I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[33542]
Open Access
Abstract: We report on the lyotropic phase behaviour of fully-hydrated mixtures of α-tocopherol (α-toc) with the unsaturated phospholipid dioleoyl phosphatidylcholine (DOPC), as studied by synchrotron small-angle x-ray diffraction. Increasing amounts of α-toc progressively swell the layer spacing of the fluid lamellar Lα phase of DOPC, and then induce a transition to an inverse hexagonal HII phase. Low-resolution electron density profiles show that this increase is largely due to an increased thickness of the bilayer, with little change in the water layer thickness. In the range 30 – 50 mol% α-toc, additional weak low-angle peaks were observed, whose characteristic ratios are in agreement with the presence of swollen inverse bicontinuous cubic phases of spacegroups Im3m / Pn3m. This research has applications both in the biological field and for industrial product development. We show that the effect of α-toc addition in DOPC membranes has some similarities to that of cholesterol by stabilizing inverse curvature structures, which play crucial roles in cell division, membrane trafficking and endocytosis. Concerning industrial applications, the stabilization of inverted hexagonal (HII) and swollen bicontinuous cubic phases offers the opportunity to develop new delivery systems.
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Aug 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[31849]
Abstract: Contraction of the muscular walls of the heart is driven by an interaction between myosin motors from the thick filaments and actin sites in the thin filaments. Each heartbeat is triggered by calcium binding to troponin in the thin filaments, which unblocks the myosin-binding sites on actin. The strength and speed of contraction is also modulated by the availability of myosin motors, which are sequestered in a helical array on the surface of the thick filaments between heartbeats. The signalling pathway controlling release of the motors from this array during the heartbeat is unknown, but there are three general hypotheses: thick-filament mechano-sensing, thin-to-thick filament signalling, and direct calcium signalling to the thick filament. Here we tested the third hypothesis by replacing the native calcium-binding subunit of troponin (TnC) with a variant which cannot bind calcium. Demembranated trabeculae from rat heart containing this variant generated no active force on addition of calcium. We measured calcium-induced release of myosin motors from the sequestered state by X-ray diffraction and from the orientation of fluorescent probes on the myosin regulatory light chain. Both methods showed the expected calcium-dependent changes in the conformation of the myosin motors in trabeculae containing native TnC, but all these changes were abolished in those containing the TnC variant that cannot bind calcium. We conclude that thick filament activation in rat heart trabeculae is not due to direct binding of calcium to thick filaments, but is mediated by calcium activation of the thin filaments by mechano-sensing or thin-to-thick filament signalling.
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Jul 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[33006]
Open Access
Abstract: Understanding the assembly of small molecules in aqueous media is crucial for the development of adaptive biomaterials. The mechanical properties of supramolecular networks, including stiffness and stress relaxation, play a key role in cellular spreading and can be tuned via formulation strategies or monomer design. Here, we demonstrate the modulation of supramolecular polymerization and cellular response of ureidopyrimidinone (UPy) monomers in water by tailoring the length of the alkyl spacer within the monomer structure. A library of four UPy derivatives with varying hydrophilic–hydrophobic balances was synthesized by using an optimized synthetic approach. The assembly behavior and dynamics of the supramolecular polymers were investigated both in solution and gel states using a wide range of techniques. The results revealed that the alkyl spacer length significantly affects the supramolecular polymer dynamics, kinetics, and stability. Monomers with 6 and 8 methylene units formed dynamic elongated structures, while those with 10 and 12 units yielded robust and stable bundled fibers. In the gel state, a physical cross-linker was required for gel formation. The gels formed by the monomers featuring 8 and 10 methylene units exhibited optimal mechanical properties, promoting the spreading of human normal dermal fibroblasts in both 2D and 3D cultures. These findings highlight the impact of the monomer architecture on the properties of UPy supramolecular systems, paving the way for the rational design of biomaterials with tunable properties.
