TY - JOUR A1 - Orts Gil, Guillermo A1 - Natte, Kishore A1 - Drescher, Daniela A1 - Bresch, Harald A1 - Mantion, Alexandre A1 - Kneipp, J. A1 - Österle, Werner T1 - Characterisation of silica nanoparticles prior to in vitro studies: from primary particles to agglomerates N2 - The size, surface charge and agglomeration state of nanoparticles under physiological conditions are fundamental parameters to be determined prior to their application in toxicological studies. Although silica-based materials are among the most promising candidates for biomedical applications, more systematic studies concerning the characterisation before performing toxicological studies are necessary. This interest is based on the necessity to elucidate the mechanisms affecting its toxicity. We present here TEM, SAXS and SMPS as a combination of methods allowing an accurate determination of single nanoparticle sizes. For the commercial material, Ludox TM50 single particle sizes around 30 nm were found in solution. DLS measurements of single particles are rather affected by polydispersity and particles concentration but this technique is useful to monitor their agglomeration state. Here, the influence of nanoparticle concentration, ionic strength (IS), pH and bath sonication on the agglomeration behaviour of silica particles in solution has been systematically investigated. Moreover, the colloidal stability of silica particles in the presence of BSA has been investigated showing a correlation between silica and protein concentrations and the formation of agglomerates. Finally, the colloidal stability of silica particles in standard cell culture medium has been tested, concluding the necessity of surface modification in order to preserve silica as primary particles in the presence of serum. The results presented here have major implications on toxicity investigations because silica agglomeration will change the probability and uptake mechanisms and thereby may affect toxicity. KW - Silica KW - Toxicology KW - Agglomeration KW - BSA KW - Nanoparticles KW - Characterisation PY - 2011 DO - https://doi.org/10.1007/s11051-010-9910-9 SN - 1388-0764 SN - 1572-896X VL - 13 IS - 4 SP - 1593 EP - 1604 PB - Springer AN - OPUS4-21179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mantion, Alexandre T1 - Cytotoxicity of model silver nanoparticles in human macrophages T2 - Post-satellite Meeting Eurotox 2009 CY - Dresden, Germany DA - 2010-04-23 PY - 2010 AN - OPUS4-21250 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kind, L. A1 - Plamper, F.A. A1 - Göbel, R. A1 - Mantion, Alexandre A1 - Müller, A. H. E. A1 - Pieles, U. A1 - Taubert, A. A1 - Meier, W. T1 - Silsesquioxane/polyamine nanoparticle-templated formation of star- or raspberry-like silica nanoparticles KW - Silica nanoparticles KW - 3D TEM KW - Star-shaped nanoparticles KW - Raspberry-shaped nanoparticles PY - 2009 DO - https://doi.org/10.1021/la900229n SN - 0743-7463 SN - 1520-5827 VL - 25 IS - 12 SP - 7109 EP - 7115 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlaad, H. A1 - You, L. A1 - Sigel, R. A1 - Smarsly, B. A1 - Heydenreich, M. A1 - Mantion, Alexandre A1 - Masic, A. T1 - Glycopolymer vesicles with an asymmetric membrane KW - Glycopolymer vesicle PY - 2009 DO - https://doi.org/10.1039/b820887e SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x SP - 1478 EP - 1480 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-19581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - De Bruyn Ouboter, D. A1 - Schuster, T.B. A1 - Mantion, Alexandre A1 - Meier, W. T1 - Hierarchical organization of purely peptidic amphiphiles into peptide beads N2 - A broad range of new properties is emerging from supramolecular aggregates as they pass beyond the limitations of simple molecules. Self-assembled structures of purely peptidic amphiphiles may exploit such properties to produce biocompatible, smart materials for drug administration. In aqueous media, the solid-phase derived amphiphilic undecapeptide described herein (Ac-X3-gT) forms self-assembled particles of spherical shape with diameters between 200 and 1500 nm, termed 'peptide beads'. The beads result from hierarchical