All types of materials (cement, filtration membranes, batteries, etc.), biological samples (organisms, organs, plants, cells, etc.) and natural samples (soils, sediments, meteorites, etc.) can be characterised with a correlative and multi-scale approach. The issues addressed are very broad, in particular in relation to the environmental and energy transition, archaeology and new materials.
Studying the transfer of metal contaminants from soil to plants
Ex. Location of yttrium (Y, a rare earth) in the alpine plant Saxifraga paniculataThis is known to have a high tolerance and an interesting potential for metal accumulation. LA-ICP-MS and synchrotron X-ray fluorescence spectrometry (micro-XRF) were used to localise yttrium (Y) in plant tissues (roots and leaves) and to identify co-located elements.
Observing plant defence mechanisms
Ex. In-situ counting of phytoliths in durum wheat leaves under increasing water stress. In 3D images of wheat leaves (micro-CT), silicified trichomes and elongated phytoliths can be seen, which have the role of strengthening the leaf structure. In the presence of silicon, the leaves accumulate phytoliths in their veins, which improves the overall development of the plant.
Analyse the architecture of a root system
E.g. Evaluation of the toxic effects of a soil naturally rich in metals by following the development of the root system of fescue plants (Festuca laevigata). Micro-CT allows for a 3D analysis of the architecture of the root system, including the finest roots (a few tens of µm in diameter).
Assessing the environmental impact of waste reuse
E.g. Monitoring the behaviour of Cu and Zn in a tropical soil-water-plant system following the application of pig manure. LAnalysis micro-XRF of pig manure and the statistical processing spectra obtained by SIMPLISMA allow the identification of the co-location of Cu and Zn with the other elements in the liser, and then to hypothesise the nature of their carrier phases and speciation. Metal speciation can then be validated by synchrotron X-ray absorption spectroscopy (XAS).
Characterise a material, soil or sediment
Identification of the nature of the crystallised phases, minerals and/or clays present (XRD), detection of metal contamination (micro-XRF), quantification of porosity (micro-CT and nano-CT) ...
Fine-tuning the porosity of new materials
E.g. Characterisation of a silica monolith synthesised for the treatment of water contaminated by pharmaceutical products. The morphology of its pore network (macropores) is characterised by micro-CT: number, size, connectivity, tortuosity, ... of pores can be quantified.
Tracking variations in the internal structure of materials
E.g. Monitoring of the swelling of a lithium battery (Li-ions) during its charge/discharge cycles. The 3D image of the whole battery (low resolution micro-CT, 1 vx = 42 µm) allows repositioning on the same area between two states of charge (SOC) for high resolution micro-CT acquisition (1 vx = 1.6 µm). Analysis of the 3D images provides a measure of the thickness of the electrode and allows its swelling to be quantified.
Locating nanoparticle aggregates in complex matrices
Ex. Detection ex-vivo and location of nanomaterials (CeO2-NMs) in mouse lungs. The correlative and multi-scale approach used (coupling micro-CT, nano-CT, micro-XRF, XAS and histological observations) allows the visualization of the bio-distribution of CeO2NMs at the whole-lobe level and at the cellular level, i.e. in macrophages.
Ex. Localisation of gold nanoparticles (Au-NPs, 12 nm) at the root apex ofArabidopsis Thaliana. The coupling of 2D imaging (dark field microscopy combined with hyperspectral, DF-HSI) and 3D imaging (X-ray nano-tomography) improves our ability to detect and visualise nanoparticles in plant tissues, down to the cellular level. The processes that control the uptake and distribution of Au-NPs in plant tissues can be identified (e.g. accumulation of mucilage that traps Au-NPs).
Avellan et al, Environmental Science and Technology, 2017. Nanoparticle Uptake in Plants: Gold Nanomaterial Localized in Roots of Arabidopsis thaliana by X-ray Computed Nanotomography and Hyperspectral Imaging.
e.g. Determination of the accumulation, localisation and speciation of silver nanoparticles (Ag-NPs) in earthworms after the use of nanopesticides. The correlative approach used makes it possible to evaluate the accumulation capacities and mechanisms physiological factors involved in detoxification in Ag.
Tracking particle transport in a crack
E.g. Ensuring the safety of a radioactive waste package in an accidental scenario of cracking of its mortar containment barrier. Micro-CT allows in-situ visualisation of model aerosol particles that have migrated into the crack. The transport mechanisms (retention and/or diffusion) of the particles within the cracked mortar can be identified.
Assessing the durability of a material
Characterisation of the alteration of materials (paint, cement, coating, plastic, glass, etc.) during the different stages of their life cycle (use, end of life, etc.).
E.g. Characterisation of the weathering profile in the surface zone of a cement subjected to leaching. The chemical, mineralogical and structural (porosity) evolution can be quantified by a combined micro-XRF, micro-DRX, micro-CT and nano-CT approach.
E.g. Monitoring of the occurrence of cracks (micro-CT) in a building material subjected to freeze/thaw cycles.
Performing a non-destructive test
E.g. Rapid detection of defects in electronic components or solder joints by recording 2D X-rays (micro-CT).
Ex. Checking the quality of a sunscreen. 2D X-rays with very high spatial resolution (nano-CT) provide information on the optimal dispersion of nano-TiO2 for better UV absorption efficiency.
Create 3D model libraries
Digitisation of a large number of objects by micro-CT to create 3D collections for the general public, education or research.
Ex. Animation and integration of 3D models of arthropod specimens (ants) in a virtual reality environment to raise public awareness of the neglected biodiversity of French Guyana (eBREVE project).
E.g. Creation of a library of micropaleontological objects (foraminifera) in order to extend the possibility of observing and describing educational material in 3D beyond the classroom (MicrovirtualPal project).
E.g. Creation of a 3D ichthyological database to assist in the osteological identification of small present-day and archaeological teleost (bony fish) bones (Ictyo3D project).
Helping to identify archaeological objects
Non-destructive X-ray techniques are the techniques of choice for the analysis of archaeological objects!
E.g. Optimisation of the restoration of archaeological objects after determining their chemical composition (e.g. type of metal alloy) by micro-XRF.
E.g. Constitution of ceramic groups from a chemical database built with portable X-ray fluorescence (pXRF) analysis.
E.g. Virtual manipulation and analysis of very fragile archaeological objects after 3D micro-CT scanning.
Monitoring embryonic development
Ex. Verification of the correct development of the pulmonary system of a mouse embryo. 3D imaging (micro-CT) makes it possible to avoid the delicate and time-consuming step of dissection and preparation of serial sections.
A micro-CT image (volume 1x1x1 mm31 vx = 1 µm) corresponds to the observation of 1000 histological sections of 1 µm thickness!