Design optimization and characterization of a small-scale centrifugal cellseparator

A cell separator design is presented for rapid, efficient separation of ana lytical quality plasma samples from whole blood for use in a continuous seg mented flow point-of-care testing system. Sedimentation theory for multiple species suspensions, modified to account for continuity and rouleau format ion, is used to model the separation process and optimize the separation ch amber geometry. Model predictions, relating the sample separation time to a chamber taper angle, indicate respective separation times of 37-28 s for a chamber with a taper angle ranging from 16 to 20 degrees, while maintainin g sample volumes in the 1-1.5 ml range. Experimental observations of separa tion time agree to within 25% of theoretical predictions resulting in compl ete separation in 40 s, showing the ability to separate small 1-1.5 ml samp les in less than 1 min. Results of characterization experiments conducted u sing the separator indicate indiscernible hemolysis when compared with hemo globin levels measured from samples prepared in a bench-top centrifuge. Res ults show that cellular carryover is reduced in seven clean-in-place wash s teps to 0.00063% of the original cellular content, and theory based on thes e results predicts no carryover in 11 steps. (C) 2001 Elsevier Science B.V. All rights reserved.