title: The impact of different nanoparticle surface chemistry and size on uptake and toxicity in a murine macrophage cell line.
abstract: This study investigated the uptake, kinetics and cellular distribution of different surface coated quantum dots (QDs) before relating this to their toxicity. J774.A1 cells were treated with organic, COOH and NH2 (PEG) surface coated QDs (40 nM). Model 20 nm and 200 nm COOH-modified coated polystyrene beads (PBs) were also examined (50 microg ml(-1)). The potential for uptake of QDs was examined by both fixed and live cell confocal microscopy as well as by flow cytometry over 2 h. Both the COOH 20 nm and 200 nm PBs were clearly and rapidly taken up by the J774.A1 cells, with uptake of 20 nm PBs being relatively quicker and more extensive. Similarly, COOH QDs were clearly taken up by the macrophages. Uptake of NH2 (PEG) QDs was not detectable by live cell imaging however, was observed following 3D reconstruction of fixed cells, as well as by flow cytometry. Cells treated with organic QDs, monitored by live cell imaging, showed only a small amount of uptake in a relatively small number of cells. This uptake was insufficient to be detected by flow cytometry. Imaging of fixed cells was not possible due to a loss in cell integrity related to cytotoxicity. A significant reduction (p<0.05) in the fluorescent intensity in a cell-free environment was found with organic QDs, NH2 (PEG) QDs, 20 nm and 200 nm PBs at pH 4.0 (indicative of an endosome) after 2 h, suggesting reduced stability. No evidence of exocytosis was found over 2 h. These findings confirm that surface coating has a significant influence on the mode of NP interaction with cells, as well as the subsequent consequences of that interaction.
authors: Applied Research Centre for Health, Environment and Society, Biomedicine and Sport Science Research Group, School of Life Sciences, Napier University, 10 Colinton Road, Edinburgh, EH10 5DT, UK. m.clift@napier.ac.uk
authors: Martin J D
authors: MJ
authors: Clift
authors: Barbara
authors: B
authors: Rothen-Rutishauser
authors: David M
authors: DM
authors: Brown
authors: Rodger
authors: R
authors: Duffin
authors: Ken
authors: K
authors: Donaldson
authors: Lorna
authors: L
authors: Proudfoot
authors: Keith
authors: K
authors: Guy
authors: Vicki
authors: V
authors: Stone
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005089:Exocytosis; D005434:Flow Cytometry; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry; D045663:Quantum Dots
chemical_list: D011137:Polystyrenes