Maya II, or the Molecular Array of YES and AND logic gates, employs hairpin-shaped DNA strands as 128 logic gates, functioning as an equivalent number of transistors. Their molecular computer is capable of beating human opponents at tic-tac-toe.
Imagine losing tic-tac-toe to DNA in a cell culture plate
Molecular component research has previously illustrated the feasibility of creating transistor-type gates, but "the ability to integrate molecular components remains crucial" for actually producing molecular-based devices, says Joanne Macdonald, an associate research scientist at Columbia.
Macdonald sees DNA logic gates, unlike silicon transistors, as being programmable to work inside the body or other living organisms and carry out highly specified functions, such as detecting low blood sugar or releasing insulin when needed.
Unlike electricity-based computing, molecular computing can float in a solution, conceivably inside the body's bloodstream, with chemical reactions generating the inputs and outputs of the system.
Maya II's DNA strands have been preprogrammed to react in a predictable way when a human tic-tac-toe player adds a strand to a set of test tubes. Nine test tubes are set up in the shape of a tic-tac-toe board. As the human player makes a move by adding a particular DNA strand, one of the tubes contains DNA that will react to the addition. Maya II even registers the move as one DNA strand splits another in two, causing the substrate in which they float to fluoresce with green light.
Maya II isn't fast since its moves are based on slow chemical reactions. Each can take 30 minutes.