Das Projekt "From architecture to function: Elucidating the formation and structure of soil microaggregates - a key to understand organic carbon turnover in soils? - Archfunk; Elucidating the role of surface topography and properties for the formation and stability of soil nano- and micro-aggregates by atomic force microscopy" wird vom Umweltbundesamt gefördert und von Friedrich-Schiller-Universität Jena, Institut für Geowissenschaften durchgeführt. Formation and stability of soil micro-aggregates depend on the forces which are acting between the individual building blocks and in consequence on type, size and properties of the respective adjacent surfaces. While the interaction forces are the result of the superposition of short-range chemical forces and long-range van-der-Waals, electrostatic, magnetic dipole and capillary forces, the total contact surface is a function of the size, primary shape, roughness and larger-scale irregularities. By employ-ing atomic force microscopy (AFM), we will explore the role of topography, adhesion, elasticity and hardness for the formation of soil micro-aggregates and their stability against external stress. Special consideration will be put on the role of extracellular polymeric substances as glue between mineral particles and as a substance causing significant surface alteration. The objectives are to (i) identify and quantify the surface properties which control the stability of aggregates, (ii) to explain their for-mation and stability by the analysis of the interaction forces and contacting surface topography, and (iii) to link these results to the chemical information obtained by the bundle partners. Due to the spatial resolution available by AFM, we will provide information on the nano- to the (sub-)micron scale on tip-surface interactions as well as 'chemical' forces employing functionalized tips. Our mapping strategy is based on a hierarchic image acquisition approach which comprises the analysis of regions-of-interest of progressively smaller scales. Using classical and spatial statistics, the surface properties will be evaluated and the spatial patterns will be achieved. Spatial correlation will be used to match the AFM data with the chemical data obtained by the consortium. Upscaling is intended based on mathe-matical coarse graining approaches.
Das Projekt "Interactions of nanoparticles with membrane systems of cells of higher water plants - towards mechanisms of nano-phytotoxicity" wird vom Umweltbundesamt gefördert und von Ecole Polytechnique Federale de Lausanne (EPF), Institut d'Amenagement des Terres et des Eaux (IATE) durchgeführt. Nanomaterials, with at least one dimension of 100 nm or less, are increasingly being used for commercial purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and drug carriers. The production, use, and disposal of nanomaterials will inevitably lead to their release into air, water, and soil. Thus, while nanoparticles are finding their way into the environment through deliberate and accidental actions, ecotoxicological properties and the risks related to these novel materials have not yet been fully explored. Moreover, although an increasing number of scientific reports highlight the impact of nanomaterials on human/animal cells/organs, only very few studies have been performed to assess phytotoxicity of nanomaterials. Therefore, this project is focused on mechansims of nanoparticle uptake and internalization by cells of two higher water plants, Elodea Canadensis and Trianea bogotensis Karst. In particular, we will study a wide range of interaction mechanisms of nano-engineered materials with selected cellular structures of these two higher water plants. These both plants have well known electrophysiological characteristics and can easily be cultured and handled in the laboratory conditions. The 'nano-bio' interactions of our interest range from nanoparticles trafficking through cellular membranes, translocation into cytosol and subcellular compartments, to their general transmission in whole living plants. Thus, the project focuses on the nanoparticle-induced changes in the structure and transport of the plasma membranes. Epidermal cells of roots of the aquatic flowering plant Trianea bogotensis Krst and cells of leaves of Elodea Canadensis were selected as the subject of investigations. To achieve this goal, we will use a multidisciplinary approach, including electrophysiological methods, electron spin resonance (ESR) and atomic force microscopy (AFM) techniques. Three potentially toxic scenarios of interactions of nanoparticles with the primary biological barriers (plasma- and endomembranes) will be considered: (i) nanoparticles do not penetrate the plasma membrane, but cause physical disruption of its structure, (ii) nanoparticles diffuse through the plasma membrane and during their transport affect changes in the functions of active and passive ion membrane channels, and (iii) nanoparticles are internalized by endocytosis into cells and interact with endomembranes. The overall goal of the project is to contribute to a better understanding of interaction mechanisms of nano-engineered materials with water plants and set the groundwork for the development of models of nano-phytotoxicity.