A tiny, implantable device has pulled adult stem cells out of a living rat with a far greater purity than any present technique.
The test of the device designed by Michael R. King, associate professor of biomedical engineering at the University of Rochester, will be reported in the March 3 issue of the British Journal of Haematology.
Its the kind of research that, before we tried it, we never would have expected such a remarkable result straight out of the gate, says King. Were finding we can play off the hydrodynamics of moving blood to isolate and manipulate specific cell populations with great efficiency.
King is at the forefront of a new field; manipulating stem cells, white blood cells, and even cancer cells by exploiting the mechanics of the cells movement with such precision that he is having success capturing and even reprogramming several cell types as they pass through the device, he says.
A chance encounter between an engineer and a hematology clinician gave rise to the field in 2002.
King was studying how certain white blood cells, called neutrophils, know how to migrate to a point of infection. He observed how, near an injury site, the walls of the nearby blood vessels expressed an adhesive protein called a selectin, and if passing neutrophils brushed against these selectins, they stuck to the vessel wall.
But the cells did not remain stuckthey rolled. With a precise balance between the adhesion of the selectins and the forces of the flowing bloodstream, the cells could move much more slowly as they approached the infection site. With that slowed pace, the cell can look for a second signal on the vessel wall that tells the cell to exit the vessel by squeezing between cells in the wall and moving directly to the site of infection.
One reason the system is so effective is that only the neutrophils respond to those selectins, so only neutrophils slow down in the blood.
King was working out the physical dynamics of this
|Contact: Jonathan Sherwood|
University of Rochester