Figure 7. RBC Freezing with reduced β-pBrPh-Glc (13) concentrations.

(a) RBC freezing using the interrupted freezing protocol with various concentrations of β-pBrPh-Glc (13) containing cryo-solutions in 15% glycerol. RBC samples (n = 4–30) were slow cooled 1°C/min to defined sub-zero temperatures and then rapidly cooled and stored at −80°C. (b) RBC freezing using a rapid-freezing protocol. Samples in indicated cryo-solutions (n = 3–12) were nucleated at -5°C, then rapidly frozen to -80°C by plunging is solid CO₂ (dry ice). All samples were thawed at 37°C and post-thaw RBC hemolysis was determined by Drabkin's assay. Results are presented as mean post-thaw RBC integrity (100 - % hemolysis). Error bars represent standard error of the mean (SEM). Asterisks indicate statistical significance relative to the glycerol control as determined by two-tailed unpaired student's T-test: *, p < 0.05; **, p < 0.01; ***, p < 0.001.