Evaporation during long-term incubation can be the enemy—one of many enemies—throughout the cell culture process. When you use a 96-well plate to culture your cells, you hope for full use of your plate, resulting in viable, healthy cells in every well. However, when you lose the use of the outer perimeter of your plate in order to alleviate the devastating effects of evaporation, you have become a victim of edge effect.
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Threats of edge effect
If you evaluate a standard 96-well plate, you’ll observe differing rates of evaporation during long-term incubation, starting from the outer wells across the plate. A reduction in volume as low as 10 percent can concentrate the media in each well enough to affect cells’ physiology, causing variability that can compromise the viability and integrity of your cells. Assay washing and aspiration can be another cause, leading to differing reagent concentrations in your plates.
You wouldn’t be the only researcher to abandon the outer parameter of your plate, which, on a 96-well plate, costs you over a third of the available space. A small sacrifice of that size per plate adds up when you consider how many plates your lab has in use at any moment.
Minimize edge effect
There are several ways to reduce edge effect and make full use of your 96-well plate:
Evaluate your lab’s workflow. You may find steps in your processes that expose plates to temperature gradients, airflow, or vibrations that disturb the settling of the cells into the plates and encourage uneven distribution.
Cover your plates during incubation to reduce evaporation. For cell-based work, use plastic lids with condensation rings that allow gas exchange.
You may also want to explore cultureware specifically designed to reduce edge effect. Learn about our Nunc Edge Plate, whose special “moat”-style reservoir minimizes evaporation to less than two percent during a seven-day incubation.
More on maximizing your assays
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Very informative post. These details such as minimizing the edge plate really interests me a lot.