ORCID Profile
0000-0001-5483-7592
Current Organisation
RMIT University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Plant Biology | Soft Condensed Matter | Condensed Matter Physics | Structural Biology (incl. Macromolecular Modelling) | Biophysics | Membrane Biology | Conservation and Biodiversity | Plant Physiology | Other Physical Sciences | Plant Physiology | Ecology | Synthesis Of Macromolecules | Nanotechnology | Biological And Medical Chemistry | Colloid And Surface Chemistry | Synthesis of Materials | Organic Chemical Synthesis | Ecology And Evolution Not Elsewhere Classified | Physical Organic Chemistry | Biological Physics | Biological Sciences Not Elsewhere Classified | Physical Chemistry Not Elsewhere Classified | Nanotechnology | Haematology | Condensed Matter Physics—Structural Properties | Ecological Physiology | Organic Chemistry | Catalysis and Mechanisms of Reactions | Characterisation of Biological Macromolecules | Colloid and Surface Chemistry | Chemical Thermodynamics and Energetics | Global Change Biology | Physical Chemistry (Incl. Structural) | Global Change Biology | Other Biological Sciences |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Chemical sciences | Expanding Knowledge in the Physical Sciences | Biological sciences | Physical sciences | Other | Living resources (flora and fauna) | Expanding Knowledge in the Biological Sciences | Remnant Vegetation and Protected Conservation Areas in Forest and Woodlands Environments | Environmentally Sustainable Mineral Resource Activities not elsewhere classified | Clinical health not specific to particular organs, diseases and conditions | Blood Disorders | Mining Flora, Fauna and Biodiversity | Global climate change adaptation measures | Forest and Woodlands Flora, Fauna and Biodiversity | Ecosystem Adaptation to Climate Change | Rehabilitation of degraded mining lands | Rehabilitation/reafforestation | Rehabilitation of Degraded Mining Environments | Industrial Chemicals and Related Products not elsewhere classified
Related Links
Publications
Characterisation of sorghum starch granules using SAXS : effects of moisture on crystallinity and structure
Publisher: Wiley
Date: 25-10-2019
DOI: 10.1111/IJFS.13989
Abstract: In order to further characterise sorghum starch as a potential ingredient in food formulations, starch granules have been extracted from sorghum flour and characterised. The lamellar structure of granules and the uptake of water under ambient conditions have been investigated using small‐angle X‐ray scattering ( SAXS ). The lamellar structure was affected by the uptake of water and crystallinity was disrupted as water was absorbed. The diameter of sorghum granules had a bimodal distribution and the lamellar patterns were similar to those of other cereal starches. Moisture uptake occurred within the first four hours of exposure to water and SAXS provides a valuable technique for further studies of granular starch, including changes during the uptake of water.
Localization of trehalose in partially hydrated DOPC bilayers: insights into cryoprotective mechanisms
Publisher: The Royal Society
Date: 06-06-2014
Abstract: Trehalose, a natural disaccharide with bioprotective properties, is widely recognized for its ability to preserve biological membranes during freezing and dehydration events. Despite debate over the molecular mechanisms by which this is achieved, and that different mechanisms imply quite different distributions of trehalose molecules with respect to the bilayer, there are no direct experimental data describing the location of trehalose within lipid bilayer membrane systems during dehydration. Here, we use neutron membrane diffraction to conclusively show that the trehalose distribution in a dioleoylphosphatidylcholine (DOPC) system follows a Gaussian profile centred in the water layer between bilayers. The absence of any preference for localizing near the lipid headgroups of the bilayers indicates that the bioprotective effects of trehalose at physiologically relevant concentrations are the result of non-specific mechanisms that do not rely on direct interactions with the lipid headgroups.
Visible-Light-Driven “On”/“Off” Photochromism of a Polyoxometalate Diarylethene Coordination Complex
Publisher: American Chemical Society (ACS)
Date: 12-07-2018
DOI: 10.1021/JACS.8B04900
Abstract: Herein we report the first photochromic polyoxometalate (POM)-based diarylethene (DAE) coordination complex, prepared by ligation of two cobalt(III)-incorporated borotungstates [B
Dynamical signatures of freezing: Stable fluids, metastable fluids, and crystals
Publisher: American Physical Society (APS)
Date: 20-09-2006
Photoinitiated Energy Transfer in Porous‐Cage‐Stabilised Silver Nanoparticles
Publisher: Wiley
Date: 08-05-2023
Abstract: We report a new composite material consisting of silver nanoparticles decorated with three‐dimensional molecular organic cages based on light‐absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano‐resonant interaction between the porphyrin Soret band and the nanoparticle‐localised surface‐plasmon resonance. Time‐resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited‐state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2‐fold current increase in photoelectrochemical water‐splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications.
The need for novel cryoprotectants and cryopreservation protocols: Insights into the importance of biophysical investigation and cell permeability
Publisher: Elsevier BV
Date: 2021
Preparation and characterization of particles with small differences in polydispersity
Publisher: American Chemical Society (ACS)
Date: 10-10-2007
DOI: 10.1021/LA7018132
Abstract: Colloidal particles are widely used both in fundamental research and in materials science. One important parameter influencing the physical properties of colloidal materials is the particle size distribution (polydispersity) of the colloidal particles. Recent work on colloidal crystallization has demonstrated that even subtle changes in polydispersity can have significant effects. In this study we present centrifugation techniques for subtly manipulating the width and the shape of the particle size distribution, for polydispersities less than 10%. We use scanning electron microscopy as well as dynamic and static light scattering to characterize the particle size distributions. We compare the results and highlight the difficulties associated with the determination of accurate particle size distributions.
Improved Particle Size Distribution Measurements Using Multiangle Dynamic Light Scattering
Publisher: American Chemical Society (ACS)
Date: 07-1995
DOI: 10.1021/LA00007A028
Dynamical heterogeneity and the freezing transition in hard-sphere suspensions: Further analysis of the mean square displacement and the velocity autocorrelation function
Publisher: American Physical Society (APS)
Date: 14-08-2007
Two-dimensional crystallization of hard sphere particles at a liquid-liquid interface
Publisher: Elsevier BV
Date: 08-2009
Freezing, drying, and/or vitrification of membrane-solute-water systems
Publisher: Elsevier BV
Date: 09-1999
Differential dynamic microscopy for the characterisation of motility in biological systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CP02034C
Abstract: Differential Dynamic Microscopy (DDM) is a relatively new technique which measures the dynamics of suspended particles using a dynamic light scattering formalism.
Effect of polydispersity on the crystallization kinetics of suspensions of colloidal hard spheres when approaching the glass transition
Publisher: AIP Publishing
Date: 23-08-2007
DOI: 10.1063/1.2760207
Abstract: We present a comprehensive study of the solidification scenario in suspensions of colloidal hard spheres for three polydispersities between 4.8% and 5.8%, over a range of volume fractions from near freezing to near the glass transition. From these results, we identify four stages in the crystallization process: (i) an induction stage where large numbers of precursor structures are observed, (ii) a conversion stage as precursors are converted to close packed structures, (iii) a nucleation stage, and (iv) a ripening stage. It is found that the behavior is qualitatively different for volume fractions below or above the melting volume fraction. The main effect of increasing polydispersity is to increase the duration of the induction stage, due to the requirement for local fractionation of particles of larger or smaller than average size. Near the glass transition, the nucleation process is entirely frustrated, and the s le is locked into a compressed crystal precursor structure. Interestingly, neither polydispersity nor volume fraction significantly influences the precursor stage, suggesting that the crystal precursors are present in all solidifying s les. We speculate that these precursors are related to the dynamical heterogeneities observed in a number of dynamical studies.
