High-yield cell separations using magnetic nanowires

Ferromagnetic nanowires are demonstrated as a new tool in performing high-yield, single step cell separations on cultures of mammalian cells. The nanowires are made by electrochemical deposition in nanoporous templates, and when added to cultures of 3T3 mouse fibroblast cells, the nanowires can readily bind to the cells. The effectiveness in cell separations of Ni nanowires 350 nm in diameter and 5-35 μm long in field gradients of 40 T/m were compared to commercially available superparamagnetic beads. The percentage yield of the separated populations is found to be optimized when the length of the nanowire is matched to the diameter of the cells in the culture. Magnetic cell separations performed under these conditions achieve 80% purity and 85% yield, a four-fold increase over the beads.