The DNA structural scaffold used in this work is a well-characterized hollow tubular micrometer-scale structure formed by the interaction of specifically designed DNA tiles at room temperature. Such DNA tiles are formed by hybridization of five different DNA strands that have 4 sticky ends responsible for self-assembly. To directly visualize the assembled tubular structures, we conjugated a Cy3 fluorophore to the 5' end of one of the tile-forming strands. We then engineered another tile-forming strand to have an addressable 30-nucleotides (nt) singlestranded anchor domain that can be used for enzyme functionalization of the structure (Figure ). The assembled structures can be conveniently imaged by fluorescence microscopy and have an average length and count of 4.9 ± 0.3 µm and 5.2 ± 0.2 x 10 3 count/mm 2 , respectively (Figure , right).