27 February 2021



Engineers develop precision injection system for delivering life-saving treatments to plants ravaged by such diseases.

3 min read

A microinjection device (red) is attached to a citrus plant, providing the way of injecting pesticide or other materials directly into the plant’s vascular system. – Images: Courtesy of the researchers.

While the world is reeling from COVID-19 pandemic, there are several ongoing epidemics that affect crops and put risk upon the global food production.

A new method developed by engineers at MIT. The MIT team decided to require a number of the principles involved in precision medicine for humans and adapt them to develop plant-specific biomaterials and drug-delivery devices.

Professor Benedetto Marelli
Professor Jing-Ke-Weng

In the journal Advanced Science, a paper published by MIT professors Benedetto Marelli & Jing-Ke-Weng, the graduation student Yunteng Cao , postdoc Eugene Lim at MIT, & postdoc Menglong Xu at the Whitehead Institute for Biomedical Research.

The Microneedles made from silk-based material can target plant tissues for delivery of micronutrients, hormones, or genes to specific parts of the plant.

The microneedles, which the researchers call phytoinjectors, are made during a very form of sizes and shapes, and will deliver material specifically to a plant’s roots, stems, or leaves, or into its vascular Bandles.

The plant of tomato , used in the team’s experiments to prove the effectiveness of their microinjection system, has one of the devices, in red, attached to a stem of tomato. – Images: Courtesy of the researchers

In lab tests, the team used tomato plants and tobacco plants, but the system might be adapted to almost any crop, they say.
The microneedles can’t only deliver targeted payloads of molecules into the plant, but they will even be accustomed take samples from the plants for lab analysis.

The ideas on the way to address the citrus greening crisis, which is threatening the collapse.
The disease is spread by an insect called the “Asian citrus psyllid” that carries a bacterium into the plants.

Asian citrus psyllid
  • The disease infects the phloem of the entire plant, including roots, which are very difficult to succeed in with any conventional treatment, Marelli explains.
  • Most pesticides are simply sprayed or painted onto a plant’s leaves or stems, and small if any penetrates to the root system.
  • Such treatments may appear to figure for a brief while, on the other hand the bacteria regain and do their damage.
  • What is needed are some things which will target the phloem circulating system through a plant’s tissues, which could carry an antibacterial compound down into the roots. That’s just what some version of the new microneedles could potentially accomplish, he says.

The microneedles designed for human use were intended to biodegrade naturally within the body’s moisture, but plants have far less available water, therefore the material didn’t dissolve and wasn’t useful for delivering the pesticide or other macromolecules into the phloem.
The researchers had to style a replacement material, but they decided to stay with silk as its basis.

They used biotechnology tools to extend silk’s hydrophilicity (making it attract water), while keeping the fabric strong enough to penetrate the plant’s epidermis and degradable enough to then get out of the way.

Sure enough, they tested the material on their lab tomato plants and tobacco plants, and were able to observe injected materials, during this case fluorescent molecules, moving all they way through the plant, from roots to leaves.

So far, this can be a lab technique using precision equipment, so in its present form it’d not be useful for agricultural-scale applications, but the hope is that it is used, as an example, to bioengineer disease-resistant types of important crop plants.

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