Fig. 5: Directional swimming and targeted transportation of PS/Au Janus particles with a feedback control method.

a Schematic illustration of directional swimming with feedback control on the experimentally recorded images, where a focused green laser beam and a defocused red laser beam were employed for navigating and driving the swimming, respectively. b Flow chart of the feedback control method. c Optical setup and mechanical layout for the feedback control method. d Trajectories of 5 µm PS/Au Janus particles swimming in different directions. e Targeted delivery of a 5 µm PS/Au Janus particle to a 10 µm PS particle. A 5 µm 532 nm laser beam with a power of 2.6 mW was used to drive the rotation, while a 660 nm laser beam with a beam size of 31 µm and a power of 160–200 mW was applied to drive the swimming