When using fresh products, functional assays can be done without complications from cell activation or modification due to the freeze/thaw process. Fresh cells and biospecimens provide stable components for many studies, such as those into cell activation states, cell surface markers and intracellular and extracellular molecules.
Here are some of the most prevalent uses for fresh biospecimens.
Fractionation
Whole blood processes like fractionation are easier and more viable when performed soon after blood is drawn. If fractionation is done on blood that has been frozen, there will be large amounts of circulating DNA and toxins due to lysed cells and granulocytes.
Point of Care Device Testing Services
Point of Care (PoC) devices, such as home pregnancy tests, enable end-users to perform tests and get results without the need for a lab. At our donor centers, we can test your PoC devices with fresh blood, urine, saliva and other specimens, then share the data with you. For this service, fresh products emulate the situations where the PoC devices will be used, delivering accurate results.
Flow Cytometry Assays
Fresh blood is beneficial when performing flow cytometry (FC) because the blood cells are more viable, which allows for the capture of more cellular events. Some cells, like dendritic cells, do not freeze well, which means that if you don’t use fresh blood, you may not see them in FC analyses.
Functional Cell-Based Assays
For functional assays, blood components like cells and molecules need to be active and stable, making fresh blood essential. Fresh blood also allows you to analyze for the presence of microsomes and inflammasomes.
Challenges in Isolating Cell Subsets
Functional cell-based assays require isolated cells and cell subsets. However, during the cell isolation process, there are many challenges that can lead to low cell yields and poor downstream results. These challenges arise from the isolation method (such as the density gradient or magnetic system used), cell lysis during the isolation process and effects from the centrifuge device. In addition, the time between blood collection and cell subset isolation is crucial. Over time, granulocytes can activate, causing the cell population to align with the PBMC layer during density gradient isolations. For all of these reasons, having fresh blood is more advantageous.
The Importance of Fresh Blood for Cell-Based Assays
In studies that involve antibody functionality (along with the B cells that produce the antibodies), fresh materials work best. B cells frequently rupture after thawing, making it impossible to study the genetic rearrangement of antibodies. B cells, like dendritic cells, may not be preserved after the freeze/thaw process.
Neutrophil functional assays also require fresh biospecimens. Neutrophils, the most plentiful nucleated cell in a healthy human’s circulation, have a life span of 16-24 hours once matured and not activated. Neutrophils are easy to activate, and they generally do not remain so during the freeze/thaw process. When the cells are not fresh before isolation, cytokine secretion and NK cytotoxicity activity is common. When studying neutrophil-related activities such as migration, it is best to use fresh blood.
Available Fresh Cells
With BioIVT donor centers located across the globe, our ability to service you with fresh material within hours of collection means our products are suitable for a wide range of applications, including:
- Neutrophil Activation Assays
- Neutrophil Migration Studies
- Monocyte Activation Tests
- Platelet and Coagulation Functional Assays
- Flow Cytometry Assays
- Cytokine and Chemokine Cell-Based Assays
- Cytokine and Chemokine Release Assays
- Interferon Gamma Release Studies
- ELISPOT Assays
Our fresh product offerings from our donor centers include:
Blood-derived biofluidsWhole blood, plasma, sera, bone marrow & more |
Non-blood-derived biofluidsUrine, feces, saliva, sputum, semen & more  |
With fresh processed offering being:
PBMCs
 |
LEUKOMAX®
|
Buffy Coat
 |
CD34+ Hematopoietic
|
Purified Cell
|
At BioIVT, our team of research scientists can help move your research forward with many types of services including Cell-based Assays, Flow Cytometry, and more.
Resources:
https://www.flowcytometryservices.com/cytometry-blog/fresh-versus-frozen-cells-considerations-for-flow-cytometry
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4668800/
https://www.jove.com/video/745/neutrophil-isolation-protocol