Tuesday, June 20, 2017

DNA inspired baskets: Weaving Z- bent springs

Nanotechnologists are hard at work figuring out ways to self-assemble mechanical things from segments of DNA. The wire sculpture below gives an idea how they are able join several double-helix DNA molecules by strand-exchange. Such a structure can be self-assembled from a soup of single-stranded DNA if the single strands have uniquely complementary sequences, so that strands pair up as one intends.

The sculpture also reveals a mechanical weakness in using DNA in this scheme: strand exchange using double helices leaves a single-stranded section in the center of each strut where the splices are made.

Since, unlike DNA, at macro scale we are not limited to double helices, we can move up to triple helices. Triple helices can be joined with have a triple-stranded middle sections (see the octahedron in the top image) and splices near the ends of the strut where they cause less trouble mechanically.

Z-shaped segments can be used to make any mesh since every
edge has a unique clockwise neighbor at each end--automatically
giving a triple cover of each edge.

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