Search Results

You searched for all publications:

with publication states 'Published (Approved)'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

12 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I22-Small angle scattering & Diffraction	Acoustic levitation with polarising optical microscopy (AL-POM): water uptake in a nanostructured atmospheric aerosol proxy Adam Milsom , Adam M. Squires , Christopher Brasnett , William N. Sharratt , Annela M. Seddon , Christian Pfrang Environmental Science: Atmospheres 88 DOI: 10.1039/D3EA00083D Diamond Proposal Number(s): [23852, 17791] Open Access Show Abstract ▼ Abstract: Laboratory studies on levitated particles of atmospheric aerosol proxies have provided significant contributions to our understanding of aerosol processes. We present an experimental method combining acoustic levitation with polarising optical microscopy (AL-POM) to probe optically birefringent particles, such as the nanostructured surfactant atmospheric aerosol proxy studied here. Birefringent particles were subjected to a step increase in humidity. A decrease in birefringence was measured over time as a result of a nanostructure change, confirmed by complementary synchrotron X-ray scattering. A multi-layer water uptake model was created and fitted to the experimental data, revealing a water diffusion coefficient increase by ca. 5–6 orders of magnitude upon phase transition. This has implications for the timescale of water uptake in surfactant-containing aerosols and their atmospheric lifetimes. This experimental setup has strong potential to be used in conjunction with other levitation methods and in different contexts concerning birefringent materials such as crystallisation.	Sep 2023
labSAXS-Offline SAXS and Sample Environment Development I22-Small angle scattering & Diffraction	Lipid doping of the sponge (L3) mesophase Christopher Brasnett , Adam Squires , Andrew J. Smith , Annela Seddon Soft Matter DOI: 10.1039/D3SM00578J Diamond Proposal Number(s): [17767, 29558] Open Access Show Abstract ▼ Abstract: The polymorphism of lipid aggregates has long attracted detailed study due to the myriad factors that determine the final mesophase observed. This study is driven by the need to understand mesophase behaviour for a number of applications, such as drug delivery and membrane protein crystallography. In the case of the latter, the role of the so-called ‘sponge’ (L3 ) mesophase has been often noted, but not extensively studied by itself. The L3 mesophase can be formed in monoolein/water systems on the addition of butanediol to water, which partitions the headgroup region of the membrane, and decreases its elastic moduli. Like cubic mesophases, it is bicontinuous, but unlike them, has no long-range translational symmetry. In our present study, we show that the formation of the L3 phase can delicately depend on the addition of dopant lipids to the mesophase. While electrostatically neutral molecules similar in shape to monoolein (DOPE, cholesterol) have little effect on the general mesophase behaviour, others (DOPC, DDM) significantly reduce the composition at which it can form. Additionally, we show that by combining cholesterol with the anionic lipid DOPG, it is possible to form the largest stable L3 mesophases observed to date, with characteristic lengths over 220 Å.	Aug 2023
B21-High Throughput SAXS	Self-sorting in diastereomeric mixtures of functionalized dipeptides Qingwen Guan , Kate Mcaulay , Tian Xu , Sarah E. Rogers , Charlotte Edwards-Gayle , Ralf Schweins , Honggang Cui , Annela M. Seddon , Dave J. Adams Biomacromolecules DOI: 10.1021/acs.biomac.3c00246 Diamond Proposal Number(s): [29985] Open Access Show Abstract ▼ Abstract: Self-sorting in functionalized dipeptide systems can be driven by the chirality of a single amino acid, both at a high pH in the micellar state and at a low pH in the gel state. The structures formed are affected to some degree by the relative concentrations of each component showing the complexity of such an approach. The structures underpinning the gel network are predefined by the micellar structures at a high pH. Here, we describe the systems prepared from two dipeptide-based gelators that differ only by the chirality of one of the amino acids. We provide firm evidence for self-sorting in the micellar and gel phases using small-angle neutron scattering and cryo-transmission electron microscopy (cryo-TEM), showing that complete self-sorting occurs across a range of relative concentrations.	May 2023
