Pall Thordarson

Choice of Capping Group in Tripeptide Hydrogels Influences Viability in the Three‐Dimensional Cell Culture of Tumor Spheroids

Publisher: Wiley

Date: 07-12-2017

DOI: 10.1002/CPLU.201600464

Abstract: Two peptide-derived low-molecular-weight gelators bearing different capping groups, 9-fluorenylmethyloxycarbonyl (Fmoc) and phenothiazine, were synthesized and their gel networks were characterized. The variation of the N-terminal capping group affects the viability of these hydrogels as a three-dimensional cell culture for multicellular tumor spheroids. These results indicate that the phenothiazine capping group is a more biocompatible alternative to the widely used Fmoc moiety.

Oligomeric phosphate clusters in macrocyclic channels

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D2CE00756H

Abstract: Thirty-six-membered ring macrocycles form sandwich-like channels for oligomeric chains of hexaphosphate clusters.

Multivalency in Drug Delivery–When Is It Too Much of a Good Thing?

Publisher: American Chemical Society (ACS)

Date: 11-02-2019

DOI: 10.1021/ACS.BIOCONJCHEM.8B00804

Abstract: Multivalency plays a large role in many biological and synthetic systems. The past 20 years of research have seen an explosion in the study of multivalent drug delivery systems based on scaffolds such as dendrimers, polymers, and other nanoparticles. The results from these studies suggest that when it comes to the number of ligands, sometimes, to quote Shakespeare, "too much of a good thing" is an apt description. Recent theoretical studies on multivalency indicate that the field may have had a misplaced emphasis on maximizing binding strength where in fact it is the selectivity of multivalent drug delivery systems that is the key to success. This Topical Review will summarize these theoretical developments. We will then illustrate how these developments can be used to rationalize the immunoresponses and drug uptake mechanisms for multivalent systems and show the path forward toward the design of better multivalent drug delivery systems.

Unraveling the Self-Assembly Modes in Multicomponent Supramolecular Gels Using Single-Crystal X-ray Diffraction

Publisher: American Chemical Society (ACS)

Date: 04-2020

DOI: 10.1021/ACS.CHEMMATER.0C00475

Gel‐ and Solid‐State‐Structure of Dialanine and Diphenylalanine Amphiphiles: Importance of C⋅⋅⋅H Interactions in Gelation

Publisher: Wiley

Date: 07-03-2019

DOI: 10.1002/CPHC.201801104

Abstract: To investigate the role of the capping group in the solution and solid-state self-assembly of short peptide hiphiles, dialanine and diphenylalanine have been linked via the N-terminus to a benzene (phenyl) and 3-naphthyl capping groups using three different methylene linkers (CH

Characterization of Iron Core–Gold Shell Nanoparticles for Anti-Cancer Treatments: Chemical and Structural Transformations During Storage and Use

Publisher: MDPI AG

Date: 17-12-2018

DOI: 10.3390/MA11122572

Abstract: Finding a cancer-selective drug that avoids damaging healthy cells and organs is a holy grail in medical research. In our previous studies, gold-coated iron (Fe@Au) nanoparticles showed cancer selective anti-cancer properties in vitro and in vivo but were found to gradually lose that activity with storage or "ageing.” To determine the reasons for this diminished anti-cancer activity, we examined Fe@Au nanoparticles at different preparation and storage stages by means of transmission electron microscopy combined with and energy-dispersive X-ray spectroscopy, along with X-ray diffraction analysis and cell viability tests. We found that dried and reconstituted Fe@Au nanoparticles, or Fe@Au nanoparticles within cells, decompose into irregular fragments of γ-F2O3 and agglomerated gold clumps. These changes cause the loss of the particles’ anti-cancer effects. However, we identified that the anti-cancer properties of Fe@Au nanoparticles can be well preserved under argon or, better still, liquid nitrogen storage for six months and at least one year, respectively.

Design, synthesis, and characterisation of glyoxylamide-based short peptides as self-assembled gels

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7NJ02248D

Abstract: First ex le of glyoxylamide-based short peptides which can encapsulate organic solvents and water at relatively low concentrations.

Energy Transfer to Ni-Amine Complexes in Dual Catalytic, Light-Driven C–N Cross-Coupling Reactions

Publisher: American Chemical Society (ACS)

Date: 12-11-2019

DOI: 10.1021/JACS.9B11049

Singlet Fission in Concentrated TIPS-Pentacene Solutions: The Role of Excimers and Aggregates

Publisher: American Chemical Society (ACS)

Date: 16-08-2021

DOI: 10.1021/JACS.1C05767

Peptide Nanofiber Substrates for Long-Term Culturing of Primary Neurons

Publisher: American Chemical Society (ACS)

Date: 06-07-2018

DOI: 10.1021/ACSAMI.8B07560

Abstract: The culturing of primary neurons represents a central pillar of neuroscience research. Primary neurons are derived directly from brain tissue and recapitulate key aspects of neuronal development in an in vitro setting. Unlike neural stem cells, primary neurons do not ide thus, initial attachment of cells to a suitable substrate is critical. Commonly used polylysine substrates can suffer from batch variability owing to their polymeric nature. Herein, we report the use of chemically well-defined, self-assembling tetrapeptides as substrates for primary neuronal culture. These water-soluble peptides assemble into fibers which facilitate adhesion and development of primary neurons, their long-term survival (>40 days), synaptic maturation, and electrical activity. Furthermore, these substrates are permissive toward neuronal transfection and transduction which, coupled with their uniformity and reproducible nature, make them suitable for a wide variety of applications in neuroscience.

