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Instruments / Technical Area	Publication Details	Published
I14-Hard X-ray Nanoprobe	Differential phase contrast for quantitative imaging and spectro-microscopy at a nanoprobe beamline Paul D. Quinn , Fernando Cacho-Nerin , Miguel A. Gomez-Gonzalez , Julia E. Parker , Timothy Poon , Jessica M. Walker Journal Of Synchrotron Radiation 30 DOI: 10.1107/S1600577522010633 Diamond Proposal Number(s): [28142] Open Access Show Abstract ▼ Abstract: The interaction of a focused X-ray beam with a sample in a scanning probe experiment can provide a variety of information about the interaction volume. In many scanning probe experiments X-ray fluorescence (XRF) is supplemented with measurements of the transmitted or scattered intensity using a pixelated detector. The automated extraction of different signals from an area pixelated detector is described, in particular the methodology for extracting differential phase contrast (DPC) is demonstrated and different processing methods are compared across a range of samples. The phase shift of the transmitted X-ray beam by the sample, extracted from DPC, is also compared with ptychography measurements to provide a qualitative and quantitative comparison. While ptychography produces a superior image, DPC can offer a simple, flexible method for phase contrast imaging which can provide fast results and feedback during an experiment; furthermore, for many science problems, such as registration of XRF in a lighter matrix, DPC can provide sufficient information to meet the experimental aims. As the DPC technique is a quantitative measurement, it can be expanded to spectroscopic studies and a demonstration of DPC for spectro-microscopy measurements is presented. Where ptychography can separate the absorption and phase shifts by the sample, quantitative interpretation of a DPC image or spectro-microscopy signal can only be performed directly when absorption is negligible or where the absorption contribution is known and the contributions can be fitted.	Dec 2022
I14-Hard X-ray Nanoprobe	Imaging articular cartilage in osteoarthritis using targeted peptide radiocontrast agents Milan M. Fowkes , Patricia Das Neves Borges , Fernando Cacho-Nerin , Paul E. Brennan , Tonia L. Vincent , Ngee H. Lim Plos One 17 DOI: 10.1371/journal.pone.0268223 Diamond Proposal Number(s): [22977] Open Access Show Abstract ▼ Abstract: Background: Established MRI and emerging X-ray contrast agents for non-invasive imaging of articular cartilage rely on non-selective electrostatic interactions with negatively charged proteoglycans. These contrast agents have limited prognostic utility in diseases such as osteoarthritis (OA) due to the characteristic high turnover of proteoglycans. To overcome this limitation, we developed a radiocontrast agent that targets the type II collagen macromolecule in cartilage and used it to monitor disease progression in a murine model of OA. Methods: To confer radiopacity to cartilage contrast agents, the naturally occurring tyrosine derivative 3,5-diiodo-L-tyrosine (DIT) was introduced into a selective peptide for type II collagen. Synthetic DIT peptide derivatives were synthesised by Fmoc-based solid-phase peptide synthesis and binding to ex vivo mouse tibial cartilage evaluated by high-resolution micro-CT. Di-Iodotyrosinated Peptide Imaging of Cartilage (DIPIC) was performed ex vivo and in vivo 4, 8 and 12 weeks in mice after induction of OA by destabilisation of the medial meniscus (DMM). Finally, human osteochondral plugs were imaged ex vivo using DIPIC. Results: Fifteen DIT peptides were synthesised and tested, yielding seven leads with varying cartilage binding strengths. DIPIC visualised ex vivo murine articular cartilage comparably to the ex vivo contrast agent phosphotungstic acid. Intra-articular injection of contrast agent followed by in vivo DIPIC enabled delineation of damaged murine articular cartilage. Finally, the translational potential of the contrast agent was confirmed by visualisation of ex vivo human cartilage explants. Conclusion: DIPIC has reduction and refinement implications in OA animal research and potential clinical translation to imaging human disease.	May 2022
I14-Hard X-ray Nanoprobe	Synchrotron-based nano-X-ray absorption near-edge structure revealing intracellular heterogeneity of iron species in magnetotactic bacteria Daniel M. Chevrier , Elisa Cerda-Donate , Yeseul Park , Fernando Cacho-Nerin , Miguel Gomez-Gonzalez , René Uebe , Damien Faivre Small Science DOI: 10.1002/smsc.202100089 Diamond Proposal Number(s): [23693, 23602] Open Access Show Abstract ▼ Abstract: Magnetotactic bacteria (MTB) sequester iron from the environment to biomineralize magnetite or greigite nanoparticles in magnetosome organelles, though the necessity of intracellular iron storage for the formation process is still in question. Understanding the role of iron storage would make clear the contribution of MTB in geochemical iron cycling and its potential importance during the biosynthesis of application-relevant magnetic nanoparticles. Herein, how scanning X-ray fluorescence microscopy (SXFM) and nanoscale X-ray absorption near-edge structure (nano-XANES) mapping can spatially and chemically identify intracellular iron species is reported, creating an opportunity to examine the role of iron storage in magnetite biomineralization at the single-cell level. Fe K-edge nano-XANES measurements of Magnetospirillum gryphiswaldense in varied iron media conditions and iron storage capacity reveal a significant quantity of intracellular iron heterogeneities through a distinction between formed magnetosomes and intracellular iron material. This intracellular iron component is found in both early and late stages of biomineralization. The capabilities of nano-XANES in providing an experimental advantage in the multidisciplinary field of biomineralization are highlighted.	Dec 2021
