While one might anticipate a potential decrease in the coverage efficiency due to the change of the geometry from 0D to 1D nanostructures, we observed a uniform coating of the magnetic biotemplates with the nanorods throughout the entire helical structures (Figure ). Unlike photocatalytic propelled swimmers, which exhibit random motion in solutions, the integration of COF-300 nanoparticles into magnetic 3D structures allows for controlled and guided motion. Due to the helical shape of the biotemplate and the incorporation of Fe3O4 nanoparticles, an external rotating magnetic field perpendicular to the long axis of the COFBOTs can induce a corkscrew rotating motion which translates into a net displacement of the COFBOTs in water (Figure ). At a rotating magnetic field of 15 mT and a frequency from 7 Hz to 11 Hz, the COFBOTs start to move along the same axis. The minimum frequency required for corkscrew motion may vary among the microrobots due to the inherent size inhomogeneity of the Spirulina biotemplate. In addition, a 100 mT m -1 out-of-plane gradient is applied to prevent the microrobots from contacting the surface of the microfluidic channel, hence enabling a straight-line motion of the COFBOTs at a velocity of 695 µms -1 (Figure ).