  The idea is a nanoscale extension of a sporting event called a `color run'.
The filament is wrapped with a DNA origami `barrel', which acts as the
nanoscale equivalent of a white t-shirt. The DNA t-shirt has dangling ss-DNA
`handles' that bind `tags' consisting of an `anti-handle' oligo bound to a
fluorophore. The tagging methodology exploits the recent development of
DNA-based `metafluorophores' with digitally tunable optical properties based on
a collection of fluorophores bound to a single DNA origami structure. In this
idea, the filament collects different color tags at `color-stations' as it
travels through the network. These contribute to a final DNA t-shirt color that
represents of the path taken. Readout is implemented through lenseless on-chip
imaging via pixels in a CMOS backplane located at read-out points in the
network. Color-stations are implemented via microfluidic channels on a dialysis
membrane, which feed tags into the network in localised areas. A chemical
countermeasure to prevent false tagging by stray tags that have drifted in from
other stations by exploiting strand-displacement technique is also proposed.