organization of micellar-like structures, a fact determined by a combination of investigations carried out by electron and atomic force microscopy (AFM), static and dynamic light scattering, and small-angle X-ray scattering. These highly ordered structures agree with the concept of multicompartmentization and represent the first example of supramicellar assemblies based purely on peptides. New structural insights, as presented here, allow a better understanding of the beads' capacity to embed hydrophobic and hydrophilic payloads and therefore provide new perspectives for drug delivery applications that may result from this new class of material. KW - Peptide beads KW - Spherical peptide particles KW - Hierarchical self-assembly KW - Multicompartment micelles KW - Purely peptidic amphiphiles PY - 2011 DO - https://doi.org/10.1021/jp203048h SN - 1932-7447 SN - 1089-5639 VL - 115 IS - 30 SP - 14583 EP - 14590 PB - Soc. CY - Washington, DC AN - OPUS4-24212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vila-Comamala, J. A1 - Diaz, A. A1 - Guizar-Sicairos, M. A1 - Mantion, Alexandre A1 - Kewish, C.M. A1 - Menzel, A. A1 - Bunk, O. A1 - David, C. T1 - Characterization of high-resolution diffractive X-ray optics by ptychographic coherent diffractive imaging N2 - We have employed ptychographic coherent diffractive imaging to completely characterize the focal spot wavefield and wavefront aberrations of a high-resolution diffractive X-ray lens. The ptychographic data from a strongly scattering object was acquired using the radiation cone emanating from a coherently illuminated Fresnel zone plate at a photon energy of 6.2 keV. Reconstructed images of the object were retrieved with a spatial resolution of 8 nm by combining the difference-map phase retrieval algorithm with a non-linear optimization refinement. By numerically propagating the reconstructed illumination function, we have obtained the X-ray wavefield profile of the 23 nm round focus of the Fresnel zone plate (outermost zone width, Δr = 20 nm) as well as the X-ray wavefront at the exit pupil of the lens. The measurements of the wavefront aberrations were repeatable to within a root mean square error of 0.006 waves, and we demonstrate that they can be related to manufacturing aspects of the diffractive optical element and to errors on the incident X-ray wavefront introduced by the upstream beamline optics. KW - Fourier zone plate KW - Coherent diffraction imaging KW - Ptychography PY - 2011 DO - https://doi.org/10.1364/OE.19.021333 SN - 1094-4087 VL - 19 IS - 22 SP - 21333 EP - 21344 PB - Optical Society of America CY - Washington, DC AN - OPUS4-24615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vila-Comamala, J. A1 - Diaz, A. A1 - Guizar-Sicairos, M. A1 - Gorelick, S. A1 - Guzenko, V.A. A1 - Karvinen, P. A1 - Kewish, C.M. A1 - Färm, E. A1 - Ritala, M. A1 - Mantion, Alexandre A1 - Bunk, O. A1 - Menzel, A. A1 - David, C. ED - Morawe, C. ED - Khounsary, A.M. ED - Goto, S. T1 - Characterization of a 20-nm hard X-ray focus by ptychographic coherent diffractive imaging N2 - Recent advances in the fabrication of diffractive X-ray optics have boosted hard X-ray microscopy into spatial resolutions of 30 nm and below. Here, we demonstrate the fabrication of zone-doubled Fresnel zone plates for multi-keV photon energies (4-12 keV) with outermost zone widths down to 20 nm. However, the characterization of such elements is not straightforward using conventional methods such as knife edge scans on well-characterized test objects. To overcome this limitation, we have used ptychographic coherent diffractive imaging to characterize a 20 nm-wide X-ray focus produced by a zone-doubled Fresnel zone plate at a photon energy of 6.2 keV. An ordinary scanning transmission X-ray microscope was modified to acquire the ptychographic data from a strongly scattering test object. The ptychographic algorithms allowed for the reconstruction of the image of the test object as well as for the reconstruction of the focused hard X-ray beam waist, with high spatial resolution and dynamic range. This method yields a full description of the focusing performance of the Fresnel zone