Eliminate the Edge Effect with the MIC-101

Technical Note

The Edge Effect is a phenomenon in which evaporation of media or any liquid in multi-well plates placed in traditional CO2 incubators, occurs disproportionately in the outside and corner wells. This can exceed 15% to 25% of the initial volumes, depending on the incubation time, humidity, temperature, and the incubator. Such dramatic changes in liquid volume in the wells of these plates results in dramatic changes in pH, nutrient and salt concentrations, as well as the effective reagent concentration being used in the experiment. While also noticeable in 24-well plates, the effect is predominant in 96-well plates.

The Edge Effect is mainly due to constant air currents present in most modern CO2 incubators. This movement of air around the plates, even with the lid on, affects the outside wells the most. This can be verified by simply filling the wells of a 96-well plate with media or sterile water and placing it in your laboratory’s continuous flow CO2 incubator for 72 hours. Look through the edge of the plate and you will clearly see the evaporation. While continuous flow incubators tend to exacerbate the Edge Effect, even plates left on a lab bench exposed to room air circulation may also see increased edge well evaporation.

This 96-well plate side view, illustrates increased movement of air in the outer wells of the plate.

The humidity level inside the incubator is also an important factor for the Edge Effect as decreased humidity will accelerate evaporation in the outside wells. The relative humidity drops very quickly each time the door is opened on a continuous flow incubator and subsequently, recovery back to 90% humidity can take 50 minutes or more. Each time the door is opened, the humidity can drop even further. This figure demonstrates that the measured levels of humidity can drop significantly with each door opening and that recovery of humidity can be quite slow.


Because there is no airflow in the controlled environment of the Modular Incubator Chamber, evaporation is eliminated. Each well within a multi-well plate retains its original composition throughout the entire experiment, thus eliminating the Edge Effect. Placing your multi-well plates in a physiologic oxygen environment in the MIC-101 will dramatically increase cell viability and at the same time reducing experimental variability.

Now you can count on reproducible results with the Modular Incubator Chamber and at the same time eliminate variability and reduce contamination. The MIC-101 is designed so your cells will no longer be subject to a changing environment. Inside the sealed unit, temperature, humidity, and gas concentrations remain constant. Your plates are also isolated from potential contaminants stemming from the inherent unsterile environment of a traditional incubator.



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