Does fire drive fatty acid composition in seed coats of physically dormant species?

Publisher: Wiley

Date: 03-01-2023

DOI: 10.1111/PLB.13498

Abstract: Seed dormancy is the key driver regulating seed germination, hence is fundamental to the seedling recruitment life‐history stage and population persistence. However, despite the importance of physical dormancy (PY) in timing post‐fire germination, the mechanism driving dormancy‐break within seed coats remains surprisingly unclear. We suggest that seed coat chemistry may play an important role in controlling dormancy in species with PY. In particular, seed coat fatty acids (FAs) are hydrophobic, and have melting points within the range of seed dormancy‐breaking temperatures. Furthermore, melting points of saturated FAs increase with increasing carbon chain length. We investigated whether fire could influence seed coat FA profiles and discuss their potential influence on dormancy mechanisms. Seed coat FAs of 25 species within the Faboideae, from fire‐prone and fire‐free ecosystems, were identified and quantified through GC–MS. Fatty acid profiles were interpreted in the context of species habitat and interspecific variation. Fatty acid compositions were distinct between species from fire‐prone and fire‐free habitats. Fire‐prone species tended to have longer saturated FA chains, a lower ratio of saturated to unsaturated FA, and a slightly higher relative amount of FAs compared to fire‐free species. The specific FA composition of seed coats of fire‐prone species indicated a potential role of FAs in dormancy mechanisms. Overall, the distinct FA composition between fire‐prone and fire‐free species suggests that chemistry of the seed coat may be under selection pressure in fire‐prone ecosystems.

Ultra‐Low Molecular Weight Photoswitchable Hydrogelators

Publisher: Wiley

Date: 03-02-2021

DOI: 10.1002/ANGE.202015703

A convenient procedure for moderate-scale Rothemund synthesis of lipophilic porphyrins: an alternative to the Adler--Longo and Lindsey methodologies

Publisher: No publisher found

Date: 1998

DOI: 10.1002/(SICI)1099-1409(199811/12)2:6%3C511::AID-JPP102%3E3.0.CO;2-E

Double tailed scorpiand-type calix[10]phyrin: Synthesis and proton-driven anion recognition features

Publisher: Elsevier BV

Date: 06-2021

DOI: 10.1016/J.TET.2021.132157

Correction: Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0NR90160A

Abstract: Correction for ‘Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water’ by Jonathan P. Wojciechowski et al. , Nanoscale , 2020, 12 , 8262–8267, DOI: 10.1039/D0NR00289E.

A dendronised polymer architecture breaks the conventional inverse relationship between porosity and mechanical properties of hydrogels

Publisher: Royal Society of Chemistry (RSC)

Date: 2021

DOI: 10.1039/D0CC07115C

Abstract: We present a series of synthetic polymer hydrogels which break the traditional correlation between pore size and mechanical properties.

Enhanced Mechanical and Thermal Strength in Mixed-Enantiomers-Based Supramolecular Gel

Publisher: American Chemical Society (ACS)

Date: 10-2018

DOI: 10.1021/ACS.LANGMUIR.8B02729

Abstract: Mixing supramolecular gels based on enantiomers leads to re-arrangement of gel fibers at the molecular level, which results in more favorable packing and tunable properties. Bis(urea) compounds tagged with a phenylalanine methyl ester in racemic and enantiopure forms were synthesized. Both enantiopure and racemate compounds formed gels in a wide range of solvents and the racemate (1-rac) formed a stronger gel network compared with the enantiomers. The gel (1R+1S) obtained by mixing equimolar amount of enantiomers (1R and 1S) showed enhanced mechanical and thermal stability compared to enantiomers and racemate gels. The preservation of chirality in these compounds was analyzed by circular dichroism and optical rotation measurements. Analysis of the scanning electron microscopy (SEM) and atomic force microscopy (AFM) images revealed that the network in the mixed gel is a combination of enantiomers and racemate fibers, which was further supported by solid-state NMR. The analysis of the packing in xerogels by solid-state NMR spectra and the existence of twisted-tape morphology in SEM and AFM images confirmed the presence of both self-sorted and co-assembled fibers in mixed gel. The enhanced thermal and mechanical strength may be attributed to the enhanced intermolecular forces between the racemate and the enantiomer and the combination of both self-sorted and co-assembled enantiomers in the mixed gel.

