Figure 4: Darkfield microscopy of isolated BAL cells. Representive images of enchanced darkfield microsopy of cells recovered from bronchoalveolar lavage fluid. One day following citrate vehicle instillation (A), 7 days following instillation of citrate vehicle (B), 1 day following instillation of 20 nm AgNP (C), 7 days following instillation of 20 nm AgNP (D). White bar identifies 10 μm scaling. White arrows indicate the punctate accumulation of silver particles associated with alveolar macrophages.