ORCID Profile
0000-0002-4570-5595
Current Organisation
Monash 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)
Physical Chemistry (Incl. Structural) | Physical Chemistry of Materials | Optical Properties of Materials | Macromolecular and Materials Chemistry | Organic Chemical Synthesis | Nanochemistry and Supramolecular Chemistry | Structural Chemistry and Spectroscopy | Signal Transduction | Immunology not elsewhere classified | Biochemistry and Cell Biology | Chemical Spectroscopy | Synthesis of Materials | Molecular imaging (incl. electron microscopy and neutron diffraction) | Characterisation Of Macromolecules | Polymers | Theory and Design of Materials | Genetics | Biological Physics | Protein Trafficking | Functional Materials | Physical Chemistry not elsewhere classified | Materials Engineering | Epigenetics (incl. genome methylation and epigenomics) | Medical Biotechnology Diagnostics (incl. Biosensors) | Photonics, Optoelectronics and Optical Communications
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in the Biological Sciences | Energy transformation | Solar-photoelectric | Renewable energy | Chemical sciences | Expanding Knowledge in Technology | Physical and Chemical Conditions of Water for Urban and Industrial Use | Information and Communication Services not elsewhere classified | Diagnostic Methods |
Related Links
Publications
Photoinduced Energy and Electron Transfer in a Giant Zinc Porphyrin−Bridge−C60 System
Publisher: American Chemical Society (ACS)
Date: 10-2002
DOI: 10.1021/JP014155K
Synthesis and Photophysics of Core-Substituted Naphthalene Diimides: Fluorophores for Single Molecule Applications
Publisher: Wiley
Date: 30-09-2009
Release kinetics of 6-mercaptopurine and 6-thioguanine from bioinspired core-crosslinked thymine functionalised polymeric micelles
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH13125
Abstract: A bioinspired core-bound polymeric micellar system based on hydrogen bonding and photo-crosslinking of thymine has been prepared from the hiphilic block copolymers, poly(vinylbenzylthymine)-block-poly(vinylbenzyltriethylammonium chloride). The chemical loading and controlled release potential of these micelles was investigated using two drugs, 6-mercaptopurine and 6-thioguanine. The release kinetics of drug-loaded polymeric micelles was determined by pressure ultrafiltration and the effects of hydrogen bonding, core-crosslinking, and core size on the loading capacity and release kinetics were analysed. The results demonstrate that drug release rates are affected by hydrogen bonding in the micelle core. Furthermore, these studies indicate that drug release rates can be controlled by changing the size of the core and by photo-crosslinking thymine groups in the core.
Inhomogeneity of electron injection rates in dye-sensitized TiO 2 : continuous mesoporous films and single particle behavior
Publisher: SPIE
Date: 31-08-2006
DOI: 10.1117/12.681448
Electron Transport in the Long‐Range Charge‐Recombination Dynamics of Single Encapsulated Dye Molecules on TiO2 Nanoparticle Films
Publisher: Wiley
Date: 17-09-2009
Charge Transfer in Single Chains of a Donor–Acceptor Conjugated Tri-Block Copolymer
Publisher: American Chemical Society (ACS)
Date: 05-12-2014
DOI: 10.1021/JP510769P
Abstract: The photophysics of a conjugated triblock copolymer comprising poly(9,9-dioctylfluorene-co-bis-N,N'-(4-methylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine) (PFM) electron donor and poly(4-(9,9-dioctyl-9H-fluoren-2-yl)benzo[c][1,2,5]-thiadiazole) (F8BT) electron acceptor blocks has been studied in solution, in films, and as single chains. While an additional long-wavelength emission apparent in neat films of the copolymer is attributed to interchain exciplex formation, no such long-wavelength emission is apparent in solution or from single molecules. However, in these cases, time-resolved fluorescence measurements indicate the presence of a delayed fluorescence. The kinetics of the delayed emission can be interpreted in terms of an equilibrium between a locally excited and a charge-transfer state at the interface of the copolymer block components. Rate constants and thermodynamic quantities associated with these processes have been evaluated. The single-molecule results allow the assignment of an intramolecular charge-transfer state in an isolated conjugated block copolymer chain.
Melt-induced fluorescent signature in a simple naphthalenediimide
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CC00865F
Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CH09142
Abstract: The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.
Probing molecular properties and the role of the environment at the single-molecule level
Publisher: Walter de Gruyter GmbH
Date: 2006
Abstract: Evidence for intramolecular photoinduced electron transfer (ET) in synthetic systems consisting of a triphenylamine-perylenediimide donor-acceptor dendrimer or a triphenylamine-peryleneimide dendrimer at the ensemble and single-molecule (SM) level is presented. Moreover, for the first time a direct observation of the forward as well as the backward ET step is made in a single emitting entity. Fluctuations in the values of the rate constants for forward and backward ET were observed, induced by the local environment as well as by conformational changes of the dendrimer itself. The results obtained in a weakly coupled system can also be extended to a strongly coupled donor-acceptor system based on peryleneimide and penta-phenylene.
Charge transfer enhanced annihilation leading to deterministic single photon emission in rigid perylene end-capped polyphenylenes
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B509651K
Abstract: Two new peryleneimide end-capped polyphenylenes are shown to be deterministic single photon sources in PMMA films due to efficient annihilation between charge transfer states.
Live-Cell SOFI Correlation with SMLM and AFM Imaging
Publisher: American Chemical Society (ACS)
Date: 28-03-2023
Investigation of cation binding and sensing by new crown ether core substituted naphthalene diimide systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8NJ05666H
Abstract: Different modes of cation binding lead to very different optical readouts from two structurally similar sensors.
