[Optimization of lyophilization procedures for freeze-drying of human red blood cells].
OBJECTIVE
To investigate the different parameters of the lyophilization procedures that affect the recovery of the rehydrated red blood cells (RBCs).


METHODS
Human RBCs loaded in tubes were cooled with 4 different modes and subjected to water bath at 25 degrees celsius;. The morphological changes of the RBCs were observed to assess the degree of vitrification, and the specimens were placed in the freeze-dryer with the temperature set up at 40, -50, -60, -70 and -80 degrees celsius;. The rates of temperature rise of the main and secondary drying in the lyophilization procedures were compared, and the water residue in the specimens was determined.


RESULTS
The protectant did not show ice crystal in the course of freezing and thawing. No significant difference was found in the recovery rate of the rehydrated RBCs freeze-dried at the minimum temperature of -70 degrees celsius; and -80 degrees celsius; (P > 0.05). The E procedure resulted in the maximum recovery of the RBCs (83.14% ± 9.55%) and Hb (85.33% ± 11.42%), showing significant differences from the other groups(P < 0.01 or 0.05). The recovery of the RBCs showed a positive correlation to the water residue in the samples.


CONCLUSIONS
Fast cooling in liquid nitrogen and shelf precooling at -70 degrees celsius; with a moderate rate of temperature rise in lyophylization and a start dry temperature close to the shelf equilibrium temperature produce optimal freeze-drying result of human RBCs.
Chen
Lin-feng
LF
Department of Blood Transfusion, PLA General Hospital, Beijing 100853, China. TMMUChen@hotmail.com
Liu
Jing-han
JH
Wang
De-qing
DQ
Ouyang
Xi-lin
XL
Zhuang
Yuan
Y
Che
Ji
J
Yu
Yang
Y
Li
Hui
H
D004912:Erythrocytes / Q000166:cytology*; D005612:Freeze Drying; D006801:Humans; D014021:Tissue Preservation / Q000379:methods*