Singlet Fission in Concentrated TIPS-Pentacene Solutions: The Role of Excimers and Aggregates

Publisher: American Chemical Society (ACS)

Date: 04-06-2021

DOI: 10.26434/CHEMRXIV.14727708

Abstract: The exciton dynamics of 6,13-bis(triisopropylsilyl-ethynyl) pentacene is investigated to determine the role of excimer and aggregate formation in singlet fission in high concentration solutions. / br / Photoluminescence spectra were measured by excitation with the evanescent wave in total internal reflection, in order to avoid reabsorption effects. The spectra over nearly two magnitudes of concentration were near identical, with no evidence for excimer emission. Time-correlated single-photon counting measurements confirm that the fluorescence lifetime shortens with concentration, and we obtain a bimolecular rate constant of $4\\times10^9$\\,M$^{-1}$s$^{-1}$ in chloroform. The observed rate constant grows at high concentrations. This effect is modelled in terms of the hard sphere radial distribution function. / br / NMR measurements confirm that aggregation takes place with a binding constant of between 0.14 and 0.43M$^{-1}$. Transient absorption measurements are consistent with a diffusive encounter mechanism for singlet fission, with hints of more rapid singlet fission in aggregates at the highest concentration measured. / br / These data show that excimers do not play the role of an emissive intermediate in exothermic singlet fission in solution, and that while aggregation occurs at higher concentrations, the mechanism of singlet fission remains dominated by diffusive encounters. /

Biofunctionality with a twist: the importance of molecular organisation, handedness and configuration in synthetic biomaterial design

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D1CS00896J

Abstract: This review highlights the importance of incorporating molecular organisation, spatial configuration and handedness in biomaterial design to arrive at improved native biomolecule interactions.

The death of the Job plot, transparency, open science and online tools, uncertainty estimation methods and other developments in supramolecular chemistry data analysis

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C6CC03888C

Abstract: The failure of the Job plot, best-practice in uncertainty estimation in host–guest binding studies and an open access webportal for data analysis are reviewed in this Feature Article.

Decoupling the effects of hydrophilic and hydrophobic moieties at the neuron–nanofibre interface

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/C9SC05686F

Abstract: The mobility of hydrophobic moieties at a peptide nanofibre surface determines its suitability as a scaffold for sensitive primary cells.

Non-spherical polymersomes: formation and characterization

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C8CS00856F

Abstract: This tutorial review summarizes recent efforts over the past decade to study the morphological transformation of conventionally spherical polymersomes into non-spherical polymersomes.

Assessing cooperativity in supramolecular systems

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7CS00063D

Abstract: In this tutorial review , different aspects of cooperativity in supramolecular chemistry and their thermodynamic analysis are discussed.

Formation of non-spherical polymersomes driven by hydrophobic directional aromatic perylene interactions

Publisher: Springer Science and Business Media LLC

Date: 29-09-2017

DOI: 10.1038/S41467-017-01372-Z

Abstract: Polymersomes, made up of hiphilic block copolymers, are emerging as a powerful tool in drug delivery and synthetic biology due to their high stability, chemical versatility, and surface modifiability. The full potential of polymersomes, however, has been hindered by a lack of versatile methods for shape control. Here we show that a range of non-spherical polymersome morphologies with anisotropic membranes can be obtained by exploiting hydrophobic directional aromatic interactions between perylene polymer units within the membrane structure. By controlling the extent of solvation/desolvation of the aromatic side chains through changes in solvent quality, we demonstrate facile access to polymersomes that are either ellipsoidal or tubular-shaped. Our results indicate that perylene aromatic interactions have a great potential in the design of non-spherical polymersomes and other structurally complex self-assembled polymer structures.

Competing Energy Transfer Pathways in a Five-Chromophore Perylene Array

Publisher: American Chemical Society (ACS)

Date: 24-02-2018

DOI: 10.1021/ACS.JPCC.8B01084

A Tunable Tumor Microenvironment through Recombinant Bacterial Collagen-Hyaluronic Acid Hydrogels

Publisher: American Chemical Society (ACS)

Date: 07-06-2022

DOI: 10.1021/ACSABM.2C00186

Abstract: Laboratory models of the tumor microenvironment require control of mechanical and biochemical properties to ensure accurate mimicry of patient disease. In contrast to pure natural or synthetic materials, hybrid approaches that pair recombinant protein fragments with synthetic scaffolding show many advantages. Here we demonstrate production of a recombinant bacterial collagen-like protein (CLP) for thiol-ene pairing to norbornene functionalized hyaluronic acid (NorHA). The resultant hydrogel material shows an adjustable modulus with evidence for strain-stiffening behavior that resembles natural tumor matrices. Cysteine terminated peptide binding motifs are incorporated to adjust the cell-adhesion points. The modular hybrid gel shows good biocompatibility and was demonstrated to control cell adhesion, proliferation, and the invasive properties of MCF7 and MD-MBA-231 breast adenocarcinoma cells. The ease in which multiple structural and bioactive components can be integrated provides a robust framework to form models of the tumor microenvironment for fundamental studies and drug development.

Modulating the Selectivity and Stealth Properties of Ellipsoidal Polymersomes through a Multivalent Peptide Ligand Display

Publisher: Wiley

Date: 19-05-2020

DOI: 10.1002/ADHM.202000261

Ultra‐Low Molecular Weight Photoswitchable Hydrogelators

Publisher: Wiley

Date: 03-02-2021

DOI: 10.1002/ANIE.202015703

Molecular dissection of the soluble photosynthetic antenna from a cryptophyte alga

Publisher: Cold Spring Harbor Laboratory

Date: 09-08-2023

DOI: 10.1101/2023.08.08.552318

Abstract: Cryptophyte algae have a unique phycobiliprotein light-harvesting antenna that fills a spectral gap in chlorophyll absorption, however, it is unclear how it transfers energy efficiently to photosystems. We show that the cryptophyte Hemiselmis andersenii expresses an energetically complex antenna comprising three distinct spectrotypes of phycobiliprotein with different quaternary structures arising from a erse α subunit family. The bulk of the antenna consists of open quaternary form phycobiliproteins acting as primary photon acceptors, supplemented by novel open-braced forms. The final components are closed forms with a long wavelength spectral feature due to substitution of a single chromophore. We propose that the macromolecular organization of the cryptophyte antennas consists of bulk open and open-braced forms that transfer excitations to photosystems via this bridging closed form phycobiliprotein. Algae generate a rainbow of antenna proteins by combining a conserved subunit with different members of a multigene family.

Polymersomes as protocellular constructs

Publisher: Wiley

Date: 15-09-2017

DOI: 10.1002/POLA.28780

Identification of Novel Medulloblastoma Cell-Targeting Peptides for Use in Selective Chemotherapy Drug Delivery

Publisher: American Chemical Society (ACS)

Date: 26-07-2019

DOI: 10.1021/ACS.JMEDCHEM.9B00851

Abstract: Medulloblastoma is a malignant brain tumor diagnosed in children. Chemotherapy has improved survival rates to approximately 70% however, children are often left with long-term treatment side effects. New therapies that maintain a high cure rate while reducing off-target toxicity are required. We describe for the first time the use of a bacteriophage-peptide display library to identify heptapeptides that bind to medulloblastoma cells. Two heptapeptides that demonstrated high [E1-3 (

Effect of polar amino acid incorporation on Fmoc-diphenylalanine-based tetrapeptides

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0SM00320D

Abstract: The incorporation of polar amino acids into the Fmoc-FF motif yields tetrapeptide hydrogels whose biocompatibility in the gel state is inversely proportional to their biocompatibility in the solution state.

AAAA–DDDD Quadruple H-Bond-Assisted Ionic Interactions: Robust Bis(guanidinium)/Dicarboxylate Heteroduplexes in Water

Publisher: American Chemical Society (ACS)

Date: 30-11-2019

DOI: 10.1021/JACS.9B09503

Abstract: The use of geminal di(guanidinium) and acridin-9(10

Glyoxylamide-based self-assembly hydrogels for sustained ciprofloxacin delivery

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C8TB01290C

Abstract: Glyoxylamide-based hydrogels have high ciprofloxacin (CIP) loading capacity and demonstrate a sustained release profile of over 15 days.

A convenient procedure for moderate-scale rothemund synthesis of lipophilic porphyrins: An alternative to the Adler-Longo and Lindsey methodologies

Publisher: World Scientific Pub Co Pte Lt

Date: 11-1998

DOI: 10.1002/(SICI)1099-1409(199811/12)2:6<511::AID-JPP102>3.0.CO;2-E

Abstract: Rothemund synthesis of porphyrins is conveniently achieved using p-toluenesulfonic acid-catalysed reaction between pyrrole and aldehyde with azeotropic removal of the water formed in the reaction. These conditions are suitable for moderate-scale reactions and involve an easy work-up. In this way, 5,10,15,20-tetraheptylporphyrin (2), 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin (3), 5,10,15,20-tetra-tert-butylporphyrin (4) and 5,10,15,20-[pyromellitoyl(tetrakis-o-oxyethoxyphenyl)]por-phyrin (5) were prepared in moderate to good yields.

Development and Characterization of Nanoscale Gel-Core Liposomes Using a Short Self-Assembled Peptide Hydrogel: Implications for Drug Delivery

Publisher: American Chemical Society (ACS)

Date: 10-08-2023

DOI: 10.1021/ACSANM.3C02172

Cyclic peptide unguisin A is an anion receptor with high affinity for phosphate and pyrophosphate

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7OB00316A

Abstract: Unguisin A ( 1 ) is a marine-derived, GABA-containing cyclic heptapeptide with a high binding affinity for phosphates.

Tuning hydrogels through metal-based gelation triggers

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7TB02140B

Abstract: N-terminal capped tripeptides self-assemble into hydrogels with tuneable properties depending on gelation trigger, giving differences in structure, stiffness and biocompatibility.

Water‐Soluble Arylazoisoxazole Photoswitches

Publisher: Wiley

Date: 11-10-2023

DOI: 10.1002/CHEM.202302069

Abstract: Azoheteroarenes are emerging as powerful alternatives to azobenzene molecular photoswitches. Herein, we introduce water‐soluble arylazoisoxale photoswitches. UV/vis and NMR spectroscopy revealed moderate to very good photostationary states and reversible photoisomerization between the E‐ and Z‐isomers over multiple cycles with minimal photobleaching. Several arylazoisoxales form host‐guest complexes with β‐ and γ‐cyclodextrin with significant differences in binding constants for each photoisomer as shown by isothermal titration calorimetry and NMR experiments, indicating their potential for photoresponsive host‐guest chemistry in water. One carboxylic acid functionalized arylazoisoxale can act as a hydrogelator, allowing gel properties to be manipulated reversibly with light. The hydrogel was characterized by rheological experiments, atom force microscopy and transmission electron microscopy. These results demonstrate that arylazoisoxazoles can find applications as molecular photoswitches in aqueous media.

Minimum information reporting in bio-nano experimental literature

Publisher: Springer Science and Business Media LLC

Date: 09-2018

DOI: 10.1038/S41565-018-0246-4

Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0NR00289E

Abstract: A biocompatible Fmoc-hexapeptide which forms hydrogels at physiological pH upon heating is reported.

Dual‐peptide functionalized nanoparticles for therapeutic use

Publisher: Wiley

Date: 15-10-2021

DOI: 10.1002/PEP2.24205

Engineering Biocompatible Scaffolds through the Design of Elastin‐Based Short Peptides

Publisher: Wiley

Date: 2018

DOI: 10.1002/CPLU.201700493

Abstract: A small library of short peptides has been synthesized based upon the repeat tetrapeptide sequence Gly-Val-Ala-Pro (GVAP) which is found in the hydrophobic domain of tropoelastin. Of the five peptides synthesized, four formed self-supporting hydrogels with similar secondary structures. The ability to tune the mechanical properties of the resultant hydrogels was demonstrated, and this is understood in relation to fiber bundling. Finally, the cytotoxicity of these elastin-based short peptide hydrogels towards HeLa cells was assessed, with clear evidence that increased aromaticity of the peptide is detrimental towards cell viability.

A Diverse View of Science to Catalyse Change.

Publisher: American Chemical Society (ACS)

Date: 17-08-2020

DOI: 10.1021/JACS.0C07877

Cooperative Subunit Refolding of a Light‐Harvesting Protein through a Self‐Chaperone Mechanism

Publisher: Wiley

Date: 09-02-2017

DOI: 10.1002/ANGE.201607921

The correlations between structure, rheology, and cell growth in peptide-based multicomponent hydrogels

Publisher: Springer Science and Business Media LLC

Date: 05-2020

DOI: 10.1038/S41428-020-0351-8

Interaction of Nucleotides with a Trinuclear Terbium(III)-Dizinc(II) Complex: Efficient Sensitization of Terbium Luminescence by Guanosine Monophosphate and Application to Real-Time Monitoring of Phosphodiesterase Activity.

Publisher: American Chemical Society (ACS)

Date: 18-12-2019

DOI: 10.1021/ACS.INORGCHEM.8B02731

Abstract: An in-depth study of the interaction of a trinuclear terbium(III)-dizinc(II) complex with an array of nucleotides differing in the type of nucleobase and number of phosphate groups, as well as cyclic versus acyclic variants, is presented. The study examined the nature of the interaction and the efficiency at which guanine was able to sensitize terbium(III) luminescence. Competitive binding and titration studies were performed to help establish the nature/mode of the interactions. These established that (1) interaction occurs by the coordination of phosphate groups to zinc(II) (in addition to uridine in the case of uridine monophosphate), (2) acyclic nucleotides bind more strongly than cyclic counterparts because of their higher negative charge, (3) guanine-containing nucleotides are able to sensitize terbium(III) luminescence with the efficiency of sensitization following the order guanosine monophosphate (GMP) > guanosine diphosphate > guanosine triphosphate because of the mode of binding, and (4) nucleoside monophosphates bind to a single zinc(II) ion, whereas di- and triphosphates appear to bind in a bridging mode between two host molecules. Furthermore, it has been shown that guanine is a sensitizer of terbium(III) luminescence. On the basis of the ability of GMP to effectively sensitize terbium(III)-based luminescence while cyclic GMP (cGMP) does not, the complex has been utilized to monitor the catalytic conversion of cGMP to GMP by a phosphodiesterase enzyme in real time using time-gated luminescence on a benchtop fluorimeter. The complex has the potential to find broad application in monitoring the activity of enzymes that process nucleotides (co)substrates, including high-throughput drug-screening programs.

