ORCID Profile
0000-0002-7630-4874
Current Organisation
University of South Australia
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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)
Macromolecular and Materials Chemistry | Characterisation of Biological Macromolecules | Nanotechnology | Characterisation Of Macromolecules | Chemical Characterisation of Materials | Materials engineering | Pharmacology and Pharmaceutical Sciences | Synthesis Of Macromolecules | Structural Chemistry | Reaction kinetics and dynamics | Medicinal and Biomolecular Chemistry | Colloid and Surface Chemistry | Biomedical Engineering | Biomaterials | Control Systems, Robotics and Automation | Biologically Active Molecules | Biotechnology Not Elsewhere Classified | Electrical and Electronic Engineering | Pharmaceutical Sciences | Structural Chemistry and Spectroscopy | Decision Support and Group Support Systems | Functional materials | Nanoscale characterisation | Analytical Chemistry not elsewhere classified | Mineral Processing/Beneficiation | Macromolecular Chemistry Not Elsewhere Classified | Macromolecular and Materials Chemistry not elsewhere classified | Medicinal and Biomolecular Chemistry not elsewhere classified |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Chemical sciences | Expanding Knowledge in the Medical and Health Sciences | Polymeric materials (e.g. paints) | Scientific Instruments | Instrumentation not elsewhere classified | Biological sciences | Physical sciences | Expanding Knowledge in Technology | Industrial Instruments | Beneficiation or Dressing of Iron Ores | Mining and Extraction of Precious (Noble) Metal Ores | Expanding Knowledge in the Biological Sciences | Prevention—biologicals (e.g. vaccines) | Diagnostics | Mining and Extraction of Copper Ores
Related Links
Publications
Thermoresponsive polysaccharides and their thermoreversible physical hydrogel networks
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.CARBPOL.2018.11.053
Abstract: Thermoresponsive polymers have been used extensively for various applications including food additives, pharmaceutical formulations, therapeutic delivery, cosmetics and environmental remediation, to mention a few. Many thermoresponsive polymers have the ability to form physical hydrogel networks in response to temperature changes, which are particularly useful for emerging biomedical applications, including cell therapies, drug delivery systems, tissue engineering, wound healing and 3D bioprinting. In particular, the use of polysaccharides with thermoresponsive properties has been of interest due to their wide availability, versatile functionality, biodegradability, and in many cases, inherent biocompatibility. Naturally thermoresponsive polysaccharides include agarose, carrageenans and gellan gum, which exhibit upper critical solution temperatures, transitioning from a solution to a gel state upon cooling. Arguably, this limits their use in biomedical applications, particularly for cell encapsulation as they require raised temperatures to maintain a solution state that may be detrimental to living systems. Conversely, significant progress has been made over recent years to develop synthetically modified polysaccharides, which tend to exhibit lower critical solution temperatures, transitioning from a solution to a gel state upon warming. Of particular interest are thermoresponsive polysaccharides with a lower critical solution temperature in between room temperature and physiological temperature, as their solutions can conveniently be manipulated at room temperature before gelling upon warming to physiological temperature, which makes them ideal candidates for many biological applications. Therefore, this review provides an introduction to the different types of thermoresponsive polysaccharides that have been developed, their resulting hydrogels and properties, and the exciting applications that have emerged as a result of these properties.
1,1‐Diphenyl Ethylene‐Mediated Radical Polymerisation: A General Non‐Metal‐Based Technique For The Synthesis Of Precise Core Cross‐Linked Star Polymers
Publisher: Wiley
Date: 29-01-2010
Abstract: This communication details the successful synthesis of low polydispersity core cross-linked star (CCS) polymers via DPE-mediated polymerisation. We demonstrate the ability to produce poly(methyl methacrylate) and poly(acrylonitrile) CCS polymers that are currently inaccessible via the two most common non-metal-based controlled radical polymerisation techniques (NMP and RAFT polymerisations).
Evaluation of ultra-sensitive leucomalachite dye derivatives for use in the PRESAGE® dosimeter
Publisher: Elsevier BV
Date: 04-2013
Delaying the onset of macrogelation for the synthesis of branched and star-like polymers via conventional free-radical polymerisation: Binary solvent effects and incorporation of surfmers
Publisher: Elsevier BV
Date: 11-2008
Influence of Polymer Composition on the Controlled Release of Docetaxel: A Comparison of Non-Degradable Polymer Films for Oesophageal Drug-Eluting Stents
Publisher: MDPI AG
Date: 11-05-2020
DOI: 10.3390/PHARMACEUTICS12050444
Abstract: Following the huge clinical success of drug-eluting vascular stents, there is a significant interest in the development of drug-eluting stents for other applications, such as the treatment of gastrointestinal (GI) cancers. Central to this process is understanding how particular drugs are released from stent coatings, which to a large extent is controlled by drug-polymer interactions. Therefore, in this study we investigated the release of docetaxel (DTX) from a selection of non-degradable polymer films. DTX-polymer films were prepared at various loadings (1, 5 and 10% w/w) using three commercially available polymers including poly(dimethylsiloxane) (PSi), poly (ethylene-co-vinyl acetate) (PEVA) and Chronosil polyurethane (PU). The formulations were characterised using different techniques such as photoacoustic Fourier-transform infrared (PA-FTIR) spectrophotometry, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of DTX on the mechanical properties of the films, in-vitro release, and degradation tests were also assessed. For all polymers and DTX loadings, the drug was found to disperse homogenously without crystallisation within the polymer matrix. While no specific interactions were observed between DTX and PSi or PEVA, hydrogen-bonding appeared to be present between DTX and PU, which resulted in a concentration-dependent decrease in the Young’s moduli of the films due to disruption of inter-polymeric molecular interactions. In addition, the DTX-PU interactions were found to modulate drug release, providing near-linear release over 30 days, which was accompanied by a significant reduction in degradation products. The results indicate that DTX-loaded PU films are excellent candidates for drug-eluting stents for the treatment of oesophageal cancer.
Peptide-based star polymers as potential siRNA carriers
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13525
Abstract: 16- and 32-arm star polymers were synthesised using poly(amido amine) (PAMAM) dendrimers as multifunctional initiators for the ring-opening polymerisation (ROP) of ϵ-Z-l-lysine N-carboxyanhydride (Lys NCA) via the core-first approach. The resulting star polymers were subsequently post-functionalised with poly(ethylene glycol) (PEG) via carbodiimide coupling, potentially improving the biodistribution of the stars in vivo. De-protection of the carboxybenzyl (Cbz)-protected star arms yielded water-soluble cationic poly(l-lysine) (PLL) star polymers with hydrodynamic radii ranging from 2.0 to 3.3 nm. Successful complexation of the PLL star polymers with double-stranded oligodeoxynucleotides (ODNs)—a mimic for small interfering RNA (siRNA)—was achieved at a nitrogen-to-phosphate (N/P) ratio of 5. Cell viability studies using HEK293T cells indicated the ‘safe’ concentration for these polymers is within a suitable window for the delivery of siRNA therapeutics.
Thermoresponsive polysaccharides with tunable thermoresponsive properties via functionalisation with alkylamide groups
Publisher: Elsevier BV
Date: 02-2021
Synthesis of Hyperbranched Poly(aryl ether)s via Carbene Insertion Processes
Publisher: American Chemical Society (ACS)
Date: 20-01-2007
DOI: 10.1021/MA061951L
A novel one-pot approach towards dynamically cross-linked hydrogels
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SM50638J
Strategies for the Development of pH-Responsive Synthetic Polypeptides and Polymer-Peptide Hybrids: Recent Advancements
Publisher: MDPI AG
Date: 19-02-2021
Abstract: Synthetic polypeptides and polymer-peptide hybrid materials have been successfully implemented in an array of biomedical applications owing to their biocompatibility, biodegradability and ability to mimic natural proteins. In addition, these materials have the capacity to form complex supramolecular structures, facilitate specific biological interactions, and incorporate a erse selection of functional groups that can be used as the basis for further synthetic modification. Like conventional synthetic polymers, polypeptide-based materials can be designed to respond to external stimuli (e.g., light and temperature) or changes in the environmental conditions (e.g., redox reactions and pH). In particular, pH-responsive polypeptide-based systems represent an interesting avenue for the preparation of novel drug delivery systems that can exploit physiological or pathological pH variations within the body, such as those that arise in the extracellular tumour microenvironment, intracellularly within endosomes/lysosomes, or during tissue inflammation. Here, we review the significant progress made in advancing pH-responsive polypeptides and polymer-peptide hybrid materials during the last five years, with a particular emphasis on the manipulation of ionisable functional groups, pH-labile linkages, pH-sensitive changes to secondary structure, and supramolecular interactions.
Folic Acid Conjugated Amino Acid-Based Star Polymers for Active Targeting of Cancer Cells
Publisher: American Chemical Society (ACS)
Date: 02-09-2011
DOI: 10.1021/BM200604H
Abstract: Amino acid-based core cross-linked star (CCS) polymers (poly(L-lysine)(arm)poly(L-cystine)(core)) with peripheral allyl functionalities were synthesized by sequential ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCAs) via the arm-first approach, using N-(trimethylsilyl)allylamine as the initiator. Subsequent functionalization with a poly(ethylene glycol) (PEG)-folic acid conjugate via thiol-ene click chemistry afforded poly(PEG-b-L-lysine)(arm)poly(L-cystine)(core) stars with outer PEG coronas decorated with folic acid targeting moieties. Similarly, a control was prepared without folic acid, using just PEG. A fluorophore was used to track both star polymers incubated with breast cancer cells (MDA-MB-231) in vitro. Confocal microscopy and flow cytometry revealed that the stars could be internalized into the cells, and higher cell internalization was observed when folic acid moieties were present. Cytotoxicity studies indicate that both stars are nontoxic to MDA-MB-231 cells at concentrations of up to 50 μg/mL. These results make this amino acid-based star polymer an attractive candidate in targeted drug delivery applications including chemotherapy.
Bromoisobutyramide as an Intermolecular Surface Binder for the Preparation of Free-standing Biopolymer Assemblies
Publisher: Wiley
Date: 07-11-2011
Abstract: Bromoisobutyramide (BrIBAM)-modified silica templates facilitate the formation of bio-functional thin films made of a range of biopolymers (e.g., polypeptides, nucleic acids or polysaccharides). Upon template removal, non-covalent free-standing biopolymeric assemblies (e.g., hollow capsules or replicated spheres and fibers) are formed without the need for covalent cross-linking.
Film-Stabilizing Attributes of Polymeric Core–Shell Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 21-07-2015
Abstract: Self-organization of nanoparticles into stable, molecularly thin films provides an insightful paradigm for manipulating the manner in which materials interact at nanoscale dimensions to generate unique material assemblies at macroscopic length scales. While prior studies in this vein have focused largely on examining the performance of inorganic or organic/inorganic hybrid nanoparticles (NPs), the present work examines the stabilizing attributes of fully organic core-shell microgel (CSMG) NPs composed of a cross-linked poly(ethylene glycol dimethacrylate) (PEGDMA) core and a shell of densely grafted, but relatively short-chain, polystyrene (PS) arms. Although PS homopolymer thin films measuring from a few to many nanometers in thickness, depending on the molecular weight, typically dewet rapidly from silica supports at elevated temperatures, spin-coated CSMG NP films measuring as thin as 10 nm remain stable under identical conditions for at least 72 h. Through the use of self-assembled monolayers (SAMs) to alter the surface of a flat silica-based support, we demonstrate that such stabilization is not attributable to hydrogen bonding between the acrylic core and silica. We also document that thin NP films consisting of three or less layers (10 nm) and deposited onto SAMs can be fully dissolved even after extensive thermal treatment, whereas slightly thicker films (40 nm) on Si wafer become only partially soluble during solvent rinsing with and without sonication. Taken together, these observations indicate that the present CSMG NP films are stabilized primarily by multidirectional penetration of relatively short, unentangled NP arms caused by NP layering, rather than by chain entanglement as in linear homopolymer thin films. This nanoscale "velcro"-like mechanism permits such NP films, unlike their homopolymer counterparts of comparable chain length and thickness, to remain intact as stable, free-floating sheets on water, and thus provides a viable alternative to ultrathin organic coating strategies.
