Magnets Keep Blood Flowing - ScienceNOW

Magnets Keep Blood Flowing - ScienceNOW: The magnetic effect, the researchers say, all comes down to hemoglobin, the iron-based protein inside red blood cells. In the same way that iron filings align themselves along the field lines around a bar magnet, so the red blood cells align themselves along the straight field lines of Tao and Huang’s electromagnet. This reduces viscosity in several ways. For one, the cells become streamlined with the direction of flow. The alignment also encourages the cells to stick together, forming clumps of various sizes. Although one might think clumps would increase viscosity, they actually have a lower total surface area compared with single cells, and this cuts down on friction. What's more, the mixture of clump sizes allows more cells to pack into the same volume, with small cells fitting around the big clumps and allowing more room for movement.