Figure 4

Comparison of the effect of DMSO addition procedures on graded freezing using a 1 °C/min cooling rate.

The three different DMSO procedures tested were: (i) adding a 20% DMSO solution to the HUVEC suspension to a final concentration of 10% DMSO with 15 minute exposure at 0 °C; (ii) adding a 20% DMSO solution to the HUVEC suspension to a final concentration of 10% DMSO with 30-minute exposure at 0 °C; and (iii) adding a 20% DMSO solution to the HUVEC suspension to an initial concentration of 3% DMSO followed by a 10-minute exposure at 0 °C and then adding more of the 20% DMSO solution to a final concentration of 10% DMSO followed by a 20-minute exposure at 0 °C¹⁵. Three independent experiments were carried out and the mean membrane integrity was calculated for each experimental temperature. Error bars represent standard error of the mean.