An On‐Demand Microrobot with Building Block Design for Flow Manipulation

The ability to precisely maneuver miniature objects in flow through a well‐controlled manner is envisaged to have an extensive impact in micro manipulation for profound medical and biological applications. In this work, the magnetic microrobots are fabricated by employing a distinct block‐to‐block approach in which the microrobotic structures are developed using several magnetic and nonmagnetic blocks. To demonstrate the on‐board control strategies of the microrobots, two distinct modes of motion are introduced and actuated with the aid of the developed in‐house electromagnetic system. To delve into the physics of microrobot locomotion, theoretical and numerical investigations are performed that further provide practical relevance for extensive applications with profound reliability. A mixing task is conducted to elucidate the enriched controllability of the microrobot in furnishing an on‐demand flow agitation function with high efficiency. Furthermore, the directions of such mixing are engineered using the proposed modes of motion which can unlock the possibilities to precisely control the directional inhomogeneities of the fluids encountered in diversely microfluidic systems. Aside from it, the multidimensional controllability of the microrobot motions exhibiting distinct flow behaviors is further demonstrated to precisely disperse the particles suspended in the fluid medium. Subsequently, such behaviors combined with the adaptive modes of microrobot motion can be potentially employed as one of the strategies to prevent the fouling problems encountered in several microfluidic applications. The presented work provides the feasible functions of the microrobots where they can play a pivotal role in dampening their functional limitations inherent in dynamic environment, and pave to emerge as fully autonomous microrobots for future engineering applications. A simple fabrication method is proposed to fabricate the microrobots based on the building block approach for superior flow manipulation. With an in‐house eight‐coil electromagnetic system the microrobots are actuated in representative motions such as rotation and swinging for better hydrodynamic performance. In addition, these motions exhibit several flow‐induced functionalities such as adaptive‐directional mixing and non‐contact particle removing which are demonstrated through the conducted mixing and particle manipulation tasks, respectively.