Team uses CRISPR to build the world’s smallest tape recorder

24 Nov 2017

Conceptual rendition of the CRISPR tape recording system. Image: Wang Lab/Columbia University Medical Center

Microbes within the human body could soon be used to record biological data, thanks to a new breakthrough using CRISPR.

When it comes to much-anticipated technological revolutions, few are as big as CRISPR, a method whereby genetic mutations can be ‘cut’ out and modified in a cell so that they don’t carry a hereditary disease into childhood.

But now, the method is being used to convert a natural bacterial immune system into a microscopic data recorder that could one day create a class of bacterial technologies for disease diagnosis and environmental monitoring.

In a paper published to the journal Science, the Columbia University Medical Center research team explained that it achieved this by modifying an ordinary strain of the ubiquitous human gut microbe Escherichia coli.

This enabled the bacteria to not only record their interactions with the environment, but also time-stamp the events.

As CRISPR copies snippets of DNA from invading viruses to prevent further pathogens from developing, it creates a chronological record of the bacterial viruses that it and its ancestors have survived.

When those same viruses try to infect again, the CRISPR system can recognise and eliminate them, making it ideal for recording data.

The CRISPR tape recorder in action. GIF: Wang Lab/Columbia University Medical Center

Unprecedented view of our body

So, in this case, the team 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, while a separate recording plasmid drives the recorder and marks time.

When there is no external signal, the recording plasmid stays active, adding a space sequence. When the recorder is switched on by an external signal based on a cell’s environment, the other plasmid activates to insert its sequence instead.

The researchers can then examine the bacterial CRISPR locus and use computational tools to read the recording and its timing.

Speaking of its potential, senior author on the paper, Harris Wang, said: “Such bacteria, swallowed by a patient, might be able to record the changes they experience through the whole digestive tract, yielding an unprecedented view of previously inaccessible phenomena.”

Colm Gorey was a senior journalist with Silicon Republic