Magnetic Nanoparticles Prove Attractive for Tissue Engineering
Posted by Lauren Rugani on April 12, 2009
Two major challenges in tissue engineering are forming ordered patterns of cells and creating blood vessels that resemble the complex, three-dimensional networks found in large organs. Some techniques involve growing cells around a biological “scaffold” or using a small electric force to align cells into a desired pattern, but most techniques come with risks of toxicity or other damaging effects on the cells. New research out of Case Western Reserve University in Ohio has a seemingly simple solution to both challenges: magnets.
They suspended free-standing human umbilical vein endothelial cells and iron oxide nanoparticles in a ferromagnetic fluid, which becomes highly magnetized in the presence of an outside magnetic field. The magnetic nanoparticles align themselves in the same direction as the magnetic field created within the solution, and gently coax the nonmagnetic endothelial cells to line up end-to-end along the same lines. Receptors on the ends of the cells allow them to interact with each other and form long chains, which can then be transferred to a different surface where they are cultured and grown further.
This isn’t the first magnetic approach to tissue engineering. Previous methods have also involved using metallic nanoparticles and magnetic fields to align cells, but have all involved the nanoparticles being attached to or absorbed by the cells. Not only are the nanoparticles potentially toxic to the cells, but removing them could alter the structure or affect the normal function of the cells and render the new tissue useless. In this approach, the researchers coated the nanoparticles with a protein found in cow blood, which protected the cells from the toxic iron. After applying the magnetic field long enough for the cells to align, they simply washed away the solution containing the nanoparticles, and the chains remained intact and healthy.
Earlier research has shown that linear chains of endothelial cells have a tendency to form tube-like structures similar to small capillaries, so the Case Western team hopes to further investigate this behavior and attempt to use their technique to grow three-dimensional networks of blood vessels.