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):
[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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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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I16-Materials and Magnetism
I22-Small angle scattering & Diffraction
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Abstract: A polysiloxane with tris-alkoxy-ended rod-like mesogenic side groups forms an unusually low-symmetry antiferrochiral liquid crystal, space group P1̅, consisting of distorted left- and right-handed double-helices containing alternating splay and twist sections. The unit cell contains two double-helical columns. On faster cooling, a closely related metastable orthorhombic structure is formed, symmetry Fddd, with 8 double helices per cell.
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May 2025
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labSAXS-Offline SAXS and Sample Environment Development
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Diamond Proposal Number(s):
[37750]
Open Access
Abstract: We present a novel method of analyzing lyotropic liquid crystal mesophases─self-organized amphiphile-water nanomaterials─using in situ grazing-incidence small-angle X-ray scattering (GI-SAXS) on a quartz crystal microbalance (QCM) in a controlled humidity environment. This combination simultaneously gives nanostructural dimensions and phase symmetry (through SAXS), compositional data (% water by weight, from QCM data), and water activity within the sample (from the equilibrium relative humidity above the film), as the sample film takes up and releases water during humidity sweeps. Analysis of the combined data provides immediate access to information typically built up from experiments on multiple individual samples prepared at different fixed compositions. Our approach greatly reduces the required sample quantities and preparation time while avoiding issues with sample-to-sample variations thanks to the collection of the multiple parameters simultaneously. It also extends the accessible range to the low water content region of the phase diagram, which is harder to access by fixed composition measurements and is highly relevant to coatings and powders exposed to ambient humidities. Here, we present data on dimyristoylphosphatidylcholine/water lamellar phases. Our calculated bilayer thickness and interbilayer repulsion values show good agreement with published data obtained from multiple individual samples, and we clearly demonstrate the ability to extend to lower water contents.
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Apr 2025
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Open Access
Abstract: Mimicking the fibrous structures of meat is a significant challenge as natural plant protein assemblies lack the fibrous organisation ubiquitous in mammalian muscle tissues. In this work, wet-spun hydrogel fibres resembling the anisotropic fibrous microstructure of meat are fabricated using carboxymethyl cellulose as a model polysaccharide and sodium caseinate as a model protein which are crosslinked using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). Hydrogels and spun fibres were characterised using a combination of rheology (shear, oscillatory, and extensional), microscopy (light, polarised, and fluorescence), rheo-NMR, and X-ray diffraction. Examination of structuring behaviour under shear uncovered a relationship between enhanced biopolymer orientation along the fibre axis and a viscoelastic time-dependent ageing window for optimal hydrogel spinnability. This study provides novel rheological and structural insights into mechanisms of protein-polysaccharide assembly that may prove instrumental for development of tuneable fibres for applications in plant-based foods, tissue engineering, and biomaterials.
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Feb 2025
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I22-Small angle scattering & Diffraction
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Qian
Ma
,
Andri K.
Riau
,
Robert D.
Young
,
James S.
Bell
,
Olga
Shebanova
,
Nicholas J.
Terrill
,
Gary H. F.
Yam
,
Evelina
Han
,
Keith M.
Meek
,
Jodhbir S.
Mehta
,
Craig
Boote
Diamond Proposal Number(s):
[23514, 28285, 29862, 34903]
Open Access
Abstract: Purpose: Donor tissue shortfalls and postsurgical complications are driving novel corneal tissue regeneration approaches. Corneal stromal keratocytes (CSKs) have shown promise in promoting corneal repair and restoring transparency. We investigated the impact of intrastromal CSK injection on corneal ultrastructure and proteoglycan (PG) distribution in a rat injury model.
Methods: Rats were divided into four groups: normal (n = 12), injured (irregular phototherapeutic keratectomy centrally; n = 6), CSK (injured + human CSK intrastromal injection; n = 6), and PBS (injured + PBS injection; n = 6). Three weeks after treatment, corneas were examined by slit-lamp and optical coherence tomography. Corneal ultrastructure was analysed via small-angle x-ray scattering (collagen fibril diameter, interfibrillar spacing and matrix order), transmission electron microscopy with cuprolinic blue before and after chondroitinase digestion (CS/DS and KS PGs), and immunofluorescence staining (lumican and decorin).
Results: Irregular phototherapeutic keratectomy caused corneal opacity and significantly disrupted stromal ultrastructure, characterized by increased haze density (P < 0.0001), change in central corneal thickness (P = 0.0005), and interfibrillar spacing (P < 0.0001), along with decreased fibril diameter (P < 0.0001), matrix order (P < 0.0001), CS/DS (P < 0.0001) and KS (P < 0.0001) PGs, lumican, and decorin. CSK injection recovered corneal clarity and native stromal ultrastructure, with haze density (P = 0.8086), change in central corneal thickness (P = 0.9503), fibril diameter (P = 0.1139), interfibrillar spacing (P = 0.5879), matrix order (P = 0.9999), CS/DS (P = 0.9969) and KS (P = 0.2877) PGs, lumican, and decorin returning to normal. In contrast, the PBS group exhibited similar corneal injury responses to the injured group.
