Fig 8. Effect of human erythrocyte membrane engineering with NHS-pDMAA-TEMPO˙ polymers on membrane damage during oxidant exposure over time.
Human erythrocytes modified with either NHS-pDMAA-Cy3 or NHS-pDMAA-TEMPO˙ demonstrated significant or nearly significant cytoprotective trends over time when exposed to oxidizing conditions (0.1 mM CuSO4/1.25 mM ascorbate solution). Results are normalized to unmodified, oxidized hRBCs for each time point. Oxidation in this assay is indirectly measured by monitoring externalized phosphatidylserine tagging by Annexin V-Alexa488 using flow cytometry. Cell populations were gated as either positive or negative for Annexin V-Alexa488 fluorescence. *** indicates significance, p < 0.001 compared to unmodified hRBCs; * indicates significance, p < 0.05 compared to unmodified hRBCs; # indicates significance, p < 0.05 compared to NHS-pDMAA-Cy3 modified hRBCs. NHS-pDMAA-TEMPO˙-modified hRBCs are nearly significantly different to unmodified hRBCs at 30 minutes (p = 0.1190). Results were analyzed by a two-way ANOVA with Fisher’s LSD post hoc test. Bars represent group means ± SEM. n = 3.