Biological Actuators

Natto is a strain of the bacterium Bacillus subtilis commonly used in Japan to make fermented soybeans known as nattō. Researchers from MIT have recent come up with a new novel use after discovering that the bacteria expanded and contracted based on the amount of moisture it was exposed to. After the initial observation, the researchers wondered if the bacteria could be carefully controlled to make it more predictable to the point where it could act like an actuator.

Growing “Machines”

The process of putting those living actuators into a prototype, however, is still complicated. Billions of bacteria were carefully grown and monitored in bioreactors. They were cultivated for use in a micron-resolution printer. The finished films are a composite of cells sandwiched by Kapton and plastic. The team still had to use 3D computer models to simulate the reaction of the bacteria in different printed designs. The chosen designs were then given to designers at the Royal College of Art who integrated them into clothing using heat maps of where the human body sweats the most and gets the hottest during exertion. The design students then created a series of garments for dancers using fin-shaped pieces of the film that raise and lower to create airflow through the clothing.

For the MIT team, the natto bacteria project is just a start. They are keen on unveiling and harvesting responsive behaviors of microorganisms and repurposing them for design. They hope to take advantage of the special characteristics of the microbes to create "biological machines."

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