Confined polymerisation of bis-thyminyl monomers within nanoreactors: towards molecular weight control
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0PY00523A
Abstract: Controlling polymer molecular weight by topochemical polymerisation inside nanoreactors.
Remarkable Conformational Control of Photoinduced Charge Separation and Recombination in a Giant U-Shaped Tetrad
Publisher: American Chemical Society (ACS)
Date: 18-10-2000
DOI: 10.1021/JA001492I
Synthetic polymers for solar harvesting
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1FD00100K
Abstract: Synthetic polymers incorporating appropriate chromophores can act as light harvesting antennae for artificial photosynthetic systems. The photophysical processes occurring in a polymer based on phenylene vinylene have been investigated at the single chain level and in bulk solution to study energy transfer processes. Most single chains of an alternating copolymer of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and 1,4-phenylene vinylene (alt-co-MEH-PPV) dispersed in a transparent polymer matrix act as single chromophore emitters demonstrating that energy transfer is an efficient process in these polymers. However for in idual polymer chains there are fluctuations in emission intensity ('blinking') and shifts in emission spectra, decay lifetimes and emission dipole orientation occurring on a time-scale of tens of seconds. Fluorescence blinking also occurs on a sub-millisecond time-scale and follows exponential kinetics, whereas the longer blinking is better described by a power law. These observations can be interpreted as arising from environmental relaxation processes and/or changes in the emitter and demonstrate the wide distribution of photophysical behaviours that can be observed among the in idual molecules of a polymer s le. The relevance of these studies to the application of polymer materials for solar harvesting is highlighted.
Self-assembled, optically-active {naphthalene diimide}U{cucurbit[8]uril} ensembles in an aqueous environment
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1CP00659B
Abstract: Naphthalene diimides (NDIs) are shown to arrange spontaneously with cucurbit[8]uril (CB[8]) in an aqueous environment through purely non-covalent interactions to form discrete 2:2 complexes which produce intense cyan emission upon photoexcitation.
UV-reversible chain extendable polymers from thymine functionalized telechelic polymer chains
Publisher: Wiley
Date: 23-06-2014
DOI: 10.1002/POLA.27282
Electron Transfer at the Single‐Molecule Level in a Triphenylamine–Perylene Imide Molecule
Publisher: Wiley
Date: 22-04-2005
Abstract: Photoinduced electron transfer (ET) processes in a donor-acceptor system based on triphenylamine and perylene imide have been studied at the single-molecule (SM) and ensemble levels. The system exists as two isomers, one of which undergoes forward and reverse ET in toluene with decay constants of 3.0 and 2.2x10(9) s(-1), respectively, resulting in the dual emission of quenched and delayed fluorescence while the other isomer remains ET-inactive. The fluorescence of both isomers is heavily quenched in the more polar solvent, diethyl ether, by ET. A broad range of ET dynamics is seen at the SM level in polystryene with the two isomers nonresolvable indicating that the local nanoenvironment of the SMs varies considerably throughout the polymer matrix. Both the electronic coupling and the driving force for ET are shown to influence the ET dynamics. Many fluorescence trajectories of SMs show long periods (tens of milliseconds to seconds) where the count rate is attenuated either partly (a "dim" state) or to the background level (an "off-time"). During these periods, the reduction or interruption of emission is attributed to cycles of rapid charge separation followed by charge recombination to the ground state reducing the fluorescence quantum yield of the SM.
Design of Polarity-Dependent Immunosensors Based on the Structural Analysis of Engineered Antibodies
Publisher: American Chemical Society (ACS)
Date: 13-07-2023
Long-lived photoinduced charge separation in a bridged C60-porphyrin dyad
Publisher: Elsevier BV
Date: 04-1997
The H.G. Smith Award Article: Fluorescent Analogues of NAMI-A: Synthesis, Characterisation, Fluorescent Properties, and Preliminary Biological Studies in Human Lung Cancer Cells
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH14205
Abstract: Two new fluorescent ruthenium(iii) complexes, namely 7-azaindolium trans-tetrachlorido(7-azaindole)(dimethylsulfoxide)ruthen(iii)ate (F1) and N-[histaminedihydrolium]-1,8-naphthalenecarboximidic trans-tetracholoro(dimethylsulfoxide)(N-[histaminedihydro]-1,8-naphthalenecarboximide)ruthen(iii)ate (F2) and their respective tetramethylammonium analogues (F3 and F4) are reported herein. The compounds were characterised by elemental analysis, mass spectrometry, UV-vis spectrophotometry, and fluorescence spectroscopy. Molar extinction coefficients (ϵmax) and fluorescence emission spectra were compared to evaluate the electronic properties of the synthesised fluorescent analogues, and hence their value as intracellular fluorescence probes. F3 and F4 were synthesised and characterised in order to eliminate fluorescence arising from the counter-cations in F1 and F2 and thus to obtain a fluorescence quantum yield that reflects only a contribution from the metal complex anion. Half-inhibitory concentrations (IC50) were determined for A549 cells exposed to the Ru complexes for 24 h: F3 (203 ± 26 μM) and F4 (185 ± 20 μM).