Experimental determination of the influence of oxygen on the PRESAGE®dosimeter
Publisher: IOP Publishing
Date: 06-01-2016
DOI: 10.1088/0031-9155/61/2/813
Abstract: It is generally accepted that the PRESAGE(®) radiochromic dosimeter is not sensitive to oxygen, however, this claim has not been supported or verified experimentally. Therefore, the aim of this study was to experimentally determine the potential influence of oxygen on dose sensitivity of the PRESAGE(®) dosimeter and its reporting system. Batches of PRESAGE(®) and its radical initiator-leuco dye reporting system were prepared in aerobic and anaerobic conditions. The anaerobic batches were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. The overall results show that oxygen has some influence on the dosimetric characteristics of PRESAGE(®), although the radical initiator does appear to oxidize the leucomalachite green even in the presence of oxygen. Deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ~30% when compared to the non-deoxygenated system. A minor increase in sensitivity (~5%) was also achieved by deoxygenating the PRESAGE(®) precursor prior to casting. In addition, dissolved oxygen measurements revealed low levels of dissolved oxygen (0.40 ± 0.04 mg l(-1)) in the polyurethane precursor used to fabricate the PRESAGE(®) dosimeters, as compared to water (8.60 ± 0.03 mg l(-1)) and the reporting system alone (1.30 ± 0.10 mg l(-1)). The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE(®) system. However, deoxygenation of the dosimeter precursors prior to casting improves the dosimeters dose sensitivity by ~5%, which might be particularly useful for measuring low radiation doses. Nevertheless, we believe this is not sufficient enough to recommend the deoxygenation of commercial PRESAGE(®) precursor prior to casting. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of the PRESAGE(®) under the conditions investigated.
Nanoengineered Films via Surface‐Confined Continuous Assembly of Polymers
Publisher: Wiley
Date: 24-08-2011
Microstructure—Thermal Property Relationships of Poly (Ethylene Glycol-b-Caprolactone) Copolymers and Their Micelles
Publisher: MDPI AG
Date: 16-10-2022
Abstract: The crystallinity of polymers strongly affects their properties. For block copolymers, whereby two crystallisable blocks are covalently tethered to one another, the molecular weight of the in idual blocks and their relative weight fraction are important structural parameters that control their crystallisation. In the case of block copolymer micelles, these parameters can influence the crystallinity of the core, which has implications for drug encapsulation and release. Therefore, in this study, we aimed to determine how the microstructure of poly(ethylene glycol-b-caprolactone) (PEG-b-PCL) copolymers contributes to the crystallinity of their hydrophobic PCL micelle cores. Using a library of PEG-b-PCL copolymers with PEG number-average molecular weight (Mn) values of 2, 5, and 10 kDa and weight fractions of PCL (fPCL) ranging from 0.11 to 0.67, the thermal behaviour and morphology were studied in blends, bulk, and micelles using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD), and Synchrotron wide-angle X-ray scattering (WAXS). Compared to PEG and PCL homopolymers, the block copolymers displayed reduced crystallinity in the bulk phase and the in idual blocks had a large influence on the crystallisation of one another. The fPCL was determined to be the dominant contributor to the extent and order of crystallisation of the two blocks. When fPCL 0.35, the initial crystallisation of PEG led to an amorphous PCL phase. At fPCL values between 0.35 and 0.65, PEG crystallisation was followed by PCL crystallisation, whereas this behaviour was reversed when fPCL 0.65. For lyophilised PEG-b-PCL micelles, the crystallinity of the core increased with increasing fPCL, although the core was predominately amorphous for micelles with fPCL 0.35. These findings contribute to understanding the relationships between copolymer microstructure and micelle core crystallinity that are important for the design and performance of micellar drug delivery systems, and the broader application of polymer micelles.
The effect of acrylamide-co-vinylpyrrolidinone copolymer on the depression of talc in mixed nickel mineral flotation
Publisher: Elsevier BV
Date: 04-2011
Soft nanoparticles assembled from linear poly(ethylene glycol) and linear brush polydimethylsiloxane diblock copolymers
Publisher: Wiley
Date: 18-02-2014
DOI: 10.1002/POLA.27111
Abstract: A series of novel hiphilic diblock copolymers composed of hydrophilic linear poly(ethylene glycol) (PEG) and linear brush hydrophobic polydimethylsiloxane (PDMS) were synthesized. Three different molecular weights of monomethyl ether PEG were initially functionalized with 2‐bromo iso butyryl bromide to afford macroinitiators suitable for atom‐transfer radical polymerization. The macroinitiators were characterized by gel permeation chromatography, 1 H and 13 C nuclear magnetic resonance spectroscopic analysis and matrix‐assisted laser desorption ionization time‐of‐flight mass spectroscopy. The three different molecular weight macroinitiators were then chain extended with monomethacryloxypropyl‐terminated PDMS and photoactive 2‐(methylacyloyloxy)ethyl anthracene‐9‐carboxylate in different molar ratios to afford a series of photoresponsive hiphilic diblock copolymers with high conversions. Self‐assembly of these linear–linear brush diblock copolymers in N , N ‐dimethylformamide afforded nanoparticles with hydrodynamic diameters ( d H ) ranging from 41 to 268 nm, as determined by dynamic light scattering analysis. Crosslinking and stabilization of the nanoparticles was achieved via [4+4] photodimerization of the anthracene moieties upon exposure to UV radiation at 365 nm with the reverse reaction studied at a wavelength of 254 nm. Transmission electron microscopy revealed that the self‐assembled nanoparticles and their crosslinked derivatives had spherical morphologies. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 1251–1262
Nanoparticles assembled via pH-responsive reversible segregation of cyclodextrins in polyrotaxanes
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR04841B
Abstract: Supramolecular polymers with monomers bound together by secondary interactions, such as polyrotaxanes (PRXs), consisting of alpha cyclodextrin (αCD) threaded onto poly(ethylene glycol) (PEG), have attracted interest as a result of their ability to overcome physical limitations present in conventional, covalently structured polymers. Herein, we describe the formation of pH-responsive supramolecular assemblies from carboxyethylester bearing αCD and PEG PRXs. These PRXs were formed using PEG of Mw 20 kDa and a threading degree of 28%. Upon charge neutralisation the threaded αCDs co-localise, resulting in aggregation of the PRXs and the formation of a suspension by self-assembly. This process is shown to be reversible and possible via the mobility of CDs along the PEG guest chain. As a result of the inherent properties of PRXs, such as enhanced multivalent interactions and degradation, these responsive supramolecular polymers are expected to be of interest in fields where PRX-based materials have already found application, including paints, self-healing materials, surface coatings, and polymer therapeutics.
The effect of block copolymer additives for a highly active polymeric metal-free oxygen reduction electrode
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA00319B
Abstract: The effect of triblock copolymer additives on polymeric ORR electrodes is studied and a highly efficient polymeric electrode is developed.
Synthesis and evaluation of a solid supported molecular tweezer type receptor for cholesterolElectronic supplementary information (ESI) available: synthetic procedures and analytical data for compound
Publisher: Royal Society of Chemistry (RSC)
Date: 21-02-2003
DOI: 10.1039/B210427J
Gel dosimetry enables volumetric evaluation of dose distributions from an MR-guided linac
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4954102
Recycling of Selective Laser Sintering Waste Nylon Powders into Fused Filament Fabrication Parts Reinforced with Mg Particles
Publisher: MDPI AG
Date: 22-06-2021
Abstract: This paper presents recycling of selective laser sintering (SLS) waste nylon into printable filaments and parts reinforced with Mg particles. Waste nylon and waste–Mg powder mixture with 2%, 4%, and 8% Mg to nylon were extruded into the filaments. Moisture absorption, differential scanning calorimetry, and melt flow index experiments were conducted to determine the thermal characteristics, while tensile and flexural tests were conducted to evaluate mechanical properties and failure mechanisms. The results were compared with off-the-self (OTS) nylon. Waste powder was found to be extrudable and printable as FFF filament. Waste filament diameter closely matched standard filament size, while exhibiting reduced moisture absorption. High melting and crystallisation temperature for the waste nylon demonstrated a degradation of the plastic during the SLS process. Young’s modulus and ultimate tensile strength for the waste filament increased by 1.6-fold compared to that for OTS, while Mg-composite filament surpassed the waste and OTS. Waste and Mg composite dog bone results showed an increase in strength and stiffness, but the ductility deteriorated. Both flexural strength and modulus for the waste nylon increased by 13% and 26%, respectively, over OTS, and the addition of Mg enhanced flexural strength by up to 5-fold at 8% Mg over the waste. Printed surface topography demonstrated that the waste and Mg composite filaments can print the parts with desired geometric shapes and acceptable surface texture. The findings showed that recycling waste SLS powder into FFF prints would be a viable and useful alternative to disposal, given its abundance.
Ultrathin chitosan-poly(ethylene glycol) hydrogel films for corneal tissue engineering
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.ACTBIO.2013.01.020
Abstract: Due to the high demand for donor corneas and their low supply, autologous corneal endothelial cell (CEC) culture and transplantation for treatment of corneal endothelial dysfunction would be highly desirable. Many studies have shown the possibility of culturing CECs in vitro, but lack potential robust substrates for transplantation into the cornea. In this study, we investigate the properties of novel ultrathin chitosan-poly(ethylene glycol) (PEG) hydrogel films (CPHFs) for corneal tissue engineering applications. Cross-linking of chitosan films with diepoxy-PEG and cystamine was employed to prepare ~50 μm (hydrated) hydrogel films. Through variation of the PEG content (1.5-5.9 wt.%) it was possible to tailor the CPHFs to have tensile strains and ultimate stresses identical to or greater than those of human corneal tissue while retaining similar tensile moduli. Light transmission measurements in the visible spectrum (400-700 nm) revealed that the films were >95% optically transparent, above that of the human cornea (maximum ~90%), whilst in vitro degradation studies with lysozyme revealed that the CPHFs maintained the biodegradable characteristics of chitosan. Cell culture studies demonstrated the ability of the CPHFs to support the attachment and proliferation of sheep CECs. Ex vivo surgical trials on ovine eyes demonstrated that the CPHFs displayed excellent characteristics for physical manipulation and implantation purposes. The ultrathin CPHFs display desirable mechanical, optical and degradation properties whilst allowing attachment and proliferation of ovine CECs, and as such are attractive candidates for the regeneration and transplantation of CECs, as well as other corneal tissue engineering applications.
Retro Diels–Alder Fragmentation of Fulvene–Maleimide Bioconjugates for Mass Spectrometric Detection of Biomolecules
Publisher: American Chemical Society (ACS)
Date: 31-08-2021
Synthesis of Anisotropic, Amphiphilic Grafted Multi-Star Polymers and Investigation of their Self-Assembling Characteristics
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13357
Abstract: Herein, we report the synthesis of hiphilic multi-star architectures consisting of discrete poly(methacrylic acid)-based core cross-linked star polymers joined together by polystyrene-grafted linear connectors by a combination of atom transfer radical polymerisation of protected macroinitiator precursors and a copper-catalysed azide-alkyne cycloaddition grafting-to approach. The anisotropic multi-star architectures, which were obtained as in idual di- and tri-star polymers with segregated hydrophobic and hydrophilic domains, undergo aggregation in apolar solvents resulting in the formation of large nanometre-scale vesicles. The self-assembling behaviour of these large hiphilic multi-star polymers (Mw = 869–1097 kDa) was studied using dynamic light scattering, transmission electron microscopy, and atomic force microscopy.
