A5091452400- Electrostatics and Colloid Interactions
- Lipid Membrane Structure and Behavior
- Plant and Biological Electrophysiology Studies
- Supramolecular Self-Assembly in Materials
- Diffusion and Search Dynamics
- Photoreceptor and optogenetics research
- Material Dynamics and Properties
- Surfactants and Colloidal Systems
- Force Microscopy Techniques and Applications
- Blood properties and coagulation
- Rheology and Fluid Dynamics Studies
- Polydiacetylene-based materials and applications
- Polysaccharides Composition and Applications
- Microfluidic and Bio-sensing Technologies
- Antimicrobial Peptides and Activities
- Advanced Thermodynamics and Statistical Mechanics
- Polymer Surface Interaction Studies
- Gene Regulatory Network Analysis
- Microtubule and mitosis dynamics
- Advanced Fluorescence Microscopy Techniques
- stochastic dynamics and bifurcation
- Genetics, Bioinformatics, and Biomedical Research
- Cellular transport and secretion
- Proteins in Food Systems
- Food composition and properties
University of Manchester
2016-2025
Astronomy and Space
2025
Turing Institute
2023-2024
Genomics (United Kingdom)
2024
University of Genoa
2024
Photonic Science (United Kingdom)
2020
Unilever (United Kingdom)
2007-2008
China University of Petroleum, East China
2008
University of Strathclyde
2008
University of Leeds
2000-2007
The field of microrheology is concerned with how materials store and dissipate mechanical energy as a function length scale. Recent developments in the theory instrumentation complex fluids are reviewed. Equal emphasis given to physical phenomena probed, advances instrumentation, specific experimental systems which this has already had an impact. inversion compliance data, measurement sample heterogeneity, high frequency viscoelasticity, effects shear flow, single molecule experiments,...
New developments in the microrheology of complex fluids are considered. Firstly requirements for a simple modern particle tracking experiment introduced, error analysis methods associated with it and mathematical techniques required to calculate linear viscoelasticity. Progress instrumentation is then described respect detectors, light sources, colloidal probes, magnetic tweezers, optical diffusing wave spectroscopy, coherence tomography, fluorescence correlation elastic- quasi-elastic...
Mixed thermoreversible gels were successfully fabricated by the addition of a thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), to fibrillar nanostructures self-assembled from short peptide I3K. When temperature was increased above lower critical solution PNIPAM, molecules collapsed form condensed globular particles, which acted as cross-links connect different nanofibrils and freeze their movements, resulting in formation hydrogel. Since these processes physically driven, such...
We present a new particle tracking software algorithm designed to accurately track the motion of low-contrast particles against background with large variations in light levels. The method is based on polynomial fit intensity around each feature point, weighted by Gaussian function distance from centre, and especially suitable for endogeneous cell, imaged bright field, phase contrast or fluorescence optical microscopy. Furthermore, can simultaneously all different sizes, allows significant...
We remove the need for Laplace/inverse-Laplace transformations of experimental data, by presenting a direct and straightforward mathematical procedure obtaining frequency-dependent storage loss moduli ($G'(ω)$ $G"(ω)$ respectively), from time-dependent measurements. The is applicable to ordinary rheological creep (stress-step) measurements, as well all microrheological techniques, whether they access Brownian mean-square displacement, or forced compliance. Data can be substituted directly...
Peptide amphiphiles readily self-assemble into a variety of nanostructures, but how molecular architectures affect the size and shape nanoaggregates formed is not well understood. From combined TEM AFM study series cationic peptide surfactants AmK (m = 3, 6, 9), we show that structural transitions (sheets, fibers/worm-like micelles, short rods) can be induced by increasing length hydrophobic region. The trend interpreted using packing theory developed to describe surfactant transitions,...
Coherent diffractive imaging (CDI) is a means of overcoming the resolution and image contrast limitations electron x-ray lenses. The central tenet method that intensity diffraction pattern must be measured on sufficiently fine pixel pitch, which inversely related to size illuminated region object. We show here ptychography---a form CDI uses many patterns---is not subject this constraint. Using variant ePIE inversion algorithm, we demonstrate experimentally sampling requirement in...
The rheological characteristics of gastric and duodenal mucin solutions, the building blocks mucus layer that covers epithelia two organs, were investigated using particle tracking microrheology. We used biochemically well characterized purified porcine mucins (MUC5AC MUC2) as models for human mucins, to probe their viscoelasticity a function concentration pH. Furthermore, we both reducing (dithiothreitol, DTT) chaotropic agents (guanidinium chloride urea) mesoscopic forces mediate integrity...
Abstract Peptide self-assembly is a hierarchical process, often starting with the formation of α-helices, β-sheets or β-hairpins. However, how secondary structures undergo further assembly to form higher-order architectures remains largely unexplored. The polar zipper originally proposed by Perutz formed between neighboring β-strands poly-glutamine via their side-chain hydrogen bonding and helps stabilize sheet. By rational design short amphiphilic peptides self-assembly, here we demonstrate...