Effects of vitrified and nonvitrified sugars on phosphatidylcholine fluid-to-gel phase transitions
Publisher: Elsevier BV
Date: 04-2000
The inverse hexagonal - inverse ribbon - lamellar gel phase transition sequence in low hydration DOPC:DOPE phospholipid mixtures
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.CHEMPHYSLIP.2008.10.003
Abstract: The inverse hexagonal to inverse ribbon phase transition in a mixed phosphatidylcholine-phosphatidylethanolamine system at low hydration is studied using small and wide angle X-ray scattering. It is found that the structural parameters of the inverse hexagonal phase are independent of temperature. By contrast the length of each ribbon of the inverse ribbon phase increases continuously with decreasing temperature over a range of 50 degrees C. At low temperatures the inverse ribbon phase is observed to have a transition to a gel lamellar phase, with no intermediate fluid lamellar phase. This phase transition is confirmed by differential scanning calorimetry.
Exclusion of maltodextrins from phosphatidylcholine multilayers during dehydration: effects on membrane phase behaviour
Publisher: Springer Science and Business Media LLC
Date: 13-02-2003
DOI: 10.1007/S00249-003-0277-Z
Abstract: The effect of increasing solute size on phosphatidylcholine phase behaviour at a range of hydrations was investigated using differential scanning calorimetry. Dehydration of phospholipid membranes gives rise to a compressive stress within the bilayers that promotes fluid-to-gel phase transitions. According to the Hydration Forces Explanation, sugars in the intermembrane space minimize the compressive stress and limit increases in the fluid-gel transition temperature, T(m), by acting as osmotic and volumetric spacers that hinder the close approach of membranes. However, the sugars must remain between the bilayers in order to limit the rise in T(m). Large polymers are excluded from the interlamellar space during dehydration and do not limit the dehydration-induced rise in T(m). In this study, we used maltodextrins with a range of molecular weights to investigate the size-exclusion limit for polymers between phosphatidylcholine bilayers. Solutes with sizes ranging from glucose to dextran 1000 limited the rise in lipid T(m) during dehydration, suggesting that they remain between dehydrated bilayers. At the lowest hydrations the solutions vitrified, and T(m) was further depressed to about 20 degrees C below the transition temperature for the lipid in excess water, T(o). The depression of T(m) below T(o) occurs when the interlamellar solution vitrifies between fluid phase bilayers. The larger maltodextrins, dextran 5000 and 12,000, had little effect on the T(m) of the PCs at any hydration, nor did vitrification of these larger polymers affect the lipid phase behaviour. This suggests that the larger maltodextrins are excluded from the interlamellar region during dehydration.
Impact of Comonomer Chemistry on Phase Behavior of Polymerizable Lyotropic Ionic Liquid Crystals: A Pre- and Post-Polymerization Study
Publisher: Wiley
Date: 30-10-2018
From Knock-Out Phenotype to Three-Dimensional Structure of a Promising Antibiotic Target from Streptococcus pneumoniae
Publisher: Public Library of Science (PLoS)
Date: 13-12-2013
Amino Acid-Coated Zeolitic Imidazolate Framework for Delivery of Genetic Material in Prostate Cancer Cell
Publisher: MDPI AG
Date: 20-06-2023
DOI: 10.3390/MOLECULES28124875
Abstract: Metal–organic frameworks (MOFs) are currently under progressive development as a tool for non-viral biomolecule delivery. Biomolecules such as proteins, lipids, carbohydrates, and nucleic acids can be encapsulated in MOFs for therapeutic purposes. The favorable physicochemical properties of MOFs make them an attractive choice for delivering a wide range of biomolecules including nucleic acids. Herein, a green fluorescence protein (GFP)-expressing plasmid DNA (pDNA) is used as a representative of a biomolecule to encapsulate within a Zn-based metal–organic framework (MOF) called a zeolitic imidazolate framework (ZIF). The synthesized biocomposites are coated with positively charged amino acids (AA) to understand the effect of surface functionalization on the delivery of pDNA to prostate cancer (PC-3) cells. FTIR and zeta potential confirm the successful preparation of positively charged amino acid-functionalized derivatives of pDNA@ZIF (i.e., pDNA@ZIFAA). Moreover, XRD and SEM data show that the functionalized derivates retain the pristine crystallinity and morphology of pDNA@ZIF. The coated biocomposites provide enhanced uptake of genetic material by PC-3 human prostate cancer cells. The AA-modulated fine-tuning of the surface charge of biocomposites results in better interaction with the cell membrane and enhances cellular uptake. These results suggest that pDNA@ZIFAA can be a promising alternative tool for non-viral gene delivery.
Water redistribution determines photosynthetic responses to warming and drying in two polar mosses
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/FP13160
Abstract: Predicting impacts of climate change requires an understanding of the sensitivity of species to temperature, including conflated changes in humidity. Physiological responses to temperature and clump-to-air vapour pressure difference (VPD) were compared in two Antarctic moss species, Ceratodon purpureus (Hedw.) Brid. and Schistidium antarctici (Cardot) L.I. Savicz & Smirnova. Temperatures from 8 to 24°C had no significant effects on photosynthesis or recovery from drying, whereas high VPD accelerated drying. In Schistidium, which lacks internal conduction structures, shoots dried more slowly than the clump, and photosynthesis ceased at high shoot relative water content (RWC), behaviour consistent with a strategy of drought avoidance although desiccation tolerant. In contrast, shoots of Ceratodon have a central vascular core, but dried more rapidly than the clump. These results imply that cavitation of the hydroid strand enables hydraulic isolation of extremities during rapid drying, effectively slowing water loss from the clump. Ceratodon maintained photosynthetic activity during drying to lower shoot RWC than Schistidium, consistent with a strategy of drought tolerance. These ecophysiological characteristics may provide a functional explanation for the differential distribution of Schistidium and Ceratodon along moisture gradients in Antarctica. Thus, predicting responses of non-vascular vegetation to climate change at high latitudes requires greater focus on VPD and hydraulics than temperature.
Encapsulation, Visualization and Expression of Genes with Biomimetically Mineralized Zeolitic Imidazolate Framework‐8 (ZIF‐8)
Publisher: Wiley
Date: 07-2019
Abstract: Recent work in biomolecule-metal-organic framework (MOF) composites has proven to be an effective strategy for the protection of proteins. However, for other biomacromolecules such as nucleic acids, the encapsulation into nano MOFs and the related characterizations are in their infancy. Herein, encapsulation of a complete gene-set in zeolitic imidazolate framework-8 (ZIF-8) MOFs and cellular expression of the gene delivered by the nano MOF composites are reported. Using a green fluorescent protein (GFP) plasmid (plGFP) as a proof-of-concept genetic macromolecule, successful transfection of mammalian cancer cells with plGFP for up to 4 days is shown. Cell transfection assays and soft X-ray cryo-tomography (cryo-SXT) demonstrate the feasibility of DNA@MOF biocomposites as intracellular gene delivery vehicles. Expression occurs over relatively prolonged time points where the cargo nucleic acid is released gradually in order to maintain sustained expression.