Bioinspired core-crosslinked micelles from thymine-functionalized amphiphilic block copolymers: Hydrogen bonding and photo-crosslinking study
Publisher: Wiley
Date: 12-07-2011
DOI: 10.1002/POLA.24853
Abstract: Bioinspired core‐bound polymeric micelles, based on hydrogen bonding and photo‐crosslinking, of thymine have been prepared from poly(vinylbenzylthymine)‐ b ‐poly(vinylbenzyltriethylammonium chloride). The hiphilic block copolymer was synthesized by 2,2‐tetramethylpiperidin‐1‐oxyl‐mediated living radical polymerization in water/ethylene glycol solution. Micelle characterization and critical micelle concentration measurements demonstrated that the hydrogen bonding of the attached thymine units stabilizes the micelles. Further, core‐crosslinked polymeric micelles were formed by ultraviolet (UV) radiation showing that the stability of the micelle could be controlled by the UV crosslinking of the attached thymines. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Switching of the fluorescence emission of single molecules between the locally excited and charge transfer states
Publisher: Elsevier BV
Date: 2005
Distance and wavelength dependent quenching of molecular fluorescence by Au@SiO2 core-shell nanoparticles
Publisher: American Chemical Society (ACS)
Date: 17-06-2013
DOI: 10.1021/NN401775E
Abstract: Gold nanoparticles and nearby fluorophores interact via electromagnetic coupling upon light excitation. We determine the distance and wavelength dependence of this coupling theoretically and experimentally via steady-state and time-resolved fluorescence spectroscopy. For the first time, the fluorescence quenching of four different dye molecules, which absorb light at different wavelengths across the visible spectrum and into the near-infrared, is studied using a rigid silica shell as a spacer. A comprehensive experimental determination of the distance dependence from complete quenching to no coupling is carried out by a systematic variation of the silica shell thickness. Electrodynamic theory predicts the observed quenching quantitatively in terms of energy transfer from the molecular emitter to the gold nanoparticle. The plasmonic field enhancement in the vicinity of the 13 nm gold nanoparticles is calculated as a function of distance and excitation wavelength and is included in all calculations. Relative radiative and energy transfer rates are determined experimentally and are in good agreement with calculated rates. We demonstrate and quantify the severe effect of dye-dye interactions on the fluorescence properties of dyes attached to the surface of a silica nanoparticle in control experiments. This allows us to determine the experimental conditions, under which dye-dye interactions do not affect the experimental results.
Single Photon Emission from a Dendrimer Containing Eight Perylene Diimide Chromophores
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH04133
Abstract: A novel dendrimer containing eight perylene diimide chromophores has been synthesized and studied by ensemble and single-molecule spectroscopic techniques. Photon anti-bunching (coincidence) measurements on single molecules embedded in zeonex polymer films show that the dendrimer behaves as a deterministic (triggered) single photon source with only one fluorescence photon being emitted following pulsed laser excitation, even when more than one chromophore is excited. This behaviour is due to efficient singlet–singlet annihilation being operative in this dendrimer. Preliminary results indicate that the triplet lifetime and yield for this molecule are similar to the values for a molecule containing a single perylene diimide chromophore.
Optimising correlative super resolution and atomic force microscopies for investigating the cellular cytoskeleton.
Publisher: IOP Publishing
Date: 16-08-2022
Abstract: Correlative imaging methods can provide greater information for investigations of cellular ultra-structure, with separate analysis methods complementing each other's strengths and covering for deficiencies. Here we present a method for correlative applications of super resolution and atomic force microscopies, optimising the s le preparation for correlative imaging of the cellular cytoskeleton in COS-7 cells. This optimisation determined the order of permeabilisation and fixation, the concentration of Triton X-100 surfactant used and time required for sufficient removal of the cellular membrane while maintaining the microtubule network. Correlative SMLM/AFM imaging revealed the different information that can be obtained through each microscopy. The widths of microtubules and microtubule clusters were determined from both AFM height measurements and Gaussian fitting of SMLM intensity cross sections, these were then compared to determine the orientation of microtubules within larger microtubule bundles. The ordering of microtubules at intersections was determined from the AFM height profiles as each microtubule crosses the other. The combination of both microtubule diameter measurements enabled greater information on their structure to be found than either measurement could in idually.
Synthesis and Single Chain Fluorescence of a Sulfonated Conjugated Polymer
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CH09348
Abstract: A water-soluble sulfonated conjugated phenylene vinylene polymer (Alt-Co-DPS-PPV) has been prepared by a Horner–Emmons reaction involving the condensation of a disulfonyl aryl bisphosphonate and terephthaldehyde. The photoluminescence from single chains of the polymer dispersed in a poly(vinyl alcohol) film at room temperature has been studied by confocal imaging techniques. Fluorescence intensity trajectories from Alt-Co-DPS-PPV single chains exhibit intermittencies or ‘blinking’ on both short (sub-millisecond) and long (seconds) time scales. The short time-scale intensity fluctuation data has been successfully analyzed using a simple model involving excursions from the fluorescent excited singlet state of the polymer chromophore to a non-emitting triplet state. It is found that the triplet state lifetime is molecule dependent and can be perturbed by the presence of the added heavy atom, iodide. These single chain fluorescence studies provide an insight into the distribution of excited state behaviours that make up the bulk polymer photochemical properties.
CT−CT Annihilation in Rigid Perylene End-Capped Pentaphenylenes
Publisher: American Chemical Society (ACS)
Date: 21-12-2006
DOI: 10.1021/JA064794E
Abstract: The time-dependent spectral properties of a rigid, extended system consisting of three pentaphenylene units end-capped with perylene monoimide were investigated in detail by femtosecond transient absorption and single photon timing measurements. In polar solvents, the molecular system shows the occurrence of photoinduced charge transfer. Upon gradually increasing the excitation power, annihilation involving two states with charge-transfer character has been observed. Quantum-chemical calculations performed on the system consisting of two pentaphenylene units end-capped with perylene monoimide strongly support the experimental data.
