Scientists create living LED screens out of glowing bacteria

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Here’s some cool news for people who love anything that glows in the dark: Scientists at UC San Diego have figured out how to make millions of fluorescent E. coli bacteria flash all at once, creating a sort of living LED screen.

Jeff Hasty, a professor of biology and bioengineering who headed the research team in the university’s Division of Biological Sciences and BioCircuits Institute, said it took him and his team about five years and a series of papers to develop what he calls the ‘biopixels’ that make up the living LED screen.

Back in 2008 Hasty and his team published a paper that showed how they built a biological clock inside a single bacterial cell that would tell the bacteria when to produce a flashing, glowing light.

In a second paper published in 2010 they showed they could synchronize thousands of bacteria in the same colony to blink on and off in unison.

The next step was to find out if they could get bacteria in different colonies to blink on and off at the same time.

‘We were wondering if we could get the bacteria to communicate over large distances,’ Hasty said.

A long distance in the bacterial world might be 1 centimeter, he added.

As it turned out, they could communicate over long distances by having the bacterial cells create a vapor that allows the different colonies to communicate with each other almost instantaneously.

And so the living LED screen was born.

It’s all on a very micro scale right now. So far, the scientists have made screens -- or chips -- of two sizes. The larger chip contains about 13,000 colonies, or biopixels, (50 to 60 million bacterial cells) and is about the size of a paper clip. The smaller chip (pictured above) contains about 2.5 million cells -- or 500 colonies -- and is about a 10th of the size of the larger chip.

Hasty said his team could eventually get the bacteria to communicate over by another order of magnitude.

We wondered if the ability to program bacteria to light up at will might make its way into a living neon signs -- no electricity needed.

‘There is nothing that would preclude a company from making a beer sign out of these, but I’m not sure how marketable that is given that a bar would have a sign full of living bacteria hanging in its window,’ Hasty said.

He and his team have other applications for their living LED screen in mind. They have been able to engineer a simple bacterial sensor that can detect low levels of arsenic, and cause the bacteria to flash more quickly if arsenic is found.

‘So if you are in Bangladesh and you want to know if there is arsenic in your water, you could use a sensor made out of these chips,’ Hasty said. ‘That’s more the direction we are headed.’

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-- Deborah Netburn