Imperial College London

Emeritus ProfessorAndrewHolmes

Faculty of Natural SciencesDepartment of Chemistry

Distinguished Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 9286andrew.holmes Website

 
 
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Assistant

 

Ms Maria Tortelli +44 (0)20 7594 9286

 
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Location

 

Molecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Publication Type
Year
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552 results found

Thaler MA, Bietenbeck A, Yin M-X, Steigerwald U, Holmes AB, Lindhoff-Last E, Luppa PBet al., 2016, Evaluation of antiphospholipid antibody assays using latent class analysis to address the lack of a reference standard., Clin Chem Lab Med, Vol: 54, Pages: 1929-1937

BACKGROUND: Method evaluation of new assays for the detection of antiphospholipid antibodies (aPL) such as anti-cardiolipin (aCL) or anti-β2-glycoprotein I (aβ2-GPI) is challenging, as no internationally accepted reference material is available yet. Besides a lack of standardization, unacceptable inter-laboratory comparability of established tests is regularly observed. Owing to the absence of a commonly accepted reference standard, the evaluation of two research surface plasmon resonance (SPR) biosensor assays was performed using statistical methods from latent class analysis (LCA). METHODS: aCL and aβ2-GPI IgG and IgM were measured in sera from 63 antiphospholipid syndrome patients, fulfilling the Sydney criteria, and in 34 healthy controls with four commercial assays. LCA was performed on the results and sera were assigned to the antibody-positive or antibody-negative group. Sera were subsequently evaluated in the SPR assays for aCL and aβ2-GPI. Optimal cutoffs and diagnostic performances of the research systems were established employing the LCA-derived gold standard. RESULTS: With area under the curve results of 0.96 and 0.89 for the detection of aCL and aβ2-GPI, the research SPR assays discriminated well between antibody-positive and antibody-negative sera. Their sensitivities and specificities were comparable to the investigated commercial immunoassays. CONCLUSIONS: SPR assays are a suitable tool for the detection of aCL and aβ2-GPI with diagnostic performances not different from currently available commercial tests. LCA enabled the calculation of sensitivities and specificities for aPL assays in absence of a reference standard.

Journal article

Gao M, Subbiah J, Geraghty PB, Chen M, Purushothaman B, Chen X, Qin T, Vak D, Scholes FH, Watkins SE, Skidmore M, Wilson GJ, Holmes AB, Jones DJ, Wong WWHet al., 2016, Development of a High-Performance Donor-Acceptor Conjugated Polymer: Synergy in Materials and Device Optimization, Chemistry of Materials, Vol: 28, Pages: 3481-3487, ISSN: 0897-4756

The development of a high-performance polymer PBDT-BT for bulk heterojunction solar cell devices is summarized. The polymer was first synthesized by Stille polycondensation, and solar cell devices in conventional geometry were optimized through the use of a lithium salt cathode interlayer reaching 6% power conversion efficiency. Improvements were made to the synthesis of the polymer using Suzuki polycondensation giving high-molecular-weight material in the Mn = 100 kg/mol range. Further device optimization in inverted geometry gave power conversion efficiency of over 9%. The synthesis scalability as well as the batch-to-batch reproducibility of the polymer were extensively investigated.

Journal article

Yin M-X, Catimel B, Gregory M, Condron M, Kapp E, Holmes AB, Burgess AWet al., 2016, Synthesis of an inositol hexakisphosphate (IP6) affinity probe to study the interactome from a colon cancer cell line., Integr Biol (Camb), Vol: 8, Pages: 309-318

Inositol hexakisphosphate (InsP6 or IP6) is an important signalling molecule in vesicular trafficking, neurotransmission, immune responses, regulation of protein kinases and phosphatases, activation of ion channels, antioxidant functions and anticancer activities. An IP6 probe was synthesised from myo-inositol via a derivatised analogue, which was immobilised through a terminal amino group onto Dynabeads. Systematic analysis of the IP6 interactome has been performed using the IP6 affinity probe using cytosolic extracts from the LIM1215 colonic carcinoma cell line. LC/MS/MS analysis identified 77 proteins or protein complexes that bind to IP6 specifically, including AP-2 complex proteins and β-arrestins as well as a number of novel potential IP6 interacting proteins. Bioinformatic enrichment analysis of the IP6 interactome reinforced the concept that IP6 regulates a number of biological processes including cell cycle and division, signal transduction, intracellular protein transport, vesicle-mediated transport and RNA splicing.

