A, DSPE-PEG-IgG was synthesized as described in Methods. The construct was incubated with washed mouse RBCs in order to be incorporated into the RBC membrane; B, The incorporated IgG was detected with Alexa 488 labeled anti-mouse IgG. The antibody forms punctuate label on the RBC surface; C, DSPE-PEG-IgG was quantified with western blotting. Purified mouse IgG was used for calibration curve. Painted RBCs were lysed and loaded on the gel. RBC lysate shows incorporation of the construct. Note that IgG construct shows a retardation in the gel as compared to native IgG heavy chain (50 kDa); D, Amount of incorporated IgG vs. FL-1 fluorescence by flow cytometry; E, Incorporation efficiency as a function of IgG concentration. Note a decrease in the percentage of incorporated IgG with the increase in DSPE-PEG-IgG concentration during incubation.