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Jun 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[29532]
Open Access
Abstract: Ultrasound standing waves (USW) produce a force capable of displacing micrometer-sized free-flowing particles in a fluid, wherein this phenomenon is also referred to as acoustophoresis. However, the effect of acoustophoresis on dynamically changing and growing crystal networks is unclear. An example of such a system are monoglyceride (MG)-based oleogels, which are free-flowing lipids (e.g., vegetable oils) structured with a lipid-crystal network. In this work, we use MG oleogels as an example system to investigate the acoustophoretic effect on the structuration of a growing crystal network. For this purpose, multifaceted characterization is conducted utilizing optical and coded excitation scanning acoustic microscopy as well as small-angle X-ray scattering, respectively. The optical microscopy results show that USW produces local density differences of the structuring crystalline material and induces the orientation of the MG platelets. X-ray diffraction measurements confirm these findings and show a 23% average increase in MG platelet correlation length, which can be linked to platelet thickness, as well as an increase in the MG nanoplatelet surface smoothness. These findings produce a foundation for better understanding the effect of acoustophoresis in dynamically developing lipid-based materials and illuminate the mechanical changes that arise because of USW treatment.
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Jun 2025
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I22-Small angle scattering & Diffraction
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Oleksii
Avdieiev
,
Sergey A.
Denisov
,
Ashkan
Ajeer
,
Lois
Adams
,
Charlene
Greenwood
,
Heather
Nesbitt
,
Keith
Thomas
,
Keith
Rogers
,
Olga
Solovyeva
,
Lev
Mourokh
,
Pavel
Lazarev
Open Access
Abstract: Structural biomarkers determined by X-ray scattering of the tissues can complement conventional diagnostics and provide a pathway for early detection of diseases. In the present study, mouse models were utilized to observe the progression of prostate cancer. We induced cancer in the left lobe of the mouse prostate, whilst the right lobe was left uninoculated. The mice were sacrificed at increasing systematic time points, and lobe samples were subsequently analyzed using X-ray scattering. Control samples were also collected from healthy mice sacrificed at the same time points. This investigation revealed that the ratio between the X-ray scattering peaks associated with the lipids and water can serve as a structural biomarker of cancer, and this biomarker develops as the tumor advances. The obtained cancer trajectory can serve as a baseline for the determination of the disease stage, and the biomarker movement along the trajectory can be evidence of the healing or disease progression.
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Jun 2025
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B21-High Throughput SAXS
I22-Small angle scattering & Diffraction
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Ester
Serrano
,
Tianxiao
Zhao
,
David R.
Mark
,
Mostafa
Soroor
,
Iris
Floria
,
Nicholas J.
Terrill
,
Nikil
Kapur
,
Arwen I. I.
Tyler
,
Mathew H.
Horrocks
,
Andrew J.
Roe
,
Olwyn
Byron
Diamond Proposal Number(s):
[28516]
Open Access
Abstract: Enterohaemorrhagic Escherichia coli causes sporadic, and sometimes large-scale, food poisoning outbreaks, for which antibiotic treatment in humans is contraindicated. As an alternative form of therapy, previous studies developed the family of salicylidene acylhydrazide (SA) anti-virulence compounds. One target of the SA compounds is AdhE, an enzyme that converts acetyl-CoA to ethanol and vice versa. AdhE oligomerizes, forming helicoidal filaments, heterogeneous in length, called spirosomes. We show it is possible to only partially fractionate AdhE spirosomes because in vitro they oligomerize in the absence of stimuli, and that spirosome formation is necessary to regulate the direction of AdhE enzymatic reactions. We also show that the SA compound ME0054 binds and perturbs AdhE spirosomes, enhancing the conversion of ethanol to acetyl-CoA. This mechanistic understanding of how ME0054 impacts AdhE function will help in the development of SA compounds as novel anti-virulence inhibitors.
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Jun 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[28022]
Open Access
Abstract: The mixing of Guanosine (Gua) and Guanosine 5′-monophosphate (GMP) in water in selected compositions yields highly hydrated, transparent, and self-healing self-assembled supramolecular G-hydrogels, attractive for biomedical applications. This work investigates how hydrogel composition affects solute transport, including diffusion, binding, loading, and release properties, using a set of fluorescent probes with varying size and polarity. Although small/wide-angle X-ray scattering techniques showed that no structural changes are induced by probe addition, even when intercalation into G-quadruplexes is expected, the internal mesh structure of the hydrogel, modulated by the Gua:GMP ratio, directly impacts probe diffusivity and loading. Tighter networks (e.g., 1:1) slow diffusion and enhance retention compared to looser configurations (e.g., 1:4). Moreover, UV–visible titrations revealed markedly different binding affinities (Kb ≈ 5.7 × 104 M–1 for DAPI, 8.0 × 103 M–1 for ThT, and 1.4 × 102 M–1 for RhB), which are expected to result in lower diffusion coefficients and slower release, especially for DAPI and ThT. Indeed, diffusion coefficients, obtained via fluorescence recovery after photobleaching and time-resolved fluorescence spectroscopy, reach 90, 20, and 60 μm2/s for FITC-dextran, ThT, and RhB, respectively. Probe release kinetics, modeled via Weibull fitting, indicated sustained release with characteristic times (τ) between 9.6 and 23.2 h and β ≈ 1 in 1× PBS, consistent with predominantly Fickian diffusion. Remarkably, switching to 10× PBS significantly accelerated release (τ reduced by ≈ 40–50%), suggesting that ionic strength and/or pH changes critically affect not only probe-hydrogel interactions but also the internal gel architecture, altering porosity, mesh size, and network tortuosity, thus enhancing molecular mobility. Overall, the G-hydrogel system offers a structurally tunable and composition-dependent platform capable of finely regulating molecular transport and release profiles, making it highly suitable for controlled drug delivery and adaptive biomaterial applications.
