Movements of Magnetite-Encapsulated Graphene Particles at Air–Water Interface and Their Cell Growths under Dynamic Magnetic Field

Abstract

The motion of magnetic particles under magnetic fields is an object to be solved in association with basic and practical phenomena. Movement phenomena of magnetite-encapsulated graphene particles at air–water interfaces were evaluated by manufacturing a feedback control system of the magnetic field to cause the motion of particles due to magnetic torque. A homogeneous magnetic field was generated using two pairs of electromagnets located perpendicular to each other, which were connected to an electronic switch. The system influenced the translational movement and the self-rotational speed of magnetic particles located at a center on the surface of fluid media in a continuous duty cycle. Operating the particle at a remote control in the same duty cycle at the air–water surface, the short and elongated magnetic particles successfully rotated. In addition, the rotational speed of the curved particle was slower than that of the elongated particle. The results indicate that the translational and self-rotational movements of magnetite-encapsulated graphene particles at the air–water interface under the external magnetic field are size- and shape-dependent for the speed and the direction. A short magnetic particle was used as a target particle to rotate on cancer cell lines, aiming to study the advantage of this method to induce the growth of HeLa cells. It was monitored for up to 4 days with and without magnetic particles by checking the viability and morphology of cells before and after the electromagnetic treatment. As an outcome, the movement of magnetic particles reduced the number of biological cells, at least on HeLa cells, but it was inactive on the viability of HeLa cells.