Development of a reliable low-cost controlled cooling rate instrument for the cryopreservation of hematopoietic stem cells.
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.
Shu
Zhiquan
Z
Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 , USA.
Kang
Xianjiang
X
Chen
Hsiuhung
H
Zhou
Xiaoming
X
Purtteman
Jester
J
Yadock
David
D
Heimfeld
Shelly
S
Gao
Dayong
D
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
D018952:Antigens, CD34