Can you provide an overview of the cell harvest procedure vs. traditional microcarriers?

Answer

The harvest procedure is available as a detailed resource document that your local Corning sales representative can provide. Essentially, once cells are ready for harvest, a wash step is performed with DPBS to rinse away culture media. This is often performed by settle-aspirate operation. Since Corning Dissolvable Microcarriers (DMC) are made of polygalacturonic acid (PGA) polymer chains cross-linked via calcium ions, dissolution is achieved with the addition of EDTA (which chelates calcium ions and destabilizes the polymer crosslinking), pectinase (which targets degradation of the PGA polymer), and a standard cell culture protease (which breaks down cell and extracellular matrices). Microcarriers are completely dissolved within 10 to 20 minutes. As compared to a traditional microcarrier harvest, a media wash and exchange into buffer occurs followed by proteolytic dissociation in the presence of mechanical shear via agitator mixing. Harvest may be more difficult, depending on on the degree of cell binding to the carrier (i.e.: charge based interactions, confluence, or the amount of extracellular matrix and adhesion proteins produced) or the extent of microcarrier aggregation. This step may require hold times and shear profiles that can negatively impact subsequent performance of the cells. Once cells have been released, the cells must then be physically separated from the microcarriers. Requiring added steps such as low speed batch or continuous centrifugation, settle aspirate, filtration, or mesh-bag sieving to trap carriers. All add processing time, equipment, consumables, and labor. This method also increases the sterile envelope of the process and, in some cases, also increases contamination risk. The more consumables or equipment in a system can contribute to total particle input of a process. Most importantly, yield losses often occur as a result of additional processing, which can greatly impact the amount of usable final material.