TY - JOUR A1 - Bantz, C. A1 - Koshkina, Olga A1 - Lang, Thomas A1 - Galla, H.-J. A1 - Kirkpatrick, C.J. A1 - Stauber, R.H. A1 - Maskos, M. T1 - The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions JF - Beilstein journal of nanotechnology N2 - Due to the recent widespread application of nanomaterials to biological systems, a careful consideration of their physiological impact is required. This demands an understanding of the complex processes at the bio–nano interface. Therefore, a comprehensive and accurate characterization of the material under physiological conditions is crucial to correlate the observed biological impact with defined colloidal properties. As promising candidates for biomedical applications, two SiO2-based nanomaterial systems were chosen for extensive size characterization to investigate the agglomeration behavior under physiological conditions. To combine the benefits of different characterization techniques and to compensate for their respective drawbacks, transmission electron microscopy, dynamic light scattering and asymmetric flow field-flow fractionation were applied. The investigated particle systems were (i) negatively charged silica particles and (ii) poly(organosiloxane) particles offering variable surface modification opportunities (positively charged, polymer coated). It is shown that the surface properties primarily determine the agglomeration state of the particles and therefore their effective size, especially under physiological conditions. Thus, the biological identity of a nanomaterial is clearly influenced by differentiating surface properties. KW - Nanomaterial characterization KW - Physiological conditions KW - Surface properties KW - Silica nanoparticles KW - Siloxane nanoparticles KW - Nanoparticles KW - Colloids KW - Silica KW - Polyorganosiloxane KW - Siloxane KW - Characterization KW - Transmission electron microscopy KW - TEM KW - Cryo-TEM KW - Asymetrical flow field-flow fractionation KW - AF-FFF KW - Field-flow fractionation KW - FFF KW - Dynamic light scattering KW - DLS KW - PCS PY - 2014 DO - https://doi.org/10.3762/bjnano.5.188 SN - 2190-4286 VL - 5 SP - 1774 EP - 1786 CY - Frankfurt, M. AN - OPUS4-32575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lang, Thomas A1 - Eslahian, Kyriakos-Alexandros A1 - Maskos, Michael T1 - Ion effects in field-flow fractionation of aqueous colloidal polystyrene JF - Macromolecular chemistry and physics N2 - We discuss the effect of electrolytes on retention of aqueous colloidal polystyrene particles in asymmetrical flow (AF-FFF) and thermal field-flow fractionation (ThFFF). In both FFF subtechniques, interparticle interaction leads to non-ideal fractionation behavior, which can result in a sample load dependency. Electrostatic repulsion is reduced with increasing electrolyte concentration, resulting in a pronounced increase of retention. At higher salinities, hydrophobic interactions dominate, thus applications of AF-FFF under physiological conditions are limited. In ThFFF, also the separation mechanism of thermophoresis is affected by ionic shielding and experimental data are in accordance with recent theoretical models of thermophoresis. KW - Asymmetrical flow field-flow fractionation KW - Colloids KW - Interfaces KW - Ion effects KW - Thermal field-flow fractionation PY - 2012 DO - https://doi.org/10.1002/macp.201200132 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2353 EP - 2361 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Bienert, Ralf A1 - Appelhans, Dietmar A1 - Voit, B. T1 - Core-shell structures of oligosaccharide-functionalized hyperbranched poly(ethylene imines) JF - Macromolecular chemistry and physics N2 - Hyperbranched poly(ethylene imine)s (PEIs) functionalized with maltose, maltotriose, and maltoheptaose form distinct core-shell globular nanoparticles as revealed by small-angle X-ray scattering (SAXS). The solution structures are quantified using the Beaucage unified exponential/power-law approach. SAXS results were confirmed with dynamic light scattering (DLS). We found that all PEI structures are completely insensitive to changes of temperature (5 °C < T < 80 °C) and pH (1 < pH < 10). This remarkable stability of a compact spherical polymeric structure makes the modified PEIs promising for a wide range of biomedical applications. KW - Colloids KW - Core-shell polymers KW - Nanoparticles KW - Polyamines KW - Small-angle X-ray scattering (SAXS) PY - 2012 DO - https://doi.org/10.1002/macp.201100490 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2362 EP - 2369 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-26975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yasutaka, T. A1 - Imoto, Y. A1 - Kurosawa, A. A1 - Someya, M. A1 - Higashino, K. A1 - Kalbe, Ute A1 - Sakanakura, H. T1 - Effects of colloidal particles on the results and reproducibility of batch leaching tests for heavy metal-contaminated soil JF - Soils and Foundations N2 - A simple batch test leaching procedure is used in many countries, as a compliance test, to evaluate the leaching of mainly inorganic substances from soil. However, agitating certain types of soil and then passing the solution through a membrane filter with 0.45-µm pores yields filtrates that have been colored by the colloidal particles. These colloids might affect the results of the inorganic substances obtained in the batch tests. In this study, we evaluated the effects of colloidal particles on the results and the reproducibility of batch tests on contaminated soil using different agitation methods and membrane filters with different pore sizes. The leaching behaviors of As, Pb, Se, F and Cl from three types of soil were studied. The As and Pb concentrations in the leachates of some types of soil were clearly affected by the amount of colloidal particles with a diameter of 0.10–0.45 µm and by the agitation method used. This was probably because As and Pb were present mainly in the particulate form in the leachate that had been passed through a membrane filter with 0.45-µm pores. This is not the case for every type of soil. The results of batch leaching tests showed that not only dissolved but also colloidal forms with a diameter of 0.10–0.45 µm might be included and that the existence of colloidal particles in the leachate decreases the batch leaching test reproducibility. KW - Leaching KW - Contaminated soil KW - Heavy metals KW - Colloids PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429940 UR - https://www.sciencedirect.com/science/article/pii/S0038080617301166#! DO - https://doi.org/10.1016/j.sandf.2017.08.014 SN - 0038-0806 VL - 57 IS - 5 SP - 861 EP - 871 PB - Elsevier B.V. AN - OPUS4-42994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -