emphasized the research's objective to imitate living beings' strategies and structures in order to develop environmentally-friendly robotic technologies.
The IIT-BSR Lab, under Mazzolai's guidance, has long been inspired by plants in their research. After exploring the growth and movement strategies of roots and climbing plants, the group concentrated on the movement and dispersal features of seed-carrying structures found in Gerianaceae plants. When the appropriate environmental conditions arise, these seeds separate from the plant and use the hygroscopic properties of their materials to change shape and independently move through the soil, thereby increasing the likelihood of germination. Intriguingly, these seeds rely on dead cellulose-based tissues, which can deform solely based on environmental humidity changes.
A robot with the shape of a seed and with the ability to explore the soil based on humidity changes. It is made of biodegradable materials and able to move within the surrounding environment without requiring batteries or other external sources of energy.
Utilizing histological analysis of these tissues, researchers replicated the seed design by combining 3D printing and electrospinning techniques. Various materials were tested to identify the optimal solution for the desired application, including humidity-absorbing and expanding materials like cellulose nanocrystals and polyethylene oxide, which were coupled with biodegradable and thermoplastic polymers based on Polycaprolactone.
Mazzolai highlighted the significance of this research in demonstrating the feasibility of creating innovative solutions that monitor the well-being of our planet without altering it. Luca Cecchini, a PhD student at IIT collaborating with the University of Trento and the study's first author, added that these biodegradable and energy-autonomous robots could serve as wireless, battery-free tools for surface soil exploration and monitoring. This bioinspired approach enables the development of low-cost instruments that can gather in-situ data with high spatial and temporal resolution, particularly in remote areas where no monitoring data is currently available.
Source: Italian Institute of Technology (Note: Content may be edited for style and length)