Naphthalene diimides as tunable fluorophores suitable for single molecule applications
Publisher: SPIE
Date: 08-02-2007
DOI: 10.1117/12.701443
Image artifacts in single molecule localization microscopy: Why optimization of sample preparation protocols matters
Publisher: Springer Science and Business Media LLC
Date: 21-01-2015
DOI: 10.1038/SREP07924
Unexpected photoluminescence of fluorinated naphthalene diimides.
Publisher: Wiley
Date: 29-01-2015
Inhomogeneity of Electron Injection Rates in Dye-Sensitized TiO2: Comparison of the Mesoporous Film and Single Nanoparticle Behavior
Publisher: American Chemical Society (ACS)
Date: 31-10-2006
DOI: 10.1021/JP064005F
Abstract: As it has been shown by pump-probe experiments electron injection at the interface between a dye molecule and mesoporous TiO2 proceeds with rates exceeding 1 x 10(13) s(-1). However, similar dye-TiO2 systems exhibit residual dye emission with lifetimes extending into the long nanosecond range. To address this inhomogeneity of injection rates time-correlated single photon counting microscopy was used to compare the emission behavior of dye-sensitized mesoporous films of TiO2 with that of in idual anatase nanoparticles that had undergone extensive dialysis. The sensitized films produce intense residual emission with multiexponential decay components as long as 220 ns. The channels of mesoporous films contain physisorbed and trapped dye, which is the dominant source of the emission. It is likely that the wide range of lifetimes reflects the distribution of mean free paths experienced by the loose dye molecules diffusing within the film prior to undergoing oxidative quenching. In contrast, the intensity of emission from in idual nanoparticles from which the loose dye was removed by dialysis is orders of magnitude lower. The lifetimes obtained from such particles are much shorter, with the primary component on a sub-nanosecond time scale. The presence of residual emission with a 230 ps lifetime shows that even on the surfaces of dialyzed nanoparticles there is a fraction of sensitizer molecules that do not inject electrons with the same high rate as is observed in ultrafast pump-probe experiments on films. Since the physisorbed dye was removed from these s les by dialysis, the residual emission is likely to originate from dye molecules bound to surface defects. Unusual collective emission bursts were observed in some of the measurements on sensitized nanoparticles. We attribute this behavior to stimulated emission from in idual nanocrystallites.
Understanding DNA organization, damage, and repair with super-resolution fluorescence microscopy
Publisher: IOP Publishing
Date: 05-05-2021
Abstract: Super-resolution microscopy (SRM) comprises a suite of techniques well-suited to probing the nanoscale landscape of genomic function and dysfunction. Offering the specificity and sensitivity that has made conventional fluorescence microscopy a cornerstone technique of biological research, SRM allows for spatial resolutions as good as 10 nanometers. Moreover, single molecule localization microscopies (SMLMs) enable examination of in idual molecular targets and nanofoci allowing for the characterization of subpopulations within a single cell. This review describes how key advances in both SRM techniques and s le preparation have enabled unprecedented insights into DNA structure and function, and highlights many of these new discoveries. Ongoing development and application of these novel, highly interdisciplinary SRM assays will continue to expand the toolbox available for research into the nanoscale genomic landscape.
Correlative Synchrotron Fourier Transform Infrared Spectroscopy and Single Molecule Super Resolution Microscopy for the Detection of Composition and Ultrastructure Alterations in Single Cells
Publisher: American Chemical Society (ACS)
Date: 23-10-2015
DOI: 10.1021/ACSCHEMBIO.5B00754
Abstract: Single molecule localization microscopy (SMLM) and synchrotron Fourier transform infrared (S-FTIR) spectroscopy are two techniques capable of elucidating unique and valuable biological detail. SMLM provides images of the structures and distributions of targeted biomolecules at spatial resolutions up to an order of magnitude better than the diffraction limit, whereas IR spectroscopy objectively measures the holistic biochemistry of an entire s le, thereby revealing any variations in overall composition. Both tools are currently applied extensively to detect cellular response to disease, chemical treatment, and environmental change. Here, these two techniques have been applied correlatively at the single cell level to probe the biochemistry of common fixation methods and have detected various fixation-induced losses of biomolecular composition and cellular ultrastructure. Furthermore, by extensive honing and optimizing of fixation protocols, many fixation artifacts previously considered pervasive and regularly identified using IR spectroscopy and fluorescence techniques have been avoided. Both paraformaldehyde and two-step glutaraldehyde fixation were identified as best preserving biochemistry for both SMLM and IR studies while other glutaraldehyde and methanol fixation protocols were demonstrated to cause significant biochemical changes and higher variability between s les. Moreover, the potential complementarity of the two techniques was strikingly demonstrated in the correlated detection of biochemical changes as well as in the detection of fixation-induced damage that was only revealed by one of the two techniques.
