Spin Analytical AUC Product Line

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.

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 tool has been proven to perform well in terms of maximum precision [2]. However, it should be stressed that a tremendous advantage lies in the speed and ease of handling. The rotor does not to be balanced on its side in order to access top and bottom at the same time – where other cells may shift or turn. No visual inspection is required, the cells are simply turned until the blades engage. All cells are aligned in less than 30 seconds.
Also calibration cells can be aligned with this tool, using such from the Spin Analytical AUC product line, as these are equipped with bottom notches as well – in contrast to conventional counterbalances.

[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.

[2] Channell G, Dinu V, Adams GG, Harding SE, Eur Bioph J. 2018 Aug; 47:809-813. doi: 10.1007/s00249-018-1328-9. A simple cell alignment protocol for sedimentation velocity analytical ultracentrifugation to complement mechanical and optical alignment procedures.

For quotations, purchase orders, questions and further information contact sales@nanolytics-instruments.com.