Patent GB-1337398-A (GB)
Title: Apparatus and method for gradient zonal centrifugation
IPC: B04B1/00
Filed: 1970-12-18
Abstract: 1337398 Centrifugal separators P SHEELER and J R WELLS 18 Dec 1970 [19 Dec 1969 14 Sept 1970] 60335/70 Heading B2P The rotor 22, Figs. 1 and 2, of a gradient zonal centrifuge for separating biological cell components has an internal annular centrifugation chamber bounded by coaxial spaced apart outer and inner vertical walls 42, 43 and divided into compartments by radial septa 51, the bottom or the top of the chamber being formed with sloping walls 44, 46, Fig. 1, or 146, Fig. 8, converging either to an annular V-shaped groove, Fig. 1, or to a plurality of funnel-shaped recesses 142, ports 68 being located at or adjacent the apex 48 or apices 147 of the groove or recesses for supplying and removing liquid density gradient and biological cell components to the chamber. As shown in Figs. 1 and 2, the rotor 22 is mounted on a hub 21 at the upper end of a motor-driven shaft and is closed by a cover plate 35. The septa 51 are integral with a tubular core 52 which is removably mounted on a core portion 23 of the rotor. The bottom of each septum is bounded by converging edges which match the sloping walls 44, 46 of the annular V-shaped groove and terminate in a narrow horizontal edge 63 parallel to, and spaced apart from, the annular apex surface 48 of the groove. This allows liquid communication between adjacent compartments of the chamber. The ports 68 are formed in the lower edges 63 of the septa and communicate with sloping channels 67 in the septa and vertical channels 66 in the core 52. The channels 66 communicate with sloping channels 76 and a central channel 74 in a circular distributor block 71 removably mounted on top of the axial core portion 23 of the rotor and located within an aperture 38 in the cover plate 35. In operation, the liquid density gradient is pumped via tubing through the channels 74, 76, 66, 67 and ports 68 into the chamber compartments. The rotor is then accelerated so that the density gradient undergoes reorientation in which the preliminarily vertically arranged, sector-shaped, isodense layers in each compartment gradually become concentrically arranged about the axis of rotation. A sample of biological cell components may be introduced by initially placing it in the bottom of the V-shaped groove after which it becomes displaced upwardly upon introduction of the density gradient, with both the gradient and the sample underging reorientation during acceleration. Alternatively, after preliminary acceleration of the rotor, the sample may be spread onto the reoriented density gradient through an opening in the cover plate 35. Thereafter, the rotor is accelerated to a higher speed for effecting separation of the cell components into a series of concentric zones about the axis of rotation. The rotor is then brought to rest so that after reorientation the separated cell components are arranged as a series of layers in the now vertical density gradient. Finally, the gradient and the separated particles are pumped from the rotor through the ports 68 and the channels 67, 66, 76, 74 beginning with the dense end of the gradient at the bottom of the V-shaped groove and the cells are collected as a series of fraction.  In a modification. Figs. 5-7 (not shown), the top of the chamber opens into an annular V-shaped groove formed in the rotor cover plate and is provided with a flat bottom. In a further modification, Fig. 8, funnelshaped recesses 142 are formed in the bottom of the annular chamber 141 of the rotor 140. The lower portions of the septa (not shown) descend into respective recesses, the parts in the lower edges of the septa being adjacent the apices 147 of the recesses.