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"Bryant, Gary"
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Macbeth : the graphic novel : plain text version
In graphic novel format, presents an adaptation of Shakespeare's classic tale about a man who kills his king after hearing the prophesies of three witches.
BOOK
Physico-Chemical Characterization of Amino Acid-Based Deep Eutectic Solvents
Deep eutectic solvents are an exciting class of designer solvents that are increasingly gaining popularity. Deep eutectic solvents based on amino acids are particularly interesting for biomedical applications due to their potential low toxicity. However, very few have been reported to date, and only one of these has been comprehensively studied, made from a combination of proline and glycerol. Here, we report for the first time a systematic investigation into amino acid-based deep eutectic solvents, with a particular focus on the structural features of amino acids that promote eutectic formation and their influence on viscosity, refractive index, surface tension and thermal behavior. Of the 22 amino acids (and related compounds) examined, only 3 (lysine, arginine and, as previously reported, proline) formed stable homogenous liquids in combination with glycerol or ethylene glycol. For these mixtures, it was found that the second component (glycerol or ethylene glycol) had a much more significant influence on the physical properties than the identity of the amino acid. Most significantly, it was found that far fewer amino acids readily formed deep eutectic solvents than has been generally assumed. This is the first work to systematically characterize deep eutectic solvents based on amino acids and, as such, paves the way for future biomedical applications of these solvents.
Journal Article
Analysis of Pathogenic Bacterial and Yeast Biofilms Using the Combination of Synchrotron ATR-FTIR Microspectroscopy and Chemometric Approaches
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 samples, and other spectral regions corresponding to amides, lipids, and polysaccharides all contributed to sample 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.
Journal Article
Amino Acid-Coated Zeolitic Imidazolate Framework for Delivery of Genetic Material in Prostate Cancer Cell
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.
Journal Article
Synthesis of Tertiary Amine Assisted Cytocompatible Zn‐MOFs for Efficient Nucleic Acid Encapsulation and Delivery to Prostate Cancer Cells
Metal–organic frameworks (MOFs) are advanced hybrid materials with highly tunable structures, making them attractive candidates for biomedical applications, including nucleic acid delivery. Zeolitic imidazolate framework‐8 (ZIF‐8) is particularly promising due to its pH‐responsive degradation and biocompatibility. However, controlling the crystal phase and particle size of ZIF‐8 is critical for optimizing cellular uptake and therapeutic efficacy. Here, a one‐pot biomimetic mineralization strategy using a tertiary amine (e.g., triethylamine) to modulate the phase and size of DNA@ZIF biocomposites is reported. Without triethylamine, the resulting biocomposites form microscale carbonate‐phase particles, whereas the introduction of triethylamine induces the formation of nanoscale sodalite‐phase ZIF‐8. Moreover, triethylamine not only reduces particle size but also enhances the water stability and nucleic acid protection capabilities of the biocomposites. Triethylamine‐incorporated DNA@ZIF‐8 demonstrates negligible cytotoxicity and efficient gene delivery into prostate cancer cells compared to unmodified formulations. This study highlights the critical role of triethylamine as a modulating agent in fine‐tuning the crystallinity, particle size, and biological performance of DNA@ZIF, offering valuable insights into the design of advanced MOF‐based gene delivery systems for therapeutic applications. The study explores the influence of a tertiary amine in loading genetic material in a hybrid composite. The study highlights how structural attributes and chemical composition govern the crystallinity and cytocompatibility of ZIF‐biocomposites that effectively deliver nucleic acid to cancer cells.
Journal Article
Using patient-reported measures to predict hospitalisation in a population-based lupus cohort
ObjectiveSLE is a multisystem autoimmune disease where periods of disease activity, often difficult to predict, can cause irreversible disease damage. This study aimed to develop a patient-centric predictive model using real-world data that can identify patients with SLE at a higher risk of hospitalisation compared with the general SLE population.MethodsThis observational, retrospective analysis used data from the Georgians Organized Against Lupus (GOAL) cohort from 2011 to 2013. The GOAL cohort is a population-based SLE cohort that collects yearly self-report surveys covering participants’ sociodemographic characteristics, clinical characteristics and perceived SLE symptoms (using the Systemic Lupus Activity Questionnaire (SLAQ)). GOAL data were linked to the Georgia Hospital Discharge Database to collect participants’ all-cause hospitalisation events in the 6 months following survey completion. A two-step approach was used to predict all-cause hospitalisations—logistic regressions selected a list of GOAL predictors that were subsequently included in the classification and regression tree (CART) models to generate patient subsets based on estimated hospitalisation rates.ResultsThere were 846 participants who completed 1486 surveys. Participants who were hospitalised within 6 months after survey completion were more likely to be younger, living in poverty and have more reported SLE symptoms than participants without a hospitalisation. CART modelling identified participants who reported any weight loss without trying, severe fatigue and Raynaud’s symptoms as most likely to have an all-cause hospitalisation: one in three (34%) patients in this subset were hospitalised in the 6 months following survey completion, 2.6-fold the hospitalisation rates of the overall GOAL cohort (13%) and 6.8-fold the rate in the subset with the lowest hospitalisation rate (5%).ConclusionsThis study suggests that patient-reported SLE symptoms and disease activity, specifically certain components of the SLAQ, may be of value in SLE risk management when considering hospitalisation reduction as a treatment goal.