Journal article

Gregory M, Catimel B, Yin MX, Condron M, Burgess AW, Holmes ABet al., 2016, Synthesis of a Tethered myo -Inositol (1,3,4,5,6)Pentakisphosphate (IP5) Derivative as a Probe for Biological Studies, Synlett, Vol: 27, Pages: 121-125, ISSN: 0936-5214

There is sufficient evidence to suggest that myo-inositol pentakisphosphate is a vital intermediate species in higher inositol phosphate metabolism, however, its biological roles and physiological function in cells remain uncertain. A tethered myo-inositol pentakisphosphate (IP5) derivative with a terminal amine group is synthesised allowing facilitated immobilisation onto M-270 magnetic Dynabeads for pull-down experiments and biosensor chip preparation for surface plasmon resonance studies. The probes are validated by both pull-down and surface plasmon resonance (SPR) studies of the known binding protein GRP-1 (general receptor for phosphoinositides 1), and furthermore by SPR studies of protein kinase B (PKB or AKT) binding.

Journal article

Hooper JF, James NC, Bozkurt E, Aviyente V, White JM, Holland MC, Gilmour R, Holmes AB, Houk KNet al., 2015, Medium-Ring Effects on the Endo/Exo Selectivity of the Organocatalytic Intramolecular Diels-Alder Reaction., J Org Chem, Vol: 80, Pages: 12058-12075

The intramolecular Diels-Alder reaction has been used as a powerful method to access the tricyclic core of the eunicellin natural products from a number of 9-membered-ring precursors. The endo/exo selectivity of this reaction can be controlled through a remarkable organocatalytic approach, employing MacMillan's imidazolidinone catalysts, although the mechanistic origin of this selectivity remains unclear. We present a combined experimental and density functional theory investigation, providing insight into the effects of medium-ring constraints on the organocatalyzed intramolecular Diels-Alder reaction to form the isobenzofuran core of the eunicellins.

Journal article

Wong WWH, Banal JL, Geraghty PB, Hong Q, Zhang B, Holmes AB, Jones DJet al., 2015, Organic Photovoltaic Materials - Design, Synthesis and Scale-Up, Chemical Record, Vol: 15, Pages: 1006-1020, ISSN: 1527-8999

This account describes the work of our group in the area of organic photovoltaics in the past six years. The emphasis is on our experiences in the development of the organic materials, their characterization, scale-up and application in devices. We share our insight into the relationship between synthetic methods, molecular properties, bulk material properties and device performance. Experience and insight into organic photovoltaic materials research are presented in this account. The emphasis is on our experiences in the development of the organic materials, their characterization, scale-up and application in devices. We share our insight into the relationship between synthetic methods, molecular properties, bulk material properties and device performance.

Journal article

Han HG, Weerasinghe HC, Min Kim K, Soo Kim J, Cheng YB, Jones DJ, Holmes AB, Kwon THet al., 2015, Ultrafast Fabrication of Flexible Dye-Sensitized Solar Cells by Ultrasonic Spray-Coating Technology, Scientific Reports, Vol: 5

This study investigates novel deposition techniques for the preparation of TiO 2 electrodes for use in flexible dye-sensitized solar cells. These proposed new methods, namely pre-dye-coating and codeposition ultrasonic spraying, eliminate the conventional need for time-consuming processes such as dye soaking and high-temperature sintering. Power conversion efficiencies of over 4.0% were achieved with electrodes prepared on flexible polymer substrates using this new deposition technology and N719 dye as a sensitizer.

Journal article

Maniam S, Holmes AB, Leeke GA, Bilic A, Collis GEet al., 2015, Chemically Altering the Solubility and Durability of Dyes for Sensitized Solar Cells, Organic Letters, Vol: 17, Pages: 4022-4025, ISSN: 1523-7060

By designing dyes with fluoroalkyl groups, the optical and electronic properties of the alkyl analogue were maintained while dramatically altering the solubility. Dyes, F-TABTA (8) and its masked derivative F-TABTSi (9), that enable them to be deposited under conventional organic solvent and scCO<inf>2</inf> conditions, respectively, were developed. In liquid DSSC devices, the fluoroalkyl dye (F-TABTA, 8) performs slightly better than its alkyl analogue (D21L6, 10), and interestingly, it was found that the former device showed better stability over time. Deploying the silyl-masked precursor F-TABTSi (9), this dye was deposited onto TiO<inf>2</inf> photoanodes from scCO<inf>2</inf> in very short contact times (2.5 h), and ECEs of 7.70% were obtained that exceed the performance of the alkyl dye when deposited by conventional methods.

Journal article

Olshina MA, Angrisano F, Marapana DS, Riglar DT, Bane K, Wong W, Catimel B, Yin MX, Holmes AB, Frischknecht F, Kovar DR, Baum JACOBet al., 2015, Plasmodium falciparum coronin organizes arrays of parallel actin filaments potentially guiding directional motility in invasive malaria parasites, Malaria Journal, Vol: 14, ISSN: 1475-2875