plate and we demonstrate the usefulness ptychographic coherent diffractive imaging for metrology and alignment of nanofocusing diffractive X-ray lenses. T2 - SPIE Optics and photonics CY - San Diego, USA DA - 20.08.2011 KW - X-ray imaging KW - Diffractive X-ray optics KW - Electron beam lithography KW - Ptychographic coherent diffractive imaging PY - 2011 DO - https://doi.org/10.1117/12.893235 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8139 SP - 81390E-1 EP - 81390E-7 AN - OPUS4-24613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haase, A. A1 - Rott, S. A1 - Mantion, Alexandre A1 - Graf, P. A1 - Plendl, J. A1 - Thünemann, Andreas A1 - Meier, W.P. A1 - Taubert, A. A1 - Luch, A. A1 - Reiser, G T1 - Effects of silver nanoparticles on primary mixed neural cell cultures: uptake, oxidative stress and acute calcium responses N2 - 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 µg/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 µg/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. KW - Silver nanoparticles KW - Neurons KW - Oxidative stress KW - Protein carbonyls KW - Calcium KW - Reference material KW - Nanoparticle KW - Small-angle X-ray scattering KW - SAXS PY - 2012 DO - https://doi.org/10.1093/toxsci/kfs003 SN - 1096-6080 SN - 1096-0929 VL - 126 IS - 2 SP - 457 EP - 468 PB - Oxford University Press CY - Oxford AN - OPUS4-25633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, P. A1 - Mantion, Alexandre A1 - Haase, A. A1 - Thünemann, Andreas A1 - Masic, A. A1 - Luch, A. A1 - Taubert, A. T1 - Silicification of peptide-coated chiral nanosilver: Novel core-shell structures N2 - Nanosilver is increasingly used in optics, medicine and analytical chemistry. We recently reported on the synthesis and properties of novel peptide-coated chiral nanosilver [1] using a small hexapeptide based on the amino acids CKK. In a continuation of our previous work, we use the peptides to catalyse TEOS hydrolysis in order to form a dense silica layer shell around a single nanoparticle, preventing chemical etching, allowing their inclusion in other inorganics, and making them biocompatible. Because of mild reaction conditions, the peptide integrity is ensured, as the chiral information which is contained in the nanoparticle. Moreover, these novel core-shell structures remain well-dispersed and are biocompatible. The possibility of further processing (creation of metamaterials etc.) is also in the focus of our interest. KW - Hybrid materials KW - Nanosilver KW - Core shell PY - 2010 DO - https://doi.org/10.1002/zaac.201009133 SN - 0044-2313 SN - 1521-3749 SN - 0372-7874 SN - 0863-1786 SN - 0863-1778 VL - 636 IS - 11 SP - 2115 PB - Wiley-VCH CY - Weinheim AN - OPUS4-22409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, P. A1 - Mantion, Alexandre A1 - Haase, A. A1 - Thünemann, Andreas A1 - Masic, A. A1 - Meier, W. A1 - Luch, A. A1 - Taubert, A. T1 - Silicification of peptide-coated silver nanoparticles - a biomimetic soft chemistry approach toward chiral hybrid core-shell materials N2 - 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. KW - Peptide-templated materials KW - Silver nanoparticles KW - Chiral nanoparticles KW - Ag/peptide@SiO2 nanostructures KW - Core-shell structures PY - 2011 DO - https://doi.org/10.1021/nn102969p SN - 1936-0851 VL - 5 IS - 2 SP - 820 EP - 833 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-23207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haase, A. A1 - Arlinghaus, H. F. A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Graf, P. A1 - Mantion, Alexandre A1 - Draude, F. A1 - Galla, S. A1 - Plendl, J. A1 - Goetz, M.E. A1 - Masic, A. A1 - Meier, W. A1 - Thünemann, Andreas A1 - Taubert, A. A1 - Luch, A. T1 - 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 N2 - 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. KW - Nanosilver KW - Laser-SNMS KW - TOF-SIMS KW - Confocal Raman microscopy KW - Oxidative stress KW - Protein carbonyls PY - 2011 DO - https://doi.org/10.1021/nn200163w SN - 1936-0851 VL - 5 IS - 4 SP - 3059 EP - 3068 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-23656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -