ORCID Profile
0000-0002-9412-632X
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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)
Organic Chemistry | Free Radical Chemistry | Organic Chemical Synthesis | Synthesis of Materials | Macromolecular and Materials Chemistry | Characterisation of biological macromolecules | Structure and dynamics of materials | Biological And Medical Chemistry | Organic Chemical Synthesis | Nanochemistry and Supramolecular Chemistry | Biologically Active Molecules | Chemical Characterisation of Materials | Macromolecular and materials chemistry | Organic Chemistry Not Elsewhere Classified | Polymers and Plastics | Materials Engineering | Crop and Pasture Biomass and Bioproducts | Forestry Biomass and Bioproducts | Bacteriology | Electrochemical energy storage and conversion
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Plastics in primary forms | Environmentally Sustainable Manufacturing not elsewhere classified | Chemical sciences | Expanding Knowledge in Technology | Plastic Products (incl. Construction Materials) | Expanding Knowledge in Engineering | Expanding Knowledge in the Biological Sciences | Treatments (e.g. chemicals, antibiotics) |
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Publications
Pro-fluorescent mitochondria-targeted real-time responsive redox probes synthesised from carboxy isoindoline nitroxides: Sensitive probes of mitochondrial redox status in cells
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.FREERADBIOMED.2018.03.008
Abstract: Here we describe new fluorescent probes based on fluorescein and rhodamine that provide reversible, real-time insight into cellular redox status. The new probes incorporate bio-imaging relevant fluorophores derived from fluorescein and rhodamine linked with stable nitroxide radicals such that they cannot be cleaved, either spontaneously or enzymatically by cellular processes. Overall fluorescence emission is determined by reversible reduction and oxidation, hence the steady state emission intensity reflects the balance between redox potentials of critical redox couples within the cell. The permanent positive charge on the rhodamine-based probes leads to their rapid localisation within mitochondria in cells. Reduction and oxidation also leads to marked changes in the fluorophore lifetime, enabling monitoring by fluorescence lifetime imaging microscopy. Finally, we demonstrate that administration of a methyl ester version of the rhodamine-based probe can be used at concentrations as low as 5 nM to generate a readily detected response to redox stress within cells as analysed by flow cytometry.
Investigations into the Parallel Synthesis of Novel Pyrrole-Oxazole Analogues of the Insecticide Pirate
Publisher: Georg Thieme Verlag KG
Date: 06-2006
Engineering Nitroxide Functional Surfaces Using Bioinspired Adhesion
Publisher: American Chemical Society (ACS)
Date: 14-02-2018
DOI: 10.1021/ACS.LANGMUIR.7B03755
Abstract: We pioneer a versatile surface modification strategy based on mussel-inspired oxidative catecholamine polymerization for the design of nitroxide-containing thin polymer films. A 3,4-dihydroxy-l-phenylalanine (l-DOPA) monomer equipped with a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-derived oxidation-labile hydroxylamine functional group is employed as a universal coating agent to generate polymer scaffolds with persistent radical character. Various types of materials including silicon, titanium, ceramic alumina, and inert poly(tetrafluoroethylene) (PTFE) were successfully coated with poly(DOPA-TEMPO) thin films in a one-step dip-coating procedure under aerobic, slightly alkaline (pH 8.5) conditions. Steadily growing polymer films (∼1.1 nm h
Dynamic Nitroxide Functional Materials.
Publisher: Wiley
Date: 16-11-2018
Abstract: A substrate-independent and versatile coating platform for (spatially resolved) surface functionalization, based on nitroxide radical coupling (NRC) reactions and the formation of thermo-labile alkoxyamine functional groups, was introduced. Nitroxide-decorated poly(glycidyl methacrylate) (PGMA) microspheres, obtained through bioinspired copolymer surface deposition using dopamine and a nitroxide functional dopamine derivative as monomers, were conjugated with small functional groups in a rewritable process. Reversible coding of the nitroxide functional microspheres by NRC and decoding through thermal alkoxyamine fission were monitored and characterized by electron paramagnetic resonance (EPR) spectroscopy and X-ray photoelectron spectroscopy (XPS). In addition, this nitroxide coating system was exploited in "grafting-to" polymer surface ligations of poly(methyl methacrylate) (PMMA) and poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) in spatially confined areas. Polymer strands terminated with an Irgacure 2959 (2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone) photoinitiator were obtained through chain-transfer polymerization, and subsequently coupled to nitroxide-immobilized poly(dopamine) (PDA)-coated silicon substrates by using rapid photoclick NRC reactions. Light-driven polymer surface coding was visualized by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and XPS imaging.
