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Many biological materials exhibit a multiscale porosity with small, mostly nanoscale pores as well as large, macroscopic capillaries to simultaneously achieve optimized mass transport capabilities and lightweight structures with large inner surfaces. Realizing such a hierarchical porosity in artificial materials necessitates often sophisticated and expensive top-down processing that limits scalability. Here, an approach that combines self-organized porosity based on metal-assisted chemical etching (MACE) with photolithographically induced macroporosity for the synthesis of single-crystalline silicon with a bimodal pore-size distribution is presented, i.e., hexagonally arranged cylindrical macropores with 1 µm diameter separated by walls that are traversed by pores 60 nm across. The MACE process is mainly guided by a metal-catalyzed reduction–oxidation reaction, where silver nanoparticles (AgNPs) serve as the catalyst. In this process, the AgNPs act as self-propelled particles that are constantly removing silicon along their trajectories. High-resolution X-ray imaging and electron tomography reveal a resulting large open porosity and inner surface for potential applications in high-performance energy storage, harvesting and conversion or for on-chip sensorics and actuorics. Finally, the hierarchically porous silicon membranes can be transformed structure-conserving by thermal oxidation into hierarchically porous amorphous silica, a material that could be of particular interest for opto-fluidic and (bio-)photonic applications due to its multiscale artificial vascularization.

Functional composites are ubiquitous in technology. They allow to simultaneously optimize functional properties against multiple application demands by combining several phases, each contributing desired functions. However, the forming structure and internal interfaces govern the overall properties of the composite in complex ways. Without understanding these complex structure-property relationships, rational design of advanced functional composites is impossible. Here we present new capabilities and ambitions of the CTCentre for Functional Composites, touching on infrastructure, advanced image processing, image-based modelling, as well as a selection of use cases and applications.

Developments in X-Ray Tomography XIII, San Diego, United States, 1 Aug 2021 - 5 Aug 2021; Proceedings of SPIE 11840, 118400U (2021). doi:10.1117/12.2596240 special issue: "SPIE Optical Engineering + Applications, 2021, San Diego, California, United States", The Helmholtz-Zentrum Geesthacht, Germany, is operating the user experiments for microtomography at the beamlines P05 and P07 using synchrotron radiation produced in the storage ring PETRA III at DESY, Hamburg, Germany. Attenuation-contrast and phase-contrast techniques were established to provide an imaging tool for applications in biology, medical science and materials science. In the recent years we rebuilt the integration of imaging detectors. This allows the user to choose from a set of cameras based on different CMOS and CCD sensors. Here we will present the features of the different camera system together with the advantage for different applications. Furthermore, we rebuilt the data preprocessing before reconstruction to provide different scanning techniques to investigate samples larger than the field of view of the X-ray beam. Multi-scale tomography is realized by using different setups or to integrate a low-resolution together with a high-resolution region-of-interest invest, Published by SPIE, Bellingham, Wash.

International audience; Characterizing nanoparticles (NPs) distribution in multiple and complex metastases is of fundamental relevance for the development of radiological protocols based on NPs administration. In the literature, there have been advances in monitoring NPs in tissues. However, the lack of 3D information is still an issue. X-ray phase-contrast tomography (XPCT) is a 3D label-free, non-invasive and multi-scale approach allowing imaging anatomical details with high spatial and contrast resolutions. Here an XPCT qualitative study on NPs distribution in a mouse brain model of melanoma metastases injected with gadolinium-based NPs for theranostics is presented. For the first time, XPCT images show the NPs uptake at micrometer resolution over the full brain. Our results revealed a heterogeneous distribution of the NPs inside the melanoma metastases, bridging the gap in spatial resolution between magnetic resonance imaging and histology. Our findings demonstrated that XPCT is a reliable technique for NPs detection and can be considered as an emerging method for the study of NPs distribution in organs.

Data in Brief 21, 1924 - 1936 (2018). doi:10.1016/j.dib.2018.10.076, This data article describes the detailed parameters for synthesizing mullite inverse opal photonic crystals via Atomic Layer Deposition (ALD), as well as the detailed image analysis routine used to interpret the data obtained by the measurement of such photonic crystals, before and after the heat treatment, via Ptychographic X-ray Computed Tomography (PXCT). The data presented in this article are related to the research article by Furlan and co-authors entitled “Photonic materials for high-temperature applications: Synthesis and characterization by X-ray ptychographic tomography” (Furlan et al., 2018). The data include detailed information about the ALD super-cycle process to generate the ternary oxides inside a photonic crystal template, the raw data from supporting characterization techniques, as well as the full dataset obtained from PXCT. All the data herein described is publicly available in a Mendeley Data archive “Dataset of synthesis and characterization by PXCT of ALD-based mullite inverse opal photonic crystals” located at https://data.mendeley.com/datasets/zn49dsk7x6/1 for any academic, educational, or research purposes., Published by Elsevier, Amsterdam [u.a.]