B22-Multimode InfraRed imaging And Microspectroscopy I14-Hard X-ray Nanoprobe	Elucidating the significance of copper and nitrate speciation in Cu-SSZ-13 for N2O formation during NH3-SCR Leila Negahdar , Naomi E. Omori , Matthew G. Quesne , Mark D. Frogley , Fernando Cahco-Nerin , Wilm Jones , Stephen W. T. Price , C. Richard A. Catlow , Andrew Beale Acs Catalysis 38, 13091 - 13101 DOI: 10.1021/acscatal.1c03174 Diamond Proposal Number(s): [22298] Show Abstract ▼ Abstract: Unwanted N2O formation is a problem that has been noted in selective catalytic reduction (SCR) where copper zeolite catalysts are utilized. With its immense global warming potential and long-term stability, elevated atmospheric N2O has already been identified as a future challenge in the war on climate change. This paper explores the phenomenon of N2O formation during NH3-SCR over Cu-SSZ-13 catalysts, which are currently commercialized in automotive emissions control systems, and proposes a link between N2O production and the local copper environment found within the zeolite. To achieve this, a comparison is made between two Cu-SSZ-13 samples with different copper co-ordinations produced via different synthesis methods. A combination of synchrotron X-ray absorption near-edge spectroscopy, UV–vis, Raman, and density functional theory (DFT) is used to characterize the nature of copper species present within each sample. Synchrotron IR microspectroscopy is then used to compare their behavior during SCR under operando conditions and monitor the evolution of nitrate intermediates, which, along with further DFT, informs a mechanistic model for nitrate decomposition pathways. Increased N2O production is seen in the Cu-SSZ-13 sample postulated to contain a linear Cu species, providing an important correlation between the catalytic behavior of Cu-zeolites and the nature of their metal ion loading and speciation.	Oct 2021
I14-Hard X-ray Nanoprobe	Beam and sample movement compensation for robust spectro-microscopy measurements on a hard X-ray nanoprobe Paul D. Quinn , Miguel Gomez-Gonzalez , Fernando Caco-Nerin , Julia E. Parker Journal Of Synchrotron Radiation 28 DOI: 10.1107/S1600577521007736 Diamond Proposal Number(s): [25187] Open Access Show Abstract ▼ Abstract: Static and in situ nanoscale spectro-microscopy is now routinely performed on the Hard X-ray Nanoprobe beamline at Diamond and the solutions implemented to provide robust energy scanning and experimental operation are described. A software-based scheme for active feedback stabilization of X-ray beam position and monochromatic beam flux across the operating energy range of the beamline is reported, consisting of two linked feedback loops using extremum seeking and position control. Multimodal registration methods have been implemented for active compensation of drift during an experiment to compensate for sample movement during in situ experiments or from beam-induced effects.	Sep 2021
I14-Hard X-ray Nanoprobe	The Hard X-ray Nanoprobe beamline at Diamond Light Source Paul D. Quinn , Lucia Alianelli , Miguel Gomez-Gonzalez , David Mahoney , Fernando Cacho-Nerin , Andrew Peach , Julia E. Parker Journal Of Synchrotron Radiation 28 DOI: 10.1107/S1600577521002502 Open Access Show Abstract ▼ Abstract: The Hard X-ray Nanoprobe beamline, I14, at Diamond Light Source is a new facility for nanoscale microscopy. The beamline was designed with an emphasis on multi-modal analysis, providing elemental mapping, speciation mapping by XANES, structural phase mapping using nano-XRD and imaging through differential phase contrast and ptychography. The 185 m-long beamline operates over a 5 keV to 23 keV energy range providing a ≤50 nm beam size for routine user experiments and a flexible scanning system allowing fast acquisition. The beamline achieves robust and stable operation by imaging the source in the vertical direction and implementing horizontally deflecting primary optics and an overfilled secondary source in the horizontal direction. This paper describes the design considerations, optical layout, aspects of the hardware engineering and scanning system in operation as well as some examples illustrating the beamline performance.	May 2021
I14-Hard X-ray Nanoprobe	A passive hutch-cooling system for achieving high thermal-stability operation at the Nanoprobe beamline, Diamond Light Source Fernando Cacho-Nerin , Julia E. Parker , Paul D. Quinn Journal Of Synchrotron Radiation 27 DOI: 10.1107/S1600577520004932 Open Access Show Abstract ▼ Abstract: The development of low-emittance storage rings and the rapid developments in nano-optics and imaging techniques are leading to decreasing X-ray spot sizes and increasing requirements on the environmental and mechanical stability of beamline components. In particular, temperature stability in the experimental hutches is critical to minimize uncontrolled displacements caused by thermal expansion and ensure consistent performance. Here, the design and thermal performance of the experimental hutches of the Nanoprobe beamline at Diamond Light Source are described, where a standard deviation of the room temperature down to 0.017°C over extended periods is demonstrated. The rooms are kept at constant temperature using water-cooled radiant panels which line the ceiling and walls. Radiant panels are relatively common in high-end electron microscopy rooms, but this is the first demonstration of their use for fine temperature control in an X-ray hutch and may provide a useful basis for future upgrades at upcoming low-emittance sources.	Jul 2020
