Plants that can send emails, warn us about climate change — All about plant nanobionics

Coimbatore: In a latest advancement in the emerging field of plant nanobionics — an experimental research that involves using electronic sensors on plants — engineers at the Massachusetts Institute of Technology (MIT) have managed to fit spinach plants with sensors that are capable of sending emails when toxic pollutants accumulate inside plants.

Using a combination of carbon nanotubes and infrared cameras, the plant has been programmed to send an email whenever it senses the presence of toxic chemicals in the soil. The spinach roots can detect the presence of toxic material in groundwater.

The experiment was intended to discover explosives, but the engineers have said that such systems can be tweaked to warn us about dangers associated with climate change and pollution, as plants are highly sensitive to ecological changes.

The research is part of a 2016 study, published in the journal Nature Materials, but it made news only earlier this week after a Euronews report covered the research along with another new study from the MIT.

Toxic compounds called nitroaromatics, which are found in industrial emissions and explosives, often seep into the ground and enter plant bodies. When transpiration (water loss from leaves), occurs, these chemicals get accumulated in mesophylls — tissues present in the thick central part of leaves.

The engineers had implanted single-walled carbon nanotubes equipped with fluorescent nanosensors inside leaf mesophylls. When nitrogen dioxide, the toxic pollutant tested in the experiment, accumulated inside a leaf, a signal was emitted which in turn triggered a pre-programmed email alert.

Since plants are quick to pick up and react to environmental changes, researchers have also said that plant nanobionics could be used to monitor the environment.

Using similar technology, scientists had earlier also ‘taught‘ plants to take selfies by harvesting energy from photosynthesis. Plants convert sunlight to energy using photosynthesis through which they produce glucose and oxygen.

Microorganisms and bacteria present in the soil then break down this glucose, releasing more energy in the form of protons and electrons. This energy ultimately triggers a camera that takes a ‘selfie’ of the plant.

Such release of energy also leads the plant to function as a fuel cell, and theoretically a more promising, clean source of energy, especially for vehicles.

Spinach as fuel cells

In a new and more recent research by another MIT team, it was found that powdered spinach can be used as a source of carbon, iron, and nitrogen for preparing carbon nanosheets. Since spinach is high in iron and nitrogen, which are catalysts for oxygen reduction reactions that produce energy in fuel cells, the carbon nanosheet cells were found to be more efficient.

Fuel cells such as these metal-air batteries, are also more energy efficient than traditional lithium-ion batteries. Using powdered spinach as a catalyst showed not just increased energy output but also long-term stability. The plants were found to be non-responsive to methanol too, which affects traditional cells.

Netizens on social media, meanwhile, came up with several entertaining reactions to the idea of spinach plants sending emails.

Scientists have taught spinach to send emails #wfh pic.twitter.com/pMYNoAnDdf

— TwistedDoodles (@twisteddoodles) February 2, 2021

Finally. I was going to scream if spinach insisted on another meeting that should have been an email. https://t.co/L6vsoA2a8S

— Ambrose Persimmon (@MrPersimmon) February 1, 2021

Length of spinach's email.
vs
Content in spinach's email. pic.twitter.com/ZB1JoMHMZT

— Ólafur Waage (@olafurw) February 2, 2021

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