Fig. 4
TEM imaging of IONPs-PAA-PEG-MAN and Rif@IONPs-PAA-PEG-MAN promoted M.tb-nanodecoy co-localization for intracellular Mtb killings in THP-1 macrophages. A Control THP-1 macrophages infected with H37Rv, H37Rv in phagosome was indicated by yellow arrow. B, C H37Rv infected THP-1 macrophages after IONPs-PAA-PEG-MAN treatment, H37Rv in phagosomes (indicated by yellow arrow) were surrounded by IONPs-PAA-PEG-MAN in lysosomes (indicated by red arrow) and IONPs-PAA-PEG-MAN in endosomes (indicated by blue arrow). D–F H37Rv infected THP-1 macrophages after IONPs-PAA-PEG-MAN treatment, some H37Rv (indicated by white arrow) were fused into lysosomes or located in lysosomes with IONPs-PAA-PEG-MAN (indicated by red arrow) co-localized inside. G, H H37Rv infected THP-1 macrophages after Rif@IONPs-PAA- PEG-MAN treatment, H37Rv in phagosomes (indicated by yellow arrow) were surrounded by Rif@IONPs-PAA-PEG-MAN in lysosomes (indicated by red arrow) and Rif@IONPs- PAA-PEG-MAN in cytoplasm (indicated by blue arrow). I–K H37Rv infected THP-1 macrophages after Rif@IONPs-PAA-PEG-MAN treatment, some H37Rv (indicated by white arrow) were fused into or located in lysosomes with Rif@IONPs-PAA-PEG-MAN (indicated by red arrow) co-localized inside. H37Rv in lysosomes from (J–K) were partially destroyed by Rif@IONPs-PAA-PEG-MAN to show very incompact and penetrable cross section morphology. L H37Rv infected THP-1 macrophages after rifampicin treatment, H37Rv in phagosome was indicated by yellow arrow. For TEM imaging, THP-1 cells were seeded at a density of 1 × 106 into 6 plates with 100 nM PMA stimulation for 24 h, and then infected with H37Rv (4 h infection) using MOI = 1. The infected cells were treated with IONPs-PAA-PEG- MAN or Rif@IONPs-PAA-PEG-MAN for 72 h, and then collected, washed with PBS and fixed by 2.5% glutaraldehyde and 2% paraformaldehyde for 48 h at 4 ℃. The fixed cell samples were washed with PBS and then further fixed with 0.1% osmic acid for 2 h. After washed with PBS, the samples were dehydrated with sequential treatment of 50%, 70%, 85%, 90%, and 100% ethanol, respectively. Then, the samples were embedded in resin, cut into ultrathin slices, stained with 2% uranyl acetate and 0.2% lead citrate before TEM observation