Biopixels: Bioluminescent Bacteria on Duty

Bangalore:  A group of researchers from the University of California San Diego has engineered a genetically powered lightning system by inserting a protein into the E. coli bacteria which causes the bacteria to fluoresce. When these bacteria’s are accumulated in a colony they act as a light source, just like the pixels on the screen. ‘Biopixel’ comprises of about 500 such individual bacteria clubbed into one colony. These Biopixel are engineered to make a display as big as 13,000 Biopixels.

These living Neon Signs are sensitive to many toxic substances like heavy metal pollutants and disease-causing organisms. Scientists believe that these biological sensors will detect the harmful substances more promptly than other chemical sensors. During the tests Biopixel successfully detected arsenic by blinking on and off. To make the blinking more synchronized and unanimous researchers has designed a microfluidic chips to make the gas flow between colonies and makes the bacteria interact with each other using the  quorum sensing mechanism  in which bacteria communicate with their fellows and gives them group-like behavior.

Jeff Hasty, a professor of biology and bioengineering at UC San Diego who headed the research team in the university’s Division of Biological Sciences and BioCircuits Institute says “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. The colonies are synchronized via the gas signal, but the cells are synchronized via quorum sensing. The coupling is synergistic in the sense that the large, yet local, quorum communication is necessary to generate a large enough signal to drive the coupling via gas exchange”.

It is expected that within five years researchers will develop a small hand held sensor which will detect the existence and concentration of various toxic substances and disease-causing organisms in the field by reading the oscillations of the bacteria on disposable microfluidic chips.