In Brief
Scientists from the University of Washington have constructed digital logic gates in living cells. Though they're not the first to do so, the researchers' living circuitry is the largest and most complex of any created thus far.

Living Circuits

Thanks to projects like Elon Musk’s Neuralink, a future in which humankind merges with machines is on everyone’s minds. While a brain computer interface (BCI) like the one Musk is proposing would involve making a computer function as part of a human body, other researchers are taking an opposite route. Instead of making machines that can imitate biology, they’re looking for ways to make biological systems function more like computers.

One such project is the topic of a study by researchers from the University of Washington (UW) that was just published in Nature Communications. They have developed a new method of turning cells into computers that process information digitally instead of following their usual macromolecular processes. They did so by building cellular versions of logic gates commonly found in electric circuits.

Image credit: University of Washington
An artist’s impression of connected CRISPR-dCas9 NOR gates. Image credit: University of Washington

The team built their NOR gates, digital logic gates that pass a positive signal only when their two inputs are negative, in the DNA of yeast cells. Each of these cellular NOR gates was made up of three programmable DNA stretches, with two acting as inputs and one as an output. These specific DNA sequences were targeted using CRISPR-Cas9, with the Cas9 proteins serving as the molecular gatekeeper that determined if a certain gate should be active or not.

Controlling Cellular Function

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This UW study isn’t the first to build circuits in cells, but it is the most extensive one to date, with seven cellular NOR gates in a single eukaryotic cell. This added complexity puts us one step closer to transforming cells into biological computers with a number of potential medical applications.

“While implementing simple programs in cells will never rival the speed or accuracy of computation in silicon, genetic programs can interact with the cell’s environment directly,” senior author Eric Klavins explained in a press release. “For example, reprogrammed cells in a patient could make targeted, therapeutic decisions in the most relevant tissues, obviating the need for complex diagnostics and broad spectrum approaches to treatment.”

If given the ability to “hack” our biology in this way, we could potentially engineer immune cells to respond to cancer markers or cellular biosensors to diagnose infectious diseases. Essentially, we’d have an effective way to fight diseases on the cellular level, ushering in a new era in human evolution.