Composition-Property Relationships of pH-Responsive Poly[(2-vinylpyridine)-co-(butyl methacrylate)] Copolymers for Reverse Enteric Coatings
Publisher: MDPI AG
Date: 30-01-2023
DOI: 10.3390/PHARMACEUTICS15020454
Abstract: The taste-masking of bitter-tasting active pharmaceutical ingredients is key to ensuring patient compliance when producing oral pharmaceutical formulations. This is generally achieved via the incorporation of pH-responsive, reverse enteric polymers, that prevent the dissolution of the formulation in the oral environment, but rapidly mediate it within the gastric environment. Reverse enteric polymers are commonly applied as coatings on oral dosage forms via spray atomisation (e.g., fluidised-bed spray coating), and generally exhibit the most efficient taste-masking. However, currently used reverse enteric coatings require high mass gains (% w/w) during coating to mediate taste-masking, and thereby exhibit delayed release within the gastric environment. Therefore, there remains a need for the development of new reverse enteric coatings, that can efficiently taste-mask at low mass gains and maintain rapid release characteristics within the gastric environment. Herein we report the synthesis and evaluation of a series of addition copolymers of 2-vinylpyridine and butyl methacrylate, methyl methacrylate and isobornyl methacrylate. The thermal, solubility, and water absorption properties of the copolymers were effectively tuned by altering the mol% fraction of the constitutive monomers. Based on their physical properties, selected copolymers were preliminarily evaluated for their compatibility with fluidised-bed spray coating, and effectiveness as taste-masking reverse enteric coatings. The copolymers poly[(2-vinylpyridine)-co-(butyl methacrylate)] (mol% ratio 40:60) and poly[(2-vinylpyridine)-co-(butyl methacrylate)-co-(methyl methacrylate)] (mol% ratio 40:50:10) were found to exhibit excellent taste-masking properties following fluidised-bed spray coating onto Suglets® sugar spheres. Suglets® bearing a film coating of either copolymer (5.2–6.5% w/w mass gain) were found to effectively impede the release of a model drug formulation for up to 72 h in a simulated salivary environment, and rapidly release it ( min) within a simulated gastric environment. The results demonstrated the potential of poly[(2-vinylpyridine)-co-(butyl methacrylate)] copolymers to form effectively taste-masked, reverse enteric dosage forms, and suggested that these copolymers may provide improved performance compared to currently available polymers.
Bettering the devil you know: Can we drive predator adaptation to restore native fauna?
Publisher: Wiley
Date: 05-05-2021
DOI: 10.1111/CSP2.447
Abstract: Predation of threatened fauna by native and introduced predators can drive extinction and prevent population recovery. Most predator management involves exclusion or culling. Evidence suggests that exclusion may have detrimental effects on a prey species' predator awareness. At the same time, culling can cause selection of control‐resistant predators. There is increasing interest in harnessing evolutionary processes to drive adaptation of threatened fauna to cope, but there is limited attention on trying this from the predator direction. We need to shift the survival advantage away from predators that avoid lethal control, and go on to kill, towards those that demonstrate behaviors that reduce impact on threatened fauna. Instead of driving undesirable predator selection, could we select through management actions desirable traits to make them “less lethal” to threatened fauna? We draw on experimental research on predator aversion that suggests there may be an alternative way to mitigate the impacts of predators, while maintaining the learning opportunities of prey species. Using the case study of the invasive red fox in Australia, we propose a conceptual framework within which future research and management could occur to select for these desirable traits in predators and develop practical regimes for predator impact mitigation.
The behaviour of honeycomb film formation from star polymers with various fluorine content
Publisher: Elsevier BV
Date: 08-2013
Tailoring substrate hydrophilicity using grafted polypeptide nanocoatings
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13519
Abstract: Peptide nanocoatings with tailored surface-wetting properties were formed on a range of organic (cellulose and cotton) and inorganic (glass) substrates via surface-initiated ring-opening polymerization of amino acid N-carboxyanhydride derivatives. The film thickness, surface roughness, and wettability can be tuned by controlling the polymerization time and the type of N-carboxyanhydride derivative used (i.e. lysine or valine). Whereas poly(l-lysine) coatings are hydrophilic, poly(l-valine) coatings exhibit water-repellent properties. The functional polypeptide nanocoatings can potentially be applied to waterproof woven fabrics, macromolecular separation technologies, biodiagnostic sensors, and sustained drug-release wound dressings.
Oxygen-Releasing Coatings for Improved Tissue Preservation
Publisher: American Chemical Society (ACS)
Date: 30-08-2017
Mechanically Tunable Bioink for 3D Bioprinting of Human Cells
Publisher: Wiley
Date: 21-07-2017
Abstract: This study introduces a thermogelling bioink based on carboxylated agarose (CA) for bioprinting of mechanically defined microenvironments mimicking natural tissues. In CA system, by adjusting the degree of carboxylation, the elastic modulus of printed gels can be tuned over several orders of magnitudes (5-230 Pa) while ensuring almost no change to the shear viscosity (10-17 mPa) of the bioink solution thus enabling the fabrication of 3D structures made of different mechanical domains under identical printing parameters and low nozzle shear stress. Human mesenchymal stem cells printed using CA as a bioink show significantly higher survival (95%) in comparison to when printed using native agarose (62%), a commonly used thermogelling hydrogel for 3D-bioprinting applications. This work paves the way toward the printing of complex tissue-like structures composed of a range of mechanically discrete microdomains that could potentially reproduce natural mechanical aspects of functional tissues.
Appearance-ideal internalization, body dissatisfaction, and suicidality among sexual minority men
Publisher: Elsevier BV
Date: 09-2021
Stereoregular High-Density Bottlebrush Polymer and Its Organic Nanocrystal Stereocomplex through Triple-Helix Formation
Publisher: American Chemical Society (ACS)
Date: 21-01-2016
TH-CD-BRA-08: Novel Iron-Based Radiation Reporting Systems as 4D Dosimeters for MR-Guided Radiation Therapy
Publisher: Wiley
Date: 06-2016
DOI: 10.1118/1.4958151
Iodine complexed poly(vinyl pyrrolidone) plasma polymers as broad-spectrum antiseptic coatings
Publisher: Elsevier BV
Date: 2021
Synthesis and Characterization of Core Cross-Linked Star Clusters by Conventional Free-Radical Polymerization
Publisher: American Chemical Society (ACS)
Date: 10-2007
DOI: 10.1021/MA070996Z
Photocontrolled Cargo Release from Dual Cross-Linked Polymer Particles
Publisher: American Chemical Society (ACS)
Date: 23-02-2016
Abstract: Burst release of a payload from polymeric particles upon photoirradiation was engineered by altering the cross-linking density. This was achieved via a dual cross-linking concept whereby noncovalent cross-linking was provided by cyclodextrin host-guest interactions, and irreversible covalent cross-linking was mediated by continuous assembly of polymers (CAP). The dual cross-linked particles (DCPs) were efficiently infiltrated (∼80-93%) by the biomacromolecule dextran (molecular weight up to 500 kDa) to provide high loadings (70-75%). Upon short exposure (5 s) to UV light, the noncovalent cross-links were disrupted resulting in increased permeability and burst release of the cargo (50 mol % within 1 s) as visualized by time-lapse fluorescence microscopy. As sunlight contains UV light at low intensities, the particles can potentially be incorporated into systems used in agriculture, environmental control, and food packaging, whereby sunlight could control the release of nutrients and antimicrobial agents.
Polypeptide films via N-carboxyanhydride ring-opening polymerization (NCA-ROP): Past, present and future
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC00293H
Abstract: The formation of surface-grafted polypeptide films and interfaces via N-carboxyanhydride ring-opening polymerization (NCA-ROP) holds great potential for the facile preparation of next-generation multifunctional and responsive materials with excellent biocompatibility, biodegradability, tunable conformations and chemical functionalities. Therefore, the aim of this feature article is to provide a topical review of developments in the area of polypeptide films derived through NCA-ROP. It is evident that studies reported thus far have only started to unveil the full potential of peptide-based interfaces and materials, and with continued advancements it is anticipated that the strategic combination of NCA-ROP with modern synthetic chemistries will continue to yield versatile platforms for broader applications in the fields of polymer therapeutics, tissue engineering, (bio)nanocoatings, (bio)chemosensors, catalysis and separation technologies.
pH-Responsive Polymer Implants for the Protection of Native Mammals: Assessment of Material Properties and Poison Incorporation on Performance
Publisher: MDPI AG
Date: 10-02-2023
Abstract: Efforts to mitigate the effects of feral cats through the management of remnant or reintroduced populations of threatened species, are often unsuccessful due to predation by control-averse feral cats, or ‘problem in iduals’. In order to target these animals, we have developed the Population Protecting Implant (PPI). PPIs are designed to be implanted subcutaneously in a native animal. If the animal is preyed upon, and the implant ingested by a feral cat, release of a toxic payload is triggered in the acidic stomach environment and the problem in idual is eliminated. We introduce the first toxic implant incorporating the poison sodium fluoroacetate. Manufactured via fluidised-bed spray coating, toxic implants exhibited uniform reverse enteric coatings and low intra-batch variation. Toxic implants were found to exhibit favourable stability at subcutaneous pH in vitro, and rapidly release their toxic payload in vitro at gastric pH. However, limited stability was demonstrated in rats in vivo (~39–230 d), due to the use of a filament scaffold to enable coating and was likely exacerbated by metachromatic interactions caused by 1080. This work highlights that future development of the PPIs should primarily focus on removal of the filament scaffold, to afford implants with increased in vivo stability.
Azobenzene-functionalised core cross-linked star polymers and their host-guest interactions
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CH13425
Abstract: Water-soluble poly(2-hydroxyethyl acrylate) (PHEA)-based core cross-linked star polymers were efficiently synthesised with high macroinitiator-to-star-conversion ( %) in a one-pot system via single electron transfer-living radical polymerisation. The star polymers display excellent water solubility and the pendant hydroxyl groups provide a platform for facile post-functionalisation with various molecules. In demonstrating this, a photo-isomerisable molecule, 4-(phenylazo)benzoic acid was conjugated onto the preformed stars through partial esterification of the available hydroxyl groups (5–20 %). The azobenzene functionalised stars were subsequently employed to form reversible inclusion complexes with α-cyclodextrin.
Micromechanical properties of almond kernels with various moisture content levels
Publisher: Informa UK Limited
Date: 2018
Pion and kaon structure at the electron-ion collider
Publisher: Springer Science and Business Media LLC
Date: 10-2019
Development and application of diazirines in biological and synthetic macromolecular systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B501989C
Oxygen-permeable microwell device maintains islet mass and integrity during shipping
Publisher: Bioscientifica
Date: 03-2018
DOI: 10.1530/EC-17-0349
Abstract: Islet transplantation is currently the only minimally invasive therapy available for patients with type 1 diabetes that can lead to insulin independence however, it is limited to only a small number of patients. Although clinical procedures have improved in the isolation and culture of islets, a large number of islets are still lost in the pre-transplant period, limiting the success of this treatment. Moreover, current practice includes islets being prepared at specialized centers, which are sometimes remote to the transplant location. Thus, a critical point of intervention to maintain the quality and quantity of isolated islets is during transportation between isolation centers and the transplanting hospitals, during which 20–40% of functional islets can be lost. The current study investigated the use of an oxygen-permeable PDMS microwell device for long-distance transportation of isolated islets. We demonstrate that the microwell device protected islets from aggregation during transport, maintaining viability and average islet size during shipping.
Drug-Loaded, Polyurethane Coated Nitinol Stents for the Controlled Release of Docetaxel for the Treatment of Oesophageal Cancer
Publisher: MDPI AG
Date: 04-2021
DOI: 10.3390/PH14040311
Abstract: For several decades, self-expanding metal stents (SEMSs) have shown significant clinical success in the palliation of obstructive metastatic oesophageal cancer. However, these conventional oesophageal stents can suffer from stent blockage caused by malignant tumour cell growth. To overcome this challenge, there is growing interest in drug-releasing stents that, in addition to palliation, provide a sustained and localized release of anticancer drugs to minimise tumour growth. Therefore, in this study we prepared and evaluated an oesophageal stent-based drug delivery platform to provide the sustained release of docetaxel (DTX) for the treatment of oesophageal cancer-related obstructions. The DTX-loaded oesophageal stents were fabricated via dip-coating of bare nitinol stents with DTX-polyurethane (PU) solutions to provide PU coated stents with DTX loadings of 1.92 and 2.79% w/w. Mechanical testing of the DTX-PU coated stents revealed that an increase in the drug loading resulted in a reduction in the ultimate tensile strength, toughness and Young’s modulus. In vitro release studies showed a sustained release of DTX, with ~80–90% released over a period of 33 days. While the DTX-loaded stents exhibited good stability to gamma radiation sterilisation, UV sterilisation or accelerated storage at elevated temperatures (40 °C) resulted in significant DTX degradation. Cell proliferation, apoptosis and Western blotting assays revealed that the DTX released from the stents had comparable anticancer activity to pure DTX against oesophageal cancer cells (KYSE-30). This research demonstrates that the dip-coating technique can be considered as a promising approach for the fabrication of drug-eluting stents (DESs) for oesophageal cancer treatment.
