A continuous cell separator based on buoyant force in dissimilar density fluid flows

We present a continuous particle density separator to achieve density-dependent and size-independent particle separation based on the gravity and buoyancy on the particles in dissimilar density fluids. The previous particle separators, based on the size or dielectrophoretic property of particles, are suitable for size-dependent and density-independent particle separation; thus having difficulty to collect the same kind of particle having an identical density in size variations. Experimental study verifies the present device, flowing a diluted whole blood in dissimilar density fluids (upper fluid density, ¿₁ is 1.0 g/ml and lower fluid density, ¿₂ is 1.1 g/ml), by successfully extracting 82% Red Blood Cells (RBCs, ¿_b = 1.1-1.15 g/ml, d = 8-9 ¿m) and 97% White Blood Cells (WBCs, ¿_a = 1.06-1.09 g/ml, d = 8-15 ¿m) based on their densities, respectively. Therefore, the present particle density separator demonstrates the performance of separating RBCs and WBCs based on their density without size effect.