The technique of double cell separation is applied depleting that way erythrocytes and accomplishing a small final cryopreservation volume which allows better viability and reclamation.
Patient’s protection from the complications of severe haemolysis and the toxic cryoprotectant reagent (DMSO) is accomplished by this procedure and gives the potential of partial freezing and multiple use of the sample.
The cryopreservation of large volume samples results in stem cell’s death during defrozing as during that step, DMSO and hemoglobin must be removed. Large volume cryopreservation demands plastic freezing bags and cryopreservation in liquid nitrogen vapor phase.
The cryopreservation is taking place with a validated, digitally adjustable, controlled rate freezing procedure. The procedure, as it is described above, provides gradual transition in lower temperatures and higher cell viability.
Samples are fully immersed into the liquid nitrogen in a stable temperature of -196 ˚C, according to the only published protocol which excellent viability results of the stem cells even after 15 years of cryopreservation (Broxmeyeretal 2003, PNAS, 100: 645-650). It is generally accepted that this preservation protocol is the only one which promises unlimited viability time (up to 2000 years) and for this reason it is followed by the biggest private cord blood banks of the world.
On the contrary, public banks, limiting the use of the umbilical cord blood stem cells only for haematopoietic diseases, without substantial financial resources, they store their samples in liquid nitrogen vapour phase as they do not aim in long term preservation.
Biohellenika, like other well known international big cord blood banks, preserves the stem cells in two places. One of two equal parts is preserved at Thessalonikis laboratories and the other in Athens laboratories.
The preservation places are completely secure, monitored in a 24-hours basis and away from sources of radioisotopes and ionized radiation.
The reasons that lay the double preservation is the biggest security in case of natural disaster, the potential of multiple use without de-freezing and re-freezing the initial sample and the immediate disposition of the sample upon request all over Greece.