Figure 2.

Principle of quantitative chemotactic analysis. A) Chemotactic behavior of the catalytic motors is quantified determining the opening angle β. Negative control experiments: B) non-catalytic fluorescent polystyrene particles in the gradient of hydrogen peroxide (10% H₂O₂ wt/wt in i1, 0% H₂O₂ in i3) do not experience chemotactic deviation of the motion towards fuel-rich area; Plot represents histogram from the opening-angle analysis for the non-catalytic particles, which shows zero opening angle. C) Catalytic tubular microjets, injected through the central inlet do not deviate (0% H₂O₂ in i1, 0% H₂O₂ in i3) if there is no fuel added to the solution. Histogram shows that majority of the motors do not experience any deviation. Injection flow rates are fixed to 140 μLh⁻¹.