System Duetz: A Solution To Reduce Water Loss and Prevent Contamination In A Microtiter Plate

Minimizing water loss in small scale cultivations is essential for success in most microbial and mammalian cell culture applications. By reducing water loss, users can better preserve the osmo-balance of the culture media and ensure a physiologically-favorable environment for their organisms. System Duetz is a solution by Enzyscreen that reduces water loss down to 50uL/well/day in a 24-well plate and 22uL/well/day in a 96-well plate. The System Duetz sandwich covers are clamped down onto the top of a microtiter plate and function to restrict airflow down to a small fraction of the well diameter. By forming at tight seal with each individual well, this technology also reduces cross contamination between wells and homogenizes airflow across the plate.

Two of the key parameters to consider when optimizing the conditions for a microtiter plate cultivation include the centrifugal force applied to the vessel (RPM and orbital diameter pairing) and the filling volume. To achieve efficient mixing, the centrifugal force applied to the vessel must be great enough to push the liquid up the side of the vessel until the surface of the liquid makes contact with the bottom of the well. The AppNote below describes how to determine these parameters.

An inefficient mixing angle can result in mixing ‘deadzones’ at the bottom of the wells, where cells can precipitate and likely die. The red lines on the graphs below demonstrate how the threshold for this can vary with respect to filling volume and shaking speed (RPM). The results are based on the following publications:

The graphs show oxygen-transfer rates (OTRs) in cultures in 96- and 24-square deepwell MTPs, shaken on a shaker with a 50mm or 25mm orbital diameter, at various shaking frequencies and culture volumes. The kLa values are calculated from the OTRs, assuming a maximal concentration of O2 in the medium of 0.2 mM.