LT13043 - Blood contains many different types of cells, each with specific functions in the body. As blood flows, these cells segregate, with the white blood cells (WBCs) and platelets preferentially found near blood vessel walls. This phenomenon, called margination, allows for efficient immune surveillance by the WBCs and rapid response to vessel wall injuries by platelets. Our work demonstrates how the physical properties of different cells lead to this important observation. As the stiff WBCs and platelets collide with the more flexible red blood cells during flow, they are pushed aside while having little effect on the motion of the red blood cells, a process that ultimately leads to the trapping of WBCs and platelets near the vessel walls. A simple model of blood flow that accounts only for these collisions and the flow-induced repulsion of the cells from the vessel walls is able to match results from detailed numerical simulations. The understanding provided by this study will be helpful in designing effective drug delivery particles that target the vascular walls for treatment of cancer or atherosclerosis. Margination has also been employed in biomimetic microfluidic devices to separate WBCs and platelets from whole blood, which could be helpful in treating leukemia or for platelet rich plasma therapy (used by athletes for healing injuries). The principles established in our study will aid the development of these devices.
Friday, August 10, 2012
Sorting out blood flow
LT13043 - Blood contains many different types of cells, each with specific functions in the body. As blood flows, these cells segregate, with the white blood cells (WBCs) and platelets preferentially found near blood vessel walls. This phenomenon, called margination, allows for efficient immune surveillance by the WBCs and rapid response to vessel wall injuries by platelets. Our work demonstrates how the physical properties of different cells lead to this important observation. As the stiff WBCs and platelets collide with the more flexible red blood cells during flow, they are pushed aside while having little effect on the motion of the red blood cells, a process that ultimately leads to the trapping of WBCs and platelets near the vessel walls. A simple model of blood flow that accounts only for these collisions and the flow-induced repulsion of the cells from the vessel walls is able to match results from detailed numerical simulations. The understanding provided by this study will be helpful in designing effective drug delivery particles that target the vascular walls for treatment of cancer or atherosclerosis. Margination has also been employed in biomimetic microfluidic devices to separate WBCs and platelets from whole blood, which could be helpful in treating leukemia or for platelet rich plasma therapy (used by athletes for healing injuries). The principles established in our study will aid the development of these devices.