Mixed-Metal Hybrid Polyoxometalates with Amino Acid Ligands: Electronic Versatility and Solution Properties
Publisher: American Chemical Society (ACS)
Date: 15-11-2016
DOI: 10.1021/ACS.INORGCHEM.6B02218
Abstract: Eight new members of a family of mixed-metal (Mo,W) polyoxometalates (POMs) with amino acid ligands have been synthesized and investigated in the solid state and solution using multiple physical techniques. While the peripheral POM structural framework is conserved, the different analogues vary in nuclearity of the central metal-oxo core, overall redox state, metal composition, and identity of the zwitterionic α-amino acid ligands. Structural investigations reveal site-selective substitution of Mo for W, with a strong preference for Mo to occupy the central metal-oxo core. This core structural unit is a closed tetrametallic loop in the blue reduced species and an open trimetallic loop in the colorless oxidized analogues. Density functional theory calculations suggest the core as the favored site of reduction and reveal that the corresponding molecular orbital is much lower in energy for a tetra- versus trimetallic core. The reduced species are diamagnetic, each with a pair of strongly antiferromagnetically coupled Mo
Antibacterial Action of Nanoparticles by Lethal Stretching of Bacterial Cell Membranes
Publisher: Wiley
Date: 12-11-2020
Interactions of cryoprotective agents with phospholipid membranes - A Langmuir monolayer study
Publisher: Elsevier BV
Date: 09-2020
Differential dynamic microscopy to measure the translational diffusion coefficient of nanorods
Publisher: IOP Publishing
Date: 16-12-2020
Illuminating the biochemical interaction of antimicrobial few-layer black phosphorus with microbial cells using synchrotron macro-ATR-FTIR
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1TB02575A
Abstract: Black phosphorus (BP) nanoflakes have shown high antimicrobial activity. The interaction of microbial cells and black phosphorus nanoflakes was investigated using microscopic techniques and synchrotron source ATR-FTIR spectroscopy.
A Hitchhiker’s Guide to Particle Sizing Techniques
Publisher: American Chemical Society (ACS)
Date: 10-08-2020
Cellular cryobiology: Thermodynamic amd mechanical effects
Publisher: Elsevier BV
Date: 08-2001
Intrinsically Disordered Stress Protein COR15A Resides at the Membrane Surface during Dehydration
Publisher: Elsevier BV
Date: 08-2017
Effects of cryoprotectants on phospholipid monolayers – concentration and species dependence
Publisher: CSIRO Publishing
Date: 21-01-2022
DOI: 10.1071/CH21161
Abstract: The effects of four cryoprotectants (dimethylformamide (DMF), ethylene glycol (EG), glycerol and dimethyl sulfoxide (DMSO)) on monolayers of four phospholipids were investigated at high cryoprotectant concentration (10% v/v) relevant to cryoprotection, and compared with previous work at lower concentrations (5% v/v). The results show that the interactions between cryoprotective agents (CPAs) and lipids are complex, with significant differences identified as functions of CPA, concentration and phospholipid species. It was observed that generally DMF and EG cause monolayer compaction, whereas glycerol causes expansion (penetrating the monolayer), although each exhibited subtle differences with different phospholipids. DMSO showed significant differences depending on the headgroup (phosphatidylcholine vs phosphatidylethanolamine) and the physical state of the monolayer. In addition, it was found that DMF was the only CPA capable of penetrating monolayers at physiologically relevant lateral pressures. The results highlight that conclusions based on a single model system (e.g. DPPC) should not be extrapolated to other lipids, and there is a need to study a wider range of lipid species and CPA concentrations in order to understand their mechanisms of action more fully.
Deep eutectic solvents as cryoprotective agents for mammalian cells
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TB00573E
Abstract: A deep eutectic solvent is an effective cryoprotective agent for several human cell lines.
Synthesis of ultra‐high molecular weight polymers by controlled production of initiating radicals
Publisher: Wiley
Date: 10-01-2019
DOI: 10.1002/POLA.29318
Crystallization of dense binary hard-sphere mixtures with marginal size ratio
Publisher: American Physical Society (APS)
Date: 04-06-2008
A Gallium-Based Magnetocaloric Liquid Metal Ferrofluid.
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
DOI: 10.1021/ACS.NANOLETT.7B04050
Abstract: We demonstrate a magnetocaloric ferrofluid based on a gadolinium saturated liquid metal matrix, using a gallium-based liquid metal alloy as the solvent and suspension medium. The material is liquid at room temperature, while exhibiting spontaneous magnetization and a large magnetocaloric effect. The magnetic properties were attributed to the formation of gadolinium nanoparticles suspended within the liquid gallium alloy, which acts as a reaction solvent during the nanoparticle synthesis. High nanoparticle weight fractions exceeding 2% could be suspended within the liquid metal matrix. The liquid metal ferrofluid shows promise for magnetocaloric cooling due to its high thermal conductivity and its liquid nature. Magnetic and thermoanalytic characterizations reveal that the developed material remains liquid within the temperature window required for domestic refrigeration purposes, which enables future fluidic magnetocaloric devices. Additionally, the observed formation of nanometer-sized metallic particles within the supersaturated liquid metal solution has general implications for chemical synthesis and provides a new synthetic pathway toward metallic nanoparticles based on highly reactive rare earth metals.
Bulk and interfacial nanostructure and properties in deep eutectic solvents: Current perspectives and future directions
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.JCIS.2021.10.163
Abstract: Deep eutectic solvents (DESs) are a tailorable class of solvents that are rapidly gaining scientific and industrial interest. This is because they are distinct from conventional molecular solvents, inherently tuneable via careful selection of constituents, and possess many attractive properties for applications, including catalysis, chemical extraction, reaction media, novel lubricants, materials chemistry, and electrochemistry. DESs are a class of solvents composed solely of hydrogen bond donors and acceptors with a melting point lower than the in idual components and are often fluidic at room temperature. A unique feature of DESs is that they possess distinct bulk liquid and interfacial nanostructure, which results from intra- and inter-molecular interactions, including coulomb forces, hydrogen bonding, van der Waals interactions, electrostatics, dispersion forces, and apolar-polar segregation. This nanostructure manifests as preferential spatial arrangements of the different species, and exists over several length scales, from molecular- to nano- and meso-scales. The physicochemical properties of DESs are dictated by structure-property relationships however, there is a significant gap in our understanding of the underlying factors which govern their solvent properties. This is a major limitation of DES-based technologies, as nanostructure can significantly influence physical properties and thus potential applications. This perspective provides an overview of the current state of knowledge of DES nanostructure, both in the bulk liquid and at solid interfaces. We provide definitions which clearly distinguish DESs as a unique solvent class, rather than a subset of ILs. An appraisal of recent work provides hints towards trends in structure-property relationships, while also highlighting inconsistencies within the literature suggesting new research directions for the field. It is hoped that this review will provide insight into DES nanostructure, their potential applications, and development of a robust framework for systematic investigation moving forward.
Location of sugars in multilamellar membranes at low hydration
Publisher: Elsevier BV
Date: 11-2006
Insights into Chemical Interactions and Related Toxicities of Deep Eutectic Solvents with Mammalian Cells Observed Using Synchrotron Macro–ATR–FTIR Microspectroscopy
Publisher: MDPI AG
Date: 04-05-2023
DOI: 10.3390/BIOPHYSICA3020021
Abstract: Deep eutectic solvents (DESs) and ionic liquids (ILs) are highly tailorable solvents that have shown a lot of promise for a variety of applications including cryopreservation, drug delivery, and protein stabilisation. However, to date, there is very limited information on the detailed interactions of these solvents with mammalian cells. In this work, we studied six DESs and one IL that show promise as cryoprotective agents, applying synchrotron macro–ATR–FTIR to examine their effects on key biochemical components of HaCat mammalian cells. These data were paired with resazurin metabolic assays and neutron reflectivity experiments to correlate cellular interactions with cellular toxicity. Stark differences were observed even between solvents that shared similar components. In particular, it was found that solvents that are effective cryoprotective agents consistently showed interactions with cellular membranes, while high toxicity correlated with strong interactions of the DES/IL with nucleic acids and proteins. This work sheds new light on the interactions between novel solvents and cells that may underpin future biomedical applications.
