Fig 2. Human erythrocyte membrane engineering with NHS-pDMAA-Rh polymers.

NHS-pDMAA-Rh polymers exhibit significant non-specific binding and initial high-density fluorescence quenching. Human RBCs were modified with 182 μM NHS-pDMAA-Rh or 98 μM HO-pDMAA-Rh for 30 minutes at 37°C. (A) Representative images of NHS-pDMAA-Rh-exposed hRBC for each designated time point. (B) Representative images of HO-pDMAA-Rh-exposed hRBC for each designated time point. Epifluorescent images were capture after washing on a Leica inverted microscope at 20X. Scale bars measure 100 μm. (C) Supernatant, cytosolic, and membrane fractions were collected at 0, 1, 4, and 8 hours. Polymer retention and internalization was assessed by monitoring the relative fluorescence of each fraction over time and calculated as the number of polymer molecules per hRBC using a standard curve. (D) The number of polymer molecules per nm² hRBC surface area was calculated using an average hRBC surface area of 140 μm². Images were background corrected and the brightness/contrast for each channel was balanced using Image J software. n = 3.