Biologists and bio-engineers have created a living neon sign composed of millions of bacterial cells that periodically light up in unison like blinking bulbs.Their achievement involved attaching a fluorescent protein to the biological clocks of the bacteria, synchronising the clocks of the thousands of bacteria within a colony, then synchronising 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, the journal Nature reported.Using the same method to create the flashing signs, the researchers engineered a simple bacterial sensor capable of detecting low levels of arsenic, according to a California statement.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,’ said Jeff Hasty, professor of biology and bioengineering at University of California San Diego, who led the study.Because bugs are sensitive to many kinds of environmental pollutants and organisms, 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.