When an artist, a designer and seven Cambridge University biology undergraduates team up, what do you get? Purple poop. Or yellow, or green, or red, or blue.
Those who maybe inclined to pooh-pooh such an idea should know that the technology developed by one such collaboration of artists and scientists goes well beyond giving the ho-hum stool sample a punch of color
What they actually developed is E. chromi, an engineered strain of E. coli that secretes color in the presence of pollutants. Like many kinds of bacteria, E. coli are sensitive to environmental pollutants. By equipping them with a pigment-producing device that switches on in the presence of certain toxins, the team of scientists and artists created a way to use bacteria as an inexpensive, user-friendly biosensor.
For example, some E. chromi could be designed to turn blue in the presence of arsenic. Another possible application is a probiotic drink that would alert patients to possible ailments by coloring their poop. Purple poop might indicate the presence of a Salmonella infection, for example.
It may sound unusual, but it isn’t the only instance where bacteria have been used to create biosensors. Recently, scientists at the University of California San Diego (UCSD) attached a fluorescent protein to a colony of E.coli and synchronized it to blink on and off in unison like a neon sign. When the colony detected arsenic, it slowed its rate of flashing, alerting scientists to the presence of a dangerous toxin.
E. chromi won MIT’s International Genetically Engineered Machine Competition in 2009, was a finalist for the 2011 Index Awards, and a winner of the 2011 World Technology Awards. But it’s probably still a few years away from coming to a toilet near you.