A fluorescent 2 in 1 proton sensor and polarity probe based on core substituted naphthalene diimide.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CC41622D
Divalent Tetra- and Penta-phenylcyclopentadienyl Europium and Samarium Sandwich and Half-Sandwich Complexes: Synthesis, Characterization, and Remarkable Luminescence Properties
Publisher: American Chemical Society (ACS)
Date: 25-11-2015
Multichromophoric Dendrimers as Single-Photon Sources: A Single-Molecule Study
Publisher: American Chemical Society (ACS)
Date: 10-2004
DOI: 10.1021/JP047804B
Harnessing Brightness in Naphthalene Diimides
Publisher: Wiley
Date: 18-03-2019
Abstract: The development of brightly emissive compounds is of great research and commercial interest, with established and emerging applications across chemistry, biology, physics, medicine and engineering. Among the many types of molecules available, naphthalene diimides have been widely used for both fundamental photophysical studies and in practical applications that utilise fluorescence as an information readout. The monomeric naphthalene diimide is weakly fluorescent, however through various methods of core-derivatisation, it can be developed to be highly fluorescent and further functionalised to add utility. In this review, we highlight recent advances made in naphthalene diimide chemistry that have led to development of molecules with improved optical properties, and the design strategies utilised to produce bright fluorescence emission as small molecules or in supramolecular architectures.
Controlled Growth of Monocrystalline Organo-Lead Halide Perovskite and Its Application in Photonic Devices
Publisher: Wiley
Date: 04-07-2017
Abstract: Organo-lead halide perovskites (OHPs) have recently emerged as a new class of exceptional optoelectronic materials, which may find use in many applications, including solar cells, light emitting diodes, and photodetectors. More complex applications, such as lasers and electro-optic modulators, require the use of monocrystalline perovskite materials to reach their ultimate performance levels. Conventional methods for forming single crystals of OHPs like methylammonium lead bromide (MAPbBr
Modular synthesis of 4-aminocarbonyl substituted 1,8-naphthalimides and application in single molecule fluorescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC07922B
Abstract: Robust 1,8-naphthalimide cross-coupling methodology unlocks access to derivatives with interesting photophysical properties and erse applications.
Tuning the structure, thermal stability and rheological properties of liquid crystal phases via the addition of silica nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP04908H
Abstract: The effects of adding silica nanoparticles of varying size and surface chemistry to a liquid crystal system were analysed using small-angle scattering and polarising light microscopy, with varying temperature and applied shear.
Viral regulation of host cell biology by hijacking of the nucleolar DNA-damage response.
Publisher: Springer Science and Business Media LLC
Date: 03-08-2018
DOI: 10.1038/S41467-018-05354-7
Abstract: Recent studies indicate that nucleoli play critical roles in the DNA-damage response (DDR) via interaction of DDR machinery including NBS1 with nucleolar Treacle protein, a key mediator of ribosomal RNA (rRNA) transcription and processing. Here, using proteomics, confocal and single molecule super-resolution imaging, and infection under biosafety level-4 containment, we show that this nucleolar DDR pathway is targeted by infectious pathogens. We find that the matrix proteins of Hendra virus and Nipah virus, highly pathogenic viruses of the Henipavirus genus in the order Mononegavirales , interact with Treacle and inhibit its function, thereby silencing rRNA biogenesis, consistent with mimicking NBS1–Treacle interaction during a DDR. Furthermore, inhibition of Treacle expression/function enhances henipavirus production. These data identify a mechanism for viral modulation of host cells by appropriating the nucleolar DDR and represent, to our knowledge, the first direct intranucleolar function for proteins of any mononegavirus.
Energy transfer in PPV-based conjugated polymers: a defocused widefield fluorescence microscopy study
Publisher: Royal Society of Chemistry (RSC)
Date: 04-03-2014
DOI: 10.1039/C4CP00276H
Abstract: Both pendant and main chain conjugated MEH-PPV based polymers have been studied at the level of single chains using confocal and widefield fluorescence microscopy techniques. In particular, defocused widefield fluorescence is applied to reveal the extent of energy transfer in these polymers by identifying whether they act as single emitters. For main chain conjugated MEH-PPV, molecular weight and the surrounding matrix play a primary role in determining energy transport processes and whether single emitter behaviour is observed. Surprisingly in polymers with a saturated backbone but containing the same pendant MEH-PPV oligomer on each repeating unit, intra-chain energy transfer to a single emitter is also apparent. The results imply there is chromophore heterogeneity that can facilitate energy funneling to the emitting site. Both main chain conjugated and pendant MEH-PPV polymers exhibit changes in orientation of the emission dipole during a fluorescence trajectory of many seconds, whereas a model MEH-PPV oligomer does not. The results suggest that, in the polymers, the nature of the emitting chromophores can change during the time trajectory.
Super-resolution single-molecule localization microscopy: Tricks of the trade
Publisher: American Chemical Society (ACS)
Date: 13-01-2015
DOI: 10.1021/JZ5019702
Abstract: Application of single-molecule fluorescence detection has led to the development of light microscopy techniques that make it possible to study fluorescent s les at spatial resolutions significantly improved upon the diffraction limit of light. The biological and materials science applications of these "super-resolution" microscopy methods are vast, causing current demand for them to be high. However, implementation, execution, and interpretation of these techniques, particularly involving biological s les, require a broad interdisciplinary skillset, not often found in a single laboratory. Those already used to interdisciplinary work as well as navigating communication and collaboration between more pure forms of physics, chemistry, and biology are well-positioned to spearhead such efforts. In this Perspective, we describe various aspects of single-molecule super-resolution imaging, discussing, in particular, the role that physical chemistry has so far played in its development and establishment. We also highlight a selection of some of the remarkable recent research achievements in this vibrant field.
