When Art Meets Science, Purple Poop
Take one artist, one designer and seven Cambridge University biology undergraduates and what do you get? Purple poop.
Actually, what you get is E. chromi, an engineered strain of E. coli that secretes color in the presence of pollutants. Bacteria, such as E. coli, are sensitive to environmental pollutants. By equipping them with a pigment-producing device that switches on in the presence of various toxins, the team of scientists and artists created a way to use bacteria as an inexpensive, user-friendly biosensor.
These colorful bacterial colonies have a rainbow of potential applications as biosensors including a cheap, disposable biosensor for arsenic and probiotic drink that would alert patients to possible ailments by coloring their poop. A purple output may indicate the presence of a Salmonella infection, for example.
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. Although it may sound unusual, it isn’t the only example of a bacterial biosensor. Recently, scientists at the University of California San Diego (UCSD) attached a fluorescent protein to some E.coli and synchronized the colony to blink on and off in unison like a flashing neon sign. When the blinking colony detected low levels of arsenic, it slowed its rate of flashing.