Comparative Assessment of Docking Programs for Docking and Virtual Screening of Ribosomal Oxazolidinone Antibacterial Agents
Publisher: MDPI AG
Date: 24-02-2023
DOI: 10.3390/ANTIBIOTICS12030463
Abstract: Oxazolidinones are a broad-spectrum class of synthetic antibiotics that bind to the 50S ribosomal subunit of Gram-positive and Gram-negative bacteria. Many crystal structures of the ribosomes with oxazolidinone ligands have been reported in the literature, facilitating structure-based design using methods such as molecular docking. It would be of great interest to know in advance how well docking methods can reproduce the correct ligand binding modes and rank these correctly. We examined the performance of five molecular docking programs (AutoDock 4, AutoDock Vina, DOCK 6, rDock, and RLDock) for their ability to model ribosomal–ligand interactions with oxazolidinones. Eleven ribosomal crystal structures with oxazolidinones as the ligands were docked. The accuracy was evaluated by calculating the docked complexes’ root-mean-square deviation (RMSD) and the program’s internal scoring function. The rankings for each program based on the median RMSD between the native and predicted were DOCK 6 AD4 Vina RDOCK RLDOCK. Results demonstrate that the top-performing program, DOCK 6, could accurately replicate the ligand binding in only four of the eleven ribosomes due to the poor electron density of said ribosomal structures. In this study, we have further benchmarked the performance of the DOCK 6 docking algorithm and scoring in improving virtual screening (VS) enrichment using the dataset of 285 oxazolidinone derivatives against oxazolidinone binding sites in the S. aureus ribosome. However, there was no clear trend between the structure and activity of the oxazolidinones in VS. Overall, the docking performance indicates that the RNA pocket’s high flexibility does not allow for accurate docking prediction, highlighting the need to validate VS. protocols for ligand-RNA before future use. Later, we developed a re-scoring method incorporating absolute docking scores and molecular descriptors, and the results indicate that the descriptors greatly improve the correlation of docking scores and pMIC values. Morgan fingerprint analysis was also used, suggesting that DOCK 6 underpredicted molecules with tail modifications with acetamide, n-methylacetamide, or n-ethylacetamide and over-predicted molecule derivatives with methylamino bits. Alternatively, a ligand-based approach similar to a field template was taken, indicating that each derivative’s tail groups have strong positive and negative electrostatic potential contributing to microbial activity. These results indicate that one should perform VS. c aigns of ribosomal antibiotics with care and that more comprehensive strategies, including molecular dynamics simulations and relative free energy calculations, might be necessary in conjunction with VS. and docking.
The Use of a Nitroxide Probe in DMSO to Capture Free Radicals in Particulate Pollution
Publisher: Wiley
Date: 11-09-2012
Oxidative Potential of Logwood and Pellet Burning Particles Assessed by a Novel Profluorescent Nitroxide Probe
Publisher: American Chemical Society (ACS)
Date: 04-08-2010
DOI: 10.1021/ES100963Y
Abstract: This study reports the potential toxicological impact of particles produced during biomass combustion by an automatic pellet boiler and a traditional logwood stove under various combustion conditions using a novel profluorescent nitroxide probe, BPEAnit. This probe is weakly fluorescent but yields strong fluorescence emission upon radical trapping or redox activity. S les were collected by bubbling aerosol through an impinger containing BPEAnit solution, followed by fluorescence measurement. The fluorescence of BPEAnit was measured for particles produced during various combustion phases: at the beginning of burning (cold start), stable combustion after refilling with the fuel (warm start), and poor burning conditions. For particles produced by the logwood stove under cold-start conditions, significantly higher amounts of reactive species per unit of particulate mass were observed compared to emissions produced during a warm start. In addition, s ling of logwood burning emissions after passing through a thermodenuder at 250 degrees C resulted in an 80-100% reduction of the fluorescence signal of the BPEAnit probe, indicating that the majority of reactive species were semivolatile. Moreover, the amount of reactive species showed a strong correlation with the amount of particulate organic material. This indicates the importance of semivolatile organics in particle-related toxicity. Particle emissions from the pellet boiler, although of similar mass concentration, were not observed to lead to an increase in fluorescence signal during any of the combustion phases.
Chapter 3. Synthesis of Nitroxides and Alkoxyamines
Publisher: Royal Society of Chemistry
Date: 2015
Porphyrin containing isoindoline nitroxides as potential fluorescence sensors of free radicals
Publisher: World Scientific Pub Co Pte Lt
Date: 04-2011
DOI: 10.1142/S1088424611003203
Abstract: A series of new spin-labeled porphyrin containing isoindoline nitroxide moieties were synthesized and characterized as potential free radical fluorescence sensors. Fluorescence-suppression was observed in the free-base monoradical porphyrins, whilst the free-base biradical porphyrins exhibited highly suppressed fluorescence about three times greater than the monoradical porphyrins. The observed fluorescence-suppression was attributed to enhanced intersystem crossing resulting from electronexchange between the doublet nitroxide and the excited porphyrin fluorophore. Notably, fluorescencesuppression was not as strong in the related metalated porphyrins, possibly due to insufficient spin coupling between the nitroxide and the porphyrin. Continuous wave EPR spectroscopy of the diradical porphyrins in fluid solution suggests that the nitroxyl-nitroxyl interspin distance is long enough and tumbling is fast enough not to detect dipolar coupling.
Eradicating uropathogenic Escherichia coli biofilms with a ciprofloxacin–dinitroxide conjugate
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9MD00062C
Abstract: Biofilm-related UTIs are problematic infectious diseases worldwide here we have developed a novel ciprofloxacin–dinitroxide conjugate with potent UPEC biofilm-eradication activity.
Molecular Orientational Order of Nitroxide Radicals in Liquid Crystalline Media
Publisher: American Chemical Society (ACS)
Date: 12-05-2014
DOI: 10.1021/JP411729J
Abstract: The orientational distribution of a set of stable nitroxide radicals in aligned liquid crystals 5CB (nematic) and 8CB (smectic A) was studied in detail by numerical simulation of EPR spectra. The order parameters up to the 10th rank were measured. The directions of the principal orientation axes of the radicals were determined. It was shown that the ordering of the probe molecules is controlled by their interaction with the matrix molecules more than the inherent geometry of the probes themselves. The rigid fused phenanthrene-based (A5) and 2-azaphenalene (A4) nitroxides as well as the rigid core elongated C11 and 5α-cholestane (CLS) nitroxides were found to be most sensitive to the orientation of the liquid crystal matrixes.
Photo-induced proton coupled electron transfer from a benzophenone ‘antenna’ to an isoindoline nitroxide
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA20100D
Abstract: When exposed to light, a novel nitroxide-benzophenone hybrid will undergo an energy transfer process whereby the nitroxide enters an excited state which induces an efficient hydrogen atom transfer from unactivated alkanes.
A Versatile Light‐Triggered Radical‐Releasing Surface Coating Technology
Publisher: Wiley
Date: 17-10-2021
Abstract: Organic based redox active materials and coatings are increasingly being investigated as solutions for more efficient energy devices, catalysts, sensors, and biomedical technologies. Their advantage is negating the necessity for expensive and unsustainable rare earth metals seen in other redox active materials. Challenges to their wide‐spread usage remain, including versatility of coatings on a wide range of substrates, and creating smart devices that can respond to environmental stimuli. A new light responsive radical releasing redox coating has been developed, that can be rapidly and stably applied to a erse range of substrates including silicon dioxide, plastics, and microparticles. These coatings rapidly cleave upon irradiation with UV‐A light to release stable nitroxides from the surface coating. These coatings are developed into microparticle sensors for radical oxygen species, which are able to detect the generation of free radicals in a model system for particulate matter pollution. These new responsive organic redox coatings also offer future potential to function as switchable organic electrodes, and biomedical surface coatings to prevent biofouling and reduce inflammation.
The Hendrickson reagent and the Mitsunobu reaction: a mechanistic study
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B305375J
Abstract: The alkoxytriphenylphosphonium ion intermediate of the Mitsunobu reaction can be generated using the Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, 1. Strangely, while the reagent 1 can be used in place of the Mitsunobu reagents (triphenylphosphine and a dialkylazodicarboxylate) for the esterification of primary alcohols, secondary alcohols such as menthol undergo elimination. Evidence is presented to show that this unexpected result is due to the presence of trialkylammonium triflate salts. Such salts lead to a dramatic decrease in the rate of esterification relative to competing elimination. The Mitsunobu esterification of menthol with p-nitrobenzoic acid was re-examined and the occurrence of elimination reported for the first time. The presence of traces of tetrabutylammonium triflate led to a dramatic reduction in the yield of inverted ester and a corresponding increase in the yield of anti elimination product 2-menthene. The mechanism of the Mitsunobu reaction is discussed in the light of the dramatic salt effect on both the rate and outcome of the reaction and the possible involvement of ion pair clustering. In contrast, use of the reagent 1 resulted in syn elimination to give a 1:2 mixture of 2- and 3-menthenes. Finally, 1 and sodium azide can be used to convert a primary alcohol into an azide in high yield. There was no reaction under Mitsunobu conditions.
Edaravone containing isoindoline nitroxides for the potential treatment of cardiovascular ischaemia
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1MD00041A
Direct-write crosslinking in vacuum-deposited small-molecule films using focussed ion and electron beams
Publisher: IOP Publishing
Date: 21-05-2019
Abstract: Recent advances in helium ion microscopy (HIM) have enabled the use of fine-focused He
Novel polymer synthesis methodologies using combinations of thermally- and photochemically-induced nitroxide mediated polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4PY01270D
Abstract: The combination of thermally- and photochemically-induced polymerization using light sensitive alkoxyamines was investigated.
Bacterial Biofilm Eradication Agents: A Current Review
Publisher: Frontiers Media SA
Date: 28-11-2019
The palladium-catalysed copper-free Sonogashira coupling of isoindoline nitroxides: a convenient route to robust profluorescent carbon–carbon frameworks
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B806963H
Abstract: A series of novel acetylene-substituted isoindoline nitroxides were synthesised via palladium-catalysed copper-free Sonogashira coupling. These results demonstrate that the Sonogashira reaction is suitable for the generation of a wide range of aryl nitroxides of expanded structural variety. The novel aryl-iodide containing nitroxide, 5-iodo-1,1,3,3-tetramethylisoindolin-2-yloxyl, 3, was a key intermediate for this coupling, giving acetylene-substituted isoindoline nitroxides in high yield. Subsequent reaction of the deprotected ethynyl nitroxide 12 with iodinated polyaromatics furnished novel aromatic nitroxides with extended-conjugation. Such nitroxides have been described as profluorescent, as their quantum yields are significantly lower than those of the corresponding diamagnetic derivatives. The quantum yields of the naphthyl- and phenanthryl-acetylene isoindoline nitroxides (13 and 14) were found to be 200-fold and 65-fold less than the non-radical methoxyamine derivatives (23 and 24). Ethyne- and butadiyne-linked nitroxide dimers could also be synthesised by this cross coupling methodology.
Spin-coated carbon
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SC51396C
Physicochemical Characterization of Particulate Emissions from a Compression Ignition Engine Employing Two Injection Technologies and Three Fuels
Publisher: American Chemical Society (ACS)
Date: 31-05-2011
DOI: 10.1021/ES200388F
Abstract: Alternative fuels and injection technologies are a necessary component of particulate emission reduction strategies for compression ignition engines. Consequently, this study undertakes a physicochemical characterization of diesel particulate matter (DPM) for engines equipped with alternative injection technologies (direct injection and common rail) and alternative fuels (ultra low sulfur diesel, a 20% biodiesel blend, and a synthetic diesel). Particle physical properties were addressed by measuring particle number size distributions, and particle chemical properties were addressed by measuring polycyclic aromatic hydrocarbons (PAHs) and reactive oxygen species (ROS). Particle volatility was determined by passing the polydisperse size distribution through a thermodenuder set to 300 °C. The results from this study, conducted over a four point test cycle, showed that both fuel type and injection technology have an impact on particle emissions, but injection technology was the more important factor. Significant particle number emission (54%-84%) reductions were achieved at half load operation (1% increase-43% decrease at full load) with the common rail injection system however, the particles had a significantly higher PAH fraction (by a factor of 2 to 4) and ROS concentrations (by a factor of 6 to 16) both expressed on a test-cycle averaged basis. The results of this study have significant implications for the health effects of DPM emissions from both direct injection and common rail engines utilizing various alternative fuels.
Profluorescent Nitroxides as Sensitive Probes of Oxidative Change and Free Radical Reactions
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CH10442
Abstract: This paper presents a review on the use of tethered nitroxide–fluorophore molecules as probes of oxidative change and free radical generation and reaction. The proximity of the nitroxide free radical to the fluorophore suppresses the normal fluorescence emission process. Nitroxide free radical scavenging, metabolism or redox chemistry return the system to its natural fluorescent state and so these tethered nitroxide–fluorophore molecules are described as being profluorescent. A survey of profluorescent nitroxides found in the literature is provided as well as background on the mechanism of action and applications of these compounds as fluorometric probes within the fields of biological, materials and environmental sciences.
Concentration and oxidative potential of on-road particle emissions and their relationship with traffic composition: Relevance to exposure assessment
Publisher: Elsevier BV
Date: 11-2012
A Profluorescent Azaphenalene Nitroxide for Nitroxide-Mediated Polymerization
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CH10404
Abstract: A novel nitroxide‐mediated polymerization (NMP) control agent 1,1,3,3‐tetramethyl‐2,3‐dihydro‐2‐azaphenalen‐2‐yloxyl (TMAO), was used in the free‐radical polymerization of styrene. The conversion of styrene during NMP was studied using FT‐Raman spectroscopy and the effectiveness of TMAO as a NMP control agent was assessed by GPC analysis. Fidelity of the TMAO‐alkoxyamine end‐group on the synthesized polymers was confirmed by GPC, UV‐Vis and fluorescence spectroscopic analyses. Comparison to the well known NMP control agent, TEMPO was made. TMAO showed control of molecular weight approaching that of TEMPO. Attempts to improve the properties of TMAO as an NMP control agent by synthesizing an analogue with bulkier substituents around the nitroxide did not generate the target molecule but demonstrated some of the interesting chemistry of the azaphenalene ring system.
A novel protecting group methodology for syntheses using nitroxides
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC46146G
Abstract: Protecting a nitroxide as the methyl ether is highly effective. It can be de-protected in good yield using a peracid.
Light-active azaphenalene alkoxyamines: fast and efficient mediators of a photo-induced persistent radical effect
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA18500B
Abstract: Reported is the first ex le of an alkoxyamine that quantitatively yields a nitroxide upon light exposure. The alkoxyamine is used to generate a light driven persistent radical effect and applied to radical insertion, exchange and polymerization reactions.
BODIPY‐Based Profluorescent Probes Containing Meso‐ and β‐Substituted Isoindoline Nitroxides
Publisher: Wiley
Date: 02-01-2017
Novel polymer-supported coupling/dehydrating reagents for use in organic synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B406770C
Abstract: Two novel dehydrating reagents and, based on a phosphonium anhydride and an oxyphosphonium triflate respectively, were prepared by reaction of the corresponding polymer-supported phosphine oxides with triflic anhydride. Reagent, based on the novel phosphorus heterocycle 1,1,3,3-tetraphenyl-2-oxa-1,3-diphospholanium bis(trifluoromethanesulfonate), was found to be a useful reagent for ester and amide formation. A wide range of coupling/dehydration-type reactions, such as ester, amide, anhydride, peptide, ether and nitrile formation, were performed in high yield using the more readily prepared polymer-supported triphenylphosphine ditriflate, which was easily recovered and re-used several times without loss of efficiency. With primary alcohols, both reagents and provide an alternative to the Mitsunobu reaction, where the use of azodicarboxylates and chromatography to remove the phosphine oxide by-product can be avoided. The use of 4-dimethylaminopyridine allowed the esterification of secondary alcohols with to proceed in high yield but with retention of configuration.
Strategies to Improve the Potency of Oxazolidinones towards Bacterial Biofilms
Publisher: Wiley
Date: 13-04-2022
Abstract: Biofilms are part of the natural lifecycle of bacteria and are known to cause chronic infections that are difficult to treat. Most antibiotics are developed and tested against bacteria in the planktonic state and are ineffective against bacterial biofilms. The oxazolidinones, including the last resort drug linezolid, are one of the main classes of synthetic antibiotics progressed to clinical use in the last 50 years. They have a unique mechanism of action and only develop low levels of resistance in the clinical setting. With the aim of providing insight into strategies to design more potent antibiotic compounds with activity against bacterial biofilms, we review the biofilm activity of clinically approved oxazolidinones and report on structural modifications to oxazolidinones and their delivery systems which lead to enhanced anti‐biofilm activity.