Mixed alkoxy/hydroxy 1,8-naphthalimides: expanded fluorescence colour palette andin vitrobioactivity
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC01251C
Abstract: An efficient and functional group tolerant route to access hydroxy 1,8-naphthalimides has been used to synthesise a range of mono- and disubstituted hydroxy-1,8-naphthalimides with fluorescence emissions covering the visible spectrum.
Fluorescence of Single Molecules in Polymer Films: Sensitivity of Blinking to Local Environment
Publisher: American Chemical Society (ACS)
Date: 26-05-2007
DOI: 10.1021/JP072864D
Abstract: The single-molecule fluorescence blinking behavior of the organic dye Atto647N in various polymer matrixes such as Zeonex, PVK, and PVA as well as aqueous media was investigated. Fluorescence blinking with off-times in the millisecond to second time range is assigned to dye radical ions formed by photoinduced electron transfer reactions from or to the environment. In Zeonex and PVK, the measured off-time distributions show power law dependence, whereas, in PVA, no such dependence is observed. Rather, in this polymer, off-time distributions can be best fitted to monoexponential or stretched exponential functions. Furthermore, treatment of PVA s les to mild heating and low pressure greatly reduces the frequency of blinking events. We tentatively ascribe this to the removal of water pockets within the polymer film itself. Measurements of the dye immobilized in water in the presence of methylviologen, a strongly oxidizing agent, reveal simple exponential on- and off-time distributions. Thus, our data suggest that the blinking behavior of single organic molecules is sensitive to their immediate environment and, moreover, that fluorescence blinking on- and off-time distributions do not inherently and uniquely obey a power law.
Structural and rheological changes of lamellar liquid crystals as a result of compositional changes and added silica nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP02101E
Abstract: By adding silica nanoparticles to lamellar liquid crystals, their flow and structure can be changed dramatically, indicating new ways to understand particle–membrane interactions.
New brightly coloured, water soluble, core-substituted naphthalene diimides for biophysical applications
Publisher: Elsevier BV
Date: 2015
Amphiphilic conjugated block copolymers as NIR-bioimaging probes
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2PY00258B
Abstract: A novel method for creating a semiconducting nanoparticles of the donor–acceptor conjugated polymer p(IDT-NDI) containing indacenodithienothiophene (IDT) and naphthalene diimide (NDI) units is presented.
Photoinduced electron transfer dynamics in porphyrin donor dyads
Publisher: Elsevier BV
Date: 06-2008
'Live and Large': Super-Resolution Optical Fluctuation Imaging (SOFI) and Expansion Microscopy (ExM) of Microtubule Remodelling by Rabies Virus P Protein
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/CH19571
Abstract: The field of super-resolution microscopy continues to progress rapidly, both in terms of evolving techniques and methodologies as well as in the development of new multi-disciplinary applications. Two current drivers of innovation are increasing the possible resolution gain and application in live s les. Super-resolution optical fluctuation imaging (SOFI) is well suited to live s les while expansion microscopy (ExM) enables obtainment of sub-diffraction information via conventional imaging. In this Highlight we provide a brief outline of these methods and report results from application of SOFI and ExM in our on-going study into microtubule remodelling by rabies virus P proteins. We show that MT bundles in live cells transfected with rabies virus P3 protein can be visualised using SOFI in a time-lapse fashion for up to half an hour and can be expanded using current Pro-ExM protocols and imaged using conventional microscopy.
A Redox Switchable Dihydrobenzo b pyrazine Push-Pull System
Publisher: Wiley
Date: 12-03-2014
Frontispiece: Harnessing Brightness in Naphthalene Diimides
Publisher: Wiley
Date: 23-05-2019
X-Ray Crystal Structure and Properties of Phanta, a Weakly Fluorescent Photochromic GFP-Like Protein
Publisher: Public Library of Science (PLoS)
Date: 29-04-2015
The WD40 Protein BamB Mediates Coupling of BAM Complexes into Assembly Precincts in the Bacterial Outer Membrane
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.CELREP.2018.04.093
Abstract: The β-barrel assembly machinery (BAM) complex is essential for localization of surface proteins on bacterial cells, but the mechanism by which it functions is unclear. We developed a direct stochastic optical reconstruction microscopy (dSTORM) methodology to view the BAM complex in situ. Single-cell analysis showed that discrete membrane precincts housing several BAM complexes are distributed across the E. coli surface, with a nearest neighbor distance of ∼200 nm. The auxiliary lipoprotein subunit BamB was crucial for this spatial distribution, and in situ crosslinking shows that BamB makes intimate contacts with BamA and BamB in neighboring BAM complexes within the precinct. The BAM complex precincts swell when outer membrane protein synthesis is maximal, visual proof that the precincts are active in protein assembly. This nanoscale interrogation of the BAM complex in situ suggests a model whereby bacterial outer membranes contain highly organized assembly precincts to drive integral protein assembly.
Characterizing the Fluorescence Intermittency and Photobleaching Kinetics of Dye Molecules Immobilized on a Glass Surface
Publisher: American Chemical Society (ACS)
Date: 06-01-2006
DOI: 10.1021/JP055496R
Abstract: The blinking behavior of single Atto565 molecules on a glass surface is studied under air or nitrogen atmospheres using confocal microscopy. The broad distributions for both on- and off-time durations obey power law kinetics that are rationalized using a charge tunneling model. In this case, a charge is transferred from the Atto565 molecule to localized states found on the glass surface. Subsequent charge recombination by back charge tunneling from trap to Atto565 cation (i.e., dark state) restores the fluorescence. The off-time distribution is independent of excitation intensity (I), whereas the on-time distribution exhibits a power law exponent that varies with I. Two pathways have been identified to lead to the formation of the radical dark state. The first involves direct charge tunneling from the excited singlet S1 state to charge traps in the surrounding matrix, and the second requires charge ejection from the triplet T1 state after intersystem crossing from S1. Monte Carlo simulation studies complement the two-pathway model. Photobleaching curves of both single and ensemble molecules do not exhibit monoexponential decays suggesting complex bleaching dynamics arising from triplet and radical states.
