Novel Arsenic Nanoparticles Are More Effective and Less Toxic than As (III) to Inhibit Extracellular and Intracellular Proliferation of Leishmania donovani

Figure 3

As-NPs treated parasites show reduced infectivity in vitro. (a) Infection of RAW 264.7 macrophages with Leishmania promastigote was carried out as described in Section 2. Leishmania infected macrophages were incubated at 37^°C for 4 hours (panels (A), (B), (E), (F), (I), and (J)) and 24 hours (panels (C), (D), (G), (H), (K), and (L)) in absence (panels (A), (B), (C), and (D)) and in presence (panels (E), (F), (G), and (H)) of As-NPs (2 μM) and in presence of 2.0 μM As (III) (panels (I), (J), (K), and (L)) as described earlier, after which cells were prepared for fluorescence microscopy. Pictures were taken in phase (panels (A), (C), (E), (G), (I), and (K)), GFP filter (green), and DAPI filter (blue). The GFP and DAPI images were merged (panels (B), (D), (F), (H), (J), and (L)). Arrows indicate internalized parasites. Scale bar indicates 2 μm. These images only represent one of multiple independent sets. (b) Determination of IC₅₀ value from the plot of log (internalized cells or amastigotes per 100 infected macrophages) was obtained after 24 hours of incubation with indicated concentrations of As-NPs. The error bars indicate SEM. (c) Treatment with As-NPs reduced macrophage attached Leishmania parasites. Attachment of Leishmania parasite on macrophages was determined by incubating the Leishmania infected macrophages at 4^°C for 4 hours in absence (panels (A) and (B)) and presence (panels (C) and (D)) of As-NPs. Fluorescent pictures were captured in phase (panels (A) and (C)), GFP filter (green), and DAPI filter (blue). Panels (C) and (D) show merged images captured by GFP and DAPI filters (panels (B) and (D)). Arrows indicate macrophage attached parasites. These images only represent one of multiple independent sets. Scale bar indicates 2 μm.

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