Flow cytometric analysis of charged and uncharged liposome formulations.
(A) FACS analysis of the uptake of rhodamine-B-PE–labeled liposomes by leukocytes in whole blood after 60 minutes. Shown is the percentage of fluorescence-positive cells (mean ± SD, n = 3). ▪ indicates EPC:SPS:Chol; ░, EPC:EPG:Chol (both 4:3:3 mole ratio and negatively charged); ■, EPC:Chol (7:3 mole ratio, uncharged). Results of 2-group t test are marked with asterisk; P < .001. (B) FACS analysis of the time-dependent uptake of rhodamine-B-PE–labeled liposomes by granulocytes (5 × 105 cells/mL). Liposomal lipid concentration is 1 mM. Values are given as percentage of the whole population, showing a single experiment of 3 independent experiments; ▪ indicates EPC:SPS:Chol; ●, EPC:EPG:Chol (both 4:3:3 mole ratio); ▴, EPC:Chol (70:30 mol%).