Hydrogels offer great potential for many biomedical and technological applications. For clinical uses, hydrogels that act as scaffold materials cell culture, regenerative medicine, drug delivery are required to have bactericidal properties. The amphiphilic peptide A9K2 was designed effectively inhibit bacterial growth via a mechanism of membrane permeabilization. present study demonstrated addition fetal bovine serum (FBS) or plasma amine oxidase (PAO) induced sol-gel transition in aqueous...
Antimicrobial peptides (AMPs) can target bacterial membranes and kill bacteria through membrane structural damage cytoplasmic leakage. A group of surfactant-like cationic AMPs was developed from substitutions to selective amino acids in the general formula G(IIKK)3I-NH2, (called G3, a de novo AMP), explore correlation between AMP hydrophobicity bioactivity. threshold surface pressure over 12 mN/m required cause measurable antimicrobial activity this corresponded critical concentration....
Abstract Self-assembling peptides have the ability to spontaneously aggregate into large ordered structures. The reversibility of peptide hydrogen bonded supramolecular assembly make them tunable a host different applications, although it leaves highly dynamic and prone disassembly at low concentration needed for biological applications. Here we demonstrate that secondary hydrophobic interaction, near core, can stabilise bonds, without losing vital solubility systems in aqueous conditions....
Gram-negative bacteria are covered by both an inner cytoplasmic membrane (IM) and outer (OM). Antimicrobial peptides (AMPs) must first permeate through the OM cell wall before attacking IM to cause leakage kill bacteria. The bacterial is asymmetric bilayer with leaflet primarily composed of lipopolysaccharides (LPSs) phospholipids (PLs). Two cationic α-helical AMPs were designed target bacteria, a full peptide G(IIKK)3I-NH2 (G3), hydrophobic lipopeptide C8-G(IIKK)2I-NH2 (C8G2, C8 denoting...
Histidine, a widely used buffer in monoclonal antibody (mAb) formulations, is known to reduce aggregation. While experimental studies suggest nonelectrostatic, nonstructural (relating secondary structure preservation) origin of the phenomenon, underlying microscopic mechanism behind histidine action still unknown. Understanding this will help evaluate and predict stabilizing effect under different conditions for mAbs. We have all-atom molecular dynamics simulations contact-based free energy...
A chiral side-chain liquid-crystalline polymeric model for the structure and physical properties of starch was reviewed extended [1—6]. The lamellae in are considered terms three components: backbone, side-chains double helices. It is degree mobility these components, coupled with helix-coil transition, which gives its distinctive properties. used to help explain phenomena involved during hydration, gelatinisation, plasticisation, freezing, morphogenesis. new technique scanning microfocus...
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTChiral Side-Chain Liquid-Crystalline Polymeric Properties of StarchThomas A. Waigh, Paul Perry, Christian Riekel, Michael J. Gidley, and Athene M. DonaldView Author Information Polymers Colloids, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, England, ESRF, B.P. 220, F-38043 Grenoble, France, Unilever Research Colworth, Sharnbrook, MK44 1LQ Bedford, England Cite this: Macromolecules 1998, 31, 22,...
Results of microfocus X-ray diffraction at the ESRF are presented which provide unique evidence supporting a model for structure starch, much this having been previously derived only on basis circumstantial evidence. Here we present data from ∼2 μm regions within granules have subjected to no sample preparation and obtain oriented 2-D fiber patterns edge B-type potato starch granules. This is in good agreement with that calculated by Imberty/Perez1 amylose fiber. The peripheral amylopectin...
The rheology of bacterial biofilms at the micron scale is an important step to understanding communal lifecycles bacteria that adhere solid surfaces, as it measures how they mutually and desorb. Improvements in particle-tracking software imaging hardware have allowed us successfully employ microrheology measuring single-species biofilms, based on Staphlococcus aureus Pseudomonas aeruginosa. By tracking displacements cells a range timescales, we separate active thermal contributions cell...
We retrieve x-ray phase images from ptychographical data which, according to the conventional coherent diffractive imaging (CDI) criterion, have been grossly undersampled. Ptychographical are intrinsically oversampled in real space, as illumination function of subsequent exposures overlap. By exploiting real-space redundancy ptychography, we able recover CDI reciprocal sampling, despite an increase solid angle detector pixels. As a result current experimental geometrical constraints placed...
The use of smart drug carriers to realize cancer-targeted delivery is a promising method improve the efficiency chemotherapy and reduce its side effects. A surfactant-like peptide, Nap-FFGPLGLARKRK, was elaborately designed for based on an enzyme-triggered morphological transition self-assembled nanostructures. peptide has three functional motifs: aromatic motif Nap-FF- promote self-assembly, enzyme-cleavable segment -GPLGLA- introduce enzyme sensitivity, positively charged -RKRK- balance...