Automatic Molecular Weaving Prototyped Using Single-Stranded DNA**

One of the goals of molecular-based nanoscience is the organization of matter into strong molecular structures that display the advantageous properties of analogous macroscopic structures.[1] A woven fabric is an example of such a macroscopic structure, but deliberately braided woven molecules have not been reported, because nodes of designated[2] and alternating signs must be placed specifically. Owing to its double helical structure, DNA is an ideal programmable molecule to build synthetic topological targets.[3] A half-turn of DNA, about six nucleotide pairs, corresponds to a node or a crossing point in a knot or a catenane.[4] Deliberate trefoil knots,[5,6] a figure-8 knot,[7] polyhedral catenanes,[8,9] specifically linked electrophoretic mobility standards,[10] and Borromean rings[11] are examples of previous DNA topological constructs. Nevertheless, a woven arrangement requires an even greater level of control over the placement of nodes. Here, we have prototyped a planar woven arrangement, using the B-DNA conformation for all nodes by strategically combining D-nucleotides and L-nucleotides. This work represents the first step on the way to automatic molecular-scale weaving. A previous use of L-nucleotides in DNA nanotechnology has been reported,[12] indicating that opposite-handed deviations from idea