Nanobiotic uptake by phagocytic cells and in vitro efficacy against M. tuberculosis.a. Nanobiotics uptake by white blood cells quantified by fluorescence-activated cell sorting (FACS). Coumarin 6-labelled Nano INH are preferentially uptaken by phagocytic cells, namely monocytes (CD14+) and neutrophils (CD15+), rather than lymphocytes, such as T cells (CD3+) and B cells (CD19+), likely reflecting their large size distribution. b. Confocal microscopy images of differentiated THP-1 cells infected with a mCherry fluorescent reporter strain of M. tuberculosis H37Rv ΔleuD ΔpanCD (red) and treated with Cou-6-labelled Nano INH (green) (scale bar, 10 μm) c. Differentiated THP-1 cells were infected with a luminescent reporter strain M. tuberculosis H37Rv ΔleuD ΔpanCD, treated with 100 μM INH either as a free drug or as nanodrug and intracellular M. tuberculosis was assessed 48 h post-infection by relative luminescence units (RLUs). Untreated cells and cells treated with drug-free nanobiotics (Nano Blank) were used as negative controls. Results are presented in terms of RLUs normalized to untreated cells (Mean ± SEM, n = 6). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).
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