Biological cell manipulation by magnetic nanoparticles

We report a manipulation of biological cells (erythrocytes) by magnetite (Fe3O4) nanoparticles in the presence of a magnetic field. The experiment was accomplished on the top of a micro-electromagnet consisting of two magnetic field generating contours. An electric current flowing through the contour(s) produces a non-uniform magnetic field, which is about 1.4 mT/μm in strength at 100 mA current in the vicinity of the current-carrying wire. In responses to the magnetic field, magnetic nanoparticles move towards the systems energy minima. In turn, magnetic nanoparticles drag biological cells in the same direction. We present experimental data showing cell manipulation through the control of electric current. This technique allows us to capture and move cells located in the vicinity (10-20 microns) of the current-carrying wires. One of the most interesting results shows a periodic motion of erythrocytes between the two conducting contours, whose frequency is controlled by an electric circuit. The obtained results demonstrate the feasibility of non-destructive cell manipulation by magnetic nanoparticles with micrometer-scale precision.