Halide Noninnocence and Direct Photoreduction of Ni(II) Enables Coupling of Aryl Chlorides in Dual Catalytic, Carbon–Heteroatom Bond-Forming Reactions

Publisher: American Chemical Society (ACS)

Date: 19-05-2023

DOI: 10.1021/JACS.3C02784

Faceted polymersomes: a sphere-to-polyhedron shape transformation

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C8SC04206C

Abstract: We uncover how our polymersomes facet through a sphere-to-polyhedron shape transformation pathway that is driven by perylene aggregation confined within a topologically spherical polymersome shell.

Exploring Artificial Nucleic Acid Mimicking Peptide Nanofibers

Publisher: American Chemical Society (ACS)

Date: 17-05-2023

DOI: 10.1021/ACS.CHEMMATER.3C00445

Beyond Fmoc: a review of aromatic peptide capping groups

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/C9TB02539A

Abstract: Self-assembling short peptides have widespread applications in energy materials, tissue engineering, sensing and drug delivery. In this review we discuss the effect of functional N-terminal capping groups on peptide structure and function.

Cooperative Subunit Refolding of a Light‐Harvesting Protein through a Self‐Chaperone Mechanism

Publisher: Wiley

Date: 27-01-2017

DOI: 10.1002/ANIE.201607921

Abstract: The fold of a protein is encoded by its amino acid sequence, but how complex multimeric proteins fold and assemble into functional quaternary structures remains unclear. Here we show that two structurally different phycobiliproteins refold and reassemble in a cooperative manner from their unfolded polypeptide subunits, without biological chaperones. Refolding was confirmed by ultrafast broadband transient absorption and two-dimensional electronic spectroscopy to probe internal chromophores as a marker of quaternary structure. Our results demonstrate a cooperative, self-chaperone refolding mechanism, whereby the β-subunits independently refold, thereby templating the folding of the α-subunits, which then chaperone the assembly of the native complex, quantitatively returning all coherences. Our results indicate that subunit self-chaperoning is a robust mechanism for heteromeric protein folding and assembly that could also be applied in self-assembled synthetic hierarchical systems.

Oligomer Electrolytes for Light-Emitting Electrochemical Cells: Influence of the End Groups on Ion Coordination, Ion Binding, and Turn-on Kinetics

Publisher: American Chemical Society (ACS)

Date: 17-10-2019

DOI: 10.1021/ACSAMI.9B15233

Abstract: The electrolyte is an essential constituent of the light-emitting electrochemical cell (LEC), since its operating mechanism is dependent on the redistribution of mobile ions in the active layer. Recent developments of new ion transporters have yielded high-performance devices, but knowledge about the interactions between the ionic species and the ion transporters and the influence of these interactions on the LEC performance is lacking. We therefore present a combined computational and experimental effort that demonstrates that the selection of the end group in a star-branched oligomeric ion transporter based on trimethylolpropane ethoxylate has a paramount influence on the ionic interactions in the electrolyte and thereby also on the performance of the corresponding LECs. With hydroxyl end groups, the cation from the salt is strongly coordinated to the ion transporter, which leads to suppression of ion pairing, but the penalty is a hindered ion release and a slow turn-on for the LEC devices. With methoxy end groups, an intermediate coordination strength is seen together with the formation of contact ion pairs, but the LEC performance is very good with fast turn-on. Using a series of ion transporters with alkyl carbonate end groups, the ion transporter:cation coordination strength is lowered further, but the turn-on kinetics are slower than what is seen for devices comprising the methoxy end-capped ion transporter.

Singlet Fission in Concentrated TIPS-Pentacene Solutions: The Role of Excimers and Aggregates

Publisher: American Chemical Society (ACS)

Date: 04-06-2021

DOI: 10.26434/CHEMRXIV.14727708.V1

Abstract: The exciton dynamics of 6,13-bis(triisopropylsilyl-ethynyl) pentacene is investigated to determine the role of excimer and aggregate formation in singlet fission in high concentration solutions. Photoluminescence spectra were measured by excitation with the evanescent wave in total internal reflection, in order to avoid reabsorption effects. The spectra over nearly two magnitudes of concentration were near identical, with no evidence for excimer emission. Time-correlated single-photon counting measurements confirm that the fluorescence lifetime shortens with concentration, and we obtain a bimolecular rate constant of $4\\times10^9$\\,M$^{-1}$s$^{-1}$ in chloroform. The observed rate constant grows at high concentrations. This effect is modelled in terms of the hard sphere radial distribution function. NMR measurements confirm that aggregation takes place with a binding constant of between 0.14 and 0.43M$^{-1}$. Transient absorption measurements are consistent with a diffusive encounter mechanism for singlet fission, with hints of more rapid singlet fission in aggregates at the highest concentration measured. These data show that excimers do not play the role of an emissive intermediate in exothermic singlet fission in solution, and that while aggregation occurs at higher concentrations, the mechanism of singlet fission remains dominated by diffusive encounters.

