Fig. 3: Preparation and characterization of the MPDOLs.

a Schematic illustration of the MPDOL fabrication process. b Agarose gel electrophoresis showing plasmid DNA complexation by PβAE at different weight ratios. c Size distribution and morphological images of PDs, OLs, PDOLs, and MPDOLs, scale bar, 200 nm. d Fluorescence microscopy image of MSCs transfected by LV-Sftpb with GFP for 24 h, scale bar, 100 μm. e Western blot analysis confirming high SP-B expression in SP-B⁺ MSC cells. f The emission spectrum of the FRET pair generated by Dil-labeled membranes and DiO-labeled liposomes in MPDOLs. g SDS-PAGE analysis of membrane proteins in MPDOLs. h Release kinetics of OST from MPDOLs in two different pH environments (n = 3 independent samples). i Representative in vivo imaging of LLC tumor-bearing mice after inhalation of DiR, DiR-labeled PDOLs, and DiR-labeled MPDOLs, and j quantitative analysis of fluorescence radiant efficiency in major organs (n = 3 mice). k Immunofluorescence images of lung sections from mice administered with DiR, DiR-labeled PDOLs, and DiR-labeled MPDOLs, scale bar, 500 μm. l Flow cytometry analysis showing cell percentage that internalizes MPDOLs in CD45⁻ cells, lymphocytes, and macrophages in total cells of the lung tissues (n = 3 mice). Data are shown as mean ± SD. j was calculated using the one-way ANOVA with a Tukey post hoc test in each kind of organ. Source data are provided as a Source Data file.