PMC

MCF-7 cells were treated with 100 μg/mL Fe₃O₄ nanoparticles and were washed with PBS twice before freezing. A. At 20°C before freezing. B. At -13.6°C during freezing. C. At -13.8°C during freezing. D. At -16.3°C during freezing. E. At -25.9°C during freezing. F. At -32.6°C during freezing. G. At -40°C, the final state before thawing. H. At -30.7°C during thawing. I. At -17.7°C during thawing. J. At -11.3°C during thawing. K. At -7.9°C during thawing. L. At 20°C after thawing.

Effect of controlled freezing rate on bulk glycerol frozen samples. Recovery of RBCs preserved by various glycerol freezing and thawing methods over a period of two weeks (mean ± SD). Controlled freezing rate (n=2; Δ) compared to regular bulk glycerol freezing (n=2; □) with standard thawing protocol, and controlled freezing rate (n=4; ▲) compared to regular bulk glycerol freezing (n=4; ■) with the modified thawing protocol.

A) ‘FS-NHB’ before freezing stress; B) ‘FT-JJ’ before freezing stress; C) ‘FS-NHB’ after freezing stress; D) ‘FT-JJ’ after freezing stress. CW, cell wall; the arrow indicates the dense labeling on the plasma membrane; Bar  =  0.5 µm.

MSC freezing and impact on replicative senescence. (A) Cumulative population doubling (PD) numbers at each passage of the same MSC line without any freezing steps, one freezing step, two freezing steps or freezing at every passage until reaching replicative senescence. The results are presented as mean ± SEM of four individual MSC lines. The box with the dashed boarder lines containing the results for passage 4 and passage 5 is enlarged on the right. (B) Example of the growth kinetics of one of the four individual MSC lines presented in . (C) Mean cell area compared to population doubling (PD) numbers of either unfrozen MSCs or after either one or two freezing steps. ^**p < 0.01.