MAGNETIC NANOPARTICLES FOR POSITIONING CELLS AND CONTROLLING NETWORK ORGANIZATION

The ability to manipulate neuronal organization and growth has extensive implications in neuronal regeneration and tissue engineering. In the present study we are focusing on positioning neuronal cells at preferable locations and controlling cell motility by applying external magnetic fields and by fabricated magnetic pads. We use magnetic nanoparticles (maghemite, γ-Fe₂O₃) as mediators to transform cells into magnetic sensitive units. Due to their superparamagnetic properties, these particles experience force in inhomogeneous magnetic fields and hence can be manipulated through this field. We characterized and optimized cell uptake of MNPs and studied, theoretically and experimentally, cell motility and network organization of neuronal cells under external magnetic fields. We designed and generated magnetic fields with controlled magnetic flux densities at multiple scales of size and strength.

We incubated, prior to plating, the treated cells, PC12 cells and primary neurons, in medium enriched with iron oxide nanoparticles conjugated to fluorescent tag. Both types of cells uptake the nanoparticles and turned sensitive to the magnetic stimulation with no cytotoxic effect. The morphology and electrical activity patterns of the neuronal cells were not affected by MNPs uptake. We observed that the cellular uptake of the MNPs depends on the time of incubation and the concentration of nanoparticles in the medium. We successfully controlled the cells motility and attracted the cells towards the magnetic sites leading to an organized network of clusters of cells. Our study presents an emerging magneto-chemical method for the manipulation of neuronal growth opening new directions in non-invasive neuronal repair.