Nanostructure of a deep eutectic solvent at solid interfaces
Publisher: Elsevier BV
Date: 06-2021
Crystallization kinetics of polydisperse colloidal hard spheres. II. Binary mixtures
Publisher: American Physical Society (APS)
Date: 24-02-2005
Fluorescent HPHT nanodiamonds have disk- and rod-like shapes
Publisher: Elsevier BV
Date: 03-2023
Synthesis and self-assembly of polyimide/poly(dimethylsiloxane) brush triblock copolymers
Publisher: Elsevier BV
Date: 2013
Dehydration of solute-lipid systems: Hydration forces analysis
Publisher: Elsevier BV
Date: 05-2004
Phospholipid Membrane Protection by Sugar Molecules during Dehydration-Insights into Molecular Mechanisms Using Scattering Techniques
Publisher: MDPI AG
Date: 12-04-2013
DOI: 10.3390/IJMS14048148
A Depolarized Dynamic Light Scattering Method to Calculate Translational and Rotational Diffusion Coefficients of Nanorods
Publisher: Wiley
Date: 29-11-2019
Compositional relaxation on the approach to the glass transition in a model trehalose solution
Publisher: American Physical Society (APS)
Date: 07-03-2019
Arrest of Flow and Emergence of Activated Processes at the Glass Transition of a Suspension of Particles with Hard Spherelike Interactions
Publisher: American Physical Society (APS)
Date: 23-04-2009
Microwave assisted synthesis of a mono organoimido functionalized Anderson polyoxometalate
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5DT04000K
Abstract: The synthesis of an aliphatic organoimido functionalized polyoxometalate has been achieved through a microwave assisted reaction protocol in the absence of any activating reagents.
Effect of deuteration on the phase behaviour and structure of lamellar phases of phosphatidylcholines – Deuterated lipids as proxies for the physical properties of native bilayers
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.COLSURFB.2019.01.040
Abstract: Deuteration of phospholipids is a common practice to elucidate membrane structure, dynamics and function, by providing selective visualisation in neutron scattering, nuclear magnetic resonance and vibrational spectroscopy. It is generally assumed that the properties of the deuterated lipids are identical to those of the protiated lipids, and while a number of papers have compared the properties of different forms, to date this has been no systematic study of the effects over a range of conditions. Here we present a study of the effects of deuteration on the organisation and phase behaviour of four common phospholipids (DSPC, DPPC, DMPC, DOPC), observing the effect of chain deuteration and headgroup deuteration on lipid structure and phase behaviour. For saturated lipids in excess water the gel-fluid phase transition temperature is 4.3 ± 0.1 °C lower for lipids with deuterated chains compared to protiated chains, consistent with previous work. Despite this significant change, well away from the transition structural changes as measured by powder small angle X-ray scattering are small and within errors. To investigate this further, measurements were carried out on oriented multilamellar stacks of DOPC in the fluid phase at reduced hydration. Neutrons are used in conjunction with contrast variation to elucidate the role of the deuteration explicitly. It is found that deuterated chains cause a reduction in the lamellar repeat spacing and bilayer thickness, but deuterated headgroups cause an increase. Consequences for the interpretation of Neutron Scattering data with deuterated lipids are discussed.
Membrane behaviour in seeds and other systems at low water content: The various effects of solutes
Publisher: CABI Publishing
Date: 03-2001
DOI: 10.1079/SSR200056
Optical contrast variation study of nonaqueous suspensions of polymer particles
Publisher: Elsevier BV
Date: 08-1999
Blood-Catalyzed RAFT Polymerization
Publisher: Wiley
Date: 12-07-2018
Abstract: The use of hemoglobin (Hb) contained within red blood cells to drive a controlled radical polymerization via a reversible addition-fragmentation chain transfer (RAFT) process is reported for the first time. No pre-treatment of the Hb or cells was required prior to their use as polymerization catalysts, indicating the potential for synthetic engineering in complex biological microenvironments without the need for ex vivo techniques. Owing to the naturally occurring prevalence of the reagents employed in the catalytic system (Hb and hydrogen peroxide), this approach may facilitate the development of new strategies for in vivo cell engineering with synthetic macromolecules.
The human factor: results of a small-angle scattering data analysis round robin
Publisher: International Union of Crystallography (IUCr)
Date: 31-10-2023
Phytantriol phase behaviour in choline chloride urea and water mixtures
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3TB00554B
Abstract: Phytantriol forms a Pn 3 m cubic phase in both water and neat choline chloride:urea. However, mixtures of the DES with water result in phytantriol forming an inverse hexagonal phase and influenced phase transition temperatures.
Accurate measurement of small polydispersities in colloidal suspensions
Publisher: American Chemical Society (ACS)
Date: 31-12-2003
DOI: 10.1021/LA026636G
Long-range attraction between nucleosides with short-range specificity: Direct measurements
Publisher: American Physical Society (APS)
Date: 14-11-1994
Freeze avoidance: a dehydrating moss gathers no ice
Publisher: Wiley
Date: 07-09-2010
DOI: 10.1111/J.1365-3040.2010.02178.X
Abstract: Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type water-filled hydroid cells cavitated and were embolized at -4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ∼ 20% of their original volume at a nadir temperature of -20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from -20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ∼-12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to -20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing remove that which freezes.
Effects of Sugars on Lipid Bilayers during Dehydration - SAXS/WAXS Measurements and Quantitative Model
Publisher: American Chemical Society (ACS)
Date: 03-02-2009
DOI: 10.1021/JP808670T
Abstract: We present an X-ray scattering study of the effects of dehydration on the bilayer and chain-chain repeat spacings of dipalmitoylphosphatidylcholine bilayers in the presence of sugars. The presence of sugars has no effect on the average spacing between the phospholipid chains in either the fluid or gel phase. Using this finding, we establish that for low sugar concentrations only a small amount of sugar exclusion occurs. Under these conditions, the effects of sugars on the membrane transition temperatures can be explained quantitatively by the reduction in hydration repulsion between bilayers due to the presence of the sugars. Specific bonding of sugars to lipid headgroups is not required to explain this effect.
Behavior of Citrate-Capped Ultrasmall Gold Nanoparticles on a Supported Lipid Bilayer Interface at Atomic Resolution
Publisher: American Chemical Society (ACS)
Date: 19-09-2022
Abstract: Nanomaterials have the potential to transform biological and biomedical research, with applications ranging from drug delivery and diagnostics to targeted interference of specific biological processes. Most existing research is aimed at developing nanomaterials for specific tasks such as enhanced biocellular internalization. However, fundamental aspects of the interactions between nanomaterials and biological systems, in particular, membranes, remain poorly understood. In this study, we provide detailed insights into the molecular mechanisms governing the interaction and evolution of one of the most common synthetic nanomaterials in contact with model phospholipid membranes. Using a combination of atomic force microscopy (AFM) and molecular dynamics (MD) simulations, we elucidate the precise mechanisms by which citrate-capped 5 nm gold nanoparticles (AuNPs) interact with supported lipid bilayers (SLBs) of pure fluid (DOPC) and pure gel-phase (DPPC) phospholipids. On fluid-phase DOPC membranes, the AuNPs adsorb and are progressively internalized as the citrate capping of the NPs is displaced by the surrounding lipids. AuNPs also interact with gel-phase DPPC membranes where they partially embed into the outer leaflet, locally disturbing the lipid organization. In both systems, the AuNPs cause holistic perturbations throughout the bilayers. AFM shows that the lateral diffusion of the particles is several orders of magnitude smaller than that of the lipid molecules, which creates some temporary scarring of the membrane surface. Our results reveal how functionalized AuNPs interact with differing biological membranes with mechanisms that could also have implications for cooperative membrane effects with other molecules.
Translational and rotational diffusion coefficients of gold nanorods functionalized with a high molecular weight, thermoresponsive ligand: a depolarized dynamic light scattering study
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SM00077B
Abstract: Collapse of high molecular weight, thermoresponsive polymer ligands on gold nanorods increases the translational and rotational diffusion coefficients due to an increase in aspect ratio and thus particles become less ellipsoidal.
A Bragg scattering spectrometer for studying crystallization of colloidal suspensions
Publisher: AIP Publishing
Date: 25-10-2002
DOI: 10.1063/1.1512332
Abstract: A light scattering spectrometer is described that is used for the study of crystallization in hard sphere colloidal suspensions. Collimated laser light is Bragg scattered from the crystals as they form, and the diffracted light is focused by a liquid filled hemispherical lens onto low cost charge coupled device array detectors that are rotated about the optical axis to average the intensities around the whole Debye–Sherrer cone of scattered light. The temperature of the s le can be controlled, and this is utilized to control the amount of scattering from the s le. The spectrometer exploits the refractive index match of the colloidal particles, the solvent, the bath liquid, and the glass used for both the s le bottle and the hemispherical lens. Parameters measured are crystallization rate, the amount of crystal formed, and the average lattice spacing, all as functions of time. Results presented show that this spectrometer gives insight into the crystallization process more than 1 order of magnitude of time earlier than previous light scattering experiments, leading to understanding of the crystallization process.
Characterization of the interactions within fine particle mixtures in highly concentrated suspensions for advanced particle processing
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CIS.2015.07.005
Abstract: This paper aims to summarize recent investigations into the dispersion of fine particles, and the characterization of their interactions, in concentrated suspensions. This summary will provide a better understanding of the current status of this research, and will provide useful feedback for advanced particle processing. Such processes include the fabrication of functional nanostructures and the sustainable beneficiation of complex ores. For ex le, there has been increasing demand for complex ore utilization due to the noticeable decrease in the accessibility of high grade and easily extractable ores. In order to maintain the sustainable use of mineral resources, the effective beneficiation of complex ores is urgently required. It can be successfully achieved only with selective particle/mineral dispersion/liberation and the assistance of mineralogical and particle characterization.
Structural aspects of a self-emulsifying multifunctional amphiphilic excipient: Part I. The case of Gelucire® 44/14
Publisher: Elsevier BV
Date: 10-2021
Sonication synthesis of micro-sized silver nanoparticle/oleic acid liquid marbles: A novel SERS sensing platform
Publisher: Elsevier BV
Date: 02-2016
Direct Comparison of Disaccharide Interaction with Lipid Membranes at Reduced Hydrations
Publisher: American Chemical Society (ACS)
Date: 11-08-2015
DOI: 10.1021/ACS.LANGMUIR.5B02127
Abstract: Understanding sugar-lipid interactions during desiccation and freezing is an important step in the elucidation of cryo- and anhydro-protection mechanisms. We determine sucrose, trehalose, and water concentration distributions in intra-bilayer volumes between opposing dioleoylphosphatidylcholine bilayers over a range of reduced hydrations and sugar concentrations. Stacked lipid bilayers at reduced hydration provide a suitable system to mimic environmental dehydration effects, as well as a suitable system for direct probing of sugar locations by neutron membrane diffraction. Sugar distributions show that sucrose and trehalose both behave as typical uncharged solutes, largely excluded from the lipid bilayers regardless of sugar identity, and with no correlation between sugar distribution and the lipid headgroup position as the hydration is changed. These results are discussed in terms of current opinions about cryo- and anhydro-protection mechanisms.
Dramatic slowing of compositional relaxations in the approach to the glass transition for a bimodal colloidal suspension
Publisher: American Physical Society (APS)
Date: 22-08-2017
Small changes in particle-size distribution dramatically delay and enhance nucleation in hard sphere colloidal suspensions
Publisher: American Physical Society (APS)
Date: 04-12-2006
How hard is a colloidal hard-sphere interaction?
Publisher: American Physical Society (APS)
Date: 30-12-2002
Can hydration forces induce lateral phase separations in lamellar phases?
Publisher: Springer Science and Business Media LLC
Date: 02-1989
DOI: 10.1007/BF00257886
Abstract: Currently, electroencephalography (EEG) cannot be used to record cortical activity during clinically effective DBS due to the presence of large stimulation artifact with components that overlap the useful spectrum of the EEG. A filtering method is presented that removes these artifacts whilst preserving the spectral and temporal fidelity of the underlying EEG. The filter is based on the H el identifier that treats artifacts as outliers in the frequency domain and replaces them with interpolated values. Performance of the filter was tested with a synthesized DBS signal and actual data recorded during bilateral monopolar DBS. Mean increases in signal-to-noise ratio of 7.8dB for single-frequency stimulation and 13.8dB for dual-frequency stimulation are reported. Correlation analysis between EEG with synthesized artifacts and artifact-free EEG reveals that distortion to the underlying EEG in the filtered signal is negligible (r(2)>0.99). Frequency-domain H el filtering has been shown to remove monopolar DBS artifacts under a number of common stimulation conditions used for the treatment of Parkinson's disease. Application of frequency-domain H el filtering will allow the measurement of EEG in patients during clinically effective DBS and thus may increase our understanding of the mechanisms of action of this important therapeutic intervention.
Micro- to nano-scale chemical and mechanical mapping of antimicrobial-resistant fungal biofilms
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR05617K
Abstract: The heterogeneity of fungal biofilms are spatially characterized using a combination of AFM, nanoindentation, and ATR-FTIR.
Phase separation in a ternary DPPC/DOPC/POPC system with reducing hydration
Publisher: Elsevier BV
Date: 05-2023
Sum rules for Mie scattering
Publisher: Optica Publishing Group
Date: 05-1987
Improved particle size distribution measurements using multiangle dynamic light scattering .2. Refinements and applications
Publisher: American Chemical Society (ACS)
Date: 1996
DOI: 10.1021/LA960224O
Velocity autocorrelation functions of hard-sphere fluids: Long-time tails upon undercooling
Publisher: American Physical Society (APS)
Date: 28-02-2006
Change in relaxation scenario at the order-disorder transition of a colloidal fluid of hard spheres seen from the Gaussian limit of the self-intermediate scattering function
Publisher: American Physical Society (APS)
Date: 02-09-2005
Two-step crystallization kinetics in colloidal hard-sphere systems
Publisher: American Physical Society (APS)
Date: 04-05-2006
Photomodulation of bacterial growth and biofilm formation using carbohydrate-based surfactants
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SC03020C
Abstract: The photocontrollable antibacterial and biofilm modulatory activity of a panel of light responsive carbohydrate-based surfactants is reported.
Structure Analysis of Solid Lipid Nanoparticles for Drug Delivery: A Combined USANS/SANS Study
Publisher: Wiley
Date: 22-11-2019
Scaling of the Space-Time Correlation Function of Particle Currents in a Suspension of Hard-Sphere-Like Particles: Exposing When the Motion of Particles is Brownian
Publisher: American Physical Society (APS)
Date: 17-12-2009
Observation of a smecticlike crystalline structure in polydisperse colloids
Publisher: American Physical Society (APS)
Date: 27-06-2003
Molecular dynamics simulation study of the static and dynamic properties of a model colloidal suspension with explicit solvent
Publisher: Informa UK Limited
Date: 26-08-2016
Measurement of glucose exclusion from the fully hydrated DOPE inverse hexagonal phase
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B919086D
Crystallization of hard-sphere colloids - Deviations from classical nucleation theory
Publisher: IEEE
Date: 2006
Disordered Cold Regulated15 Proteins Protect Chloroplast Membranes during Freezing through Binding and Folding, But Do Not Stabilize Chloroplast Enzymes in Vivo
Publisher: Oxford University Press (OUP)
Date: 05-08-2014
Size, shape and surface chemistry of nano-gold dictate its cellular interactions, uptake and toxicity
Publisher: Elsevier BV
Date: 10-2016
Structure of solid lipid nanoparticles produced by a microwave-assisted microemulsion technique
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA02020H
Abstract: The current study investigates the structure of solid lipid nanoparticles, prepared using a recently reported microwave-assisted microemulsion technique, by multi-angle static and dynamic light scattering and small angle X-ray scattering techniques.
