Cellular biodistribution of liposomes at 4- and 24-hour time points. DiD-labeled liposomes were injected intravenously into male ob/ob mice and tissues were harvested four or 24 hours later. Peritoneal lavages, bone marrow, blood and Epid and SC AT were harvested to stain peritoneal cavity (PerC), bone marrow (BM), blood, and SVF cells, respectively, for analysis by flow cytometry. (A-D) DiD+ macrophages and other cell subsets were also quantified as a percent of total DiD+ cells at four (A,C) and 24 hours (B,D) post-injection in the Epid AT (A,C) and SC AT (B, D), n = 6 in each group. The cell subsets analyzed were macrophages (Mac, CD45+F4/80+), B cells (CD45+CD19+), T cells (CD45+CD3+), monocytes (Mono, CD45+CD115+), dendritic cells (DC, CD45+CD11c+), other CD45+ Cells (Other 45+, CD45+CD19-CD3-F4/80- CD11c- CD115-), endothelial cells (EC, CD45-CD31+), and other CD45- cells (Other 45-, CD45-CD31-). (E) The mean fluorescence intensity (MFI) of DiD within each of these subsets was also quantified in Epid AT. (F) The percent of total cells in all aforementioned tissues that were DiD+ was also quantified. Data represents the mean ± SD.