Snaked Proofreading

In , Chen and Goel demonstrated a tile set transformation which provided improvements over the previous proofreading technique. In fact, their snaked proofreading technique not only provides substantial improvements in error correction, it also provides for "provably good" assembly time, or specifically that it allows for close to linear assembly time (within a logarithmic factor of irreversible error-free growth). Snaked proofreading relies on a block replacement scheme similar to the proofreading of Winfree and Bekbolatov , but with a different internal bond structure. An example of the difference can be seen in Figure 1 (below). The general technique is to force multiple insufficient attachments to occur and be locked into place before an error can persist.

Especially notable is the fact that snaked proofreading does not only provide benefits in simulations of the kTAM, but in Chen, Schulman, Goel, and Winfree actually created a tile set which utilized the technique and experimented with it in a wet-lab setting. They created tile sets which self-assembled into long ribbons, some which were designed to implement snaked proofreading and some which were not, and were able to verify via atomic force microscopy that the snaked proofreading tile sets experienced a 4-fold reduction in facet nucleation errors.

A tile type from the original, unaltered tile set.

The block used as a replacement in standard proofreading.

The block used as a replacement in snaked proofreading.

Figure 1. A comparison of the block replacement transformations used in standard proofreading and snaked proofreading