Kinetically Controlled Lifetimes in Redox-Responsive Transient Supramolecular Hydrogels

Publisher: American Chemical Society (ACS)

Date: 16-02-2018

DOI: 10.1021/JACS.7B12198

Abstract: It remains challenging to program soft materials to show dynamic, tunable time-dependent properties. In this work, we report a strategy to design transient supramolecular hydrogels based on kinetic control of competing reactions. Specifically, the pH-triggered self-assembly of a redox-active supramolecular gelator, N,N'-dibenzoyl-l-cystine (DBC) in the presence of a reducing agent, which acts to disassemble the system. The lifetimes of the transient hydrogels can be tuned simply by pH or reducing agent concentration. We find through kinetic analysis that gel formation hinders the ability of the reducing agent and enables longer transient hydrogel lifetimes than would be predicted. The transient hydrogels undergo clean cycles, with no kinetically trapped aggregates observed. As a result, multiple transient hydrogel cycles are demonstrated and can be predicted. This work contributes to our understanding of designing transient assemblies with tunable temporal control.

Ultra-Low Molecular Weight Photoswitchable Hydrogelators

Publisher: American Chemical Society (ACS)

Date: 22-09-2020

DOI: 10.26434/CHEMRXIV.12950858.V3

Abstract: Photoswitchable arylazopyrozoles 2 and 3 form hydrogels at a concentration of 1.2% (w/v). With a molecular weight of 258.11 g/mol, these are the lowest known molecular weight hydrogelators that respond reversibly to light. Single-crystal X-ray structures show anisotropic aggregation of 2 and 3 is driven by in-plane hydrogen bonding interactions and 𝝅 - 𝝅 stacking. Photoswitching of 2 and 3 from the E- to the Z-form by 365 nm light results in a macrocopic gel→sol transition nearly an order of magnitude reduction in the measured elastic and loss moduli. Cryogenic transmission electron microscopy suggests that the 29±7 nm wide sheets in the E-2 gel state narrow to 13±2 nm upon photoswitching to the predominantly Z-2 solution state. In the case of 2, photoswitching is reversible through cycles of 365 nm and 520 nm excitation with little fatigue. The release of a Rhodamine B dye encapsulated in gels formed from 2 and 3 can be accelerated more than 20-fold upon photoswitching with 365 nm light, demonstrating these materials are suitable for light-controlled cargo release.

Ultra-Low Molecular Weight Photoswitchable Hydrogelators

Publisher: American Chemical Society (ACS)

Date: 25-11-2020

DOI: 10.26434/CHEMRXIV.12950858.V4

Abstract: Photoswitchable arylazopyrozoles 2 and 3 form hydrogels at a concentration of 1.2% (w/v). With a molecular weight of 258.11 g/mol, these are the lowest known molecular weight hydrogelators that respond reversibly to light. Single-crystal X-ray structures show anisotropic aggregation of 2 and 3 is driven by in-plane hydrogen bonding interactions and 𝝅 - 𝝅 stacking. Photoswitching of 2 and 3 from the E- to the Z-form by 365 nm light results in a macrocopic gel→sol transition nearly an order of magnitude reduction in the measured elastic and loss moduli. Cryogenic transmission electron microscopy suggests that the 29±7 nm wide sheets in the E-2 gel state narrow to 13±2 nm upon photoswitching to the predominantly Z-2 solution state. In the case of 2, photoswitching is reversible through cycles of 365 nm and 520 nm excitation with little fatigue. The release of a Rhodamine B dye encapsulated in gels formed from 2 and 3 can be accelerated more than 20-fold upon photoswitching with 365 nm light, demonstrating these materials are suitable for light-controlled cargo release.

Ultra-Low Molecular Weight Photoswitchable Hydrogelators

Publisher: American Chemical Society (ACS)

Date: 15-09-2020

DOI: 10.26434/CHEMRXIV.12950858.V1

Abstract: Photoswitchable arylazopyrozoles 2 and 3 form hydrogels at a concentration of 1.2% (w/v). With a molecular weight of 258.11 g/mol, these are the lowest known molecular weight hydrogelators that respond reversibly to light. Single-crystal X-ray structures show anisotropic aggregation of 2 and 3 is driven by in-plane hydrogen bonding interactions and 𝝅 - 𝝅 stacking. Photoswitching of 2 and 3 from the E- to the Z-form by 365 nm light results in a macrocopic gel→sol transition nearly an order of magnitude reduction in the measured elastic and loss moduli. Cryogenic transmission electron macroscopy suggests that the 29±7 nm wide sheets in the E-2 gel state narrow to 13±2 nm upon photoswitching to the predominantly Z-2 solution state. In the case of 2, photoswitching is reversible through cycles of 365 nm and 520 nm excitation with little fatigue. The release of a Rhodamine B dye encapsulated in gels formed from 2 and 3 can be accelerated more than 20-fold upon photoswitching with 365 nm light, demonstrating these materials are suitable for light-controlled cargo release.

