What is the split line?

This article will explain the split line and provide some best practices for setting a split line

When completing a levitation protocol, the system will prompt you to set a split line value before moving the sample to the outlet wells.

This split line indicates the position in the separation channel where the sample will diverge and flow into the top or bottom outlet well during collection. It serves as a visual guide, determining the flow rates of the top and bottom channels to achieve the desired separation. The split line can be adjusted within a range of -15 to 15, with 0 representing a neutral split line where the sample is evenly divided down the middle.

Pre-setting the split line automatically aspirates the sample at the end of the run

When the split line is assigned prior to starting a run, the separation flow will start as soon as the levitation process finishes without the need to manually interact. However, there remains flexibility and so if you instead need to interact with the split line’s assignment, you can still change the separation line position during this process.

Which split line value should I use?

T0 decide which split line value to use, one should consider what has happened during their levitation run on screen, as well as to consider the nature of their biological sample - such as input viability and total live cell number.

  • In general, a higher split line can lead to a higher viability of output sample, however at a cost of viable cells going to the waste channel - affecting yield.
  • A lower split line can be beneficial when yield is a critical factor and as many cells need to be recovered.
  • A negative split line, of (e.g. -1 to -5) should be used when running low cell number samples (~10k total cells)
  • A negative split line (e.g. -1 to -5 ) may also be useful when using the Levicell as a clean up step before flow sorting. 
  • When there is no clear separation of the live and dead bands, using a split line of 0 is a recommended safe value