title: Theoretical requirements for the density separation of platelets with comparison of continuous and discontinuous gradients.
abstract: In continuous density gradients platelets will approach their equilibrium position with exponential deceleration. The time taken to reach an acceptable approximation to equilibrium will depend upon platelet radius, density and medium viscosity. If centrifugation is stopped before equilibrium has been achieved then platelet "subpopulations" produced will not be density dependent. Discontinuous gradients take longer to reach equilibrium. Separation of platelets by density must conform to theoretical physical criteria.
mesh_terms: D001792:Blood Platelets / Q000145:classification; D002465:Cell Movement; D002469:Cell Separation / Q000379:methods*; D002499:Centrifugation, Density Gradient; D010976:Platelet Count; D013997:Time Factors