The Synthesis and Physical Properties of Novel Polyaromatic Profluorescent Isoindoline Nitroxide Probes
Publisher: Wiley
Date: 23-10-2008
Inhibition of myeloperoxidase- and neutrophil-mediated oxidant production by tetraethyl and tetramethyl nitroxides
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.FREERADBIOMED.2014.02.011
Abstract: The powerful oxidant HOCl (hypochlorous acid and its corresponding anion, (-)OCl) generated by the myeloperoxidase (MPO)-H2O2-Cl(-) system of activated leukocytes is strongly associated with multiple human inflammatory diseases consequently there is considerable interest in inhibition of this enzyme. Nitroxides are established antioxidants of low toxicity that can attenuate oxidation in animal models, with this ascribed to superoxide dismutase or radical-scavenging activities. We have shown (M.D. Rees et al., Biochem. J. 421, 79-86, 2009) that nitroxides, including 4-amino-TEMPO (4-amino-2,2,6,6-tetramethylpiperidin-1-yloxyl radical), are potent inhibitors of HOCl formation by isolated MPO and activated neutrophils, with IC50 values of ~1 and ~6 µM respectively. The utility of tetramethyl-substituted nitroxides is, however, limited by their rapid reduction by biological reductants. The corresponding tetraethyl-substituted nitroxides have, however, been reported to be less susceptible to reduction. In this study we show that the tetraethyl species were reduced less rapidly than the tetramethyl species by both human plasma (89-99% decreased rate of reduction) and activated human neutrophils (62-75% decreased rate). The tetraethyl-substituted nitroxides retained their ability to inhibit HOCl production by MPO and activated neutrophils with IC50 values in the low-micromolar range in some cases inhibition was enhanced compared to tetramethyl substitution. Nitroxides with rigid structures (fused oxaspiro rings) were, however, inactive. Overall, these data indicate that tetraethyl-substituted nitroxides are potent inhibitors of oxidant formation by MPO, with longer plasma and cellular half-lives compared to the tetramethyl species, potentially allowing lower doses to be employed.
Oxidative polymerization of catecholamines: structural access by high-resolution mass spectrometry
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY00506G
Abstract: We introduce an avenue for the structural elucidation of bio-inspired functional poly(catecholamines) via high-resolution electrospray ionization mass spectrometry.
High resolution mass spectrometric access to nitroxide containing polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01316G
Abstract: We introduce a mass spectrometric access route to nitroxide containing polymers via high resolution electrospray ionization mass spectrometry (HR ESI MS), a polymer class that is – due to the presence of unpaired spins – highly challenging to analyze via NMR techniques.
Approaches to the Synthesis of a Water‐Soluble Carboxy Nitroxide
Publisher: Wiley
Date: 08-01-2013
Spin fluorescence silencing enables an efficient thermally driven self-reporting polymer release system
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7PY01437F
Abstract: A self-reporting profluorescent release system driven by the thermo-reversible dynamic covalent ligation of chromophores to polymer chain, whose fluorescence is silenced by unpaired spins of nitroxides prior to release is introduced.
Generation of Bioactive Materials with Rapid Self‐Assembling Resorcinarene‐Peptides
Publisher: Wiley
Date: 27-07-2009
Synthesis and Evaluation of Ciprofloxacin-Nitroxide Conjugates as Anti-Biofilm Agents
Publisher: MDPI AG
Date: 27-06-2016
Direct Iodination of Isoindolines and Isoindoline Nitroxides as Precursors to Functionalized Nitroxides
Publisher: Wiley
Date: 17-06-2013
The application of profluorescent nitroxides to detect reactive oxygen species derived from combustion-generated particulate matter: Cigarette smoke – A case study
Publisher: Elsevier BV
Date: 06-2010
Back Cover Image
Publisher: Wiley
Date: 12-2022
DOI: 10.1002/INF2.12395
Abstract: This cover (DOI: 10.1002/inf2.12345 ) shows a multifunctional TPA‐azaBODIPY‐TPA small molecule with superior optoelectronic and photophysical properties. Material is shown to function as an efficient hole transport layer in perovskite solar cells reaching a power conversion efficiency of 17.4%, and as a robust electron donor in near‐infrared organic photodetectors absorbing light in the wavelength range of up to 800 nm. Offering two distinct optoelectronic functions, TPA‐azaBODIPY‐TPA is particularly attractive as it enables multi‐purpose applications while maintaining the ease of fabrication. image
Physicochemical Characterization of Particulate Emissions from a Compression Ignition Engine: The Influence of Biodiesel Feedstock
Publisher: American Chemical Society (ACS)
Date: 15-11-2011
DOI: 10.1021/ES2018797
Abstract: This study undertook a physicochemical characterization of particle emissions from a single compression ignition engine operated at one test mode with 3 biodiesel fuels made from 3 different feedstocks (i.e., soy, tallow, and canola) at 4 different blend percentages (20%, 40%, 60%, and 80%) to gain insights into their particle-related health effects. Particle physical properties were inferred by measuring particle number size distributions both with and without heating within a thermodenuder (TD) and also by measuring particulate matter (PM) emission factors with an aerodynamic diameter less than 10 μm (PM(10)). The chemical properties of particulates were investigated by measuring particle and vapor phase Polycyclic Aromatic Hydrocarbons (PAHs) and also Reactive Oxygen Species (ROS) concentrations. The particle number size distributions showed strong dependency on feedstock and blend percentage with some fuel types showing increased particle number emissions, while others showed particle number reductions. In addition, the median particle diameter decreased as the blend percentage was increased. Particle and vapor phase PAHs were generally reduced with biodiesel, with the results being relatively independent of the blend percentage. The ROS concentrations increased monotonically with biodiesel blend percentage but did not exhibit strong feedstock variability. Furthermore, the ROS concentrations correlated quite well with the organic volume percentage of particles - a quantity which increased with increasing blend percentage. At higher blend percentages, the particle surface area was significantly reduced, but the particles were internally mixed with a greater organic volume percentage (containing ROS) which has implications for using surface area as a regulatory metric for diesel particulate matter (DPM) emissions.
