To gain more insights on the growth mechanisms in TANa buffer when compared to TAEMg buffer, we plotted the cumulative complementary distribution function (CCDF) of the nanotube length in each case (Figure ). These CCDF plots estimate the likelihood to find a nanotube larger than a given value. DNA nanotube length is expected to follow an exponential distribution , whose CCDF is a straight line in a semilogarithmic plot, as confirmed in Figures and. When normalized with respect to its average, any exponential CCDF should collapse on a straight line with slope -1 . While data for both TANa and TAEMg incubated nanotubes generally follow this trend (Figure , J), we note significant discrepancy with respect to the exponential model for TANa incubated nanotubes. In particular, during the initial phases of growth the system is less likely to present long nanotubes when compared to the exponential case, while at later phases it is more likely to produce long nanotubes. A possible explanation for this behavior is that TANa-assembled tiles may be initially less abundant, hindering polymerization; alternatively, nucleation events may be very frequent in TANa conditions due to the more dynamic interactions among DNA strands, which would result in a larger number of shorter nanotubes. At a longer timescale, we hypothesize that again the enhanced capacity of tiles to dynamically interact in TANa may promote end-joining of existing nanotubes, resulting in overall longer assemblies. We then verified that a different nanotube variant, including two distinct tiles (a total of ten DNA strands), assembles correctly in TANa buffer (Figure ). These tiles (dubbed SEp and REp by Rothemund ) have mutually complementary sticky ends that result in the assembly of nanotubes with parallel "rings" of distinct tiles (Figure ). Surprisingly, the average length of these nanotubes does not increase as much as in the single tile case, although trends for the length histograms, length fractions, and CCDF plots are consistent with the single tile case when compared with tiles annealed in TAEMg (Figure ). We hypothesize that the lack of sustained growth may be due to a loss of end-joining capability introduced by "irregular" growth edges when the parallel rings are incomplete. Interestingly, the TANa buffer allows the growth of the nanotubes with or without prior incubation of the strands to form the tiles (Figure ).