Novel Multicompartment 3-Dimensional Radiochromic Radiation Dosimeters for Nanoparticle-Enhanced Radiation Therapy Dosimetry
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.IJROBP.2012.05.029
Abstract: Gold nanoparticles (AuNps), because of their high atomic number (Z), have been demonstrated to absorb low-energy X-rays preferentially, compared with tissue, and may be used to achieve localized radiation dose enhancement in tumors. The purpose of this study is to introduce the first ex le of a novel multicompartment radiochromic radiation dosimeter and to demonstrate its applicability for 3-dimensional (3D) dosimetry of nanoparticle-enhanced radiation therapy. A novel multicompartment phantom radiochromic dosimeter was developed. It was designed and formulated to mimic a tumor loaded with AuNps (50 nm in diameter) at a concentration of 0.5 mM, surrounded by normal tissues. The novel dosimeter is referred to as the Sensitivity Modulated Advanced Radiation Therapy (SMART) dosimeter. The dosimeters were irradiated with 100-kV and 6-MV X-ray energies. Dose enhancement produced from the interaction of X-rays with AuNps was calculated using spectrophotometric and cone-beam optical computed tomography scanning by quantitatively comparing the change in optical density and 3D datasets of the dosimetric measurements between the tissue-equivalent (TE) and TE/AuNps compartments. The interbatch and intrabatch variability and the postresponse stability of the dosimeters with AuNps were also assessed. Radiation dose enhancement factors of 1.77 and 1.11 were obtained using 100-kV and 6-MV X-ray energies, respectively. The results of this study are in good agreement with previous observations however, for the first time we provide direct experimental confirmation and 3D visualization of the radiosensitization effect of AuNps. The dosimeters with AuNps showed small (<3.5%) interbatch variability and negligible (<0.5%) intrabatch variability. The SMART dosimeter yields experimental insights concerning the spatial distributions and elevated dose in nanoparticle-enhanced radiation therapy, which cannot be performed using any of the current methods. The authors concluded that it can be used as a novel independent method for nanoparticle-enhanced radiation therapy dosimetry.
S-Nitrosothiol Plasma-Modified Surfaces for the Prevention of Bacterial Biofilm Formation
Publisher: American Chemical Society (ACS)
Date: 25-09-2019
Core cross-linked star polymers via controlled radical polymerisation
Publisher: Elsevier BV
Date: 2009
Combating multidrug-resistant Gram-negative bacteria with structurally nanoengineered antimicrobial peptide polymers
Publisher: Springer Science and Business Media LLC
Date: 12-09-2016
DOI: 10.1038/NMICROBIOL.2016.162
Abstract: With the recent emergence of reports on resistant Gram-negative 'superbugs', infections caused by multidrug-resistant (MDR) Gram-negative bacteria have been named as one of the most urgent global health threats due to the lack of effective and biocompatible drugs. Here, we show that a class of antimicrobial agents, termed 'structurally nanoengineered antimicrobial peptide polymers' (SNAPPs) exhibit sub-μM activity against all Gram-negative bacteria tested, including ESKAPE and colistin-resistant and MDR (CMDR) pathogens, while demonstrating low toxicity. SNAPPs are highly effective in combating CMDR Acinetobacter baumannii infections in vivo, the first ex le of a synthetic antimicrobial polymer with CMDR Gram-negative pathogen efficacy. Furthermore, we did not observe any resistance acquisition by A. baumannii (including the CMDR strain) to SNAPPs. Comprehensive analyses using a range of microscopy and (bio)assay techniques revealed that the antimicrobial activity of SNAPPs proceeds via a multimodal mechanism of bacterial cell death by outer membrane destabilization, unregulated ion movement across the cytoplasmic membrane and induction of the apoptotic-like death pathway, possibly accounting for why we did not observe resistance to SNAPPs in CMDR bacteria. Overall, SNAPPs show great promise as low-cost and effective antimicrobial agents and may represent a weapon in combating the growing threat of MDR Gram-negative bacteria.
Low-fouling, biospecific films prepared by the continuous assembly of polymers
Publisher: American Chemical Society (ACS)
Date: 10-07-2013
DOI: 10.1021/BM400680D
Abstract: We report that the continuous assembly of polymers (CAP) approach, mediated by ring-opening metathesis polymerization (ROMP), is a facile and versatile technology to prepare engineered nanocoatings for various biomedical applications. Low-fouling coatings on particles were obtained by the formation of multicompositional, layered films via simple and efficient tandem CAP(ROMP) processes that are analogous to chain extension reactions. In addition, the CAP(ROMP) approach allows for the efficient postfunctionalization of the CAP films with bioactive moieties via cross-metathesis reactions between the surface-immobilized catalysts and symmetrical alkene derivatives. The combined features of the CAP(ROMP) approach (i.e., versatile polymer selection and facile functionalization) allow for the fabrication and surface modification of various types of polymer films, including those with intrinsic protein-repellent properties and selective protein recognition capabilities. This study highlights the various types of advanced coatings and materials that the CAP approach can be used to generate, which may be useful for biomedical applications.
Antifogging Surface Facilitated by Nanoscale Coatings with Controllable Hydrophobicity and Cross-Linking Density
Publisher: Wiley
Date: 08-2017
Exploring the versatility of pentafulvene-maleimide cycloaddition as a ligation strategy: buffer and pH effects.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2OB01453J
Abstract: Ligation chemistries are often required to perform under stringent conditions that preserve the integrity and function of (bio)conjugates, including specific biological buffers. To explore the versatility of the pentafulvene-maleimide ligation for (bio)conjugations, we studied the stability of the coupling partners and their Diels-Alder cycloaddition (DAC) in buffers used commonly in biological assays, protein chemistry and bioconjugates. The stability of 6,6-dialkylpentafulvene and maleimide derivatives to a panel of buffers with pH values between 3.7 and 10.1 was monitored via 1 H NMR spectroscopy. While the pentafulvene displayed excellent stability, hydrolysis of the maleimide was observed in several cases, although the extent of hydrolysis did not correlate with pH. For almost all buffers the pentafulvene-maleimide DAC proceeded efficiently and at a significantly faster rate than maleimide hydrolysis under the conditions studied. The buffer composition nor pH appeared to have a significant effect on the kinetics of the DAC with second-order rate constants ( k 2 ) ranging from 0.14 to 0.33 M -1 s -1 (23 ± 1 °C). This study highlights the versatility of the pentafulvene-maleimide ligation to proceed under a wide range of conditions relevant for (bio)conjugations and that maleimide hydrolysis in aqueous system may be promoted or inhibited by certain buffers.
Injectable Diels-Alder cycloaddition hydrogels with tuneable gelation, stiffness and degradation for the sustained release of T-lymphocytes
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TB00274D
Abstract: Highly efficient, selective and cytocompatible fulvene–maleimide cycloaddition chemistry was applied for the preparation of injectable, cell encapsulating/releasing hydrogels with tuneable gelation and degradation kinetics.
Influence of polymerisation conditions on the kinetics of poly(lactic-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) triblock synthesis and the o
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3PY00139C
Abstract: Investigating how different reaction conditions influence the reaction kinetics, monomer sequence and side reactions for the synthesis of a PLGA-PEG-PLGA triblock copolymer.
Biocompatible Porous Polyester-Ether Hydrogel Scaffolds with Cross-Linker Mediated Biodegradation and Mechanical Properties for Tissue Augmentation
Publisher: MDPI AG
Date: 12-02-2018
Synthesis of Buckminsterfullerene C60 functionalised core cross-linked star polymers
Publisher: Elsevier BV
Date: 02-2008
Quantitative formation of core cross-linked star polymers via a one-pot two-step single electron transfer-living radical polymerization
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3PY00726J
Synthesis and self-assembly of polyimide/poly(dimethylsiloxane) brush triblock copolymers
Publisher: Elsevier BV
Date: 2013
In vivo studies of biocompatible PEG-based hydrogel scaffolds with biofactors
Publisher: IEEE
Date: 12-2014
Fabrication of ultra-thin polyrotaxane-based films via solid-state continuous assembly of polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC08759C
Abstract: Surface-confined ultra-thin polyrotaxane (PRX)-based films with tunable composition, surface topology and swelling characteristics were prepared by solid-state continuous assembly of polymers (ssCAP).
Functional and well-defined β-sheet-assembled porous spherical shells by surface-guided peptide formation
Publisher: Wiley
Date: 03-04-2015
SU-G-TeP2-06: Development of Novel Radiochromic Films for Radiotherapy Dosimetry
Publisher: Wiley
Date: 06-2016
DOI: 10.1118/1.4957041
Pentafulvene-Maleimide Cycloaddition for Bioorthogonal Ligation
Publisher: American Chemical Society (ACS)
Date: 13-07-2021
DOI: 10.1021/ACS.BIOCONJCHEM.1C00287
Abstract: The applications of bioconjugation chemistry are rapidly expanding, and the addition of new strategies to the bioconjugation and ligation toolbox will further advance progress in this field. Herein, we present a detailed study of the Diels-Alder cycloaddition (DAC) reaction between pentafulvenes and maleimides in aqueous solutions and investigate the reaction as an emerging bioconjugation strategy. The DAC reactions were found to proceed efficiently, quantitatively yielding cycloadducts with reaction rates ranging up to ∼0.7 M
Antibacterial and Anti-Inflammatory pH-Responsive Tannic Acid-Carboxylated Agarose Composite Hydrogels for Wound Healing
Publisher: American Chemical Society (ACS)
Date: 14-10-2016
Abstract: pH-sensitive hydrogels play an important role in controlled drug release applications and have the potential to impact the management of wounds. In this study, we report the fabrication of novel carboxylated agarose/tannic acid hydrogel scaffolds cross-linked with zinc ions for the pH-controlled release of tannic acid. The resulting hydrogels exhibited negligible release of tannic acid at neutral and alkaline pH and sustained release at acidic pH, where they also displayed maximum swelling. The hydrogels also displayed favorable antibacterial and anti-inflammatory properties, and a lack of cytotoxicity toward 3T3 fibroblast cell lines. In simulated wound assays, significantly greater cell migration and proliferation was observed for cells exposed to tannic acid hydrogel extracts. In addition, the tannic acid hydrogels were able to suppress NO production in stimulated human macrophages in a concentration-dependent manner, indicating effective anti-inflammatory activity. Taken together, the cytocompatibility, antibacterial, and anti-inflammatory characteristics of these novel pH-sensitive hydrogels make them promising candidates for wound dressings.
Toward Targeted Invasive Predator Control: Developing pH-Responsive Subcutaneous Implants for Native Mammals
Publisher: American Chemical Society (ACS)
Date: 22-08-2022
An overview of the cycloaddition chemistry of fulvenes and emerging applications
Publisher: Beilstein Institut
Date: 06-09-2019
DOI: 10.3762/BJOC.15.209
Abstract: The unusual electronic properties and unique reactivity of fulvenes have interested researchers for over a century. The propensity to form dipolar structures at relatively low temperatures and to participate as various components in cycloaddition reactions, often highly selectively, makes them ideal for the synthesis of complex polycyclic carbon scaffolds. As a result, fulvene cycloaddition chemistry has been employed extensively for the synthesis of natural products. More recently, fulvene cycloaddition chemistry has also found application to other areas including materials chemistry and dynamic combinatorial chemistry. This highlight article discusses the unusual properties of fulvenes and their varied cycloaddition chemistry, focussing on applications in organic and natural synthesis, dynamic combinatorial chemistry and materials chemistry, including dynamers, hydrogels and charge transfer complexes. Tables providing comprehensive directories of fulvene cycloaddition chemistry are provided, including fulvene intramolecular and intermolecular cycloadditions complete with reactant partners and their resulting cyclic adducts, which provide a useful reference source for synthetic chemists working with fulvenes and complex polycyclic scaffolds.