Journal Article
Gold Nanoparticle Adsorption and Uptake are Directed by Particle Capping Agent
Nanomaterials are revolutionizing the development of novel therapies, with applications ranging from drug delivery and diagnostics to controlling specific biological processes. However, the specific interactions that govern nanomaterial behavior in biological systems remain difficult to elucidate due to the complex dynamic nature of the lipid bilayer environment. Here, a combination of atomic force microscopy and molecular dynamics simulations is used to discover the precise mechanisms by which various ligand‐capped 5 nm gold nanoparticles (AuNPs) interact with supported lipid bilayers of pure fluid phospholipids (1,2‐di(9Z‐octadecenoyl)‐sn‐glycero‐3‐phosphocholine (DOPC)). When the ligand capping agent is altered, differences in adsorption and bilayer disruption as a function of capping agent size and charge are observed. Weakly physiosorbed ligands enable the absorption of the AuNP into the bilayer's hydrophobic core, whereas more strongly adsorbed ligands inhibit the complete insertion of the AuNP. However, ligand‐dependent headgroup interactions can lead to interfacial adhesion or inhibition of adsorption. These results reveal that the interaction of AuNPs with biological membranes varies depending on the specific capping agent. Notably, the mechanisms may involve cooperative (or synergistic) effects with membrane components, highlighting the importance of understanding these interactions at molecular resolution. This study explores how ligand‐coated gold nanoparticles (NPs) interact with model membranes. Combining atomic force microscopy (AFM) and molecular dynamics (MD) simulations, it shows how coating properties affect adsorption. The AFM‐MD approach offers a predictive platform for nanoparticle design and toxicity, enabling tailored nanomedicine development and forecasting of NP‐induced cytotoxic effects.
Journal Article
Mapping the Three‐Dimensional Nanostructure of the Ionic Liquid–Solid Interface Using Atomic Force Microscopy and Molecular Dynamics Simulations
Ionic liquids (ILs) are a widely investigated class of solvents for scientific and industrial applications due to their desirable and “tunable” properties. The IL–solid interface is a complex entity, and despite intensive investigation, its true nature remains elusive. The understanding of the IL–solid interface has evolved over the last decade from a simple 1D double layer, to a 2D ordered interface, and finally a liquid‐specific, complex 3D ordered liquid interface. However, most studies depend solely on one technique, which often only examine one aspect of the interfacial nanostructure. Here, a holistic study of the protic IL–solid interface is presented, which provides a more detailed picture of IL interfacial solvation. The 3D nanostructure of the ethylammonium nitrate (EAN)–mica interface is investigated using a combination of 1D, 2D, and 3D amplitude modulated‐atomic force microscopy and molecular dynamics simulations. Importantly, it is found that the EAN–mica interface is more complex than previously reported, possessing surface‐adsorbed, near‐surface, surface‐normal, and lateral heterogeneity, which propagates at relatively large distances from the solid substrate. The work presented in this study meaningfully enhances the understanding of the IL–solid interface. The ionic liquid–solid interface is investigated using a combination of high‐resolution techniques. The 3D nanostructure of the ethylammonium nitrate (EAN)–mica interface is revealed using a combination of 1D, 2D, and 3D atomic force microscopy, molecular dynamics simulations, and theoretical calculations. Importantly, the EAN–mica interface is more complex than previously reported.
Journal Article
Insertion of Fluorescent Proteins Near the Plug Domain of MotB Generates Functional Stator Complexes
Many bacteria swim by the rotation of the bacterial flagellar motor (BFM). The BFM is powered by proton translocation across the inner membrane through the heteroheptameric MotA5MotB2 protein complex. Two periplasmic domains of MotB are critical in activating BFM rotation: (1) the peptidoglycan (PG) binding domain that anchors MotB in the PG layer and (2) the plug domain that modulates the proton flow. Existing cytoplasmic fluorescent probes have been shown to negatively affect motor rotation and switching. Here, we inserted a fluorescent probe in the periplasm near the plug of MotB to circumvent issues with cytoplasmic probes and for possible use in observing the mechanism of plug‐based regulation of proton flow. We inserted green fluorescent protein and improved light‐oxygen‐voltage (LOV), a fluorescent version of the LOV domain, in four periplasmic locations in MotB. Insertions near the plug retained motility but showed limited fluorescence for both fluorophores. Additional short, flexible glycine–serine linkers improved motility but did not improve brightness. Further optimization is necessary to improve the fluorescence of these periplasmic probes. We inserted small light‐interacting domains at various locations in the stator complex to see what sites were amenable for labeling and how these affected flagellar rotation and switching. We observed a site near the plug domain to be the best labeling site and were able to label this site with a small light‐oxygen‐voltage domain that was weakly fluorescent in the periplasm.
Journal Article
Insights into Chemical Interactions and Related Toxicities of Deep Eutectic Solvents with Mammalian Cells Observed Using Synchrotron Macro–ATR–FTIR Microspectroscopy
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.
Journal Article