Beamline operations & development

Development and innovation are always kept high at the IBN outstation, and this is reflected also by the considerable number of   550 published projects, which were performed during the last 14 years in cooperation with more than 330 research teams from 33 countries.

Concerning the beamline operation, the final statistics of the beamline operation for the year 2009 can not be given before mid-2010, since the users still have to report on their activities and contributions. Thus, we give a representative overview of the beamline statistics and activities for the period 2008-2009 (see Table 1 and Fig. 1). In addition, the group participates in the European collaboration project SAXIER (budget 7.2 million Euro), which has the goal to develop innovative and new SAXS-methods (see SAXIER report).

At present, after 14 years of operation,  the beamline up-grade is continuosly underway depending on the financial resources available. So far the optics have been improved by the installation of an automatic feedback system of the monochromator, now guaranteeing stable beam conditions for each experimental shift. Further a new fast 1D detector (Vantec-1, Bruker-AXS) has been purchased, which compared to the old detector system has a 30 (!) times higher count rate capability.

A Mar300 Image Plate detector, with a circular active area of 300mm in diameter, with a spatial resolution (pixel size) of 150μm, is available for those applications that need a large Q-range with high dynamic range,such as solution scattering from proteins and nanoparticles, temperature-step scans, slow processes like nanoparticle formation, mesophase formation, etc.

In May 2008 we extended of about 3 m our experimental hutch. This allows e.g. the permanent installation of a diffractometer or of an optimized micro focus set-up with focal spot sizes, which delivers focal spot sizes down to 10 µm. We can now increase the sample to detector distance and therefore improve our minimum SAXS resolution or maximise the flux density at sample position for certain experiments.

Contacts:
Heinz Amenitsch, Michael Rappolt & Peter Laggner

Research group:
from IBN:
Benedetta Marmiroli
Barbara Sartori
Karin Jungnikl
Fernando Cacho-Nerin

from ELETTRA:
Sigrid Bernstorff
Christian Morello

EU project SAXIER - small angle scattering at high brilliance synchrotrons for bio and nano-technology

This is an initiative of five European groups exploring novel scientific applications for the new generation of small-angle X-ray scattering (SAXS) beamlines at high brilliance synchrotron facilities. The aim of the project is development and testing of major hardware and software components of SAXS beamlines to find and implement novel solutions adequately exploiting the high brilliance synchrotron sources.

The design and feasibility studies include optical elements for nano-focussed beams and unique sample environment options for multidisciplinary studies (nano-manipulation, on-line micro-Raman, microspray and gel-filtration, cryo- and microfluidic devices). An integrated software system for automated data analysis will be created. The infrastructure will be of particular interest for structural biology of proteins and macromolecular machines, in the studies of biological and advanced nanomaterials. The IBN participates within the project in the development and application of microfluidics (together with TASC, Trieste) as well as gas phase scattering for small angle X-ray scattering.

For the first task, some microfluidic devices have been designed and fabricated in order to select and develop the most suitable microfabrication processes. The fabrication processes that have been considered include optical, electron beam, soft- and hard X-ray lithography, plasma etching (reactive ion etching, inductively coupled plasma), wet etching and lift-off techniques.

In this context, two microfluidic devices have been investigated. The first is a rapid mixing device with a free jet flow, which allows to study ultrafast chemical reactions by SAXS with time resolutions < 100 µs. The time resolution is obtained by scanning along the free jet and probing different residence times (see Fig. 2 left).

The second device is a microfluidic cell for single microparticle manipulation to study localized biological nanostructures. By combining non-contact optical mani-pulation of the sample by laser tweezers and synchrotron nano-beam investigation techniques, individual biological elements can be studied (see Fig. 2 right).

For the second task of the project (scattering in the gas-phase) an aerosol generator with dryer unit was built in order to study self-assembly of aerosol-nanoparticles by SAXS. The set-up and the results of pilot experiments on the evaporation induced self-assembly of silica particles are shown in Fig.3.

Contacts:
Heinz Amenitsch & Peter Laggner

Research group:
Benedetta Marmiroli
Shyjumon Ibrahimkutty (until April 2009)
Karin Jungnikl
Michael Rappolt
Barbara Sartori

Biomaterials: human arteries

The aim of this project is to understand the behavior of the collagen structure in human arteries under tensile load and to relate it to the general mechanical behavior of the arterial wall.

Collagen fibres are mechanically important constituents of arteries, and their angular distribution is considered the key factor to the overall mechanical properties of the tissue. Thus, understanding of the mechanics of arteries will improve existing therapeutic treatments (e.g. balloon angioplasty), stent development or tissue engineering. Models, e.g. [1], achieve a good description of the macroscopical stress-strain behavior, however, there is no theory available considering also the nanoscopic structural changes during mechanical loading.

In our fibre diffraction studies we subject layer specific stripes of different human arteries to tensile load, measuring force and geometrical distortion. In addition, SAXS images are acquired during the stretching process to identify the change in angular distribution of collagen fibres. The data gives an insight into the coupling of the macroscopic stress-strain behavior and the underlying nanoscopic changes in the fibre network.

Recently we have developed a 2D-stretching device improving the overall performance of the setup. First experiments have been successfully accomplished. In contrast to commonly applied 1D-stretching [2, 3], stress is applied more homogenously to better resemble the in‑vivo situation. For the first time, two major directions of angular distribution of the collagen fibres could be determined (Fig.4). These results will help to refine existing modelling and to define realistic boundary conditions.

