Figure 4.

“Seesaw effect” of twin-engine Janus supramolecular nanomotors (catalase/Janus stomatocytes) via precisely controlling the motion. Velocity, tracking trajectories, and MSD of catalase/Janus stomatocytes in the presence of 0 wt % H₂O₂ or 0.75 wt % H₂O₂, and irradiation with (A) 0 mW, (B) 30.1 mW, and (C) 35.7 mW NIR laser light. All scale bars in the tracking trajectories correspond to 50 μm. Inserted schematic figures display the motion behavior of catalase/Janus stomatocytes in response to the different conditions. In the absence of NIR (inset image in A), catalase/Janus stomatocytes exhibit the properties of regular enzyme-powered nanomotors, which move faster by increasing the concentration of hydrogen peroxide fuel. Upon NIR illumination (inset image in B), the photothermal effect around catalase/Janus stomatocytes results in motion in the opposite direction of the motion induced by the enzyme-driven pathway. Two opposing forces generated on catalase/Janus stomatocytes are counterbalanced under specific conditions, resulting in halting the motion of the twin-engine Janus motors (inset image in C).