Quantitative 3D Determination of Radiosensitization by Bismuth-Based Nanoparticles
Publisher: American Scientific Publishers
Date: 03-2016
Abstract: The nanoparticle-induced dose enhancement effect has been shown to improve the therapeutic efficacy of ionizing radiation in external beam radiotherapy. Whereas previous studies have focused on gold nanoparticles (AuNPs), no quantitative studies have been conducted to investigate the potential superiority of other high atomic number (Z) nanomaterials such as bismuth-based nanoparticles. The aims of this study were to experimentally validate and quantify the dose enhancement properties of commercially available bismuth-based nanoparticles (bismuth oxide (Bi2O3-NPs) and bismuth sulfide (Bi2S3-NPs)), and investigate their potential superiority over AuNPs in terms of radiation dose enhancement. Phantom cuvettes doped with and without nanoparticles where employed for measuring radiation dose enhancement produced from the interaction of radiation with metal nanoparticles. Novel 3D phantoms were employed to investigate the 3D spatial distribution of ionising radiation dose deposition. The phantoms were irradiated with kilovoltage and megavoltage X-ray beams and optical absorption changes were measured using a spectrophotometer and optical CT scanner. The radiation dose enhancement factors (DEFs) obtained for 50 nm diameter Bi2O3-NPs and AuNPs were 1.90 and 1.77, respectively, for 100 kV energy and a nanoparticle concentration of 0.5 mM. In addition, the DEFs of 5 nm diameter Bi2S3-NPs and AuNPs were determined to be 1.38 and 1.51, respectively, for 150 kV energy and a nanoparticle concentration of 0.25 mM. The results demonstrate that both bismuth-based nanoparticles can enhance the effects of radiation. For 6 MV energy the DEFs for all the investigated nanoparticles were lower (< 15%) than with kilovoltage energy.
Spatial-controlled nanoengineered films prepared: Via rapid catalyst induced cross-linking
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6PY00530F
Nanoscale iodophoric poly(vinyl amide) coatings for the complexation and release of iodine for antimicrobial surfaces
Publisher: Elsevier BV
Date: 12-2023
Titanium Dioxide Nanoparticles as Radiosensitisers: An In vitro and Phantom-Based Study
Publisher: Ivyspring International Publisher
Date: 2017
DOI: 10.7150/IJMS.19058
Surface modification of nylon 6,6 using a carbene insertion approach
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B514205A
Optimizing the sensitivity and radiological properties of the PRESAGE® dosimeter using metal compounds
Publisher: Elsevier BV
Date: 11-2012
Rapid, metal-free hydrosilanisation chemistry for porous silicon surface modification
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC02689J
Abstract: Here, we report a novel surface modification for porous silicon (pSi).
Alternative syntheses of linear polyurethanes using masked isocyanate monomers
Publisher: Elsevier BV
Date: 11-2006
Hydrogel Scaffolds: Advanced Materials for Soft Tissue Re-growth
Publisher: Springer Berlin Heidelberg
Date: 2011
A Facile Strategy for the High Yielding, Quantitative Conversion of Polyglycol End-Groups to Amines
Publisher: MDPI AG
Date: 26-04-2021
Abstract: Amino end-group functionalised polyglycols are important intermediates in the synthesis of sophisticated polymeric architectures and biomaterials. Herein, we report a facile strategy for the end-group conversion of hydroxyl-terminated polyglycols to amino-terminated polyglycols in high isolated yields and with excellent end-group fidelity. Following traditional conversion of polyglycol hydroxyl end-groups to azides via the corresponding mesylate, reduction with zinc in the presence of ammonium chloride afforded a range of amino end-group functionalised poly(ethylene glycol) and poly(propylene glycol) homopolymers and copolymers with isolated yields of 82–99% and end-group conversions of % as determined by NMR spectroscopy and MALDI ToF MS. Furthermore, this process is applicable to a sequential reagent addition approach without intermediate polymer isolation steps with only a slight reduction in yield and end-group conversion (95%). Importantly, a simple work-up procedure provides access to high purity polyglycols without contamination from other reagents.
Development of functional amino acid-based star polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1PY00436K
Abstract: Various arm and core functionalized amino acid-based star polymer are prepared. Furthermore, a detailed investigation of reaction parameters affecting star formation is presented.
Antibiofilm Nitric Oxide-Releasing Polydopamine Coatings
Publisher: American Chemical Society (ACS)
Date: 28-01-2019
Abstract: The growing number of patient morbidity related to nosocomial infections has placed an importance on the development of new antibacterial coatings for medical devices. Here, we utilize the versatile adhesion property of polydopamine (pDA) to design an antibacterial coating that possesses low-fouling and nitric oxide (NO)-releasing capabilities. To demonstrate this, glass substrates were functionalized with pDA via immersion in alkaline aqueous solution containing dopamine, followed by grafting of low-fouling polymer (poly(ethylene glycol) (PEG)) via Michael addition and subsequent formation of N-diazeniumdiolate functionalities (NO precursors) by purging with NO gas. X-ray photoelectron spectroscopy confirmed the successful grafting of PEG and formation of N-diazeniumdiolate on polydopamine-coated substrates. NO release from the coating was observed over 2 days, and NO loading is tunable by the pDA film thickness. The antibacterial efficiency of the coatings was assessed using Gram-negative Pseudomonas aeruginosa (i.e., wild-type PAO1 and multidrug-resistant PA37) and Gram-positive Staphylococcus aureus (ATCC 29213). The NO-releasing PEGylated pDA film inhibited biofilm attachment by 96 and 70% after exposure to bacterial culture solution for 24 and 36 h, respectively. In contrast, films that do not contain NO failed to prevent biofilm formation on the surfaces at these time points. Furthermore, this coating also showed 99.9, 97, and 99% killing efficiencies against surface-attached PAO1, PA37, and S. aureus bacteria. Overall, the combination of low-fouling PEG and antibacterial activity of NO in pDA films makes this coating a potential therapeutic option to inhibit biofilm formation on medical devices.
Rheology of core cross-linked star polymers
Publisher: Elsevier BV
Date: 10-2008
Synthesis of hyperbranched poly(aryl amine)s via a carbene insertion approach
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B804392M
Abstract: A novel diazirine functionalised aniline derivative, 3-(3-aminophenyl)-3-methyldiazirine 1, was prepared and employed as an AB(2)-type monomer in the synthesis of hyperbranched polymers thus providing the first instance in which polyamines have been prepared via carbene insertion polymerisation. Photolysis of the monomer 1 in bulk and in solution resulted in the formation of hyperbranched poly(aryl amine)s with degrees of polymerisation (DP) varying from 9 to 26 as determined by gel permeation chromatography (GPC). In solution, an increase in the initial monomer concentration was generally found to result in a decrease in the molecular weight characteristics of the resulting poly(aryl amine)s. Subsequent thermal treatment of the poly(aryl amine)s caused a further increase in the DP values up to a maximum of 31. Nuclear magnetic resonance (NMR) spectroscopic analysis revealed that the increase in molecular weight upon thermal treatment resulted from hydroamination of styrenic species formed in the initial photopolymerisation or activation of diazirine moieties.
Time-based measures of treatment effect: reassessment of ticagrelor and clopidogrel from the PLATO trial
Publisher: BMJ
Date: 06-2017
SU-E-T-411: Characterization of Novel Water-Equivalent PRESAGE for Megavoltage and Kilovoltage X-Ray Beam Dosimetry
Publisher: Wiley
Date: 29-05-2014
DOI: 10.1118/1.4888744
IGF-2 coated porous collagen microwells for the culture of pancreatic islets
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6TB02748B
Abstract: A new platform for the culture of pancreatic islets that improves the cell viability and quality. Paving the way for a highly efficient islet clinical transport.
Effect of EDA/PEGDGE Mole Ratios on PEG-Based Hydrogel Scaffolds Properties
Publisher: Trans Tech Publications, Ltd.
Date: 12-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.626.681
Abstract: The synthesis of biocompatible hydrogel based on poly (ethylene glycol) (PEG) and ethylene diamine (EDA) using epoxy-amine chemistry was conducted. PEG was chosen as the base material (or monomer) to synthesise hydrogels in this study due to its high hydrophilicity, biocompatibility and low toxicity properties. The effects of mole ratios of EDA to PEGDGE on the hydrogel scaffolds properties (i.e., gelling time, swelling) were investigated. It was found out for hydrogel scaffolds prepared at 1.2 and 1.4 M [PEGDG and an EDA/PEGDGE mol ratio of 0.5 in DMSO gave the optimum hydrogel properties. Swelling studies has confirmed that hydrogel prepared at 0.5 mole ratios consist of highly cross-linked network as expected.
Iron-based radiochromic systems for UV dosimetry applications
Publisher: IOP Publishing
Date: 09-01-2018
Abstract: Phototherapy treatment using ultraviolet (UV) A and B light sources has long existed as a treatment option for various skin conditions. Quality control for phototherapy treatment recommended by the British Association of Dermatologists and British Photodermatology Group generally focused on instrumentation-based dosimetry measurements. The purpose of this study was to present an alternative, easily prepared dosimeter system for the measurement of UV dose and as a simple quality assurance technique for phototherapy treatments. Five different UVA-sensitive radiochromic dosimeter formulations were investigated and responded with a measurable and visible optical change both in solution and in gel form. Iron(III) reduction reaction formulations were found to be more sensitive to UVA compared to iron(II) oxidation formulations. One iron(III) reduction formulation was found to be especially promising due to its sensitivity to UVA dose, ease of production, and linear response up to a saturation point.
Protein Capsules Assembled via Isobutyramide Grafts: Sequential Growth, Biofunctionalization, and Cellular Uptake
Publisher: American Chemical Society (ACS)
Date: 05-09-2012
DOI: 10.1021/NN302024T
Abstract: We report the sequential assembly of proteins via the alternating physical adsorption of human serum albumin (HSA) and chemical grafting with isobutyramide (IBAM) or bromoisobutyramide (BrIBAM) groups. This approach, performed on silica template particles, leads to the formation of noncovalent protein films with controlled growth at the nanometer scale. Further, after template removal, hollow protein capsules with tunable wall thicknesses and high mechanical stability are obtained. The use of BrIBAM, compared to IBAM grafts, leads to significantly thicker capsule walls, highlighting the influence of the bromine atoms in the assembly process, which is discussed in terms of a theoretical model of noncovalent interactions. Another feature of the process is the possibility to functionalize the HSA capsules with other biologically active macromolecules, including enzymes, polysaccharides, or DNA plasmids, demonstrating the versatility of this approach. We also report that BrIBAM-HSA and IBAM-HSA capsules display negligible cytotoxicity in vitro with HeLa cells and that their cellular uptake is dependent on the thickness of the capsule walls. These findings support the potential use of these protein capsules in tailored biological applications such as drug delivery.
Intra-articular Treatment of Osteoarthritis with Diclofenac-Conjugated Polymer Reduces Inflammation and Pain
Publisher: American Chemical Society (ACS)
Date: 24-05-2019
Abstract: The most common treatment for osteoarthritis is daily oral administration of a nonsteroidal anti-inflammatory drug such as diclofenac. This daily dosage regime is often associated with severe side effects. In this study, we explored the potential of utilizing a high molecular weight cross-linked polyurethane polymer covalently linked to diclofenac (
Highly Efficient Synthesis of Low Polydispersity Core Cross‐Linked Star Polymers by Ru‐Catalyzed Living Radical Polymerization
Publisher: Wiley
Date: 07-01-2011
Abstract: The efficient formation of low polydispersity core cross-linked star (CCS) polymers via controlled/living radical polymerization (LRP) and the arm-first approach was found to be dependent on the mediating catalyst system. The Ru catalyst, Ru(Ind)Cl(PPh₃)₂ Cat. 1, and tertiary amine co-catalyst were used to synthesize highly living poly(methyl methacrylate) (PMMA) macroinitiators, which were then linked together with ethylene glycol dimethacrylate (EGDMA) to form PMMA(arm)PEGDMA(core) CCS polymers. The quantitative and near-quantitative synthesis of CCS polymers were observed for low to moderate molecular weight macroinitiators (M(n) = 8 and 20 kDa), respectively. Lower conversions were observed for high-molecular weight macroinitiators (M(n) ≥ 60 kDa). Overall, an improvement of between 10 and 20% was observed when comparing the Cat. 1 system to a conventional Cu-catalyzed system. This significant improvement in macroinitiator-to-star conversion is explained in the context of catalyst system selection and CCS polymer formation.