Photoinitiated Energy Transfer in Porous‐Cage‐Stabilised Silver Nanoparticles
Publisher: Wiley
Date: 08-05-2023
Abstract: We report a new composite material consisting of silver nanoparticles decorated with three‐dimensional molecular organic cages based on light‐absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano‐resonant interaction between the porphyrin Soret band and the nanoparticle‐localised surface‐plasmon resonance. Time‐resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited‐state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2‐fold current increase in photoelectrochemical water‐splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications.
Preferred orientation and its effects on intensity-correlation measurements
Publisher: International Union of Crystallography (IUCr)
Date: 21-01-2022
DOI: 10.1107/S2052252521012422
Abstract: Intensity-correlation measurements allow access to nanostructural information on a range of ordered and disordered materials beyond traditional pair-correlation methods. In real space, this information can be expressed in terms of a pair-angle distribution function (PADF) which encodes three- and four-body distances and angles. To date, correlation-based techniques have not been applied to the analysis of microstructural effects, such as preferred orientation, which are typically investigated by texture analysis. Preferred orientation is regarded as a potential source of error in intensity-correlation experiments and complicates interpretation of the results. Here, the theory of preferred orientation in intensity-correlation techniques is developed, connecting it to the established theory of texture analysis. The preferred-orientation effect is found to scale with the number of crystalline domains in the beam, surpassing the nanostructural signal when the number of domains becomes large. Experimental demonstrations are presented of the orientation-dominant and nanostructure-dominant cases using PADF analysis. The results show that even minor deviations from uniform orientation produce the strongest angular correlation signals when the number of crystalline domains in the beam is large.
Cryopreservation of mammalian cells using protic ionic liquid solutions
Publisher: Elsevier BV
Date: 12-2021
Highly Living Stars via Core-First Photo-RAFT Polymerization: Exploitation for Ultra-High Molecular Weight Star Synthesis
Publisher: American Chemical Society (ACS)
Date: 20-09-2019
Characterization of the phase behaviour of a novel polymerizable lyotropic ionic liquid crystal
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CP03797B
Abstract: Impact of polymerizable moiety on the phase behaviour of imidazolium based ionic liquid crystal as a function of water content.
How much solute is needed to inhibit the fluid to gel membrane phase transition at low hydration?
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.BBAMEM.2007.01.008
Abstract: We present a quantitative study of the effect of sugars on the membrane gel-fluid phase transition as a function of sugar:lipid ratio. We show that the maximum effect occurs at around 1.5 sugar rings per molecule for both mono- and di-saccharides. We present a theoretical model to try to explain these results, and discuss the assumptions inherent in the model.
Incorporation of Vanadium and Molybdenum into Yttrium-Arsenotungstates Supported by Amino Acid Ligands
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/CH19326
Abstract: The preference for incorporation of molybdenum over tungsten into specific sites of a family of yttrium-arsenotungstates with amino acid ligands prompted exploration of the incorporation of other metals, affording three new vanadium-containing (V/W and V/Mo/W) analogues: K2(GlyH)10[As4(V2W2)W44Y4O160(Gly)8(H2O)12]·11Gly (1), (MBAH)9(L-NleH)3[As4(V2W2)W44Y4O160(L-Nle)8(H2O)12] (2), and (MBAH)9(L-NleH)3[As4(V2W2)Mo2W42Y4O160(L-Nle)8(H2O)12] (3) (Gly=glycine and L-Nle=l-norleucine, MBAH=4-methylbenzylammonium). These hybrid polyoxometalates all possess a tetrametallic oxo-bridged {VIV2WVI2} central core surrounded by an amino acid-ligated cyclic metal-oxo framework. X-Ray photoelectron, UV-visible reflectance, and electron paramagnetic resonance spectroscopy, together with metal analysis, confirm the incorporation of vanadium into the polyoxometalates, while single crystal X-ray diffraction analysis supports the location of the vanadium atoms in the central core.
Slow dynamics and aging of a colloidal hard sphere glass
Publisher: American Physical Society (APS)
Date: 26-09-2008
DSC MEASUREMENT OF CELL-SUSPENSIONS DURING SUCCESSIVE FREEZING RUNS - IMPLICATIONS FOR THE MECHANISMS OF INTRACELLULAR ICE FORMATION
Publisher: Elsevier BV
Date: 04-1995
Abstract: The formation of intracellular ice in biological cells during freezing is considered almost universally lethal and is the major contributor to cell damage at high cooling rates. Despite its importance, our understanding of the mechanisms of intracellular ice formation (IIF) is still incomplete. In this paper differential scanning calorimetry is used to study IIF in human lymphocytes in the presence of dimethyl sulfoxide (Me2SO). Under conditions where damage due to IIF on the initial cooling run is 40-60%, the s les are studied as a function of multiple successive cooling runs. This enables the study not only of the cell fraction which undergoes IIF, but also of the fraction which survives. The temperature at which IIF occurs and the fraction of cell volume which undergoes IIF are analyzed as functions of successive cooling runs. Taking advantage of the large number of cells present in the s les (ca. 10(6)), the effect of successive cooling runs on susceptibility to IIF is examined.
Interaction of Giant Unilamellar Vesicles with the Surface Nanostructures on Dragonfly Wings
Publisher: American Chemical Society (ACS)
Date: 10-01-2019
DOI: 10.1021/ACS.LANGMUIR.8B03470
Abstract: The waxy epicuticle of dragonfly wings contains a unique nanostructured pattern that exhibits bactericidal properties. In light of emerging concerns of antibiotic resistance, these mechano-bactericidal surfaces represent a particularly novel solution by which bacterial colonization and the formation of biofilms on biomedical devices can be prevented. Pathogenic bacterial biofilms on medical implant surfaces cause a significant number of human deaths every year. The proposed mechanism of bactericidal activity is through mechanical cell rupture however, this is not yet well understood and has not been well characterized. In this study, we used giant unilamellar vesicles (GUVs) as a simplified cell membrane model to investigate the nature of their interaction with the surface of the wings of two dragonfly species, Austrothemis nigrescens and Trithemis annulata, sourced from Victoria, Australia, and the Baix Ebre and Terra Alta regions of Catalonia, Spain. Confocal laser scanning microscopy and cryo-scanning electron microscopy techniques were used to visualize the interactions between the GUVs and the wing surfaces. When exposed to both natural and gold-coated wing surfaces, the GUVs were adsorbed on the surface, exhibiting significant deformation, in the process of membrane rupture. Differences between the tensile rupture limit of GUVs composed of 1,2-dioleoyl- sn-glycero-3-phosphocholine and the isotropic tension generated from the internal osmotic pressure were used to indirectly determine the membrane tensions, generated by the nanostructures present on the wing surfaces. These were estimated as being in excess of 6.8 mN m
Impact of nanogold morphology on interactions with human serum
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP05938A
Abstract: Following the synthesis of different shaped gold nanoparticles, their interaction with human serum albumin was studied to reveal shape affects both the affinity and strength of binding.
The effect of salt and particle concentration on the dynamic self-assembly of detonation nanodiamonds in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NR04847C
Abstract: Detonation nanodiamonds self-assemble into fractal-like structures in aqueous suspensions. Our work shows that the size and shape of these structures strongly depend on the particle concentration but not on the ionic strength of the suspension.
Dynamic self-assembly of detonation nanodiamond in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9NR08984E
Abstract: We use direct imaging and dynamic light scattering to reveal the previously unknown dynamic self-assembly of detonation nanodiamond dispersions in water which have been purified without additional surface modification.
Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution
Publisher: Wiley
Date: 2006
DOI: 10.1002/APP.23282
Asymptotic behavior of the Mie-scattering amplitude
Publisher: Optica Publishing Group
Date: 02-1986
Easy Come, Easy Go: Capillary Forces Enable Rapid Refilling of Embolized Primary Xylem Vessels
Publisher: Oxford University Press (OUP)
Date: 19-06-2015
DOI: 10.1104/PP.15.00333
Analysis of Pathogenic Bacterial and Yeast Biofilms Using the Combination of Synchrotron ATR-FTIR Microspectroscopy and Chemometric Approaches
Publisher: MDPI AG
Date: 25-06-2021
DOI: 10.3390/MOLECULES26133890
Abstract: Biofilms are assemblages of microbial cells, extracellular polymeric substances (EPS), and other components extracted from the environment in which they develop. Within biofilms, the spatial distribution of these components can vary. Here we present a fundamental characterization study to show differences between biofilms formed by Gram-positive methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative Pseudomonas aeruginosa, and the yeast-type Candida albicans using synchrotron macro attenuated total reflectance-Fourier transform infrared (ATR-FTIR) microspectroscopy. We were able to characterise the pathogenic biofilms’ heterogeneous distribution, which is challenging to do using traditional techniques. Multivariate analyses revealed that the polysaccharides area (1200–950 cm−1) accounted for the most significant variance between biofilm s les, and other spectral regions corresponding to amides, lipids, and polysaccharides all contributed to s le variation. In general, this study will advance our understanding of microbial biofilms and serve as a model for future research on how to use synchrotron source ATR-FTIR microspectroscopy to analyse their variations and spatial arrangements.
Stabilization of Peptide-Based Vesicles via in situ Oxygen-Mediated Cross-Linking
Publisher: Wiley
Date: 13-07-2012
Abstract: Reversible vesicles from poly(L-glutamic acid)(65) -block-poly[(L-lysine)-ran-(L-3,4-dihydroxyphenylalanine)](75) [PLGA(65)-b-P(LL-r-DOPA)(75)] block copolypeptide adopt different configurations depending on the surrounding pH. At pH = 3, AFM and TEM images show ellipsoidal morphologies, whereas at pH = 12 both TEM and AFM reveal the formation of hollow vesicles. At pH = 12, the P(LL-r-DOPA) block forms the internal layer of the vesicle shell and the subsequent oxygen-mediated oxidation of the phenolic groups of the DOPA lead to the formation of quinonic intermediates, which undergo intermolecular dimerization to stabilize the vesicles via in situ cross-linking. Consequently, the vesicles maintain their shape even when the pH is reversed back to 3, as confirmed by AFM and TEM.
Modular Molecules: Site-Selective Metal Substitution, Photoreduction, and Chirality in Polyoxometalate Hybrids
Publisher: Wiley
Date: 09-09-2014
Abstract: The first members of a promising new family of hybrid amino acid-polyoxometalates have emerged from a search for modular functional molecules. Incorporation of glycine (Gly) or norleucine (Nle) ligands into an yttrium-tungstoarsenate structural backbone, followed by crystallization with p-methylbenzylammonium (p-MeBzNH3(+)) cations, affords (p-MeBzNH3)6K2(GlyH)[As(III)4(Y(III)W(VI)3)W(VI)44Y(III)4O159(Gly)8(H2O)14]⋅47 H2O (1) and enantiomorphs (p-MeBzNH3)15(NleH)3[As(III)4(Mo(V)2Mo(VI)2)W(VI)44Y(III)4O160(Nle)9(H2O)11][As(III)4(Mo(VI)2W(VI)2)W(VI)44Y(III)4O160(Nle)9(H2O)11] (generically designated 2: L-Nle, 2 a D-Nle, 2 b). An intensive structural, spectroscopic, electrochemical, magnetochemical and theoretical investigation has allowed the elucidation of site-selective metal substitution and photoreduction of the tetranuclear core of the hybrid polyanions. In the solid state, markedly different crystal packing is evident for the compounds, which indicates the role of noncovalent interactions involving the amino acid ligands. In solution, mass spectrometric and small-angle X-ray scattering studies confirm maintenance of the structure of the polyanions of 2, while circular dichroism demonstrates that the chirality is also maintained. The combination of all of these features in a single modular family emphasizes the potential of such hybrid polyoxometalates to provide nanoscale molecular materials with tunable properties.
Dynamics of a model colloidal suspension from dilute to freezing
Publisher: American Physical Society (APS)
Date: 26-07-2016
Structural aspects of a self-emulsifying multifunctional amphiphilic excipient: Part II. The case of Cremophor EL
Publisher: Elsevier BV
Date: 12-2021
n-Octyl (Thio)glycosides as Potential Cryoprotectants: Glass Transition Behaviour, Membrane Permeability, and Ice Recrystallization Inhibition Studies
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/CH19159
Abstract: A series of eight n-octyl (thio)glycosides (1α, β–4α, β) with d-glucose or d-galactose-configured head groups and varying anomeric configuration were synthesized and evaluated for glass transition behaviour, membrane permeability, and ice recrystallization inhibition (IRI) activity. Of these, n-octyl β-d-glucopyranoside (2β) exhibited a high glass transition temperatures (Tg), both as a neat s le and 20 wt-% aqueous solution. Membrane permeability studies of this compound revealed cellular uptake to concentrations relevant to the inhibition of intracellular ice formation, thus presenting a promising lead candidate for further biophysical and cryopreservation studies. Compounds were also evaluated as ice recrystallization inhibitors however, no detectable activity was observed for the newly tested compounds.
Dynamics of hard sphere suspensions using dynamic light scattering and X-ray photon correlation spectroscopy: Dynamics and scaling of the intermediate scattering function
Publisher: AIP Publishing
Date: 02-02-2011
DOI: 10.1063/1.3525101
Abstract: Intermediate scattering functions are measured for colloidal hard sphere systems using both dynamic light scattering and x-ray photon correlation spectroscopy. We compare the techniques, and discuss the advantages and disadvantages of each. Both techniques agree in the overlapping range of scattering vectors. We investigate the scaling behavior found by Segré and Pusey [Phys. Rev. Lett. 77, 771 (1996)] but challenged by Lurio et al. [Phys. Rev. Lett. 84, 785 (2000)]. We observe a scaling behavior over several decades in time but not in the long-time regime. Moreover, we do not observe long-time diffusive regimes at scattering vectors away from the peak of the structure factor and so question the existence of long-time diffusion coefficients at these scattering vectors.
Electromechanical stresses produced in the plasma membranes of suspended cells by applied electric fields
Publisher: Springer Science and Business Media LLC
Date: 06-1987
DOI: 10.1007/BF01869239
Abstract: Little is known about factors contributing to children's asthma control status and health-related quality of life (HRQoL). The study objectives were to assess the relationship between asthma control and asthma-specific HRQoL in asthmatic children, and to examine the extent to which parental health literacy, perceived self-efficacy with patient-physician interaction, and satisfaction with shared decision-making (SDM) contribute to children's asthma control and asthma-specific HRQoL. This cross-sectional study utilized data collected from a s le of asthmatic children (n = 160) aged 8-17 years and their parents (n = 160) who visited a university medical center. Asthma-specific HRQoL was self-reported by children using the National Institutes of Health's Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Asthma Impact Scale. Satisfaction with SDM, perceived self-efficacy with patient-physician interaction, parental health literacy, and asthma control were reported by parents using standardized measures. Structural equation modeling (SEM) was performed to test the hypothesized pathways. Path analysis revealed that children with better asthma control reported higher asthma-specific HRQoL (β = 0.4, P < 0.001). Parents with higher health literacy and greater perceived self-efficacy with patient-physician interactions were associated with higher satisfaction with SDM (β = 0.38, P < 0.05 β = 0.58, P < 0.001, respectively). Greater satisfaction with SDM was in turn associated with better asthma control (β = -0.26, P < 0.01). Children's asthma control status influenced their asthma-specific HRQoL. However, parental factors such as perceived self-efficacy with patient-physician interaction and satisfaction with shared decision-making indirectly influenced children's asthma control status and asthma-specific HRQoL.