	The hard x-ray nanoprobe beamline at Diamond - current status Paul Quinn , Julia Parker , Fernando Cacho-Nerin , Mike Walker , Paul Howes Microscopy And Microanalysis 24, 244 - 245 14th International Conference on X-ray Microscopy (XRM2018) DOI: 10.1017/S1431927618013569 Show Abstract ▼ Abstract: The hard X-ray nanoprobe beamline at Diamond is a new facility for nanoscale microscopy. The beamline operates over a 4.5‐ to 23‐keV energy range with an emphasis on multi-modal analysis providing elemental mapping, speciation mapping by XANES, structural phase mapping by nano-XRD and imaging through differential phase contrast and ptychography. A flexible scanning system allows for fast acquisition and arbitrary scan paths, simple data acquisition software and the ability to process data in near real-time. I14 welcomed its first users for commissioning experiments in March 2017 and completed its first user run between Oct 2017 and Mar 2018. The beamline is in an optimization phase with new techniques and users tools rolling out over a two year ramp up period.	Aug 2018
I22-Small angle scattering & Diffraction	Dynamic organization of ligand-grafted nanoparticles during adsorption and surface compression at fluid-fluid interfaces Axel Huerre , Fernando Cacho-Nerin , Vincent Poulichet , Christiana E. Udoh , Marco De Corato , Valeria Garbin Langmuir DOI: 10.1021/acs.langmuir.7b02867 Diamond Proposal Number(s): [12914] Open Access Show Abstract ▼ Abstract: Monolayers of ligand-grafted nanoparticles at fluid interfaces exhibit a complex response to deformation due to an interplay of particle rearrangements within the monolayer, and molecular rearrangements of the ligand brush on the surface of the particles. We use grazing-incidence small-angle X-ray scattering (GISAXS) combined with pendant drop tensiometry to probe in situ the dynamic organization of ligand-grafted nanoparticles upon adsorption at a fluid-fluid interface, and during monolayer compression. Through the simultaneous measurements of interparticle distance, obtained from GISAXS, and of surface pressure, obtained from pendant drop tensiometry, we link the interfacial stress to the monolayer microstructure. The results indicate that, during adsorption, the nanoparticles form rafts that grow while the interparticle distance remains constant. For small-amplitude, slow compression of the monolayer, the evolution of the interparticle distance bears a signature of ligand rearrangements leading to a local decrease in thickness of the ligand brush. For large-amplitude compression, the surface pressure is found to be strongly dependent on the rate of compression. Two-dimensional Brownian Dynamics simulations show that the rate-dependent features are not due to jamming of the monolayer, and suggest that they may be due to out-of-plane reorganization of the particles (for instance expulsion or buckling). The corresponding GISAXS patterns are also consistent with out-of-plane reorganization of the nanoparticles.	Dec 2017
I22-Small angle scattering & Diffraction	The secret life of collagen: temporal changes in nanoscale fibrillar pre-strain and molecular organization during physiological loading of cartilage Sheetal Inamdar , David P. Knight , Nicholas J. Terrill , Angelo Karunaratne , Fernando Cacho-Nerin , Martin M. Knight , Himadri S. Gupta Acs Nano DOI: 10.1021/acsnano.7b00563 Diamond Proposal Number(s): [10311] Open Access Show Abstract ▼ Abstract: Articular cartilage is a natural biomaterial whose structure at the micro- and nanoscale is critical for healthy joint function and where degeneration is associated with widespread disorders such as osteoarthritis. At the nanoscale, cartilage mechanical functionality is dependent on the collagen fibrils and hydrated proteoglycans that form the extracellular matrix. The dynamic response of these ultrastructural building blocks at the nanoscale, however, remains unclear. Here we measure time-resolved changes in collagen fibril strain, using small angle X-ray diffraction during compression of bovine and human cartilage explants. We demonstrate the existence of a collagen fibril tensile pre-strain, estimated from the D-period at approximately 1-2%, due to osmotic swelling pressure from the proteoglycan. We reveal for the first time, a rapid reduction and recovery of this pre-strain which occurs during stress relaxation, approximately 60 seconds after the onset of peak load. Furthermore, we show that this reduction in pre-strain is linked to disordering in the intrafibrillar molecular packing, alongside changes in the axial overlapping of tropocollagen molecules within the fibril. Tissue degradation in the form of selective proteoglycan removal disrupts both the collagen fibril pre-strain and the transient response during stress relaxation. This study bridges a fundamental gap in the knowledge describing time-dependent changes in collagen pre-strain and molecular organisation that occur during physiological loading of articular cartilage. This previously unknown transient response is likely to transform our understanding of the role of collagen fibril nano-mechanics in the biomechanics of cartilage and other hydrated soft tissues.	Aug 2017

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