Facile preparation of tissue engineering scaffolds with pore size gradients using the muesli effect and their application to cell spheroid encapsulation
Publisher: Wiley
Date: 12-02-2020
DOI: 10.1002/JBM.B.34581
Enthalpy and Volume Relaxation of Core-Crosslinked Star Polystyrene/Poly(methyl methacrylate) Blends
Publisher: Wiley
Date: 16-06-2011
Assembly of free-standing polypeptide films via the synergistic combination of hyperbranched macroinitiators, the grafting-from approach, and cross-chain termination
Publisher: Wiley
Date: 31-05-2013
Abstract: Cross-linked polypeptide-based films are fabricated via a novel and robust method employing surface-initiated ring opening polymerization of α-amino acid N-carboxyanhydrides (NCA-ROP). The judicious combination of amine-based hyperbranched macroinitiators and benzyl ester-protected NCA derivatives promotes network formation by cross-chain terminations, which allows the formation of stable cross-linked peptide-based capsules in a one-pot system.
Challenges of plastic waste generation and management in sub-Saharan Africa: A review
Publisher: Elsevier BV
Date: 06-2020
High resolution 3D imaging of synchrotron generated microbeams
Publisher: Wiley
Date: 12-2015
DOI: 10.1118/1.4935410
Abstract: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25-50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a nikon a1 laser fluorescence confocal microscope. The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. In idual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm ixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the s le positioning by the s le stage goniometer were measured. Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery.
pH-responsive subcutaneous implants prepared via hot-melt extrusion and fluidised-bed spray coating for targeted invasive predator control
Publisher: Elsevier BV
Date: 03-2023
SU-G-JeP2-04: Comparison Between Fricke-Type 3D Radiochromic Dosimeters for Real-Time Dose Distribution Measurements in MR-Guided Radiation Therapy
Publisher: Wiley
Date: 06-2016
DOI: 10.1118/1.4957024
A General Method for the Synthesis and Isolation of Well-Defined Core Cross-Linked Multistar Assemblies: A Route toward Enhanced pH-Responsive Polymers
Publisher: American Chemical Society (ACS)
Date: 05-06-2009
DOI: 10.1021/MA802834X
Biodegradable and Biocompatible Poly(Ethylene Glycol)-based Hydrogel Films for the Regeneration of Corneal Endothelium
Publisher: Wiley
Date: 20-03-2014
Abstract: Corneal endothelial cells (CECs) are responsible for maintaining the transparency of the human cornea. Loss of CECs results in blindness, requiring corneal transplantation. In this study, fabrication of biocompatible and biodegradable poly(ethylene glycol) (PEG)-based hydrogel films (PHFs) for the regeneration and transplantation of CECs is described. The 50-μm thin hydrogel films have similar or greater tensile strengths to human corneal tissue. Light transmission studies reveal that the films are >98% optically transparent, while in vitro degradation studies demonstrate their biodegradation characteristics. Cell culture studies demonstrate the regeneration of sheep corneal endothelium on the PHFs. Although sheep CECs do not regenerate in vivo, these cells proliferate on the films with natural morphology and become 100% confluent within 7 d. Implantation of the PHFs into live sheep corneas demonstrates the robustness of the films for surgical purposes. Regular slit l examinations and histology of the cornea after 28 d following surgery reveal minimal inflammatory responses and no toxicity, indicating that the films are benign. The results of this study suggest that PHFs are excellent candidates as platforms for the regeneration and transplantation of CECs as a result of their favorable biocompatibility, degradability, mechanical, and optical properties.
Bionano Interaction Study on Antimicrobial Star-Shaped Peptide Polymer Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 29-11-2016
Abstract: 'Structurally nanoengineered antimicrobial peptide polymers' (SNAPPs), in the form of star-shaped peptide polymer nanoparticles, have been recently demonstrated as a new class of antimicrobial agents with superior in vitro and in vivo efficacy against Gram-negative pathogens, including multidrug-resistant species. Herein, we present a detailed bionano interaction study on SNAPPs by assessing their antimicrobial activities against several Gram-negative bacteria in complex biological matrices. Simulated body fluid and animal serum were used as test media to reveal factors that influence the antimicrobial efficacy of SNAPPs. With the exception of Acinetobacter baumannii, the presence of alent cations at physiological concentrations reduced the antimicrobial efficacy of SNAPPs from minimum inhibitory concentrations (MICs) within the nanomolar range (40-300 nM) against Escherichia coli, Pseudomanas aeruginosa, and Klebsiella pneumoniae to 0.6-4.7 μM. By using E. coli as a representative bacterial species, we demonstrated that the reduction in activity was due to a decrease in the ability of SNAPPs to cause outer and inner membrane disruption. This effect could be reversed through coadministration with a chelating agent. Interestingly, the potency of SNAPPs against A. baumannii was retained even under high salt concentrations. The presence of serum proteins was also found to affect the interaction of SNAPPs with bacterial membranes, possibly through intermolecular binding. Collectively, this study highlights the need to consider the possible interactions of (bio)molecules present in vivo with any new antimicrobial agent under development. We also demonstrate that outer membrane disruption/destabilization is an important but hitherto under-recognized target for the antimicrobial action of peptide-based agents, such as antimicrobial peptides (AMPs). Overall, the findings presented herein could aid in the design of more efficient peptide-based antimicrobial agents with uncompromised potency even under physiological conditions.
An investigation into ultra-sensitive substituted leucomalachite dye derivatives for use in the PRESAGE®dosimeter
Publisher: IOP Publishing
Date: 26-06-2013
A generic class of amyloid fibril inhibitors
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TB01762E
Abstract: Amyloid fibrils are large ordered fibrillar aggregates formed from mis-folded proteins. Fibril formation is inhibited using a generic macromolecular structure.
Phototriggered, metal-free continuous assembly of polymers for the fabrication of ultrathin films
Publisher: American Chemical Society (ACS)
Date: 26-07-2012
DOI: 10.1021/MZ300307E
Abstract: A facile and metal-free thin film fabrication technology based on the photoinduced continuous assembly of polymers (photoCAP) is described. The efficiency and versatility of this method is demonstrated by the formation of crosslinked and surface-confined nanoengineered thin films, in the form of surface coatings and hollow polymer capsules.
Factors influencing the growth and topography of nanoscale films fabricated by ROMP-mediated continuous assembly of polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2PY20692G
Synthesis and characterization of hyperbranched polyesters incorporating the AB2 monomer 3,5-bis(3-hydroxylprop-1-ynyl)benzoic acid
Publisher: Elsevier BV
Date: 10-2003
Replica moulded poly(dimethylsiloxane) microwell arrays induce localized endothelial cell immobilization for coculture with pancreatic islets
Publisher: American Vacuum Society
Date: 2019
DOI: 10.1116/1.5087737
Abstract: PolyJet three-dimensional (3D) printing allows for the rapid manufacturing of 3D moulds for the fabrication of cross-linked poly(dimethylsiloxane) microwell arrays (PMAs). As this 3D printing technique has a resolution on the micrometer scale, the moulds exhibit a distinct surface roughness. In this study, the authors demonstrate by optical profilometry that the topography of the 3D printed moulds can be transferred to the PMAs and that this roughness induced cell adhesive properties to the material. In particular, the topography facilitated immobilization of endothelial cells on the internal walls of the microwells. The authors also demonstrate that upon immobilization of endothelial cells to the microwells, a second population of cells, namely, pancreatic islets could be introduced, thus producing a 3D coculture platform.
Interrogating the relationship between the microstructure of amphiphilic poly(ethylene glycol-b-caprolactone) copolymers and their colloidal assemblies using non-interfering techniques
Publisher: Elsevier BV
Date: 2022
Drug-Eluting Biodegradable Implants for the Sustained Release of Bisphosphonates
Publisher: MDPI AG
Date: 07-12-2020
Abstract: Despite being one of the first-line treatments for osteoporosis, the bisphosphonate drug class exhibits an extremely low oral bioavailability ( %) due to poor absorption from the gastrointestinal tract. To overcome this, and to explore the potential for sustained drug release, bioerodible poly(lactic acid) (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) implants loaded with the bisphosphonate alendronate sodium (ALN) were prepared via hot-melt extrusion. The rate of drug release in vitro was modulated by tailoring the ratio of lactide to glycolide in the polymer and by altering the ALN-loading of the implants. All investigated implants exhibited sustained ALN release in vitro between 25 to 130 days, where implants of greater glycolide composition and higher ALN-loadings released ALN more rapidly. All PLGA implants demonstrated a sigmoidal release profile, characterised by an initial surface dissolution phase, followed by a period of zero-order drug diffusion, then relaxation or erosion of the polymer chains that caused accelerated release over the subsequent days. Contrastingly, the PLA implants demonstrated a logarithmic release profile, characterised by a gradual decrease in ALN release over time.
Organic Catalyst-Mediated Ring-Opening Polymerization for the Highly Efficient Synthesis of Polyester-Based Star Polymers.
Publisher: American Chemical Society (ACS)
Date: 17-05-2012
DOI: 10.1021/MZ300169M
Abstract: A facile, highly efficient, and metal-free synthesis of well-defined polyester-based core cross-linked star (CCS) polymers with yields of up to 96 % was achieved via an organic catalyst (i.e., methanesulfonic acid) mediated ring-opening polymerization (ROP) at room temperature, through either a two-pot or a one-pot, two-step strategy. CCS polymers with narrow molecular weight distributions (PDI ≤ 1.3) and macroinitiator (MI) conversions of 90-96% were prepared using poly(ε-caprolactone) (PCL) MIs with molecular weights ranging from 9.9 to 36.2 kDa and [4,4'-bioxepane]-7,7'-dione (BOD) as the cross-linker. Furthermore, transesterification was identified as being responsible for the small percentage of unincorporated low molecular weight polymer remaining and star-star couplings in the star formation. Compared to CCS polymers synthesized via the methanesulfonic acid-mediated ROP, CCS polymers prepared via ROP mediated by high transesterification rate catalysts (i.e., stannous octoate (Sn(Oct)
Star polymers composed entirely of amino acid building blocks: a route towards stereospecific, biodegradable and hierarchically functionalized stars
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CC03541F
Abstract: Highly functionalized water soluble core cross-linked star (CCS) polymers having degradable cores and hierarchical functionalities spanning from the peripheral groups along the arms to the core have been synthesized entirely from amino acid building blocks. The core-isolated moieties were shown to undergo further reactions, such as click chemistry, as well as being capable of encapsulating water-insoluble drugs.
(Super)hydrophobic and multilayered amphiphilic films prepared by continuous assembly of polymers
Publisher: Wiley
Date: 16-05-2013
Honeycomb Films from Perfluoropolyether-Based Star and Micelle Architectures
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CH12252
Abstract: A perfluoropolyether-b-poly(t-butyl acrylate) (PFPE-b-PtBA) block copolymer macroinitiator was used to prepare both core cross-linked star (CCS) polymers and micelles, whereby the outer shell and core, respectively, are comprised of fluorinated segments. The star polymer complete with PFPE outer shell was synthesised via atom transfer radical polymerisation (ATRP) and the arm-first approach, through cross-linking of the PFPE-b-PtBA macroinitiator with ethylene glycol diacrylate (EGDA). Alternatively, the PFPE-b-PtBA block copolymer could be self-assembled in benzene to form micelles with a PtBA shell and PFPE core. Both the micelle and CCS polymer were subsequently fabricated into non-cracking honeycomb (HC) patterned films on both planar and non-planar surfaces via the ‘Breath Figure’ (BF) technique using a static casting system.
Peptide-Based Star Polymers: The Rising Star in Functional Polymers
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CH12251
Abstract: Peptide-based star polymers show great potential as the next-generation of functional polymers due to their structure-related properties. The peptide component augments the polymer’s properties by introducing biocompatible and biodegradable segments, and enhancing their functionalities and structural ordering, which make peptide-based star polymers an attractive candidate in the field of nanomedicine. This article provides a brief summary of the recent developments of peptide-based star polymers synthesised from 2009 onwards. It is evident that the studies conducted so far have only started to uncover the true potential of what these polymers can achieve, and with continued research it is anticipated that peptide-based star polymers will be realised as versatile platforms applicable to broader fields of study, including drug delivery, tissue engineering, biocoatings, bioimaging, and self-directing templating agents.
