Microdevice for sensing and delivery of active substances in plant leaves
Introduction
Miniature device that includes one or more micro-hooks made of a soluble material, which act as sensors, monitoring the health of the plant. In addition, these devices are suitable for releasing in plants, and in particular in leaves, nutrients or curative substances, pesticides or other substances containing active ingredients mainly in the form of nanoparticles, molecules, salts, ions, nucleic acids, proteins, virus or bacteria.

Technical features
Leaves represent the most common organs of plants and the most extensive biointerface in the world. However, the application of technologies directly on the leaves are limited due to their fragile and heterogeneous structure. The proposed device is composed of a matrix of abaxial micro-hooks each with dimensions of the order of tens or hundreds of μm, arranged in arrays, which allow the anchoring and the detection of the health status of the plant. Moreover, they allow to release substances directly into the vascular tissue of the leaf, with optimized release times and easily adjustable according to the needs: the micro-hooks are made of a soluble material based on sugar alcohols, so that the micro-anchoring element penetrates the internal tissue of the plant and dissolves releases the active ingredients contained in it. The material dissolves relatively quickly, but is also very resistant: this avoids the risk of premature detachment of the device from the leaf surface. TRL=4.
Possible Applications
- Reversible clamping on different types of leaves
- Diffusion and release of active ingredients directly into the vascular tissue of the leaves, for the release of drugs, for example, ideal for treating plant diseases
- Intelligent sensor to integrate on plants, for example to monitor their health status
Advantages
- Does not require the use of expensive technologies and machinery for its production; moreover, the material that makes up the micro-hooks has enormously lower costs compared to similar materials (e.g. silk fibroin)
- Fully biodegradable and ability to dissolve quickly enough inside the leaf tissue
- Multifunctional monitoring of different parameters (light, temperature, humidity) both in the abaxial and adaxial part of the leaf