Reporting pH-sensitive drug release via unpaired spin fluorescence silencing
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7PY01942D
Abstract: We pioneer an approach for the visualization of a self-reporting pH-controlled molecular release of a fluorescent drug from a nitroxide polymer scaffold.
To Sonicate or Not to Sonicate PM Filters: Reactive Oxygen Species Generation Upon Ultrasonic Irradiation
Publisher: Informa UK Limited
Date: 20-11-2014
Synthesis of a Novel Pyrrole Oxazole Analogue of the Insecticide Pirate
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH03184
Abstract: The pyrrole oxazole 4 is a novel analogue of the broad-spectrum insecticide and miticide pirate 2. The expedient synthesis of pyrrole oxazole 4 in six steps from pyrrole is reported using a synthetic route that could have potential for the solution-phase combinatorial synthesis of analogues. Preliminary biological evaluation of the protected pyrrole oxazole 4 (LD50 1.13 μg mL–1) and the deprotected pyrrole oxazole 5 (LD50 1.06 μg mL–1) for potential cytotoxicity was carried out.
Controlling biofilm formation with nitroxide functional surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9PY00690G
Abstract: Nitroxide functional polymer coatings with inherent antibiofilm activity are introduced as an avenue to combat bacterial biofilm contamination of medical devices.
The Synthesis of Novel Isoindoline Nitroxides Bearing Water‐Solubilising Functionality
Publisher: Wiley
Date: 30-03-2009
Abstract: A range of novel tetramethyl‐ and tetraethylisoindolinenitroxides, possessing aryl‐linked carboxylic acids, amines, alcohols and phosphonic acids were prepared. Notably, the chemistry established for the aromatic dibromination of the tetramethylisoindolines was not easily transferred to the corresponding tetraethylisoindoline system. Instead, various tetraethylisoindoline analogues were accessed by the oxidation of methyl groups attached to the aromatic ring to give the carboxylic acids. The increased steric bulk of the tetraethyl structures should limit bio‐reduction and these compounds may have potential as antioxidants.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Simple and Efficient Synthesis of 3-Aryl-2-oxazolidinone Scaffolds Enabling Increased Potency toward Biofilms
Publisher: American Chemical Society (ACS)
Date: 08-06-2023
Ciprofloxacin-nitroxide hybrids with potential for biofilm control
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.EJMECH.2017.06.058
Abstract: As bacterial biofilms display extreme tolerance to conventional antibiotic treatments, it has become imperative to develop new antibacterial strategies with alternative mechanisms of action. Herein, we report the synthesis of a series of ciprofloxacin-nitroxide conjugates and their corresponding methoxyamine derivatives in high yield. This was achieved by linking various nitroxides or methoxyamines to the secondary amine of the piperazine ring of ciprofloxacin using amide bond coupling. Biological evaluation of the prepared compounds on preformed P. aeruginosa biofilms in flow cells revealed substantial dispersal with ciprofloxacin-nitroxide hybrid 25, and virtually complete killing and removal (94%) of established biofilms in the presence of ciprofloxacin-nitroxide hybrid 27. Compounds 25-28 were shown to be non-toxic in both human embryonic kidney 293 (HEK 293) cells and human muscle rhabdomyosarcoma (RD) cells at concentrations up to 40 μM. Significantly, these hybrids demonstrate the potential of antimicrobial-nitroxide agents to overcome the resistance of biofilms to antimicrobials via stimulation of biofilm dispersal or through direct cell killing.
Design, synthesis and biological evaluation of hybrid nitroxide-based non-steroidal anti-inflammatory drugs
Publisher: Elsevier BV
Date: 03-2018
Organic Electrochemical Transistors for In Vivo Bioelectronics
Publisher: Wiley
Date: 04-10-2021
Abstract: Organic electrochemical transistors (OECTs) are presently a focus of intense research and hold great potential in expanding the horizons of the bioelectronics industry. The notable characteristics of OECTs, including their electrolyte‐gating, which offers intimate interfacing with biological environments, and aqueous stability, make them particularly suitable to be operated within a living organism (in vivo). Unlike the existing in vivo bioelectronic devices, mostly based on rigid metal electrodes, OECTs form a soft mechanical contact with the biological milieu and ensure a high signal‐to‐noise ratio because of their powerful lification capability. Such features make OECTs particularly desirable for a wide range of in vivo applications, including electrophysiological recordings, neuron stimulation, and neurotransmitter detection, and regulation of plant processes in vivo. In this review, a systematic compilation of the in vivo applications is presented that are addressed by the OECT technology. First, the operating mechanisms, and the device design and materials design principles of OECTs are examined, and then multiple ex les are provided from the literature while identifying the unique device properties that enable the application progress. Finally, one critically looks at the future of the OECT technology for in vivo bioelectronic applications.