Highly porous and mechanically robust polyester poly(ethylene glycol) sponges as implantable scaffolds
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.ACTBIO.2014.02.019
Abstract: The development of suitable scaffolds plays a significant role in tissue engineering research. Although scaffolds with promising features have been produced via a variety of innovative methods, there are no fully synthetic tissue engineering scaffolds that possess all the desired properties in one three-dimensional construct. Herein, we report the development of novel polyester poly(ethylene glycol) (PEG) sponges that display many of the desirable scaffold characteristics. Our novel synthetic approach utilizes acidchloride/alcohol chemistry, whereby the reaction between a hydroxyl end-functionalized 4-arm PEG and sebacoyl chloride resulted in cross-linking and simultaneous hydrogen chloride gas production, which was exploited for the in situ formation of highly interconnected pores. Variation of the fabrication conditions, including the precursor volume and concentration, allowed the pore size and structure as well as the compressive properties to be tailored. The sponges were found to possess excellent elastic properties, preserving their shape even after 80% compressive strain without failure. The benign properties of the sponges were demonstrated in an in vivo subcutaneous rat model, which also revealed uniform infiltration of vascularized tissue by 8 weeks and complete degradation of the sponges by 16 weeks, with only a minimal inflammatory response being observed over the course of the experiments.
Synthesis and photoreactivity of aryl substituted 4,5-dithienyl[1,3]dithiol-2-ones
Publisher: Elsevier BV
Date: 05-2009
Enhancement of radiation effects by bismuth oxide nanoparticles for kilovoltage x-ray beams: A dosimetric study using a novel multi-compartment 3D radiochromic dosimeter
Publisher: IOP Publishing
Date: 26-06-2013
Drug-eluting non-vascular stents for localised drug targeting in obstructive gastrointestinal cancers
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JCONREL.2019.07.001
Abstract: Stents are currently the primary choice for the treatment of both vascular and non-vascular occlusions and/or stenosis. Despite the proven history of clinical safety and efficacy, the benefit of traditional vascular or non-vascular stenting is often limited by in-stent restenosis, resulting in failure of existing stent or reintervention by use of another stent. Coronary drug-eluting stents (DESs) significantly reduce restenosis of vascular stents and have revolutionised the percutaneous coronary intervention (PCI) treatment in coronary stenting patients. Following the similar concept of coronary DESs, non-vascular DESs are being investigated to reduce non-vascular restenosis caused by tumour growth, enhance stenting functions, and increase their effectiveness in the treatment of obstructive gastrointestinal (GI) cancers. This article summarises and updates the outcomes of preclinical and clinical studies on non-vascular DESs for localised management of malignant GI obstructions with emphasis on fabrication techniques and regulatory requirements relevant to development and marketing approval.
Samarium doped titanium dioxide nanoparticles as theranostic agents in radiation therapy
Publisher: Elsevier BV
Date: 07-2020
Autophobicity-Driven Surface Segregation and Patterning of Core−Shell Microgel Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 08-08-2008
DOI: 10.1021/NL802109X
Abstract: Core-shell microgel (CSMG) nanoparticles, also referred to as core-cross-linked star (CCS) polymers, can be envisaged as permanently cross-linked block copolymer micelles and, as such, afford novel opportunities for chemical functionalization, templating, and encapsulation. In this study, we explore the behavior of CSMG nanoparticles comprising a poly(methyl methacrylate) (PMMA) shell in molten PMMA thin films. Because of the autophobicity between the densely packed, short PMMA arms of the CSMG shell and the long PMMA chains in the matrix, the nanoparticles migrate to the film surface. They cannot, however, break through the surface because of the inherently high surface energy of PMMA. Similar thermal treatment of CSMG-containing PMMA thin films with a polystyrene (PS) capping layer replaces surface energy at the PMMA/air interface by interfacial energy at the PMMA/PS interface, which reduces the energy barrier by an order of magnitude, thereby permitting the nanoparticles to emerge out of the PMMA bulk. This nanoscale process is reversible and can be captured at intermediate degrees of completion. Moreover, it is fundamentally general and can be exploited as an alternative means by which to reversibly pattern or functionalize polymer surfaces for applications requiring responsive nanolithography.
Three-dimensional printed 5-fluorouracil eluting polyurethane stents for the treatment of oesophageal cancers
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0BM01355B
Abstract: 3D printing is introduced as rapid and facile approach to prepare personalized drug-eluting stents for the treatment of oesophageal cancers.
Influence of Lyophilization and Cryoprotection on the Stability and Morphology of Drug-Loaded Poly(ethylene glycol-b-ε-caprolactone) Micelles
Publisher: MDPI AG
Date: 21-04-2023
Abstract: Polymeric micelles are promising carriers for the delivery of poorly water-soluble drugs, providing enhanced drug solubility, blood circulation times, and bioavailability. Nevertheless, the storage and long-term stability of micelles in solution present challenges requiring the lyophilization and storage of formulations in the solid state, with reconstitution immediately prior to application. Therefore, it is important to understand the effects of lyophilization/reconstitution on micelles, particularly their drug-loaded counterparts. Herein, we investigated the use of β-cyclodextrin (β-CD) as a cryoprotectant for the lyophilization/reconstitution of a library of poly(ethylene glycol-b-ε-caprolactone) (PEG-b-PCL) copolymer micelles and their drug-loaded counterparts, as well as the effect of the physiochemical properties of different drugs (phloretin and gossypol). The critical aggregation concentration (CAC) of the copolymers decreased with increasing weight fraction of the PCL block (fPCL), plateauing at ~1 mg/L when the fPCL was .45. The blank (empty) and drug-loaded micelles were lyophilized/reconstituted in the absence and presence of β-CD (9% w/w) and analyzed via dynamic light scattering (DLS) and synchrotron small-angle X-ray scattering (SAXS) to assess for changes in aggregate size (hydrodynamic diameter, Dh) and morphology, respectively. Regardless of the PEG-b-PCL copolymer or the use of β-CD, the blank micelles displayed poor redispersibility ( % relative to the initial concentration), while the fraction that redispersed displayed similar Dh to the as-prepared micelles, increasing in Dh as the fPCL of the PEG-b-PCL copolymer increased. While most blank micelles displayed discrete morphologies, the addition of β-CD or lyophilization/reconstitution generally resulted in the formation of poorly defined aggregates. Similar results were also obtained for drug-loaded micelles, with the exception of several that retained their primary morphology following lyophilization/reconstitution, although no obvious trends were noted between the microstructure of the copolymers or the physicochemical properties of the drugs and their successful redispersion.
Thermal, Optical, and Static/Dynamic Mechanical Properties of Linear-core Crosslinked Star Polymer Blends
Publisher: Wiley
Date: 20-06-2011
Rapid fabrication of functionalised poly(dimethylsiloxane) microwells for cell aggregate formation
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6BM00916F
Abstract: Cell aggregates reproduce many features of the natural architecture of functional tissues, and have therefore become an important in vitro model of tissue function.
Development and validation of a multicultural Spanish-language version of the Muscularity-Oriented Eating Test (MOET) in Argentina
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.EATBEH.2021.101542
Abstract: The utility of traditional eating disorder measures in the assessment of muscularity-oriented disordered eating has been questioned. To address this limitation, the Muscularity-Oriented Eating Test (MOET) was recently developed and validated in a s le of U.S. college men. We aimed to develop a multicultural Spanish-language version of the MOET for use in Latin American s les and validate its use in a s le of Argentinian college men. Combined translation procedures were used to develop a version suitable for different Spanish-speaking populations. A total of 235 students (M
Mammalian Cell-Based Assays for Studying Bio-Nano Interactions
Publisher: Elsevier
Date: 2018
Ring-Opening Metathesis Polymerization with the Second Generation Hoveyda–Grubbs Catalyst: An Efficient Approach toward High-Purity Functionalized Macrocyclic Oligo(cyclooctene)s
Publisher: American Chemical Society (ACS)
Date: 08-04-2013
DOI: 10.1021/JA312418Z
Abstract: Herein, we present a facile and general strategy to prepare functionalized macrocyclic oligo(cyclooctene)s (cOCOEs) in high purity and high yield by exploiting the ring-opening metathesis polymerization (ROMP) intramolecular backbiting process with the commercially available second generation Hoveyda-Grubbs (HG2) catalyst. In the first instance, ROMP of 5-acetyloxycyclooct-1-ene (ACOE) followed by efficient quenching and removal of the catalyst using an isocyanide derivative afforded macrocyclic oligo(5-acetyloxycyclooct-1-ene) (cOACOE) in high yield (95%), with a weight-average molecular weight (Mw) of 1.6 kDa and polydispersity index (PDI) of 1.6, as determined by gel permeation chromatography (GPC). The structure and purity of the macrocycles were confirmed by NMR spectroscopy and elemental analysis, which indicated the complete absence of end-groups. This was further supported by GPC-matrix assisted laser desorption ionization time-of-flight mass spectroscopy (GPC-MALDI ToF MS), which revealed the exclusive formation of macrocyclic derivatives composed of up to 45 repeat units. Complete removal of residual ruthenium from the macrocycles was confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The same methodology was subsequently extended to the ROMP of 5-bromocyclooct-1-ene and 1,5-cyclooctadiene to prepare their macrocyclic derivatives, which were further derivatized to produce a library of functionalized macrocyclic oligo(cyclooctene)s. A comparative study using the second and third generation Grubbs catalysts in place of the HG2 catalyst for the polymerization of ACOE provided macrocycles contaminated with linear species, thus indicating that the bidendate benzylidene ligand of the Hoveyda-Grubbs catalyst plays an important role in the observed product distributions.
PMMA Star-Like Polymers via One-Pot Conventional Free-Radical Copolymerization
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CH09358
Abstract: Poly(methyl methacrylate)-based star-like polymers (SLPs) were synthesized by a one-pot conventional free-radical copolymerization. Two aryl ester-based cross-linkers, bisphenol A dimethacrylate and 1,4-bis(methacryloxy)benzene, were found to induce SLP formation by reactivity control when copolymerized with methyl methacrylate. The formulation domain diagrams for these systems were established and high monomer concentrations (up to 70 wt-%) were achievable without the occurrence of macrogelation. Kinetic experiments confirmed that the SLP formation occurs via a pseudo two-step mechanism. Parallel plate rheological analysis of the SLP solutions demonstrated that these polymers had low viscosities, typically several orders of magnitude lower than the analogous linear polymer solution.
Stabilization of Peptide-Based Vesicles via in situ Oxygen-Mediated Cross-Linking
Publisher: Wiley
Date: 13-07-2012
Abstract: Reversible vesicles from poly(L-glutamic acid)(65) -block-poly[(L-lysine)-ran-(L-3,4-dihydroxyphenylalanine)](75) [PLGA(65)-b-P(LL-r-DOPA)(75)] block copolypeptide adopt different configurations depending on the surrounding pH. At pH = 3, AFM and TEM images show ellipsoidal morphologies, whereas at pH = 12 both TEM and AFM reveal the formation of hollow vesicles. At pH = 12, the P(LL-r-DOPA) block forms the internal layer of the vesicle shell and the subsequent oxygen-mediated oxidation of the phenolic groups of the DOPA lead to the formation of quinonic intermediates, which undergo intermolecular dimerization to stabilize the vesicles via in situ cross-linking. Consequently, the vesicles maintain their shape even when the pH is reversed back to 3, as confirmed by AFM and TEM.
Stereospecific Cyclic Poly(methyl methacrylate) and Its Topology‐Guided Hierarchically Controlled Supramolecular Assemblies
Publisher: Wiley
Date: 25-11-2013
Abstract: In this study, the stereocomplexation between a novel stereospecific cyclic vinyl polymer, that is, cyclic syndiotactic poly(methyl methacrylate) (st-PMMA), with the complementary linear isotactic (it-) PMMA was investigated. Surprising new insight into the effects of the topology (i.e., end groups), size, and tacticity of the assembling components on stereocomplex formation was obtained. Characterization of the stereocomplexes revealed that the self-assembly of cyclic st-PMMAs and linear it-PMMAs resulted in the formation of an unprecedented “polypseudorotaxane-type” supramolecular assembly. This stereocomplex exhibited remarkably different physical properties as compared to the conventional PMMA triple-helix stereocomplex as a result of the restricted topology imposed by the cyclic st-PMMA assembling component.
Fabrication of chiral stationary phases via continuous assembly of polymers for resolution of enantiomers by liquid chromatography
Publisher: Wiley
Date: 07-07-2014
Assembly of nanostructured films with hydrophobic subcompartments via continuous assembly of polymers
Publisher: American Chemical Society (ACS)
Date: 27-09-2013
DOI: 10.1021/MA4017357
An investigation into the potential influence of oxygen on the efficiency of the PRESAGE®dosimeter
Publisher: IOP Publishing
Date: 12-01-2015
Cyclodextrin-based supramolecular assemblies and hydrogels: recent advances and future perspectives.