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May 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[35872, 30439]
Open Access
Abstract: Al-Zn-Mg-Cu alloys are known for their exceptional mechanical properties, primarily achieved through precipitation hardening. This study investigates the dynamic precipitation behaviour in a pre-aged AA7075 alloy under uniaxial tension and cross-die forming at 180 °C. In-situ synchrotron small-angle X-ray scattering (SAXS) revealed a non-monotonic precipitate growth behaviour under uniaxial tension, where growth was initially accelerated but slowed as strain exceeded 7%. Synchrotron SAXS and wide-angle X-ray scattering (WAXS) were used to simultaneously map precipitation and deformation across regions with varied strain conditions in samples subjected to warm cross-die forming demonstrating local variations in precipitation and dislocation arrangement, along with an inverse dependence of precipitate growth on plastic strain. A modified Kampmann-Wagner Numerical (KWN) model was applied to successfully predict the overall precipitation behaviour, highlighting that the competing effects of deformation-induced vacancies enhancing diffusivity and the reduction of supersaturation due to precipitate growth are of primary importance, while the potential influence of strain path in monotonic deformation is of secondary significance.
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May 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[35286]
Open Access
Abstract: Benzophenone-based materials remain widely used as photoinitiators for ultraviolet light-induced free radical polymerizations. Traditionally, polymerization is spatially controlled using top-down techniques such as photomasks, which produce well-defined polymeric films. In contrast, we present an alternative method for controlling polymerization by employing supramolecular materials to localize the photoinitiator. This approach uses benzophenone-functionalized dipeptides that are specifically tuned to enable supramolecular gel noodle formation, which act as structural templates. We show that polymerization of acrylate monomers around the gel noodles can increase the Young’s modulus by up to 2 orders of magnitude and produce mechanically robust structures that can be handled. The self-assembly of the supramolecular photoinitiators is also explored using viscosity and SAXS measurements, providing an understanding of why only 4BPAcFF successfully forms gel noodles. Our method offers a simple yet effective technique for localizing polymerization, enabling fine-tuning of mechanical properties and the fabrication of intricate designs such as hollow-core structures.
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May 2025
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B23-Circular Dichroism
I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[29045]
Open Access
Abstract: We investigate two unusual phenomena in self-assembly of anisotropic molecules from isotropic (Iso) melt: a heat-capacity (Cp) maximum, and spontaneous formation of the recently discovered chiral liquid (Iso*). Based on experiments on new non-chiral monomers, dimers and polymers, we construct a statistical theory that shows why many complex mesostructures form in two stages: continuous equilibrium growth of nano-clusters in melt through strong interactions, causing the Cp-maximum, followed by establishment of positional long-range order (LRO) through a weak first-order transition. We also show why many achiral compounds additionally form an intermediate chiral Iso* liquid through what we find is a second-order transition. We propose that the first process is equivalent to “supramolecular polymerization” in solutions, where the lack of inter-cluster interaction rules out LRO. Furthermore, we argue that separation into a broad and a sharp transition is universal in condensed matter where strong interactions by themselves cannot lead to LRO, either because the clusters are 1D or due to strong frustration. Clusters must first grow to critical size when, at Tc, the combined weak interactions reach ~kBTc, prompting LRO formation. A situation similar to that in soft self-assembly is seen in spin ordering in magnetic crystals, but only near 0 K.
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May 2025
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