Versatile aza‐BODIPY ‐based low‐bandgap conjugated small molecule for light harvesting and near‐infrared photodetection
Publisher: Wiley
Date: 07-07-2022
DOI: 10.1002/INF2.12345
Abstract: The versatile nature of organic conjugated materials renders their flawless integration into a erse family of optoelectronic devices with light‐harvesting, photodetection, or light‐emitting capabilities. Classes of materials that offer the possibilities of two or more distinct optoelectronic functions are particularly attractive as they enable smart applications while providing the benefits of the ease of fabrication using low‐cost processes. Here, we develop a novel, multi‐purpose conjugated small molecule by combining boron‐azadipyrromethene (aza‐BODIPY) as electron acceptor with triphenylamine (TPA) as end‐capping donor units. The implemented donor–acceptor–donor (D–A–D) configuration, in the form of TPA‐azaBODIPY‐TPA, preserves ideal charge transfer characteristics with appropriate excitation energy levels, with the additional ability to be used as either a charge transporting interlayer or light‐sensing semiconducting layer in optoelectronic devices. To demonstrate its versatility, we first show that TPA‐azaBODIPY‐TPA can act as an excellent hole transport layer in methylammonium lead triiodide (MAPbI 3 )‐based perovskite solar cells with measured power conversion efficiencies exceeding 17%, outperforming control solar cells with PEDOT:PSS by nearly 60%. Furthermore, the optical bandgap of 1.49 eV is shown to provide significant photodetection in the wavelength range of up to 800 nm where TPA‐azaBODIPY‐TPA functions as donor in near‐infrared organic photodetectors (OPDs) composed of fullerene derivatives. Overall, the established versatility of TPA‐azaBODIPY‐TPA, combined with its robust thermal stability as well as excellent solubility and processability, provides a new guide for developing highly efficient multi‐purpose electronic materials for the next‐generation of smart optoelectronic devices. image
Influence of oxygenated organic aerosols (OOAs) on the oxidative potential of diesel and biodiesel particulate matter
Publisher: American Chemical Society (ACS)
Date: 26-06-2013
DOI: 10.1021/ES4007433
Abstract: Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of the fuel's constituent molecules. Previous studies demonstrated the relationship between the organic fraction of particulate matter (PM) and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analyzed in more detail to explore the role that different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact time of flight aerosol mass spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore, the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases, shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.
Film formation from plasma-enabled surface-catalyzed dehalogenative coupling of a small organic molecule
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8RA08920E
Abstract: New surface coating pathway by plasma-enabled surface-catalyzed reaction, offering control of surface chemistry, wettability and roughness.
Synergistic or antagonistic antioxidant combinations – a case study exploring flavonoid-nitroxide hybrids
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2OB02101C
Abstract: Flavonoid-nitroxide hybrids were prepared and displayed limited antioxidant protection, performing antagonistically compared to the in idual components in a peroxyl radical scavenging assay.
Generation of Profluorescent Isoindoline Nitroxides Using Click Chemistry
Publisher: American Chemical Society (ACS)
Date: 17-05-2011
DOI: 10.1021/JO200613R
Abstract: Novel profluorescent nitroxides bearing a triazole linker between the coumarin fluorophore and an isoindoline nitroxide were prepared in good yields using the copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction (CuAAC). Nitroxides containing 7-hydroxy and 7-diethylamino substitution on their coumarin rings displayed significant fluorescence suppression, and upon reaction with methyl radicals, normal fluorescence emission was returned. The fluorescence emission for the 7-hydroxycoumarin nitroxide and its diamagnetic analogue was found to be strongly influenced by pH with maximal fluorescence emission achieved in basic solution. Solvent polarity was also shown to affect fluorescence emission. The significant difference in fluorescence output between the nitroxides and their corresponding diamagnetic analogues makes these compounds ideal tools for monitoring processes involving free-radical species.
Application of profluorescent nitroxides for measurements of oxidative capacity of combustion generated particles
Publisher: National Library of Serbia
Date: 2012
Abstract: Oxidative stress caused by generation of free radicals and related reactive oxygen species (ROS) at the sites of deposition has been proposed as a mechanism for many of the adverse health outcomes associated with exposure to particulate matter (PM). Recently, a new profluorescent nitroxide molecular probe (BPEAnit) developed at QUT was applied in an entirely novel, rapid and non-cell based assay for assessing the oxidative potential of particles (i.e. potential of particles to induce oxidative stress). The technique was applied on particles produced by several combustion sources, namely cigarette smoke, diesel exhaust and wood smoke. One of the main findings from the initial studies undertaken at QUT was that the oxidative potential per PM mass significantly varies for different combustion sources as well as the type of fuel used and combustion conditions. However, possibly the most important finding from our studies was that there was a strong correlation between the organic fraction of particles and the oxidative potential measured by the PFN assay, which clearly highlights the importance of organic species in particle-induced toxicity.
Nitroxide Functionalized Antibiotics Are Promising Eradication Agents against Staphylococcus aureus Biofilms
Publisher: American Society for Microbiology
Date: 20-12-2019
DOI: 10.1128/AAC.01685-19
Abstract: Treatment of biofilm-related Staphylococcus aureus infections represents an important medical challenge worldwide, as biofilms, even those involving drug-susceptible S. aureus strains, are highly refractory to conventional antibiotic therapy. Nitroxides were recently shown to induce the dispersal of Gram-negative biofilms in vitro , but their action against Gram-positive bacterial biofilms remains unknown.
A Novel Profluorescent Dinitroxide for Imaging Polypropylene Degradation
Publisher: American Chemical Society (ACS)
Date: 15-02-2008
DOI: 10.1021/MA701944P
Improving the Yield of the Exhaustive Grignard Alkylation of N-Benzylphthalimide
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH12528
Abstract: The tetraalkylation of N-benzylphthalimide is the major yield limiting step in the common synthetic route to isoindoline nitroxides. The progress of this reaction was found to be limited by the formation of previously unobserved mono- and dialkyl side products that do not lead to the desired product. The yield for the tetraalkylation of N-benzylphthalimide with ethylmagnesium iodide could be increased (60 % over two steps) when a stepwise addition sequence was employed. The new two-step synthesis offers a practical preparative scale alternative to the current approach.