Design, Synthesis, and Evaluation of N- and C-Terminal Protein Bioconjugates as G Protein-Coupled Receptor Agonists

Publisher: American Chemical Society (ACS)

Date: 02-02-2018

DOI: 10.1021/ACS.BIOCONJCHEM.7B00716

Abstract: A G protein-coupled receptor (GPCR) agonist protein, thaumatin, was site-specifically conjugated at the N- or C-terminus with a fluorophore for visualization of GPCR:agonist interactions. The N-terminus was specifically conjugated using a synthetic 2-pyridinecarboxyaldehyde reagent. The interaction profiles observed for N- and C-terminal conjugates were varied N-terminal conjugates interacted very weakly with the GPCR of interest, whereas C-terminal conjugates bound to the receptor. These chemical biology tools allow interactions of therapeutic proteins:GPCR to be monitored and visualized. The methodology used for site-specific bioconjugation represents an advance in application of 2-pyridinecarboxyaldehydes for N-terminal specific bioconjugations.

Ultra-Low Molecular Weight Photoswitchable Hydrogelators

Publisher: American Chemical Society (ACS)

Date: 16-09-2020

DOI: 10.26434/CHEMRXIV.12950858.V2

Abstract: Photoswitchable arylazopyrozoles 2 and 3 form hydrogels at a concentration of 1.2% (w/v). With a molecular weight of 258.11 g/mol, these are the lowest known molecular weight hydrogelators that respond reversibly to light. Single-crystal X-ray structures show anisotropic aggregation of 2 and 3 is driven by in-plane hydrogen bonding interactions and 𝝅 - 𝝅 stacking. Photoswitching of 2 and 3 from the E- to the Z-form by 365 nm light results in a macrocopic gel→sol transition nearly an order of magnitude reduction in the measured elastic and loss moduli. Cryogenic transmission electron microscopy suggests that the 29±7 nm wide sheets in the E-2 gel state narrow to 13±2 nm upon photoswitching to the predominantly Z-2 solution state. In the case of 2, photoswitching is reversible through cycles of 365 nm and 520 nm excitation with little fatigue. The release of a Rhodamine B dye encapsulated in gels formed from 2 and 3 can be accelerated more than 20-fold upon photoswitching with 365 nm light, demonstrating these materials are suitable for light-controlled cargo release.

University Of Sydney

Location: Australia

View Organisation

Radboud Universiteit Nijmegen

Location: Netherlands

View Organisation

University Of New South Wales

Location: Australia

View Organisation

University Of Iceland

Location: Iceland

View Organisation

Discovery Projects - Grant ID: DP0666325

Start Date: 2006

End Date: 06-2011

Amount: $750,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0985059

Start Date: 2009

End Date: 12-2011

Amount: $220,000.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT120100101

Start Date: 07-2012

End Date: 06-2016

Amount: $822,856.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP190101892

Start Date: 2019

End Date: 06-2022

Amount: $340,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP220101847

Start Date: 08-2022

End Date: 07-2025

Amount: $465,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130101512

Start Date: 2013

End Date: 03-2016

Amount: $330,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0348891

Start Date: 04-2004

End Date: 03-2008

Amount: $299,614.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP130100774

Start Date: 09-2013

End Date: 10-2016

Amount: $306,000.00

Funder: Australian Research Council

Industrial Transformation Training Centres - Grant ID: IC170100020

Start Date: 07-2018

End Date: 12-2024

Amount: $3,279,502.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE110100203

Start Date: 2014

End Date: 12-2014

Amount: $250,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE190100123

Start Date: 2019

End Date: 12-2020

Amount: $380,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0775598

Start Date: 10-2008

End Date: 11-2008

Amount: $1,000,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100089

Start Date: 2010

End Date: 04-2012

Amount: $700,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989567

Start Date: 03-2009

End Date: 09-2010

Amount: $500,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160100575

Start Date: 06-2017

End Date: 06-2020

Amount: $330,378.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100096

Start Date: 2010

End Date: 06-2011

Amount: $450,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE210100144

Start Date: 2021

End Date: 12-2022

Amount: $1,225,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0455238

Start Date: 02-2005

End Date: 05-2009

Amount: $1,050,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE190100160

Start Date: 2019

End Date: 12-2019

Amount: $368,994.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE160100168

Start Date: 2016

End Date: 03-2017

Amount: $650,000.00

Funder: Australian Research Council

ARC Centres Of Excellence - Grant ID: CE140100036

Start Date: 06-2014

End Date: 06-2021

Amount: $26,000,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160100573

Start Date: 05-2017

End Date: 05-2020

Amount: $228,186.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0882855

Start Date: 2008

End Date: 12-2009

Amount: $900,000.00

Funder: Australian Research Council