Conclusions: CSK injection resolved early stage corneal scarring by restoring stromal collagen arrangement and PG distribution, further endorsing its potential for treating corneal opacities.
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Feb 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[33006]
Abstract: Low molecular weight gelators (LMWG) are promising candidates for biomaterials due to their unique properties such as their reversibility and ability to hold large volumes of solvent. However, issues can arise when attempting to gel these materials under conditions acceptable for cell culture. In this thesis, the aim was to develop and comprehensively characterise a LMWG system at physiological pH. We employ a variety of techniques to investigate these materials across different length scales. By doing so, we have highlighted the significance of such characterisation when developing novel non-covalent biomaterials.
We outline how the dipeptide-based LMWG 2NapFF (diphenylalanine protected with a naphthalene group at the N-terminus) produces biocompatible hydrogels when crosslinked with ions present in cell culture media. We also explore the impact of heating and cooling the gelator solution prior to initiating gelation as well as the impact of adding PODS® (micron-scale proteins containing cargo molecules which are gradually released over prolonged peroids) to the system for functionalisation purposes. Our findings reveal that a heating and cooling cycle can be used to adjust the properties of the resulting network without changing the gelator itself. Moreover, it was found that PODS® had minimal effect on the properties of the hydrogel, indicating that they can enhance the bioactivity of the systems without altering the network structure. PODS
Furthermore, we compare the 2NapFF hydrogels previously discussed to a Ureidopyrimidinone (UPy) supramolecular hydrogel system, consisting of a monofunctional building block and bifunctional crosslinker species. We explored the effects of combining these two systems, both with and without the UPy crosslinker. Our results show that the assembly of the combined systems is primarily driven by the UPy component. Furthermore, the UPy crosslinker plays a vital role in the self-sorting of the UPy and 2NapFF components. It was also revealed that for cells to adhere effectively, the bifunctional UPy subunit was crucial to produce a supportive network.
In the final experimental chapter, we investigate the potential of the 2NapFF hydrogels crosslinked with cell culture media as bioinks for extrusion-based 3D printing. Through optimisation of the printing process, it was demonstrated that the type of media used to trigger gelation directly impacted the printability of the systems. As a result, the samples that consistently formed self-supporting structures were selected for printing macrophage cells, which remained viable within the gel after 24 hours. Bioprinting macrophages can be used in applications such as immune system and tumour microenvironment modeling.
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Feb 2025
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I22-Small angle scattering & Diffraction
labSAXS-Offline SAXS and Sample Environment Development
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Abstract: The self-assembly of materials is known to have a strong impact on their properties such as diffusion, opacity, viscosity and reactivity. Lipids are a class of material that is known to self-assemble and to exhibit rich polymorphism in the phases that are adopted. These phases are known to be concentration dependent and to vary with water content.
Aerosols are found across a wide range of applications. They are used in industry with spray drying, in drug delivery to the lungs and are present in the atmosphere. Many aerosols contain lipidic components which are known to self-assemble in solution. Despite this, there is little understanding of the self-assembly of lipids within aerosols, and where this research has been carried out is has focused on urban pollutants such as cooking emissions.
This thesis aims to further our understanding of the self-assembly of lipids in aerosols. To do this, we develop new techniques such as the simultaneous combination of Quartz Crystal Microbalance with Grazing Incidence Small Angle X-ray Scattering in a humidity-controlled environment, adapt existing techniques to the study of levitated lipids with X-ray diffraction techniques such as acoustic or electrodynamic levitation. We also study aerosols offline by collecting them on droplets conditioned in a Falling Droplet Column on a substrate and using imaging techniques to understand their morphology.
We show that deep lung respiratory aerosol proxies self-assemble into lamellar phases under ambient conditions, both as thin films and levitated droplets. We demonstrate the power of our developed techniques in accelerating previous research into phase diagrams and sorption isotherms and in making X-ray diffraction analysis of levitated droplets more accessible. We study the effect of relative humidity and concentration on the morphology and phase of D-mannitol, and, finally, we develop a model for the neutralisation of charged aerosol droplets due to exposure to X-ray radiation.
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Dec 2024
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I22-Small angle scattering & Diffraction
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Open Access
Abstract: Silica gels have a multitude of applications ranging from cosmetics and food science to oil and gas recovery. For proper design and application, it is important to have a thorough understanding of the underlying mechanisms of gel formation under different circumstances. The growth and structure of colloidal silica gels has been investigated using RheoSAXS to study the effect of silica concentration, NaCl concentration, temperature and shear rate. Additionally, SAXS in combination with a strong magnetic field has been applied to investigate the effect of magnetic microparticles and magnetic field on the development of the gel structure. Results indicate that the strongest effect on the gel kinetics are achieved by altering the activator concentration, here in the form of NaCl, followed by silica concentration and temperature. Small structural effects were also observed, with larger cluster sizes being produced at lower silica concentration and at higher NaCl concentration. Applying shear caused major changes both in structure as well as the macroscopic behavior of the silica, preventing the gel from reaching an arrested state, instead forming a viscous liquid. Applying a magnetic field appears to suppress the formation of larger clusters. The same effect is observed for increasing magnetic microparticle concentrations.
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Aug 2024
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