Magnetic nano-'shepherds' organize cells

     It is no question that a major problem facing bioengineers today is the inability to make human cells group together and form structures on command. While there are certainly ways to promote cell growth, until now any attempt to organize cells at will in a linear fashion resulted in either cell death or deformation with the occasional success. A team of students and scientists alike from Duke University, Case Western Reserve University, and the University of Massachusetts, Amherst have made collaboratively made a breakthrough in selective cell to cell adhesion.

     These researchers created an environment in which magnetic particles are suspended in a ferrofluid (Shown below) and can be manipulated through external magnetic fields to move in certain ways. This alone is a feat, but when cells are thrown into the mix these magnetic particles can now be used to 'guide' one cell to another resulting in a growing cell chain. Melissa Krebs, a third year biomedical engineering graduate student at Case Western says, "the cells have receptors on their surface that have an affinity for other cells, they become sticky and attach to each other  When endothelial cells get together in a linear fashion as they did in our experiments, it may help them to organize into tiny tubules." Using this method the researchers have been able to perform advanced tissue engineering creating three dimensional cell chains with a small budget and a method that is easily accessible.

     While the method is not exactly new, the key ingredient for the success of these particular experiments is the creation of a non-toxic ferrofluid from BSA (Bovine Serum Albumin), a protein found in cow blood. Previous attempts have failed due to the nanoparticles being composed of poisonous iron.This type of ferrofluid allows the nanoparticles to guide the cells without contacting, or poisoning them.

     "While still in the early stages, we have shown that we can form oriented cellular structures," said Eben Alsberg, assistant professor of Biomedical Engineering and Orthopedic Surgery at Case Western, "The next step is to see if the spatial arrangement of these cells in three dimensions will promote vascular formation." Being able to not only orient the cells but also vascularize the tissue in a cheap accessible manner certainly would be an amazing breakthrough for tissue engineering.

Article link here