Surfactant‐Enhanced Adsorption of Graphene Oxide for Improved Emulsification of Oil in Water
Publisher: Wiley
Date: 04-10-2017
Tuning the Photoluminescence Anisotropy of Semiconductor Nanocrystals
Publisher: American Chemical Society (ACS)
Date: 25-09-2023
Electron Transfer in a Naphthalene Diimide System Studied by Single-Molecule Delayed Fluorescence
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/CH19555
Abstract: Electron transfer (ET) is a key chemical reaction in nature and has been extensively studied in bulk systems, but remains challenging to investigate at the single-molecule level. A previously reported naphthalene diimide (NDI)-based system (Higginbotham et al., Chem. Commun. 2013, 49, 5061–5063) displays delayed fluorescence with good quantum yield (~0.5) and long-lived (nanoseconds) prompt and delayed fluorescence lifetimes, providing an opportunity to interrogate the underlying ET processes in single molecules. Time-resolved single-molecule fluorescence measurements enabled forward and reverse ET rate constants to be calculated for 45 in idual molecules embedded in poly(methylmethacrylate) (PMMA) film. Interpretation of the results within the framework of Marcus–Hush theory for ET demonstrates that variation in both the electronic coupling and the driving force for ET is occurring from molecule to molecule within the PMMA film and over time for in idual molecules.
Focus on Super-Resolution Imaging with Direct Stochastic Optical Reconstruction Microscopy (dSTORM)
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13499
Abstract: The last decade has seen the development of several microscopic techniques capable of achieving spatial resolutions that are well below the diffraction limit of light. These techniques, collectively referred to as ‘super-resolution’ microscopy, are now finding wide use, particularly in cell biology, routinely generating fluorescence images with resolutions in the order of tens of nanometres. In this highlight, we focus on direct Stochastic Optical Reconstruction Microscopy or dSTORM, one of the localisation super-resolution fluorescence microscopy techniques that are founded on the detection of fluorescence emissions from single molecules. We detail how, with minimal assemblage, a highly functional and versatile dSTORM set-up can be built from ‘off-the-shelf’ components at quite a modest budget, especially when compared with the current cost of commercial systems. We also present some typical super-resolution images of microtubules and actin filaments within cells and discuss s le preparation and labelling methods.
Elucidation of naphthalene diimide metallomacrocycles and catenanes by solvent dependent excimer and exciplex emission
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CC09191A
Abstract: The formation of metallocatenanes, and their disruption by aromatic solvents, is followed by excimer and exciplex emission.
Nanoscale characterization of drug-induced microtubule filament dysfunction using super-resolution microscopy
Publisher: Springer Science and Business Media LLC
Date: 12-2021
DOI: 10.1186/S12915-021-01164-4
Abstract: The integrity of microtubule filament networks is essential for the roles in erse cellular functions, and disruption of its structure or dynamics has been explored as a therapeutic approach to tackle diseases such as cancer. Microtubule-interacting drugs, sometimes referred to as antimitotics, are used in cancer therapy to target and disrupt microtubules. However, due to associated side effects on healthy cells, there is a need to develop safer drug regimens that still retain clinical efficacy. Currently, many questions remain open regarding the extent of effects on cellular physiology of microtubule-interacting drugs at clinically relevant and low doses. Here, we use super-resolution microscopies (single-molecule localization and optical fluctuation based) to reveal the initial microtubule dysfunctions caused by nanomolar concentrations of colcemid. We identify previously undetected microtubule (MT) damage caused by clinically relevant doses of colcemid. Short exposure to 30–80 nM colcemid results in aberrant microtubule curvature, with a trend of increased curvature associated to increased doses, and curvatures greater than 2 rad/μm, a value associated with MT breakage. Microtubule fragmentation was detected upon treatment with ≥ 100 nM colcemid. Remarkably, lower doses ( 20 nM after 5 h) led to subtle but significant microtubule architecture remodelling characterized by increased curvature and suppression of microtubule dynamics. Our results support the emerging hypothesis that microtubule-interacting drugs induce non-mitotic effects in cells, and establish a multi-modal imaging assay for detecting and measuring nanoscale microtubule dysfunction. The sub-diffraction visualization of these less severe precursor perturbations compared to the established antimitotic effects of microtubule-interacting drugs offers potential for improved understanding and design of anticancer agents.
Local determination of thin liquid film profiles using colour interferometry
Publisher: Springer Science and Business Media LLC
Date: 02-2016
DOI: 10.1140/EPJE/I2016-16014-9
Abstract: We explore theoretically the interference of white light between two interfaces as a function of the optical conditions, using separately: a) idealised conditions where the light is composed of three discrete wavelengths b) a more typically experimentally realisable case where light comprises a sum of three Gaussian wavelength distributions and c) unfiltered white light from a broadband source comprising a broad distribution of wavelengths. It is demonstrated that the latter case is not only optically simple to arrange, but also provides unambiguous absolute separation information over the range 0-1μm --a useful range in studies of cell adhesion, thin liquid films and lubrication-- when coupled to detection using a typical colour camera. The utility of this technique is verified experimentally by exploring the air film between a cylinder and surface, as well as arbitrary liquid films beneath air bubbles that are interacting with solid surfaces.
