“Computer” may commonly mean an electronic device that processes a lot of complex information, but it’s worth remembering that the etymology of the word stems from the mid-17th century. Originally, it simply meant “one who calculates”, with no electronics required.
This little bit of history lends itself neatly to a peek into the future of computing. As first spotted by New Scientist, a team from ETH Zurich and the University of Basel are making headways on constructing biocomputers – those made from living cells – and a new paper, in Nature Methods, details their most advanced system to date.
Using nine different cell populations assembled into 3D cultures, the team of synthetic biologists has managed to get them to behave like a very simple electronic computational circuit. Take out the electrical wiring and signaling, and replace them with chemical inputs, and you’ve got a living computer that responds to incoming data and can process it using rudimentary logic gates AND, NOT, and OR.
All digital systems are based on logic gates. Through a NOT gate, for example, a binary input of 1 becomes a 0 at the output. This is all very, very basic stuff, but the fact that a team has managed to get a biological computer to do this is a remarkable achievement.
As far as they know, this achievement is unprecedented. There are several previous examples of biocomputer wizardry, but they’re far more basic: From using DNA to make working transistors to using jellyfish matter to create a bio-pixel display, these are still impressive, but nowhere near as advanced as this team’s logic gate work.
It’s understandable if this all sounds a little jarring, but remember, a computer is merely something that handles data. Our brains, far more complex than (and arguably incomparable to) computers, handle data all the time; we receive sensory stimuli, our neurons process it, and we react accordingly. Is it really so surprising that a handful of cells can act as a primitive computer?
This team had previously managed to get a couple of cells to perform basic addition tasks, but for this project, they made bespoke genetic programs for each of the nine individual human cell types involved in their biocomputer.
Disallowing them to respond to a wide array of biochemical signals, as they normally would, each was altered to execute just one, clearly defined computational instruction. This allowed the collective cells – the biocomputer – to perform “full-adder” calculations, which essentially means it can perform more detailed, interrelated sums simultaneously. By rearranging the cells, different types of calculations could be carried out.
There are wires here, in a manner of speaking, but unlike static copper ones, this system can “produce and sense chemical communication wires” to perform computational tasks. It's a remarkable system, one that has the potential to adapt and evolve.
Biocomputation is a nascent research field. It’s incredibly difficult to engineer a system like this, because biological matter is far more intricate and mercurial than copper circuitry. Forget simple addition, though: If efforts like this continue, expect to see implantable, living computers within animals – those perfectly integrable with their own biology – in the near future.
A 2009 paper spoke of a world in which these systems will be used to diagnose diseases and create “designer” cell functions within other lifeforms. Noting that “biocomputers are man-made biological networks whose goal is to probe and control biological hosts – cells and organisms – in which they operate,” it's clear that a brave new world is emerging from over the horizon.