Deformable ferrofluid microrobot with omnidirectional self-adaptive mobility

Magnetic soft robots have the potential to directly access areas of the human body that are currently inaccessible or difficult to reach for minimally invasive medical operations or drug delivery. Recently, ferrofluids containing magnetic nanoparticles with unique deformation properties have been extensively investigated. In this study, a ferrofluid robot for targeted drug delivery is proposed, while the control of ferrofluid robots is implemented in a 3D vascular model. Four-solenoid control systems with visual feedback are designed to achieve said implementation. Through numerical simulation and actual measurement, the magnetic field gradient generated by the system can reach 4.14 T/m, and three-dimensional control of ferrofluid robots can be realized. The deformation ability of ferrofluid robots is investigated, and the ferrofluid robots are found to pass through slits four times smaller than the diameter of the ferrofluid robots. Also, the deformation of the ferrofluid robots can reduce the drag force in the flow field by 43.75% through finite element simulation. The maximum control error does not exceed 0.3 mm. Finally, the coil system controls a ferrofluid droplet to achieve autonomous motion in a 3D vascular model with a maximum internal diameter of 3 mm. The implementation of the control effect allows for the technical potential of ferrofluid robots in drug delivery through vascular navigation.