Rather than blinking light bulbs, these flashing neon signs have millions of bacteria that will periodically fluoresce in unison.
Cool looking, yes. But since bacteria are sensitive to many kinds of environmental contaminants and organisms, this could also be 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 toxins over time – unlike many chemical sensors.
The researchers describe it as “a liquid crystal display (LCD)-like macroscopic clock.”
The University of California, San Diego team led by Jeff Hasty attached a fluorescent protein to the biological clocks of the bacteria. “Many bacteria species are known to communicate by a mechanism known as quorum sensing,” Hasty says, “that is, relaying between them small molecules to trigger and coordinate various behaviors.”
This synchronizes the clocks of thousands of bacteria within a colony, then synchronizes thousands of blinking bacterial colonies to glow on and off in unison. Watch a cool video here.
It’s done using tiny microfluidic chips, and each blinking E. coli colony makes up a biopixel (pictured right) – like the individual points of light on TVs.
Smaller chips (pictured above) contain about 2.5 million cells and 500 biopixels. Larger chips (pictured below) contain up to 60 million bacteria and about 13,000 biopixels, and these’re about the size of a paper clip.
Using the same method to create signs, the researchers engineered a simple bacterial sensor capable of detecting low levels of arsenic. Decreases in the frequency of the oscillations of the cells’ blinking pattern indicate the presence and amount of the arsenic poison.
“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,” Hasty explains.
He believes that within 5 years, a small hand-held sensor could be developed to take readings of the bacteria on disposable microfluidic chips to determine the presence and concentrations of various toxic substances and pathogens in the field.
The work was published in Nature last month.
Via UCSD News.
Images: UCSD
