A living neon sign made of millions of glowing bacteria

In an example of life imitating art, biologists and bioengineers at UC San Diego have created a living neon sign composed of millions of bacterial cells that periodically fluoresce in unison like blinking light bulbs.

Their achievement, detailed in this week’s advance online issue of the journal Nature, involved attaching a fluorescent protein to the biological clocks of the bacteria, synchronizing the clocks of the thousands of bacteria within a colony, then synchronizing thousands of the blinking bacterial colonies to glow on and off in unison.

A little bit of art with a lot more bioengineering, the flashing bacterial signs are not only a visual display of how researchers in the new field of synthetic biology can engineer living cells like machines, but will likely lead to some real-life applications.

Using the same method to create the flashing signs, the researchers engineered a simple bacterial sensor capable of detecting low levels of arsenic. In this biological sensor, decreases in the frequency of the oscillations of the cells’ blinking pattern indicate the presence and amount of the arsenic poison.

Because bacteria are sensitive to many kinds of environmental pollutants and organisms, the scientists believe this approach could be also used to design low cost bacterial biosensors capable of detecting an array of heavy metal pollutants and disease-causing organisms. And because the senor is composed of living organisms, it can respond to changes in the presence or amount of the toxins over time unlike many chemical sensors.

Jeff Hasty, a professor of biology and bioengineering at UC San Diego, headed the research team in the university’s Division of Biological Sciences and BioCircuits Institute. He said:

These kinds of living sensors are intriguing as they can serve to continuously monitor a given sample over long periods of time, whereas most detection kits are used for a one-time measurement. Because the bacteria respond in different ways to different concentrations by varying the frequency of their blinking pattern, they can provide a continual update on how dangerous a toxin or pathogen is at any one time.

Each of the blinking bacterial colonies comprise what the researchers call a “biopixel,” an individual point of light much like the pixels on a computer monitor or television screen. The larger microfluidic chips contain about 13,000 biopixels, while the smaller chips contain about 500 pixels.

Hasty said he believes that within five years, a small hand-held sensor could be developed that would take readings of the oscillations from the bacteria on disposable microfluidic chips to determine the presence and concentrations of various toxic substances and disease-causing organisms in the field.

Bottom line: Biologists and bioengineers at UC San Diego have created a living neon sign composed of millions of bacterial cells that periodically fluoresce in unison like blinking light bulbs. Because bacteria are sensitive to many kinds of environmental pollutants and organisms, the scientists believe this approach could be used to design low cost bacterial biosensors capable of detecting heavy metal pollutants and disease-causing organisms.

Bottom line: A team of scientists has created a living neon sign composed of millions of bacterial cells that periodically fluoresce in unison like blinking light bulbs.

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