Cell Creeping and Controlled Migration by Magnetic Carbon Nanotubes
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Nanoscale Research Letters 2009, 5:257-262 doi:10.1007/s11671-009-9463-yPublished: 27 October 2009
Carbon nanotubes (CNTs) are tubular nanostructures that exhibit magnetic properties due to the metal catalyst impurities entrapped at their extremities during fabrication. When mammalian cells are cultured in a CNT-containing medium, the nanotubes interact with the cells, as a result of which, on exposure to a magnetic field, they are able to move cells towards the magnetic source. In the present paper, we report on a model that describes the dynamics of this mammalian cell movement in a magnetic field consequent on CNT attachment. The model is based on Bell’s theory of unbinding dynamics of receptor-ligand bonds modified and validated by experimental data of the movement dynamics of mammalian cells cultured with nanotubes and exposed to a magnetic field, generated by a permanent magnet, in the vicinity of the cell culture wells. We demonstrate that when the applied magnetic force is below a critical value (about Fc ≈ 10−11 N), the cell ‘creeps’ very slowly on the culture dish at a very low velocity (10–20 nm/s) but becomes detached from the substrate when this critical magnetic force is exceeded and then move towards the magnetic source.