Researchers have converted a natural bacterial immune system into the world’s smallest data recorder, laying the groundwork for a new class of technologies that use bacterial cells for everything from disease diagnosis to environmental monitoring.
The researchers at the Columbia University Medical Center (CUMC) in the U.S. modified an ordinary laboratory strain of the ubiquitous human gut microbe Escherichia coli, enabling the bacteria to not only record their interactions with the environment but also time-stamp the events.
Other applications could include environmental sensing and basic studies in ecology and microbiology, where bacteria could monitor otherwise invisible changes without disrupting their surroundings, according to the study published in the journal Science.
Mr Wang and his team created the microscopic data recorder by taking advantage of CRISPR-Cas, an immune system in many species of bacteria. CRISPR-Cas copies snippets of DNA from invading viruses so that subsequent generations of bacteria can repel these pathogens more effectively.
As a result, the CRISPR locus of the bacterial genome accumulates a chronological record of the bacterial viruses that it and its ancestors have survived.
When those same viruses try to infect again, the CRISPR-Cas system can recognise and eliminate them.
To build their microscopic recorder, the researchers modified a piece of DNA called a plasmid, giving it the ability to create more copies of itself in the bacterial cell in response to an external signal.