title: Development of a reliable low-cost controlled cooling rate instrument for the cryopreservation of hematopoietic stem cells.
abstract: OBJECTIVE
  An optimal cooling rate is one of the critical factors influencing the survival of cells during cryopreservation. We describe a novel device, called the box-in-box, that has been developed for optimal cryopreservation of human hematopoietic stem cells (HSC).
  
  
  METHODS
  This work presents the design of the device, a mathematical formulation describing the expected temperature histories of samples during the freezing process, along with actual experimental results of thermal profile tests. In experiments, when the box-in-box device was transferred from room temperature to a -80 degrees C freezer, a cooling rate of -1 to -3.5 degrees C/min, which has been widely used for the cryopreservation of HSC, was achieved. In order to evaluate this device further, HSC cryopreservation was compared between the box-in-box device and a commercially available controlled-rate freezer (CryoMed).
  
  
  RESULTS
  The experimental data, including total cell population and CD34(+) hematopoietic progenitor cell recovery rates, viability and cell culture colony assays, showed that the box-in-box worked as well as the CryoMed instrument. There was no significant difference in either survival rate or the culture/colony outcome between the two devices.
  
  
  CONCLUSIONS
  The box-in-box device can work as a cheap, durable, reliable and maintenance-free instrument for the cryopreservation of HSC. This concept of a box-in-box may also be adapted to other cooling rates to support cryopreservation of a wide variety of tissues and cells.
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 , USA.
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Shu
authors.forename: Xianjiang
authors.initials: X
authors.lastname: Kang
authors.forename: Hsiuhung
authors.initials: H
authors.lastname: Chen
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhou
authors.forename: Jester
authors.initials: J
authors.lastname: Purtteman
authors.forename: David
authors.initials: D
authors.lastname: Yadock
authors.forename: Shelly
authors.initials: S
authors.lastname: Heimfeld
authors.forename: Dayong
authors.initials: D
authors.lastname: Gao
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D002470:Cell Survival; D003080:Cold Temperature; D003114:Colony-Forming Units Assay; D015925:Cryopreservation / Q000191:economics* / Q000295:instrumentation* / Q000379:methods; D015672:Erythroid Precursor Cells / Q000166:cytology; D055014:Granulocyte-Macrophage Progenitor Cells / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D008954:Models, Biological
chemical_list: D018952:Antigens, CD34