B21-High Throughput SAXS	Isotopic control over self-assembly in supramolecular gels Kate Mcauley , Han Wang , Ana M. Fuentes-Caparros , Lisa Thomson , Nikul Khunti , Nathan P. Cowieson , Honggang Cui , Annela Seddon , Dave J. Adams Langmuir DOI: 10.1021/acs.langmuir.0c01552 Open Access Show Abstract ▼ Abstract: It is common to switch between H2O and D2O when examining peptide-based systems with the assumption being that there are no effects from this change. Here, we describe the effect of changing from H2O to D2O in a number of low molecular weight dipeptide-based gels. Gels are formed by decreasing the pH. In most cases, there is little dif-ference in the structures formed at high pH, but this is not universally true. On lowering the pH, the ki-netics of gelation are affected and, in some cases, the structures underpinning the gel network are dif-ferent. Where there are differences in the self-assembled structures, the resulting gel properties are different. We therefore show isotopic control over gel properties is possible.	Jul 2020
B21-High Throughput SAXS	Modulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitor Michele Dully , Christopher Brasnett , Ahmed Djeghader , Annela Seddon , John Neilan , David Murray , James Butler , Tewfik Soulimane , Sarah P. Hudson Journal Of Colloid And Interface Science DOI: 10.1016/j.jcis.2020.04.015 Diamond Proposal Number(s): [23127] Open Access Show Abstract ▼ Abstract: Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biological agents on account of their desirable physiochemical properties and ability to encapsulate both hydrophobic and hydrophilic molecules. The most widely studied lipid cubic systems are those of the monoacylglycerol lipid family. These formulations are susceptible to lipolysis by a variety of enzymes, including lipases and esterases, which attack the ester bond present on the lipid chain bridging the oleic acid component to the glycerol backbone. The release of poorly soluble molecules residing in the lipid membrane portions of the phase is limited by the breakdown of the matrix; thus, presenting a potential means for further controlling and sustaining the release of therapeutic agents by targeting the matrix stability and its rate of degradation. The aims of the present study were twofold: to evaluate an approach to regulate the rate of degradation of lipid cubic phase drug delivery systems by targeting the enzyme interactions responsible for their demise; and to study the subsequent drug release profiles from bulk lipid cubic gels using model drugs of contrasting hydrophobicity. Here, hybrid materials consisting of cubic phases with monoacylglycerol lipids of different chain lengths formulated with a potent lipase inhibitor tetrahydrolipstatin were designed. Modulation of the release of a hydrophobic model pharmaceutical, a clofazimine salt, was obtained by exploiting the matrices’ enzyme-driven digestion. A stable cubic phase is described, displaying controlled degradation with at least a 4-fold improvement compared to the blank systems shown in inhibitor-containing cubic systems. Sustained release of the model hydrophobic pharmaceutical was studied over 30 days to highlight the advantage of incorporating an inhibitor into the cubic network to achieve tunable lipid release systems. This is done without negatively affecting the structure of the matrix itself, as shown by comprehensive small-angle x-ray scattering experiments.	Apr 2020
B21-High Throughput SAXS	Controlling the properties of the micellar and gel phase by varying the counterion in functionalised-dipeptide systems Kate Mcaulay , Pedro Agís Ucha , Han Wang , Ana M. Fuentes-Caparros , Lisa Thomson , Osama Maklad , Nikul Khunti , Nathan Cowieson , Matthew Wallace , Honggang Cui , Robert J. Poole , Annela Seddon , Dave J. Adams Chemical Communications 97 DOI: 10.1039/D0CC01252A Diamond Proposal Number(s): [19847] Open Access Show Abstract ▼ Abstract: The micellar aggregates formed at high pH for dipeptide-based gelators can be varied by using different alkali metal salts to prepare the solutions. The nature of the micellar aggregates directly affects the properties of the resulting gels.	Mar 2020
