@article{HaaseRottMantionetal.2012,
  author    = {Haase, Andrea and Rott, Stephanie and Mantion, Alexandre and Graf, Philipp and Plendl, Johanna and Th{\"u}nemann, Andreas F. and Meier, Wolfgang P. and Taubert, Andreas and Luch, Andreas and Reiser, Georg},
  title     = {Effects of silver nanoparticles on primary mixed neural cell cultures: Uptake, oxidative stress and acute calcium responses},
  series = {Toxicological sciences},
  volume    = {126},
  journal   = {Toxicological sciences},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {1096-6080},
  doi       = {10.1093/toxsci/kfs003},
  pages     = {457 -- 468},
  year      = {2012},
  abstract  = {In the body, nanoparticles can be systemically distributed and then may affect secondary target organs, such as the central nervous system (CNS). Putative adverse effects on the CNS are rarely investigated to date. Here, we used a mixed primary cell model consisting mainly of neurons and astrocytes and a minor proportion of oligodendrocytes to analyze the effects of well-characterized 20 and 40 nm silver nanoparticles (SNP). Similar gold nanoparticles served as control and proved inert for all endpoints tested. SNP induced a strong size-dependent cytotoxicity. Additionally, in the low concentration range (up to 10 mu g/ml of SNP), the further differentiated cultures were more sensitive to SNP treatment. For detailed studies, we used low/medium dose concentrations (up to 20 mu g/ml) and found strong oxidative stress responses. Reactive oxygen species (ROS) were detected along with the formation of protein carbonyls and the induction of heme oxygenase-1. We observed an acute calcium response, which clearly preceded oxidative stress responses. ROS formation was reduced by antioxidants, whereas the calcium response could not be alleviated by antioxidants. Finally, we looked into the responses of neurons and astrocytes separately. Astrocytes were much more vulnerable to SNP treatment compared with neurons. Consistently, SNP were mainly taken up by astrocytes and not by neurons. Immunofluorescence studies of mixed cell cultures indicated stronger effects on astrocyte morphology. Altogether, we can demonstrate strong effects of SNP associated with calcium dysregulation and ROS formation in primary neural cells, which were detectable already at moderate dosages.},
  language  = {en}
}
@article{HaaseArlinghausTentschertetal.2011,
  author    = {Haase, Andrea and Arlinghaus, Heinrich F. and Tentschert, Jutta and Jungnickel, Harald and Graf, Philipp and Mantion, Alexandre and Draude, Felix and Galla, Sebastian and Plendl, Johanna and Goetz, Mario E. and Masic, Admir and Meier, Wolfgang P. and Thuenemann, Andreas F. and Taubert, Andreas and Luch, Andreas},
  title     = {Application of Laser Postionization Secondary Neutral Mass Spectrometry/Time-of-Flight Secondary Ion Mass Spectrometry in Nanotoxicology: Visualization of Nanosilver in Human Macrophages and Cellular Responses},
  series = {ACS nano},
  volume    = {5},
  journal   = {ACS nano},
  number    = {4},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1936-0851},
  doi       = {10.1021/nn200163w},
  pages     = {3059 -- 3068},
  year      = {2011},
  abstract  = {Silver nanoparticles (SNP) are the subject of worldwide commercialization because of their antimicrobial effects. Yet only little data on their mode of action exist. Further, only few techniques allow for visualization and quantification of unlabeled nanoparticles inside cells. To study SNP of different sizes and coatings within human macrophages, we introduce a novel laser postionization secondary neutral mass spectrometry (Laser-SNMS) approach and prove this method superior to the widely applied confocal Raman and transmission electron microscopy. With time-of-flight secondary ion mass spectrometry (TOF-SIMS) we further demonstrate characteristic fingerprints in the lipid pattern of the cellular membrane indicative of oxidative stress and membrane fluidity changes. Increases of protein carbonyl and heme oxygenase-1 levels in treated cells confirm the presence of oxidative stress biochemically. Intriguingly, affected phagocytosis reveals as highly sensitive end point of SNP-mediated adversity In macrophages. The cellular responses monitored are. hierarchically linked, but follow individual kinetics and are partially reversible.},
  language  = {en}
}
@article{GrafMantionHaaseetal.2011,
  author    = {Graf, Philipp and Mantion, Alexandre and Haase, Andrea and Thuenemann, Andreas F. and Masic, Admir and Meier, Wolfgang P. and Luch, Andreas and Taubert, Andreas},
  title     = {Silicification of peptide-coated silver nanoparticles-A biomimetic soft chemistry approach toward chiral hybrid core-shell materials},
  series = {ACS nano},
  volume    = {5},
  journal   = {ACS nano},
  number    = {2},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1936-0851},
  doi       = {10.1021/nn102969p},
  pages     = {820 -- 833},
  year      = {2011},
  abstract  = {Silica and silver nanoparticles are relevant materials for new applications in optics, medicine, and analytical chemistry. We have previously reported the synthesis of pH responsive, peptide-templated, chiral silver nanoparticles. The current report shows that peptide-stabilized nanoparticles can easily be coated with a silica shell by exploiting the ability of the peptide coating to hydrolyze silica precursors such as TEOS or TMOS. The resulting silica layer protects the nanoparticles from chemical etching, allows their inclusion in other materials, and renders them biocompatible. Using electron and atomic force microscopy, we show that the silica shell thickness and the particle aggregation can be controlled simply by the reaction time. Small-angle X ray scattering confirms the Ag/peptide@silica core-shell structure. UV-vis and circular dichroism spectroscopy prove the conservation of the silver nanoparticle chirality upon silicification. Biological tests show that the biocompatibility in simple bacterial systems is significantly improved once a silica layer is deposited on the silver particles.},
  language  = {en}
}
@article{MantionGrafFloreaetal.2011,
  author    = {Mantion, Alexandre and Graf, Philipp and Florea, Ileana and Haase, Andrea and Thuenemann, Andreas F. and Masic, Admir and Ersen, Ovidiu and Rabu, Pierre and Meier, Wolfgang P. and Luch, Andreas and Taubert, Andreas},
  title     = {Biomimetic synthesis of chiral erbium-doped silver/peptide/silica core-shell nanoparticles (ESPN)},
  series = {Nanoscale},
  volume    = {3},
  journal   = {Nanoscale},
  number    = {12},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2040-3364},
  doi       = {10.1039/c1nr10930h},
  pages     = {5168 -- 5179},
  year      = {2011},
  abstract  = {Peptide-modified silver nanoparticles have been coated with an erbium-doped silica layer using a method inspired by silica biomineralization. Electron microscopy and small-angle X-ray scattering confirm the presence of an Ag/peptide core and silica shell. The erbium is present as small Er(2)O(3) particles in and on the silica shell. Raman, IR, UV-Vis, and circular dichroism spectroscopies show that the peptide is still present after shell formation and the nanoparticles conserve a chiral plasmon resonance. Magnetic measurements find a paramagnetic behavior. In vitro tests using a macrophage cell line model show that the resulting multicomponent nanoparticles have a low toxicity for macrophages, even on partial dissolution of the silica shell.},
  language  = {en}
}