x 10 4 counts/mm 2 ) were obtained, demonstrating a homogeneous distribution of catalase in the DNA structure (Figure ). Such a homogeneous distribution was also confirmed by analysis of the signals from the enzyme and DNA tiles along the DNA structure (homogeneity factor: 0.8 ± 0.1) (Figure ). Finally, we also found a high degree of co-localization of catalase with the DNA structure in this case (co-localization factor = 0.9 ± 0.1) (Figure ). Next, we examined the motility of the catalase-DNA swimmers when exposed to 1.5% H2O2 (see Supporting Videos 4 and 5). The nanoswimmers showed longer trajectories (Figure ), higher MSD (Figure ), higher effective diffusion coefficient (Figure ), and speed (Figure ). Similar to the case of urease nanoswimmers, we found a value of the MSD exponent of 1< α < 2 (see Supporting Figure ) for the nanoswimmers in presence of fuel. For this reason, we decided to analyse both effective diffusion coefficient and effective speed. The average effective diffusion coefficient for catalase DNA swimmers without fuel was 0.6 ± 0.3 µm 2 /s (mean ± SD), whereas the effective diffusion coefficient increased to 0.9 ± 0.6 µm 2 /s in the presence of propellant. As for the effective speed, a mean value of 0.5 ± 0.2 µm/s was observed for the nanoswimmers exposed under control conditions, which increased to 0.9 ± 0.4 µm/s. Both the increase in effective diffusion coefficient and effective speed were statistically significant (P < 0.05).