As cell therapy manufacturing becomes more prevalent, so does the use of cryopreservation to add longevity to cell samples for transportation and storage prior to patient treatment. As we discussed in our previous blog post “Why Are You Using Trypan Blue to Determine Viability Post-Thaw?” assuring accurate cell viability is critical both pre- and post-thaw as the freezing process can alter cell characteristics
Are you accurately assessing your cell samples pre-treatment? It’s critical.
Cryopreserved samples can be suspended in buffer solutions that closely mimic human plasma. A common trend in cell therapy labs is to utilize Plasma-Lyte with human serum albumin and DMSO during cryopreservation, post-thaw and pre-injection to patients. Plasma-Lyte 148 is an isotonic buffered intravenous crystalloid solution with a physiochemical composition that closely reflects human plasma. Our users have used fluorescence-based Cellometers to generate accurate counts for cells suspended in different media or buffer systems including Plasma-Lyte.
|General Characteristics of Plasmalyte as Compared to Human Plasma|
|Sodium||Potassium||Magnesium||Calcium||Chloride||Acetate||Gluconate||Lactate||Malate (mmol/ L)||Theoretical osmolarity||Actual osmolarity||pH|
|Table adapted from Weinberg L et al. A clinical review of Plasma-Lyte 148. Expect manufacturer to manufacturer differences in osmolarity.|
Do you really know the effect of Plasma-Lyte on the viability of your samples pre and post-thaw?
We have designed validated protocols for counting primary cells in multiple buffers systems including Plasma-Lyte.
The images below represent stem cells thawed from liquid nitrogen and resuspended in Plasma-Lyte solution. Cells stained with Nexcelom AO/PI solution and counted for viability and cell concentration (right) using the Cellometer Auto 2000.