Profluorescent Fluoroquinolone-Nitroxides for Investigating Antibiotic–Bacterial Interactions
Publisher: MDPI AG
Date: 04-03-2019
DOI: 10.3390/ANTIBIOTICS8010019
Abstract: Fluorescent probes are widely used for imaging and measuring dynamic processes in living cells. Fluorescent antibiotics are valuable tools for examining antibiotic–bacterial interactions, antimicrobial resistance and elucidating antibiotic modes of action. Profluorescent nitroxides are ‘switch on’ fluorescent probes used to visualize and monitor intracellular free radical and redox processes in biological systems. Here, we have combined the inherent fluorescent and antimicrobial properties of the fluoroquinolone core structure with the fluorescence suppression capabilities of a nitroxide to produce the first ex le of a profluorescent fluoroquinolone-nitroxide probe. Fluoroquinolone-nitroxide (FN) 14 exhibited significant suppression of fluorescence ( -fold), which could be restored via radical trapping (fluoroquinolone-methoxyamine 17) or reduction to the corresponding hydroxylamine 20. Importantly, FN 14 was able to enter both Gram-positive and Gram-negative bacterial cells, emitted a measurable fluorescence signal upon cell entry (switch on), and retained antibacterial activity. In conclusion, profluorescent nitroxide antibiotics offer a new powerful tool for visualizing antibiotic–bacterial interactions and researching intracellular chemical processes.
Cyclic Analogues of the Hendrickson ‘POP’ Reagent
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH03223
Abstract: The Hendrickson reagent, triphenylphosphonium anhydride trifluoromethanesulfonate, ‘POP’ 1, is a powerful dehydrating agent. Five-, six-, and seven-membered cyclic analogues of the ‘POP’ reagent 2–4 have been prepared and their use for ester and amide synthesis investigated. A kinetic comparison of the cyclic analogues 2–4 revealed that a considerable increase in the rate of esterification could be achieved when the five-membered ring analogue 2 was used, presumably due to the ease of formation of the putative phosphorane intermediate. The rate of ester formation from a primary alcohol using the Hendrickson reagent 1 was shown to be significantly faster when non-polar solvents were employed.
Highly efficient, stoichiometric radical exchange reactions using isoindoline profluorescent nitroxides
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0PY00015A
Prognostic Tools for Lifetime Prediction of Aircraft Coatings: Paint Degradation
Publisher: Trans Tech Publications, Ltd.
Date: 10-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.138.137
Abstract: A direct interrogation, portable analysis technique (portable FT-IR) and a novel environment-monitoring profluorescent sensor for studying aircraft coating degradation have been developed. For the direct interrogation approach, a standard military aircraft paint: 459-line Anzothane flexible polyurethane (lead free) has been used to illustrate a new potential field technique to evaluate coating service lifetime, portable FT-IR. This technique allows direct analysis of chemical changes within the degrading coatings and has the potential to evaluate service lifetime when coupled with advanced statistical analysis methods (chemometrics). The degradation environment monitoring sensors are embodied in a profluorescent environment-sensitive witness patch that may be analysed in-service by a field-deployable fluorescence spectrometer. Accelerated ageing for both the paint and the witness patches has been undertaken and their capabilities as aircraft paint degradation monitors assessed.
Polymer-supported triphenylphosphine ditriflate: a novel dehydrating reagent
Publisher: Elsevier BV
Date: 03-2004
Polynitroxide copolymers to reduce biofilm fouling on surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY01101J
Abstract: Polynitroxide films – the first ex le of surface tethered nitroxides reducing biofilm fouling.
Modular design of profluorescent polymer sensors
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5PY00120J
Abstract: Through orthogonal coupling chemistries, the synthesis of profluorescent nitroxide containing polymers for applications as radical or redox sensors is achieved.
Reducing the Hydrogen Atom Abstraction Efficiencies of Benzophenone-Based Photosensitive Alkoxyamines
Publisher: American Chemical Society
Date: 2018
Direct access to biocompatible nitroxide containing polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8PY00089A
Abstract: Ring-opening copolymerization of a nitroxide containing cyclic carbonate and d / l -lactide was used to directly access well-defined biocompatible polymers.
Isothiazolone–Nitroxide Hybrids with Activity against Antibiotic-Resistant Staphylococcus aureus Biofilms
Publisher: American Chemical Society (ACS)
Date: 02-02-2022
Development of a Redox‐Responsive Polymeric Profluorescent Probe
Publisher: Wiley
Date: 31-08-2016
Related Organisations
No related organisations have been discovered for Kathryn Fairfull-Smith.
Related Funding Activities
ARC Future Fellowships - Grant ID: FT140100746
Start Date: 03-2015
End Date: 03-2024
Amount: $771,004.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150100234
Start Date: 06-2015
End Date: 06-2021
Amount: $445,300.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP210101317
Start Date: 12-2021
End Date: 11-2025
Amount: $458,000.00
Funder: Australian Research Council
View Funded ActivityIndustrial Transformation Training Centres - Grant ID: IC210100023
Start Date: 07-2022
End Date: 07-2027
Amount: $4,943,949.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE210100148
Start Date: 07-2021
End Date: 06-2023
Amount: $1,350,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE230100048
Start Date: 03-2023
End Date: 03-2024
Amount: $570,702.00
Funder: Australian Research Council
View Funded ActivityARC Centres Of Excellence - Grant ID: CE0561607
Start Date: 12-2005
End Date: 10-2015
Amount: $21,800,000.00
Funder: Australian Research Council
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