Making assays faster: Single use frozen cells prepared in house decrease assay turnaround while increasing flexibility

29th June 2020

Category: Bioanalytical / Biosimilars

By: Ben Tyrrell, PhD - Scientist, Product Development,

Bioassays are reliant on the use of either primary cells or cultured cell lines depending on the assay format. Cultured cells offer increased flexibility over primary cells and so are widely used as a substitute to primary cell lines where appropriate. The immortalisation of continuously cultured cells enables an organisation to purchase a vial of cells and prepare their own banks enabling the continuous culture of the cells as and when required.

Despite the clear advantages of the continuous culture of cell lines it is still a time consuming process with cells needing to be cultured up to 3 times a week. Furthermore, while cell lines are considered more reliable and consistent over time than their primary cell counterparts, the continuous culture of the cells can still be a source of variation within a bioassay.

At Sartorius Stedim Biotech we have a range of strict criteria around the continuous culture of cells that is tailored towards each cell line. Furthermore, we have a dedicated team of cell culture experts to control and minimise bioassay variation and to maximise the quality of data we generate. We have large onsite resource of cell banks available to use in off the shelf qualified assays or custom NBE assays. Additionally, we are now utilising this resource to generate single use vials of cells in house for a range of bioassays.

Figure 1: Workflow for generating 5 assay results from the continuous culture of cells vs generating single use vials of cells and performing 5 assay runs. Single use vials allow assay runs to be performed with cells from the same passage

Single use vials have become more popular over recent years not only for primary cells but also for cultured cells lines. At Sartorius Stedim Biotech, we have utilised our cell culture expertise to produce single use vials of cells for a selection of our assays. This combines our in depth knowledge of continuous cell culture with the significant practical advantages of single use vials of cells. A simplified schematic in figure 1 shows how 5 assay runs can be performed with more flexibility and importantly in shorter time scales with single use vials vs continuous culture of cells.

We took advantage of this process when developing a live cell binding assay using the iQue Screener PLUS, a high through put flow cytometer. For this particular assay the only target expressing cell line available was slow growing. The slow proliferation of cells impacted on the turnaround time for assays runs and resulted in a rigid assay schedule. Switching to single use vials enabled an operator to perform 3 times as many runs a week as opposed to using continuously cultured cells. The end result was a qualified live cell binding assay in a significantly shorter time frame. The assay performance from both continuously cultured cells and single use frozen vials of cells was assessed with both approaches generating robust comparable response curves (Figure 2).

Figure 2: Example live cell binding data generated in assay development comparing continuous cultured cells (A) to single use vials of cells (B). Robust response curves were generated by both approaches

To find out more about the platform live cell binding assay format we have developed utilising continuous and single use vials of cell, download our scientific poster.

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