Multimodal Imaging and Soft X‐Ray Tomography of Fluorescent Nanodiamonds in Cancer Cells
Publisher: Wiley
Date: 11-10-2021
Measuring volume kinetics of human monocytes in response to cryoprotectants using microfluidic technologies
Publisher: AIP Publishing
Date: 03-06-2019
DOI: 10.1063/1.5096199
Abstract: Cryopreservation is a common strategy for the preservation of biological cells and tissues. While conventional platforms such as cell culture well plate systems enable measuring cell responses to various cryoprotectants, the drawbacks associated with capturing and imaging of cells limit the utility of such systems. Microfluidic technologies facilitate the capturing, chemical stimulation, and imaging of cells using low s le volumes. Here, we utilized microfluidic technologies for the hydrodynamic capturing of single human monocytes and studying the cell volume kinetics in response to a cryoprotectant in real time. Our approach facilitates conducting multistep cellular assays, especially for studying in idual cell osmotic response and determining cell membrane permeability to cryoprotectants.
Crystallization kinetics of polydisperse colloidal hard spheres: Experimental evidence for local fractionation
Publisher: American Physical Society (APS)
Date: 27-06-2003
Lethal Interactions of Atomically Precise Gold Nanoclusters and Pseudomonas aeruginosa and Staphylococcus aureus Bacterial Cells
Publisher: American Chemical Society (ACS)
Date: 27-06-2022
Abstract: Ultrasmall metal nanoclusters (NCs) are employed in an array of diagnostic and therapeutic applications due to their tunable photoluminescence, high biocompatibility, polyvalent effect, ease of modification, and photothermal stability. However, gold nanoclusters' (AuNCs') intrinsically antimicrobial properties remain poorly explored and are not well understood. Here, we share an insight into the antimicrobial action of atomically precise AuNCs based on their ability to passively translocate across the bacterial membrane. Functionalized by a hydrophilic modified-bidentate sulfobetaine zwitterionic molecule (AuNC-ZwBuEt) or a more hydrophobic monodentate-thiolate, mercaptohexanoic acid (AuNC-MHA) molecule, 2 nm AuNCs were lethal to both Gram-negative
Aging dynamics of colloidal hard sphere glasses
Publisher: AIP Publishing
Date: 21-09-2010
DOI: 10.1063/1.3478542
Abstract: We report the results of dynamic light scattering measurements of the coherent intermediate scattering function (ISF) of glasses of colloidal hard spheres for several volume fractions and a range of scattering vectors around the primary peak of the static structure factor. The ISF shows a clear crossover from an initial fast decay to a slower nonstationary decay. Aging is quantified in several different ways. However, regardless of the method chosen, the perfect “aged” glass is approached in a power law fashion. In particular the coupling between the fast and slow decays, as measured by the degree of stretching of the ISF at the crossover, also decreases algebraically with waiting time. The nonstationarity of this coupling implies that even the fastest detectable processes are themselves nonstationary.
Differential Dynamic Microscopy of Bacterial Motility
Publisher: American Physical Society (APS)
Date: 05-01-2011
Anodized nanoporous WO3 Schottky contact structures for hydrogen and ethanol sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA06286H
Abstract: Reversibility of the gas sensor made of a 500 nm thick WO 3 nanoporous film upon exposure to hydrogen gas at 200 °C.
The Impact of Water on the Lateral Nanostructure of a Deep Eutectic Solvent–Solid Interface
Publisher: CSIRO Publishing
Date: 06-07-2021
DOI: 10.1071/CH21078
Abstract: Deep eutectic solvents (DESs) are tuneable solvents with attractive properties for numerous applications. Their structure–property relationships are still under investigation, especially at the solid–liquid interface. Moreover, the influence of water on interfacial nanostructure must be understood for process optimization. Here, we employ a combination of atomic force microscopy and molecular dynamics simulations to determine the lateral and surface-normal nanostructure of the DES choline chloride:glycerol at the mica interface with different concentrations of water. For the neat DES system, the lateral nanostructure is driven by polar interactions. The surface adsorbed layer forms a distinct rhomboidal symmetry, with a repeat spacing of ~0.9 nm, comprising all DES species. The adsorbed nanostructure remains largely unchanged in 75 mol-% DES compared with pure DES, but at 50 mol-%, the structure is broken and there is a compromise between the native DES and pure water structure. By 25 mol-% DES, the water species dominates the adsorbed liquid layer, leaving very few DES species aggregates at the interface. In contrast, the near-surface surface-normal nanostructure, over a depth of ~3 nm from the surface, remains relatively unchanged down to 25 mol-% DES where the liquid arrangement changed. These results demonstrate not only the significant influence that water has on liquid nanostructure, but also show that there is an asymmetric effect whereby water disrupts the nanostructure to a greater degree closer to the surface. This work provides insight into the complex interactions between DES and water and may enhance their optimization for surface-based applications.
What is dielectrophoresis?
Publisher: Elsevier BV
Date: 06-1988
Probing the dynamics of turbid colloidal suspensions using differential dynamic microscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1SM01598B
Abstract: We show that Differential Dynamic Microscopy can reliably measure the dynamics of colloidal suspensions over a wide range of turbidities, identify an additional short-time process and explore the role of the four relevant experimental length scales.
Impact of nucleic acid encapsulated MOF crystal phase on protein corona formation
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3MA00391D
Kinetics of the lamellar gel-fluid transition in phosphatidylcholine membranes in the presence of sugars
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.CHEMPHYSLIP.2009.12.001
Abstract: Phase diagrams are presented for dipalmitoylphosphatidylcholine (DPPC) in the presence of sugars (sucrose) over a wide range of relative humidities (RHs). The phase information presented here, determined by small angle X-ray scattering (SAXS), is shown to be consistent with previous results achieved by differential scanning calorimetry (DSC). Both techniques show a significant effect of sucrose concentration on the phase behaviour of this phospholipid bilayer. An experimental investigation into the effect of sugars on the kinetic behaviour of the gel to fluid transition is also presented showing that increasing the sugar content appears to slightly increase the rate at which the transition occurs.
Interactions between soluble sugars and POPC (1-palmitoyl-2- oleoylphosphatidylcholine) during dehydration: Vitrification of sugars alters the phase behavior of the phospholipid
Publisher: Elsevier BV
Date: 07-1994
DOI: 10.1016/0005-2736(94)90343-3
Abstract: The phase behavior of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) was characterized as a function of hydration in the presence of combinations of sugars representative of sugars found in seed embryos having differing degrees of desiccation tolerance. The tendency of the sugar mixes to vitrify was also monitored as a function of hydration. Using differential scanning calorimetry, it was found that all sugars diminished the increase in the gel-to-fluid phase transition temperature (Tm) of POPC that occurred upon dehydration of the pure lipid. These results are analyzed in terms of the osmotic and volumetric properties of sugars. Also, it was found that in those s les for which the glass transition temperature (Tg) was greater than the Tm of POPC, Tm was lowered by approx. 20 C degrees from the value for the fully hydrated lipid. X-ray diffraction data confirmed that acyl chain freezing was deferred to a lower temperature during cooling of vitrified s les. The significance of these results is discussed in terms of the ability of many organisms to tolerate desiccation.
Identifying Trends in Gold Nanoparticle Toxicity and Uptake: Size, Shape, Capping Ligand, and Biological Corona
Publisher: American Chemical Society (ACS)
Date: 04-01-2019
Novel drug carriers: from grafted polymers to cross-linked vesicles
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CC37319J
Abstract: A simple and straightforward method of self-assembling grafted copolymers was developed to fabricate cross-linked polymer vesicles, which could conjugate anticancer drug cis-platinum and possess the capability of a high drug loading content, and a steady release rate.
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