References:
1. Holzapfel,G.A. 2006. Determination of material models for arterial walls from uniaxial extension tests and histological structure. Journal of Theoretical Biology 238, 290-302.

2. Schmid, F., G.Sommer, M.Rappolt, P.Regitnig, G.Holzapfel, P.Laggner, and H.Amenitsch. 2006. Bidirectional tensile testing cell for in situ small angle X-ray scattering investigations of soft tissue. NIMB 246, 262-268.

3. Schmid,F., G.Sommer, M.Rappolt, C.A.J.Schulze-Bauer, P.Regitnig, G.A.Holzapfel, P.Laggner, and H.Amenitsch. 2005. In situ tensile testing of human aortas by time-resolved small-angle X-ray scattering. Journal of Synchrotron Radiation 12, 727-733

Contacts:
Heinz Amenitsch & Gerhard Holzapfel, TU-Graz

Research group:
Fabian Schmid (unitl August 2008)
Fernando Cacho-Nerin
Michael Rappolt
Barbara Sartori

Cooperation projects (Elettra)

As mentioned in the previous chapter on the beamline activity, there is a considerable output of publications each year (~ 60). In addition to the already presented in-house projects, a large number of published reports resulted from cooperation projects with external groups. Here, we present some highlights.

Molecular assembly of poly(ethylene)-block-poly(ethylene oxide) in thermosetting matrix studied by time resolved SWAXS

We studied the phase behavior and molecular assembly in blends of unsaturated polyester (thermoset polymer) and low molar weight poly(ethylene)-block-poly(ethylene oxide) (PE-PEO). At a macroscopic level, all the prepared blends are homogeneous at room temperature, with macro-phase separation occurring at 75°C. Curing at temperature < 75°C prevents macro-phase separation and permits to stabilize the structure obtained in the initial liquid state. Under these conditions, PE-PEO platelets with high aspect ratio (6 nm in thickness, 500 µm length) were observed in the cured state by TEM, and are proposed to be formed via the exfoliation of the pure layered PE-PEO in the uncured liquid (UR) (Fig. 5).

Reference:
Christophe Sinturel, Marylène Vayer, René Erre and Heinz Amenitsch, Macromolecules (accepted)

Contacts:
C. Sinturel, Centre de Recherche sur la Matière Divisée,
1 B rue de la Férollerie, 45071 Orléans Cedex 2, France;
Heinz Amenitsch

Multi-component cationic liposome/DNA complexes: new vectors for gene delivery

References:
Caracciolo, G., Pozzi, D., Amenitsch, H., and Caminiti, R. Multicomponent cationic lipid-DNA complex formation: role of lipid mixing. Langmuir, 21 (2005) 11582-11587.

Caracciolo, G., Pozzi, D., Caminiti, R., and Amenitsch, H. Two-dimensional lipid mixing entropy regulates the formation of multicomponent lipoplexes. Journal of Physical Chemistry B, 110 (2006) 20829-20835.

Contacts:
G. Caracciolo, Univ Roma La Sapienza, Dipartimento Chim, Piazzale Aldo Moro 5, I-00185 Rome, Italy; Heinz Amenitsch

Entropy-driven self-restoration in mesostructured hafnia films after x-ray damage

In the last years, extensive work of research on mesoporous silica and transition-metal oxide films has allowed to reveal the formation mechanisms of the ordered mesophases. At present, it is possible to synthesize mesoporous films with an accurate control on the physical (pore dimension, symmetry of mesophase, crystallization of inorganic walls) and chemical (composition, presence of chemical functional groups) properties by evaporation-induced self-assembly (EISA).

Reference:
Malfatti, L., Kidchob, T., Costacurta, S., Falcaro, P., Schiavuta, P., Amenitsch, H., and Innocenzi, P.
Highly ordered self-assembled mesostructured hafnia thin films: an example of rewritable mesostructure
Chemistry of Materials, 18 (2006) 4553-4560

Contacts:
P. Innocenzi, Univ Sassari, Dipartimento Architettura & Pianificaz, Lab Sci Mat & Nanotecnol, Palazzo Pou Salid, Piazza Duomo 6, I-07041 Alghero, SS, Italy; Heinz Amenitsch

Thermally stable nanocrystalline gamma - alumina layers with highly ordered 3D mesoporosity

Mesostructured materials can be obtained by combining ionic surfactants or block copoly-mers with the synthesis of metallic oxides through soft chemistry. Amongst the non- silicate mesoporous materials, alumina compounds are very attractive since the Al2O3 has perfectly controlled mesoporosity associated with hardness, hydrolytic stability, amphoteric character, and thermal stability of the g-transition-oxide phases. Nano-crystalline g-Al2 O3 layers with contracted face-centered cubic (fcc) mesoporosity that are stable up to 900 °C were prepared and characterized.

Reference:
Kuemmel, M., Grosso, D., Boissiere, U., Smarsly, B., Brezesinski, T., Albouy, P. A., Amenitsch, H., and Sanchez, C. Thermally stable nanocrystalline gamma-alumina layers with highly ordered 3D mesoporosity.

Angewandte Chemie-International Edition, 44 (2005) 4589-4592

Contacts:
D. Grosso, C. Sanchez, UPMC, CNRS, UMR 7574, 4 Pl Jussieu, F-75252 Paris, France; Heinz Amenitsch