Continuous-flow centrifugation combined with isopycnic banding: rotors B-8 and B-IX.

Pelleting inactivates SODle viruses and aggregates other dispersed :material. Methods for separation should be developed in which desired particles are always kept in suspension. Rotors that cODlbine continuous-flow centrifugation with isop"ycnic banding can achieve this effect. In our SySteDl a liquid density gradient is set up in a spinning rotor next to the wall in each of 4 sector-shaped cODlpartDlents. The virus-containing suspension is made to flow over the centripetal surface of the gradient between the gradient and the tapered core of the rotor. Virus particles sedi:ment out of the streaDl into the iDlprisoned gradient. At the co:mpletion of a run, co:mponents of the gradient are recovered by displacing the gradient centripetally with a dense fluid and channeling the gradient out a center line.-Nat Cancer Inst Monogr 21: 199-216, 1966.