Publisher: Wiley
Date: 08-04-2014
Abstract: The application of cyclodextrin (CD)-based host-guest interactions towards the fabrication of functional supramolecular assemblies and hydrogels is of particular interest in the field of biomedicine. However, as of late they have found new applications as advanced functional materials (e.g., actuators and self-healing materials), which have renewed interest across a wide range of fields. Advanced supramolecular materials synthesized using this noncovalent interaction, exhibit specificity and reversibility, which can be used to impart reversible cross-linking, specific binding sites, and functionality. In this review, various functional CD-based supramolecular assemblies and hydrogels will be outlined with the focus on recent advances. In addition, an outlook will be provided on the direction of this rapidly developing field.
Nano‐to‐Macroscale Poly(methyl methacrylate) Stereocomplex Assemblies
Publisher: Wiley
Date: 28-10-2009
pH-Responsive Poly(ethylene glycol)-b-poly(2-vinylpyridine) Micelles for the Triggered Release of Therapeutics
Publisher: MDPI AG
Date: 18-03-2023
DOI: 10.3390/PHARMACEUTICS15030977
Abstract: The use of pH-responsive polymeric micelles is a promising approach to afford the targeted, pH-mediated delivery of hydrophobic drugs within the low-pH tumour milieu and intracellular organelles of cancer cells. However, even for a common pH-responsive polymeric micelle system—e.g., those utilising poly(ethylene glycol)-b-poly(2-vinylpyridine) (PEG-b-PVP) diblock copolymers—there is a lack of available data describing the compatibility of hydrophobic drugs, as well as the relationships between copolymer microstructure and drug compatibility. Furthermore, synthesis of the constituent pH-responsive copolymers generally requires complex temperature control or degassing procedures that limit their accessibility. Herein we report the facile synthesis of a series of diblock copolymers via visible-light-mediated photocontrolled reversible addition-fragmentation chain-transfer polymerisation, with a constant PEG block length (90 repeat units (RUs)) and varying PVP block lengths (46–235 RUs). All copolymers exhibited narrow dispersity values (Đ ≤ 1.23) and formed polymeric micelles with low polydispersity index (PDI) values (typically .20) at physiological pH (7.4), within a suitable size range for passive tumour targeting ( nm). The encapsulation and release of three hydrophobic drugs (cyclin-dependent kinase inhibitor (CDKI)-73, gossypol, and doxorubicin) were investigated in vitro at pH 7.4–4.5 to simulate drug release within the tumour milieu and cancer cell endosome. Marked differences in drug encapsulation and release were observed when the PVP block length was increased from 86 to 235 RUs. With a PVP block length of 235 RUs, the micelles exhibited differing encapsulation and release properties for each drug. Minimal release was observed for doxorubicin (10%, pH 4.5) and CDKI-73 exhibited moderate release (77%, pH 4.5), whereas gossypol exhibited the best combination of encapsulation efficiency (83%) and release (91% pH 4.5) overall. These data demonstrate the drug selectivity of the PVP core, where both the block molecular weight and hydrophobicity of the core (and accordingly the hydrophobicity of the drug) have a significant effect on drug encapsulation and release. These systems remain a promising means of achieving targeted, pH-responsive drug delivery—albeit for select, compatible hydrophobic drugs—which warrants their further investigation to develop and evaluate clinically relevant micelle systems.
Thermoresponsive Poly(ε-Caprolactone)-Poly(Ethylene/Propylene Glycol) Copolymers as Injectable Hydrogels for Cell Therapies
Publisher: MDPI AG
Date: 07-02-2020
Abstract: Injectable, thermoresponsive hydrogels are promising candidates for the delivery, maintenance and controlled release of adoptive cell therapies. Therefore, there is significant interest in the development of cytocompatible and biodegradable thermoresponsive hydrogels with appropriate gelling characteristics. Towards this end, a series of thermoresponsive copolymers consisting of poly(caprolactone) (PCL), poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) segments, with various PEG:PPG ratios, were synthesised via ring-opening polymerisation (ROP) of ε-caprolactone and epoxy-functionalised PEG and PPG derivatives. The resultant PCL–PEG–PPG copolymers were characterised via proton nuclear magnetic resonance (1H NMR) spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The thermoresponsive characteristics of the aqueous copolymer solutions at various concentrations was investigated using the inversion method. Whilst all of the copolymers displayed thermoresponsive properties, the copolymer with a ratio of 1:2 PEG:PPG exhibited an appropriate sol–gel transition (28 °C) at a relatively low concentration (10 wt%), and remained a gel at 37 °C. Furthermore, the copolymers were shown to be enzymatically degradable in the presence of lipases and could be used for the encapsulation of CD4+ T-cell lymphocytes. These results demonstrate that the thermoresponsive PCL–PEG–PPG hydrogels may be suitable for use as an adoptive cell therapy (ACT) delivery vehicle.
The synthesis of novel 3-substituted polypyrroles bearing crown-ether moieties and a study of their electrochemical properties
Publisher: Elsevier BV
Date: 2006
Characterization of novel water-equivalent PRESAGE® dosimeters for megavoltage and kilovoltage x-ray beam dosimetry
Publisher: Elsevier BV
Date: 03-2015
Synthesis and characterization of fluorescently labeled core cross‐linked star polymers
Publisher: Wiley
Date: 22-02-2008
DOI: 10.1002/POLA.22576
Nonwoven Carboxylated Agarose-Based Fiber Meshes with Antimicrobial Properties
Publisher: American Chemical Society (ACS)
Date: 22-11-2016
DOI: 10.1021/ACS.BIOMAC.6B01401
Abstract: Hydrogel forming polysaccharides, such as the seaweed derived agarose, are well suited for wound dressing applications as they have excellent cell and soft tissue compatibility. For wound dressings, fibrous structure is desirable as the high surface area can favor adsorption of wound exudate and promote drug delivery. Although electrospinning offers a straightforward means to produce nonwoven fibrous polymeric structures, processing agarose and its derivatives into fibers through electrospinning is challenging as it has limited solubility in solvents other than water. In this study we describe the processing of carboxylated agarose (CA) fibers with antibacterial properties by electrospinning from a solution of the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([Bmim]
A carbene insertion approach to functionalised poly(ethylene oxide)-based gels
Publisher: Elsevier BV
Date: 04-2008
An experimental and analytical study of the effects of shear displacement, fluid type, joint roughness, shear strength, friction angle and dilation angle on proppant embedment development in tight gas
Publisher: Elsevier BV
Date: 07-2018
Synthesis of a Star Polymer Library with a Diverse Range of Highly Functionalized Macromolecular Architectures
Publisher: American Chemical Society (ACS)
Date: 05-04-2011
DOI: 10.1021/MA200283C
Cyclodextrin-based supramolecular polymeric nanoparticles for next generation gas separation membranes
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA03281D
Abstract: Cyclodextrin-based supramolecular polyrotaxanes are for the first time used as soft nanoparticle additives for the selective layer of composite membranes. They exhibit outstanding gas transport characteristics at low additive percentages, due to the dynamic nature of the PDMS side chains.
Influence of Polymer Elasticity on the Formation of Non‐Cracking Honeycomb Films
Publisher: Wiley
Date: 22-06-2012
Abstract: Non-planar non-cracking honeycomb (HC) structures are prepared from star polymers with high glass transition temperatures (T(g) ) and relatively low Young's moduli (E). This study demonstrates that the Young's modulus of a polymer is a more important factor than the glass transition temperature for determining the occurrence of cracking during HC film formation on non-planar surfaces.
Using GPCRs as Molecular Beacons to Target Ovarian Cancer with Nanomedicines
Publisher: MDPI AG
Date: 10-05-2022
Abstract: The five-year survival rate for women with ovarian cancer is very poor despite radical cytoreductive surgery and chemotherapy. Although most patients initially respond to platinum-based chemotherapy, the majority experience recurrence and ultimately develop chemoresistance, resulting in fatal outcomes. The current administration of cytotoxic compounds is h ered by dose-limiting severe adverse effects. There is an unmet clinical need for targeted drug delivery systems that transport chemotherapeutics selectively to tumor cells while minimizing off-target toxicity. G protein-coupled receptors (GPCRs) are the largest family of membrane receptors, and many are overexpressed in solid tumors, including ovarian cancer. This review summarizes the progress in engineered nanoparticle research for drug delivery for ovarian cancer and discusses the potential use of GPCRs as molecular entry points to deliver anti-cancer compounds into ovarian cancer cells. A newly emerging treatment paradigm could be the personalized design of nanomedicines on a case-by-case basis.
Optimization of the sensitivity and stability of the PRESAGE™ dosimeter using trihalomethane radical initiators
Publisher: Elsevier BV
Date: 07-2012
Development and In Vitro Evaluation of 5-Fluorouracil-Eluting Stents for the Treatment of Colorectal Cancer and Cancer-Related Obstruction
Publisher: MDPI AG
Date: 24-12-2020
DOI: 10.3390/PHARMACEUTICS13010017
Abstract: Self-expanding metal stents (SEMSs) are currently the gold standard for the localised management of malignant gastrointestinal (GI) stenosis and/or obstructions. Despite encouraging clinical success, in-stent restenosis caused by tumour growth is a significant challenge. Incorporating chemotherapeutic drugs into GI stents is an emerging strategy to provide localised and sustained release of drugs to intestinal malignant tissues to prevent tumour growth. Therefore, the aim of this work was to develop and evaluate a local GI stent-based delivery system that provides a controlled release of 5-fluorouracil (5FU) over a course of several weeks to months, for the treatment of colorectal cancer and cancer-related stenosis/obstructions. The 5FU-loaded GI stents were fabricated via sequential dip-coating of commercial GI stents with a drug-loaded polyurethane (PU) basecoat and a drug-free poly(ethylene-co-vinyl acetate) (PEVA) topcoat. For comparison, two types of commercial stents were investigated, including bare and silicone (Si) membrane-covered stents. The physicochemical properties of the 5FU-loaded stents were evaluated using photoacoustic Fourier-transform infrared (PA-FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and thermal analysis. In vitro release studies in biological medium revealed that the 5FU-loaded stents provided a sustained release of drug over the period studied (18 d), and cell viability, cell cycle distribution and apoptosis assays showed that the released 5FU had comparable anticancer activity against human colon cancer cells (HCT-116) to pure 5FU. This study demonstrates that dip-coating is a facile and reliable approach for fabricating drug-eluting stents (DESs) that are promising candidates for the treatment of GI obstructions and/or restenosis.
Development of amphiphilic multi-star polymers with highly grafted pyrene connectors as unimolecular encapsulation devices
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY01160G
Continuous assembly of polymers via solid phase reactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SC01240B
Abstract: The formation of cross-linked polymer films, with tunable thickness, proceeds directionally from the substrate surface by controlled polymerization in the solid state.
Epoxy-amine synthesised hydrogel scaffolds for soft-tissue engineering
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.BIOMATERIALS.2010.05.008
Abstract: Highly porous and biodegradable hydrogels based on poly(ethylene glycol) (PEG) and cystamine (Cys) were fabricated using epoxy-amine chemistry and investigated as scaffolds for soft-tissue engineering. Whereas the application of fused-salt templates provided a comprehensive interconnecting pore morphology, the incorporation of a specially designed poly(epsilon-caprolactone) (PCL) cross-linker provided enhanced mechanical function without adversely effecting the scaffolds positive biological interactions. The addition of only 1.2 wt% of the PCL cross-linker was sufficient to provide improvements in the ultimate stress of 30-40%. In vitro studies not only confirmed the non-cytotoxic nature of the scaffolds, but also their degradation products, which were isolated and characterised by nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionisation time-of-flight mass spectroscopy (MALDI ToF MS). In vivo trials were conducted over a period of 8 weeks through implantation of the scaffolds into the dorsal region of rats. At both 2 and 8 week time points the explants revealed complete infiltration by the surrounding tissue and the development of a vascular network to support the newly generated tissue, without an excessive foreign-body response.
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University Of Reading
Location: United Kingdom of Great Britain and Northern Ireland
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