title: Optimizing cord blood sample cryopreservation.
abstract: OBJECTIVE
  Cord blood (CB) banking is becoming more and more commonplace throughout the medical community, both in the USA and elsewhere. It is now generally recognized that storage of CB samples in multiple aliquots is the preferred approach to banking because it allows the greatest number of uses of the sample. However, it is unclear which are the best methodologies for cryopreservation and storage of the sample aliquots. In the current study we analyzed variables that could affect these processes.
  
  
  METHODS
  CB were processed into mononuclear cells (MNC) and frozen in commercially available human serum albumin (HSA) or autologous CB plasma using cryovials of various sizes and cryobags. The bacteriophage phiX174 was used as a model virus to test for cross-contamination.
  
  
  RESULTS
  We observed that cryopreservation of CB in HSA, undiluted autologous human plasma and 50% diluted plasma was equivalent in terms of cell recovery and cell viability. We also found that cryopreservation of CB samples in either cryovials or cryobags displayed equivalent thermal characteristics. Finally, we demonstrated that overwrapping the CB storage container in an impermeable plastic sheathing was sufficient to prevent cross-sample viral contamination during prolonged storage in the liquid phase of liquid nitrogen dewar storage.
  
  
  CONCLUSIONS
  CB may be cryopreserved in either vials or bags without concern for temperature stability. Sample overwrapping is sufficient to prevent microbiologic contamination of the samples while in liquid-phase liquid nitrogen storage.
authors.affiliation: Department of Immunobiology, University of Arizona, Tucson, Arizona 85724, USA. davidh@email.arizona.edu
authors.forename: David T
authors.initials: DT
authors.lastname: Harris
mesh_terms: D010584:Bacteriophage phi X 174 / Q000254:growth & development; D001771:Blood Banks / Q000592:standards; D001793:Blood Preservation / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D002470:Cell Survival; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D004926:Escherichia coli / Q000821:virology; D005615:Freezing; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology*; D009584:Nitrogen / Q000737:chemistry; D010949:Plasma / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D012709:Serum Albumin; D009584:Nitrogen