Cell alignment tool

It is mandatory to align centrifuge cells strictly along the centrifugal field so that the sector shaped walls of the compartments exactly follow the force lines. Even small deviations in cell alignment can cause convections along the cell walls that can appear as artificial sedimenting species after data evaluation [1]. Hairpin lines on the bottom of the rotor, to be aligned with lines on the measurement cell, usually serve this purpose.

However, this procedure is often not exact, and on some rotors, the hairpin lines on the outer and inner rim of the cell hole have been found to deviate. For this reason, other tools have been conceived.

Alignment tool photograph
Figure 1: Cell alignment tool.
Nanolytics Instruments offers a cell alignment tool that guarantees an alignment deviation of better than 0.1°. It is virtually a rotor stand to place the rotor upon after cells have been inserted. Precision blades with exact orientation are placed on springs. When the cell, intentionally misaligned in the beginning, is rotated into the correct position, the spring will cause the blade to snap into notches in the cell base with virtually no play. Four of these blades allow to justify all cells of a four hole rotor. For an eight hole rotor, the rotor needs to be turned by 45° after aligning the first four cells, then bringing the other cells into position.

The tool is applicable to cells equipped with notches perpendicular to the original hairpin markings. All cell housings manufactured by Nanolytics Instruments are equipped with these notches.

The cell alignment tool was developed by Nanolytics and has been in use for years, providing maximum precision. It is now offered to other users by Nanolytics Instruments.


[1] Arthur KK, Gabrielson JP, Kendrick BS, Stoner MR., J Pharm Sci. 2009 Oct;98(10):3522-39. doi: 10.1002/jps.21654. Detection of protein aggregates by sedimentation velocity analytical ultracentrifugation (SV-AUC): sources of variability and their relative importance.

Alignment tool construction drawing
Figure 2: Cell alignment tool construction drawing.