A Nanoscale Tic-Tac-Toe Board Game Made Of DNA

  • Researchers create world’s smallest tic-tac-toe board game using dynamic DNA origami technology. 
  • The technology could make it possible to modify and repair various parts of nanoscale machines. 

In biological systems, the dynamic interactions between tortuous molecular structures underlie a variety of sophisticated behaviors. The most difficult challenge in constructing artificial molecular machines out of DNA is the development of mechanisms that can effectively control the kinetics of interacting DNA and compose these interactions together to perform system-level functions.

In 2017, a research team at California Institute of Technology used a decade old technology called DNA origami to develop configurable tiles that could self-assemble into bigger nanostructures.

They created the tiniest version of Mona Lisa. Although this achievement was quite impressive, the technology had one major limitation: you can’t simply change the image.

This time, they have made another leap forward with the technology. The team has build more dynamic DNA tiles and demonstrated them in the form of a tic-tac-toe board game in which players place their O’s and X’s by adding tiles to the board.

In other words, researchers developed a new method to configure the dynamic interactions between DNA structures. Using this method, they built the world’s smallest tic-tac-toe board game, where each move involves swapping hundreds of DNA strands simultaneously.

How This Swapping Mechanism Works?

The method relies on two DNA nanotechnologies: strand displacement and self-assembling tiles. Both leverage the DNA’s ability to be configured through certain arrangements of its molecules.

A single strand of DNA contains four types of molecules (bases). They are abbreviated as A, C, G, and T. They can be linked in any order, and each order contains unique information, which can be further used by artificial nanomachines.

Read: 26 Intriguing Facts About DNA You Probably Didn’t Know

Usually, these molecules tend to pair up with their counterparts. For example, C pairs with G, and A pairs with T. The strand displacement technology utilizes this natural behavior of DNA, and forms an extended sequence of bases that can be paired with a complementary sequence.

For instance, TAATCGT can be easily paired with ATTAGCA. However, it’s possible to pair a sequence with a partially matching sequence.

If TAATCGT and ATTAGCA were placed together, their TATT and ATTA parts would easily pair up, while the non-matching part would be disconnected from the ends. The bond between two strands would be stronger if they complement each other more closely.

Reference: Nature Communications | doi:10.1038/s41467-018-07805-7 | Caltech

The other DNA nanotechnology, self-assembling tiles, helps each tile to assemble in a particular spot, where no other tile can be placed. Combination of both these technologies results in tiles that can pinpoint their appointed location in a nanostructure and then replace the tile that already occupies that spot.

Results

Players could place an O or X in any empty spot (within a solution of blank board game tiles in a test tube) by using new dynamic tiles that are programmed to go where they wanted. It took 6 days for player X to win one round of the game.

Of course, no one will buy this tiny and extremely slow tic-tac-toe board, but that’s not really the point. The objective is to apply this technology in building nanostructures that can be modified in later stages.

Read: Programmed DNA Nanorobots Can Reduce Tumor

At present, it’s quite impossible to alter or repair a nanoscale machine but the new mechanism can change this. In the future, it can be used to repair and upgrade various portions of nanoscale machines, making them more sophisticated and efficient.

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