At the time of procuring new primary cells to start cell culture for research purposes, the decision of procuring fresh cells or frozen primary cells (cryopreserved cells) may not be a simple task. There are many factors that goes on to influence the decision, based oncell maintenance, cell type, cell functionality, and logistics. To help you in making this decision a tad bit easy so that you can focus more on your hypothesis, let us discuss some essential points regarding fresh or frozen primary cells.
Fresh primary cell types are delivered in T-flasks with cells cultured in optimized medium to preserve the cell viability. These cells are generally delivered within 24 hours to prevent damage to the cells. But what is the need to procure fresh cells?
Human primary cell types are influenced by the immediate medium environment due to the presence of membrane receptors on the cell surfaces. Improper handling of thawing protocols for primary cells can decline viability by 10-15% due to over exposure to DMSO, which can be very harmful for research efficacy. Moreover, the length of storage for cryopreserved cells can affect the cellular physiology and function of primary cells. Thus presence of dead and dying cells or debris can adversely affect the viability of neighboring cells. Fresh cell procurement therefore guarantee lesser dead cells in the medium and consequently promise better response to assays and experiments. In addition, the freeze/thaw cycles for primary cells also reduce cell viability and lead to cellular damage with further passages besides affecting genetic stability.
Cryopreservation is the process by which living primary cells are preserved at cryogenic temperatures in liquid nitrogen vapor phase in the presence of DMSO or other cryopreserving agents. This process allows the cells to be stored in a state of metabolic arrest and protect them from death and damage with time. Cryopreservation requires proper technique and protocol for maintaining most of the viability and thawing of frozen cells should be handled properly to get viable cell cultures. So, why choose frozen cells?
Frozen cells are generally preferred for procuring primary cells from long distance to prevent temperature and other environment related damage to the cells. It also provide a highly convenient advantage to schedule experiments at ease without a rush for follow-ups. Frozen cells further provide an advantage of buying large lots from a potential donor organization and storing them up in proper cryopreservation canisters to omit or reduce chance of donor-to-donor variability. Besides that, frozen cell procurement reduces chances of cross-contamination and mechanical mishaps that might occur in case of fresh cells cultured in flasks.
Thus, at a glance, fresh cells help in initiating cell cultures in urgent cases when the downstream projects are being stalled and they offer an advantage of bypassing the risk of affecting cell viability due to improper handling of freeze/thaw cycles. Aside from that, when it comes to safe procuring (given the availability of experienced freeze/thaw handling), frozen primary cells are a better option for convenience in project scheduling and ensure less chance of environment-based damage during delivery.