Gradient-enhanced Electromagnetic Actuation System with a New Core Shape Design for Microrobot Manipulation

Electromagnetic-based actuation is receiving increasing attention for driving microparticles, particularly for in vivo biomedical applications. In this article, we present a core shape design for electromagnetic coils to develop a magnetic gradient field-based actuation system that can enable microrobotic manipulation. Based on the mathematical model using the finite-element method, the shape of the iron core and the size of the probe are optimized, aiming to increase the gradient at the focused area. A thin disc is also attached to the end of the iron core for reducing the waste of magnetic field energy. Through this design, the magnetic field generated by the electromagnetic actuation system can be considerably enhanced to propel microrobots in the in vivo environments. The designed system is tested in different in vitro environments, including pure water, artificial cerebrospinal fluid, mouse blood, and a special environment with an extremely high viscosity coefficient. The system is also tested for driving microrobots in an in vivo environment, namely, zebrafish yolk. Experimental results effectively demonstrate the capacity of the designed platform in manipulating microrobots for in vitro and in vivo applications.