Chemical Turing machine reads molecular tape

Chemists have created a molecular ratchet that acts as a simple chemical Turing machine. It consists of a macrocycle reading out chirality information as it moves along a molecular thread.

A Turing machine reads and writes symbols on a memory tape while moving forward and backward on the tape. Its actions are controlled by rules that define what to do for each combination of its current state and symbol that it is reading. It is an abstract description of computation, that, while simple, is capable of implementing any computer algorithm. While there are DNA-based Turing machines, completely synthetic molecular versions don’t exist yet.