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Caltech scientists used DNA to play the world’s tiniest game of tic-tac-toe

Qian Lab: World's Smallest Tic-Tac-Toe Board Built from DNA

Wondering which penny-pinching family member will hand out the smallest gifts this holidays? It would be hard to beat the one California Institute of Technology (Caltech) researchers just gave the world — with the tiniest ever version of the game tic-tac-toe. Having previously used nanoscale bioengineering to create a replica of the iconic Mona Lisa, this year the Caltech team has followed up by creating a DNA-based version of everyone’s favorite time-wasting pen-and-paper game.

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“In DNA nanotechnology, displacement between small DNA strands has been widely used to control dynamic behaviors in molecular circuits and robots,” Philip Petersen, one of the researchers on the project, told Digital Trends. “In this study, we invented a new mechanism to program displacement between large DNA tiles, which opens up the possibility to create nanomachines with complex yet reconfigurable parts.”

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The team’s tic-tac-toe board is self-assembled from nine DNA origami tiles. Each tile has a special “glue” on the edges which lets it stick to the right neighboring tiles on the board. The glues are made of a set of DNA strands which bind to one another in specific ways. Players make a move by adding a DNA origami tile, labeled either “X” or “O”, into the test tube containing the game board. Each player has nine tiles for nine possible moves. These tiles can then be used to swap out previous tile to occupy their location on the game board.

Caltech

Being able to program the appearance of these nanoscale tiles by rearranging DNA molecules is pretty darn impressive. But what makes it more exciting is what this proof of concept could mean for the future of nanotechnology.

“Man-made machines are often built from modular components that can be swapped in and out whenever necessary,” Lulu Qian, Assistant Professor of Bioengineering, told us. “For example, when a computer cluster has a hard drive failure, a hot-swap disk can be used to replace the busted one and fix the problem without even turning off the computer. When a digital camera is filled up with photos during a long trip, the memory card can be easily swapped with another… The capability to efficiently reconfigure a complex part of a machine is important under a variety of circumstances, including repair, replenish, upgrade, and repurpose the functions of the machines.”

In the future, nanoscale machines built out of molecules will also need to have reconfigurable modular modular components. To make this possible it will be essential to figure out how to do this by programming in self-reconfiguration. Thanks to Caltech, we’re one step closer.

A paper describing the research was recently published in the journal Nature Communications.

Luke Dormehl
Former Digital Trends Contributor
I'm a UK-based tech writer covering Cool Tech at Digital Trends. I've also written for Fast Company, Wired, the Guardian…
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