Now showing 1 - 6 of 6
  • Publication
    Quantitative assessment of the comparative nanoparticle-uptake efficiency of a range of cell lines
    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.
      2225Scopus© Citations 213
  • Publication
    Experimental and theoretical approach to comparative nanoparticle and small molecule intracellular import, trafficking, and export
    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.
      1546Scopus© Citations 271
  • Publication
    Paracrine signalling of inflammatory cytokines from an in vitro blood brain barrier model upon exposure to polymeric nanoparticles
    Nanoparticle properties, such as small size relative to large highly modifiable surface area, offer great promise for neuro-therapeutics and nanodiagnostics. A fundamental understanding and control of how nanoparticles interact with the blood-brain barrier (BBB) could enable major developments in nanomedical treatment of previously intractable neurological disorders, and help ensure that nanoparticles not intended to reach the brain do not cause adverse effects. Nanosafety is of utmost importance to this field. However, a distinct lack of knowledge exists regarding nanoparticle accumulation within the BBB and the biological effects this may induce on neighbouring cells of the Central Nervous System (CNS), particularly in the long-term. This study focussed on the exposure of an in vitro BBB model to model carboxylated polystyrene nanoparticles (PS COOH NPs), as these nanoparticles are well characterised for in vitro experimentation and have been reported as non-toxic in many biological settings. TEM imaging showed accumulation but not degradation of 100 nm PS COOH NPs within the lysosomes of the in vitro BBB over time. Cytokine secretion analysis from the in vitro BBB post 24 h 100 nm PS COOH NP exposure showed a low level of pro-inflammatory RANTES protein secretion compared to control. In contrast, 24 h exposure of the in vitro BBB endothelium to 100 nm PS COOH NPs in the presence of underlying astrocytes caused a significant increase in pro-survival signalling. In conclusion, the tantalising possibilities of nanomedicine must be balanced by cautious studies into the possible long-term toxicity caused by accumulation of known 'toxic' and 'non-toxic' nanoparticles, as general toxicity assays may be disguising significant signalling regulation during long-term accumulation.
      551Scopus© Citations 37
  • Publication
    Time and Space Resolved Uptake Study of Silica Nanoparticles by Human Cells
    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.
      1487Scopus© Citations 205
  • Publication
    Can an InChI for Nano Address the Need for a Simplified Representation of Complex Nanomaterials across Experimental and Nanoinformatics Studies?
    Chemoinformatics has developed efficient ways of representing chemical structures for small molecules as simple text strings, simplified molecular-input line-entry system (SMILES) and the IUPAC International Chemical Identifier (InChI), which are machine-readable. In particular, InChIs have been extended to encode formalized representations of mixtures and reactions, and work is ongoing to represent polymers and other macromolecules in this way. The next frontier is encoding the multi-component structures of nanomaterials (NMs) in a machine-readable format to enable linking of datasets for nanoinformatics and regulatory applications. A workshop organized by the H2020 research infrastructure NanoCommons and the nanoinformatics project NanoSolveIT analyzed issues involved in developing an InChI for NMs (NInChI). The layers needed to capture NM structures include but are not limited to: core composition (possibly multi-layered); surface topography; surface coatings or functionalization; doping with other chemicals; and representation of impurities. NM distributions (size, shape, composition, surface properties, etc.), types of chemical linkages connecting surface functionalization and coating molecules to the core, and various crystallographic forms exhibited by NMs also need to be considered. Six case studies were conducted to elucidate requirements for unambiguous description of NMs. The suggested NInChI layers are intended to stimulate further analysis that will lead to the first version of a “nano” extension to the InChI standard.
      283Scopus© Citations 26