Suspending & Homogenizing Cell Pellets

Why suspend & homogenize?

When working with biological cell cultures, homogenizing cell pellets can have multiple purposes. Two popular examples include preparation for protein extraction or creating an inoculum.

In protein extraction, cells need to be separated from each other to ensure effective contact with the protease inhibitor cocktail, the lysis mechanism, and the extraction buffer.

For inoculation, it is key to have homogeneous distribution so the cell number in the volume of inoculum is consistent.

For best results in either of these procedures, it is critical to create a uniform distribution of cells in the suspension medium.

 

Suspending & homogenizing

The cells are first separated from old and consumed media. Centrifugation drives the cells to the bottom of the vessel, resulting in a compacted mass so the used media can be removed by decanting. Washing buffer or fresh culture media is added. Then the cell pellet is agitated, dislodging the pellet from the bottom of the vessel.

Continued agitation separates the cells by breaking the compacted pellet into small clumps, then to single cells, resulting in a homogenized cell suspension. Washing and spinning can be repeated as needed, usually keeping the cells on ice during the process.

There are several considerations regarding the best method for suspending cells. Many cell types are sensitive to the mechanical stress forces created by vortexing. The scale of the cell culture could create suspensions too viscous for magnetic stirring, or may require an additional step of transferring the pellet and medium to a vessel able to accommodate the stir bar.

Pipetting is a safe alternative, but can be highly manual, especially for larger pellets in small suspension volumes.

 

The Caframo BDC2002

Caframo’s BDC2002 overhead stirrer can be an effective option to address many of these issues.

• Impeller selection and speeds from 40 to 2002 rpm can be matched to create balanced agitation that minimizes damage and successfully separates cells.
• The adjustable chuck allows easy swapping of the impeller size to fit the mixing vessel in use
• The shaft provides the ability to quickly raise the impeller out of the way when the pellet is homogenized.
• Direct illumination on the vessel is provided by the Stirlight™ feature.
• With the vessel nestled in ice, users have their hands free to prepare for subsequent steps once the desired homogenized cell suspension is ready.

All told, the BDC2002 is a popular way to make cell pellet homogenization & suspension time-efficient.

 

Getting help

If you'd like advice or assistance with a solution to the challenges of suspending & homogenizing cell pellets, reach out to us at hello@growinglabs.com or 1-833-476-9420. We've helped equip and supply hundreds of labs cost- and time-effectively.

 

(Information courtesy of Caframo.)