The individual-cell-based cryo-chip for the cryopreservation, manipulation and observation of spatially identifiable cells. II: functional activity of cryopreserved cells.
BACKGROUND
The cryopreservation and thawing processes are known to induce many deleterious effects in cells and might be detrimental to several cell types. There is an inherent variability in cellular responses among cell types and within individual cells of a given population with regard to their ability to endure the freezing and thawing process. The aim of this study was to evaluate the fate of cryopreserved cells within an optical cryo apparatus, the individual-cell-based cryo-chip (i3C), by monitoring several basic cellular functional activities at the resolution of individual cells.


RESULTS
In the present study, U937 cells underwent the freezing and thawing cycle in the i3C device. Then a panel of vital tests was performed, including the number of dead cells (PI staining), apoptotic rate (Annexin V staining), mitochondrial membrane potential (TMRM staining), cytoplasm membrane integrity and intracellular metabolism (FDA staining), as well as post-thawing cell proliferation assays. Cells that underwent the freezing - thawing cycle in i3C devices exhibited the same functional activity as control cells. Moreover, the combination of the multi-parametric analysis at a single cell resolution and the optical and biological features of the device enable an accurate determination of the functional status of individual cells and subsequent retrieval and utilization of the most valuable cells.


CONCLUSIONS
The means and methodologies described here enable the freezing and thawing of spatially identifiable cells, as well as the efficient detection of viable, specific, highly biologically active cells for future applications.
The Biophysical Interdisciplinary Schottenstein Center for the Research and Technology of the Cellome, Bar-Ilan University, Ramat Gan, Israel.
Elena
E
Afrimzon
Naomi
N
Zurgil
Yana
Y
Shafran
Friederike
F
Ehrhart
Yaniv
Y
Namer
Sergei
S
Moshkov
Maria
M
Sobolev
Assaf
A
Deutsch
Steffen
S
Howitz
Martin
M
Greuner
Michael
M
Thaele
Ina
I
Meiser
Heiko
H
Zimmermann
Mordechai
M
Deutsch
D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D049109:Cell Proliferation; D002470:Cell Survival; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods*; D005615:Freezing; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D020298:U937 Cells
D017304:Annexin A5