The transition from single molecule to ensemble revealed by fluorescence polarization.
Publisher: Springer Science and Business Media LLC
Date: 02-02-2015
DOI: 10.1038/SREP08158
1D Self-Assembly and Ice Recrystallization Inhibition Activity of Antifreeze Glycopeptide-Functionalized Perylene Bisimides.
Publisher: Wiley
Date: 08-05-2018
Abstract: Antifreeze glycoproteins (AFGPs) are polymeric natural products that have drawn considerable interest in erse research fields owing to their potent ice recrystallization inhibition (IRI) activity. Self-assembled materials have emerged as a promising class of biomimetic ice growth inhibitor, yet the development of AFGP-based supramolecular materials that emulate the aggregative behavior of AFGPs have not yet been reported. This work reports the first ex le of the 1D self-assembly and IRI activity of AFGP-functionalized perylene bisimides (AFGP-PBIs). Glycopeptide-functionalized PBIs underwent 1D self-assembly in water and showed modest IRI activity, which could be tuned through substitution of the PBI core. This work presents essential proof-of-principle for the development of novel IRIs as potential supramolecular cryoprotectants and glycoprotein mimics.
A new fluorescent H+ sensor based on core-substituted naphthalene diimide
Publisher: Elsevier BV
Date: 2012
Quantitative analysis of the microtubule interaction of rabies virus P3 protein
Publisher: Springer Science and Business Media LLC
Date: 21-09-2016
DOI: 10.1038/SREP33493
Abstract: Although microtubules (MTs) are known to have important roles in intracellular transport of many viruses, a number of reports suggest that specific viral MT-associated proteins (MAPs) target MTs to subvert distinct MT-dependent cellular processes. The precise functional importance of these interactions and their roles in pathogenesis, however, remain largely unresolved. To assess the association with disease of the rabies virus (RABV) MAP, P3, we quantitatively compared the phenotypes of P3 from a pathogenic RABV strain, Nishigahara (Ni) and a non-pathogenic Ni-derivative strain, Ni-CE. Using confocal/live-cell imaging and d STORM super-resolution microscopy to quantify protein interactions with the MT network and with in idual MT filaments, we found that the interaction by Ni-CE-P3 is significantly impaired compared with Ni-P3. This correlated with an impaired capacity to effect association of the transcription factor STAT1 with MTs and to antagonize interferon (IFN)/STAT1-dependent antiviral signaling. Importantly, we identified a single mutation in Ni-CE-P3 that is sufficient to inhibit MT-association and IFN-antagonist function of Ni-P3, and showed that this mutation alone attenuates the pathogenicity of RABV. These data provide evidence that the viral protein-MT interface has important roles in pathogenesis, suggesting that this interface could provide targets for vaccine/antiviral drug development.
Synthesis and photophysical studies of a porphyrin–viologen dyad covalently linked by a flexible seven-atom chain
Publisher: Elsevier BV
Date: 05-2000
Non-conjugated, phenyl assisted coupling in through bond electron transfer in a perylenemonoimide-triphenylamine system
Publisher: Springer Science and Business Media LLC
Date: 04-2007
DOI: 10.1039/B617913D
Abstract: Two donor-bridge-acceptor compounds containing triphenylamine (TPA) donors and perylenemonoimide (PMI) acceptors have been studied by spectroscopic techniques and quantum chemical computation. Both systems have been observed to emit prompt and delayed fluorescence under certain conditions indicating that forward and reverse electron transfer (ET) processes can occur between the locally excited and the charge separated states. The experimental and computational results show that the TPA and PMI chromophores are better coupled by almost 50% in the meta isomers which undergo ET more readily than the para isomers. Quantum chemical calculations indicate that this unexpected situation is the result of a phenyl group on the side of the bridge being advantageously positioned in the meta isomers. This leads to more extensive delocalisation of the TPA HOMO into the bridge enhancing the total through bond electronic coupling between the TPA and PMI chromophores. The calculations also indicate a strong angle dependence of the total coupling in both isomers. The experimental results are discussed in the context of the high temperature limit of Marcus's theory of non-adiabatic ET.
A Multifunctional, Charge-Neutral, Chiral Octahedral M12L12 Cage
Publisher: Wiley
Date: 27-05-2019
Abstract: A chiral, octahedral M
Flavodoxin Relaxes in Microseconds Upon Excitation of the Flavin Chromophore: Detection of a UV–Visible Silent Intermediate by Laser Photocalorimetry
Publisher: Wiley
Date: 2009
DOI: 10.1111/J.1751-1097.2008.00402.X
Abstract: A small contraction concomitant with the relaxation of the protein in ca. 3 mus is observed upon ns-laser excitation at 455 nm of the Cys69Ala (C69A) mutant of flavodoxin II from Azotobacter vinelandii. This constitutes another ex le of detection of a UV-vis silent transient species through a photocalorimetric technique. The contraction is attributed to reorganization of protein dihedral bonds and of water molecules at relatively long distances from the flavin chromophore, after the protein has received the heat shock from the relaxing photoproduced charge transfer state. This study constitutes a preliminary step towards the understanding of the origin of protein movements taking place upon electron transfer reactions, e.g. between a photoinduced electron donor (or acceptor) and an accepting (or donating) cofactor in a protein.
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