title: DESIGN OF A SIMPLE SLOW COOLING DEVICE FOR CRYOPRESERVATION OF SMALL BIOLOGICAL SAMPLES.
abstract: BACKGROUND
  Slow cooling is a cryopreservation methodology where samples are cooled to its storage temperature at controlled cooling rates.
  
  
  OBJECTIVE
  Design, construction and evaluation of a simple and low cost device for slow cooling of small biological samples.
  
  
  METHODS
  The device was constructed based on Pye's freezer idea. A Dewar flask filled with liquid nitrogen was used as heat sink and a methanol bath containing the sample was cooled at constant rates using copper bars as heat conductor.
  
  
  RESULTS
  Sample temperature may be lowered at controlled cooling rate (ranging from 0.4°C/min to 6.0°C/min) down to ~-60°C, where it could be conserved at lower temperatures. An example involving the cryopreservation of Neuro-2A cell line showed a marked influence of cooling rate over post preservation cell viability with optimal values between 2.6 and 4.6°C/min.
  
  
  CONCLUSIONS
  The cooling device proved to be a valuable alternative to more expensive systems allowing the assessment of different cooling rates to evaluate the optimal condition for cryopreservation of such samples.
authors.affiliation: Centro Binacional (Argentina -Italia) de Investigaciones en Criobiologia Clinica y Aplicada (CAIC); Servicio de Electronica y Optica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Leonardo Juan
authors.initials: LJ
authors.lastname: de Paz
authors.affiliation: Centro Binacional (Argentina -Italia) de Investigaciones en Criobiologia Clinica y Aplicada (CAIC), Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Maria Celeste
authors.initials: MC
authors.lastname: Robert
authors.affiliation: Centro Binacional (Argentina -Italia) de Investigaciones en Criobiologia Clinica y Aplicada (CAIC); Servicio de Electronica y Optica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Daniel Adolfo
authors.initials: DA
authors.lastname: Graf
authors.affiliation: Centro Binacional (Argentina -Italia) de Investigaciones en Criobiologia Clinica y Aplicada (CAIC), Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Edgardo Elvio
authors.initials: EE
authors.lastname: Guibert
authors.affiliation: Centro Binacional (Argentina -Italia) de Investigaciones en Criobiologia Clinica y Aplicada (CAIC), Universidad Nacional de Rosario, Rosario, Argentina. jrodrig@fbioyf.unr.edu.ar.
authors.forename: Joaquin Valentin
authors.initials: JV
authors.lastname: Rodriguez
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival; D003080:Cold Temperature; D015925:Cryopreservation / Q000379:methods*; D000432:Methanol / Q000737:chemistry; D051379:Mice; D009584:Nitrogen / Q000737:chemistry
chemical_list: D009584:Nitrogen; D000432:Methanol