Plant-like hooked miniature machines for on-leaf sensing and delivery

Isabella Fiorello,Barbara Mazzolai,Fabian Meder,Edoardo Sinibaldi,Alessio Mondini,Omar Tricinci,Carlo Filippeschi

doi:10.1038/s43246-021-00208-0

Isabella Fiorello, Barbara Mazzolai + Show 5 more

Open Access

https://doi.org/10.1038/s43246-021-00208-0

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Abstract

New sustainable strategies for preserving plants are crucial for tackling environmental challenges. Bioinspired soft and miniature machines have the potential to operate in forests and agricultural fields by adapting their morphology to plant organs like leaves. However, applications on leaf surfaces are limited due to the fragility and heterogeneity of leaves, and harsh outdoor conditions. Here, we exploit the strong shear-dependent leaf-attachment of the hook-climber Galium aparine to create miniature systems that enable precision anchoring to leaf tissues via multifunctional microhooks. We first study the anchoring forces of the microhooks and then fabricate a soft wireless multiparameter sensor to monitor the leaf proximity and degradable hooks for in-plant molecular delivery to the vascular tissues of the leaves. In addition, we use a soft robotic proof-of-concept demonstrator to highlight how our hooks enable ratchet-like motion on leaves. This research showcases opportunities for specifically designing multifunctional machines for targeted applications in plant ecosystems.

Highlights

New sustainable strategies for preserving plants are crucial for tackling environmental challenges
Microscope observations show that abaxial hooks have a unique downward orientation (Fig. 1a)[22], which enables them to anchor and to penetrate leaf surfaces (Fig. 1b, c)
IPS-MHDs are microfabricated at a high resolution and high reproducibility using two-photon lithography (Nanoscribe Photonic Professional system) on flexible polyethylene terephthalate (PET) sheet substrates with the photoresist IPS (Fig. 1e, Supplementary Fig. 4a, part A; see Methods for details)[33]

Summary

Introduction

New sustainable strategies for preserving plants are crucial for tackling environmental challenges. Living organisms can inspire scientists in the prototyping of bioinspired soft machines able to operate in dynamic real-world environments[12,13,14,15,16] to tackle environmental-related issues[17,18] When miniaturized, these machines can noninvasively and precisely access confined spaces[19,20]. The use of such machines in natural habitats is restricted, they may lead to a disruptive robotic vision where they can adapt to dense vegetation, such as on plant leaf organs, to closely monitor and preserve natural ecosystems, reducing the use of potential pollutants[21]. The hook-climber Galium aparine uses a unique parasitic ratchet-like anchoring mechanism to climb over host plants using microscopic hooks for mechanical interlocking to leaves[22,31]

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Results

Conclusion