I12-JEEP: Joint Engineering, Environmental and Processing	Structure of the crystalline core of fiber-like polythiophene block copolymer micelles Dominic W. Hayward , David J. Lunn , Annela Seddon , John Finnegan , Oliver E. C. Gould , Oxana Magdysyuk , Ian Manners , George R. Whittell , Robert M. Richardson Macromolecules DOI: 10.1021/acs.macromol.7b02552 Diamond Proposal Number(s): [10283] Show Abstract ▼ Abstract: The internal structure and cross-sectional geometry of fiber-like poly(3-hexylthiophene)-based block copolymer micelles has been determined using small- and wide-angle X-ray scattering (SAXS and WAXS, respectively) techniques alongside electron and atomic force microscopies. WAXS of concentrated micellar solutions demonstrated that the block copolymers form crystalline-core micelles in solvents selective for the corona-forming block. Furthermore, by generating macroscopic fibers from micellar solutions, it was possible to align the micelles and discern the type and orientation of the unit cell within the core. Using the unit cell information gained from the wide-angle measurements, in conjunction with the structural insights gained from the microscopy techniques, it was possible to form a complete picture of the cross-sectional geometry of the micelles, whereby the polymer chains lie perpendicular to the long axis of the micelle core and do not undergo chain folding. Finally, this information was used to propose a self-assembly mechanism and to construct and validate a model for the small-angle scattering data, revealing the inherent flexibility of the micelles.	Apr 2018
B21-High Throughput SAXS	Self-sorted oligophenylvinylene and perylene bisimide hydrogels Ana M. Castilla , Emily R. Draper , Michael C. Nolan , Christopher Brasnett , Annela Seddon , Laura L. E. Mears , Nathan Cowieson , Dave Adams Scientific Reports 7 DOI: 10.1038/s41598-017-08644-0 Diamond Proposal Number(s): [12731] Open Access Show Abstract ▼ Abstract: We describe two component hydrogels with networks composed of self-sorted fibres. The component gelators are based on 1,4-distyrylbenzene (OPV3) and perylene bisimide (PBI) units. Self-sorted gels can be formed by a slow decrease in pH, which leads to sequential assembly. We demonstrate self-sorting by NMR, rheology and small angle X-ray scattering (SAXS). Photoconductive xerogels can be prepared by drying these gels. The wavelength response of the xerogel is different to that of the PBI alone.	Aug 2017
B23-Circular Dichroism	Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue James Armstrong , Rameen Shakur , Joseph Horne , Sally C. Dickinson , Craig T. Armstrong , Katherine Lau , Juned Kadiwala , Robert Lowe , Annela Seddon , Stephen Mann , Ross Anderson , Adam Perriman , Anthony P. Hollander Nature Communications 6 DOI: 10.1038/ncomms8405 Diamond Proposal Number(s): [10505] Open Access Show Abstract ▼ Abstract: Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymersurfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymersurfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.	Jun 2015
I22-Small angle scattering & Diffraction	The effects of pressure and temperature on the energetics and pivotal surface in a monoacylglycerol/water gyroid inverse bicontinuous cubic phase T.-Y. Dora Tang , Annela Seddon , Christoph Jeworrek , Roland Winter , Oscar Ces , John M. Seddon , Richard H. Templer Soft Matter 10 (17) DOI: 10.1039/c4sm00114a Open Access Show Abstract ▼ Abstract: We have studied the effect of pressure and temperature on the location of the pivotal surface in a lipid inverse bicontinuous gyroid cubic phase (QGII), described by the area at the pivotal surface (An), the volume between the pivotal surface and the bilayer midplane (Vn), and the molecular volume of the lipid (V). Small angle X-ray scattering (SAXS) was used to measure the swelling behaviour of the lipid, monolinolein, as a function of pressure and temperature, and the data were fitted to two different geometric models: the parallel interface model (PIM), and the constant mean curvature model (CMCM). The results show that an increase in temperature leads to a shift in the location of the pivotal surface towards the bilayer midplane, whilst an increase in pressure causes the pivotal surface to move towards the interfacial region. In addition, we describe the relevance of An, Vn and V for modeling the energetics of curved mesophases with specific reference to the mean curvature at the pivotal surface and discuss the significance of this parameter for modelling the energetics of curved mesophases.	Feb 2014

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User