1. Fig. 2. CD31 provides robust NP targeting in vitro but slow kinetics.
CD31 provides robust NP targeting in vitro but slow kinetics. (A) Representative transmission electron microscopy image of poly(lactic acid)–poly(ethylene) glycol NPs. Scale bar, 200 nm. (B) Quantification of NP size distribution and polydispersity index as measured by dynamic light scattering for both 1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI)– and 3,3′-dioctadecyloxacarbocyanine perchlorate (DiO)–loaded nanoparticles (NPs; n = 3; a t test was used for statistical analysis). N.S., not statistically significant. (C) Representative 20× images of CD31-NPs versus Control-NPs after a 2-hour incubation with human umbilical vein endothelial cells (HUVECs) in static culture. DiO-loaded NPs are shown in green (right column) overlaid with brightfield images (left column). Scale bars, 150 μm. n = 3. (D) Representative fluorescence-activated cell sorting (FACS) histograms for HUVECs treated identically to (C). (E) Quantification of triplicate FACS experiments as shown in (D). n = 3. MFI, mean fluorescence intensity; a.u., arbitrary units. (F) Representative images of accumulation of DiI NPs as a function of time on HUVECs in a microfluidic cell culture during perfusion with CD31-NPs (100 μg/ml; top) or Control-NPs (100 μg/ml; bottom) at 2 dyne/cm2. Each image is 300 μm wide, representing the full width of the microfluidic channel. NPs are pseudocolored green for better visualization. (G) Quantification of mean area of positive fluorescence for flow experiments as performed in (F) at a range of concentrations (n = 3 independent imaging regions for each dose and time point). Lines through data represent fit to a rate equation. (H) Plot of rates as a function of NP concentration as extracted from quantification in (G). Line through data represents linear fit. Rates are normalized to a concentration of 10 μg/ml (dashed line, 1). All error bars represent 1 SD.
Gregory T. Tietjen et al., Sci Transl Med 2017;9:eaam6764
Published by AAAS