http://hdl.handle.net/10197/3005 2013-05-20T03:11:21Z 2013-05-20T03:11:21Z Dawson, Kenneth A. Anguissola, Sergio Lynch, Iseult http://hdl.handle.net/10197/3724 2013-02-26T09:58:56Z 2012-01-26T00:00:00Z

The need for in situ characterisation in nanosafety assessment : funded transnational access via the QNano research infrastructure Dawson, Kenneth A.; Anguissola, Sergio; Lynch, Iseult

2012-01-26T00:00:00Z Kim, Jong Ah Åberg, Christoffer Salvati, Anna Dawson, Kenneth A. http://hdl.handle.net/10197/3695 2013-01-15T11:42:35Z 2012-01-01T00:00:00Z

Role of cell cycle on the cellular uptake and dilution of nanoparticles in a cell population Kim, Jong Ah; Åberg, Christoffer; Salvati, Anna; Dawson, Kenneth A. Nanoparticles are considered a primary vehicle for targeted therapies because they can pass biological barriers, enter and distribute in cells by energy-dependent pathways1-3. Until now, most studies have shown that nanoparticle properties, such as size4-6 and surface7,8, can affect how cells internalise nanoparticles. Here we show that the different phases of cell growth, which constitute the cell cycle, can also influence nanoparticle uptake. Although cells in different cell cycle phases internalised nanoparticles with similar rates, after 24 hours of uptake the concentration of nanoparticles in the cells is ranked according to the different cell cycle phases: G2/M > S > G0/G1. Nanoparticles were not exported from cells but the internalised nanoparticle concentration is split when the cell divides. Our results suggest that future studies on nanoparticle uptake should consider the cell cycle because in a cell population, the internalised nanoparticle dose in each cell varies as the cell cycles.

2012-01-01T00:00:00Z Shapero, Kayle Fenaroli, Federico Lynch, Iseult Cottell, David C. Salvati, Anna Dawson, Kenneth A. http://hdl.handle.net/10197/3694 2012-06-21T15:38:42Z 2011-01-01T00:00:00Z

Time and Space Resolved Uptake Study of Silica Nanoparticles by Human Cells Shapero, Kayle; Fenaroli, Federico; Lynch, Iseult; Cottell, David C.; Salvati, Anna; Dawson, Kenneth A. A spatio-temporal mapping of the uptake of silica (SiO2) nanoparticles of different sizes by lung epithelial cells has been obtained. Based on high control of nanoparticle dispersion in cell media and cell exposure, one obtains reproducible and quantitative time-resolved data using a combination of flow cytometry, fluorescence and electron microscopies. We are thereby able to give a rather detailed account of the journey of SiO2 nanoparticles from the early events of uptake to their final sub-cellular localization.

2011-01-01T00:00:00Z dos Santos, Tiago Varela, Juan Lynch, Iseult Dawson, Kenneth A. Salvati, Anna http://hdl.handle.net/10197/3533 2012-03-01T11:33:18Z 2011-12-02T00:00:00Z

Quantitative assessment of the comparative nanoparticle-uptake efficiency of a range of cell lines dos Santos, Tiago; Varela, Juan; Lynch, Iseult; Dawson, Kenneth A.; Salvati, Anna Interest continues to grow in the possibility of understanding the mechanism(s) of nanoparticle-cell interactions. At present there is little knowledge, and essentially no understanding, of the relevant length and time scales for nanoparticle-intracellular entry, and localization within cells, and the cell-specificity of nanoparticle uptake and localisation. We have investigated here the effect of particle size on the in vitro intracellular uptake of model fluorescent carboxyl-modified polystyrene nanoparticles in various cell lines commonly used for uptake studies. A range of micro- and nanoparticles of defined sizes (40 nm to 2 μm)were incubated with a series of cell types, including HeLa and A549 epithelial cells, 1321N1 astrocytes, HCMEC D3 endothelial cells and murine RAW 264.7 macrophages. Techniques such as confocal microscopy and flow cytometry were used to study particle uptake and sub-cellular localisation, making significant efforts to ensure reproducibility in a semi-quantitative approach. The results indicated that internalization of (nano)particles is highly size dependent for all cell lines studied and that the kinetics of uptake for the same nanoparticle varies in the different cell types. Interestingly, even cells non specialized for phagocytosis were able to internalize the larger nanoparticles. Intracellular uptake of all sizes of (nano)particles was observed to be the highest in RAW 264.7 cells (a specialized phagocytic cell line) and the lowest in the HeLa cells. Results suggests that (nano)particle uptake might not follow commonly defined size limits for uptake processes and highlights the variability of uptake kinetics for the same material in different cell types. These conclusions have important implications for the assessment of the safety of nanomaterials and potential biomedical applications of nanoparticles.

2011-12-02T00:00:00Z Salvati, Anna Åberg, Christoffer dos Santos, Tiago Varela, Juan Pinto, Paulo Lynch, Iseult Dawson, Kenneth A. http://hdl.handle.net/10197/3340 2011-11-24T15:07:23Z 2011-12-01T00:00:00Z

Experimental and theoretical approach to comparative nanoparticle and small molecule intracellular import, trafficking, and export Salvati, Anna; Åberg, Christoffer; dos Santos, Tiago; Varela, Juan; Pinto, Paulo; Lynch, Iseult; Dawson, Kenneth A. Central to understanding how nanoscale objects interact with living matter is the need for reproducible and verifiable data that can be interpreted with confidence. Likely this will be the basis of durable advances in nanomedicine and nanomedical safety. To develop these fields, there is also considerable interest in advancing the first generation of theoretical models of nanoparticle (NP) uptake into cells, and NP biodistribution in general. Here we present an uptake study comparing the outcomes for free molecular dye and NPs labeled with the same dye. A simple flux-based approach is presented to model NP uptake. We find that the intracellular NP concentration grows linearly in time, and that the uptake is essentially irreversible, with the particles accumulating in lysosomes. A wide range of practical challenges, from labile dye release to NP aggregation and the need to account for cell division, are addressed to ensure that these studies yield meaningful kinetic information.

2011-12-01T00:00:00Z