BackgroundGliding motility in Plasmodium parasites, the aetiological agents of malaria disease, is mediated by an actomyosin motor anchored in the outer pellicle of the motile cell. Effective motility is dependent on a parasite myosin motor and turnover of dynamic parasite actin filaments. To date, however, the basis for directional motility is not known. Whilst myosin is very likely orientated as a result of its anchorage within the parasite, how actin filaments are orientated to facilitate directional force generation remains unexplained. In addition, recent evidence has questioned the linkage between actin filaments and secreted surface antigens leaving the way by which motor force is transmitted to the extracellular milieu unknown. Malaria parasites possess a markedly reduced repertoire of actin regulators, among which few are predicted to interact with filamentous (F)-actin directly. One of these, PF3D7_1251200, shows strong homology to the coronin family of actin-filament binding proteins, herein referred to as PfCoronin.MethodsHere the N terminal beta propeller domain of PfCoronin (PfCor-N) was expressed to assess its ability to bind and bundle pre-formed actin filaments by sedimentation assay, total internal reflection fluorescence (TIRF) microscopy and confocal imaging as well as to explore its ability to bind phospholipids. In parallel a tagged PfCoronin line in Plasmodium falciparum was generated to determine the cellular localization of the protein during asexual parasite development and blood-stage merozoite invasion.ResultsA combination of biochemical approaches demonstrated that the N-terminal beta-propeller domain of PfCoronin is capable of binding F-actin and facilitating formation of parallel filament bundles. In parasites, PfCoronin is expressed late in the asexual lifecycle and localizes to the pellicle region of invasive merozoites before and during erythrocyte entry. PfCoronin also associates strongly with membranes within the cell, likely medi

Journal article

Xiao Z, Sun K, Subbiah J, Qin T, Lu S, Purushothaman B, Jones DJ, Holmes AB, Wong WWHet al., 2015, Effect of molecular weight on the properties and organic solar cell device performance of a donor-acceptor conjugated polymer, Polymer Chemistry, Vol: 6, Pages: 2312-2318, ISSN: 1759-9954

Donor-acceptor conjugated polymers with 2-(2-ethylhexyl)-3-hexyl thienyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) as donor building block and 5,6-difluorobenzo[c][1,2,5]thiadiazole as acceptor building block have been synthesized by Stille coupling polymerization. The polymerization conditions were optimized to achieve high molecular weight polymers (number-average molecular weight, Mn, up to 139 kg mol-1). The molecular weight dependent polymer properties were studied and compared. Photovoltaic applications of the polymers in bulk heterojunction (BHJ) solar cells revealed that the power conversion efficiency increased significantly (from 0.9% to 4.1%) as the Mn increased from 10 kg mol-1 to 73 kg mol-1 while further increase of the molecular weight had less influence on the solar cell performance.

Journal article

Grenier F, Aïch BR, Lai YY, Guérette M, Holmes AB, Tao Y, Wong WWH, Leclerc Met al., 2015, Electroactive and photoactive poly[isoindigo-alt-EDOT] synthesized using direct (hetero)arylation polymerization in batch and in continuous flow, Chemistry of Materials, Vol: 27, Pages: 2137-2143, ISSN: 0897-4756

In this work, a combined approach was used to obtain a low-cost material for organic electronics by focusing on inexpensive monomers, short synthetic pathway, high-yielding polymerization method, low waste, and easy scalability. To achieve this, a new material, poly[isoindigo-alt-3,4-ethylenedioxythiophene], was synthesized using direct (hetero)arylation polymerization (DHAP). Only a few synthetic steps are required to obtain this material, and no organometallic intermediates are used. In order to make a bigger step toward a truly inexpensive technology, continuous flow methods were applied for the first time to DHAP. This method helped solving a common problem encountered in conjugated polymers synthesis, namely, batch-to-batch variations. Electronic properties of this polymeric material were evaluated using field effect transistors (μ<inf>h</inf> = 7 × 10<sup>-3</sup> cm<sup>2</sup>·V<sup>-1</sup>·s<sup>-1</sup>) and solar cells (η = 3.0%).

Journal article

Subbiah J, Purushothaman B, Chen M, Qin T, Gao M, Vak D, Scholes FH, Chen X, Watkins SE, Wilson GJ, Holmes AB, Wong WWH, Jones DJet al., 2015, Organic solar cells using a high-molecular-weight benzodithiophene-benzothiadiazole copolymer with an efficiency of 9.4%., Adv Mater, Vol: 27, Pages: 702-705

A high molecular weight donor-acceptor conjugated polymer is synthesized using the Suzuki polycondensation method. Using this polymer, a single-junction bulk-heterojunction solar cell is fabricated giving a power conversion efficiency of 9.4% using a fullerene-modified ZnO interlayer at the cathode contact.

Journal article

Sun K, Xiao Z, Lu S, Zajaczkowski W, Pisula W, Hanssen E, White JM, Williamson RM, Subbiah J, Ouyang J, Holmes AB, Wong WWH, Jones DJet al., 2015, A molecular nematic liquid crystalline material for high-performance organic photovoltaics, Nature Communications, Vol: 6

Solution-processed organic photovoltaic cells (OPVs) hold great promise to enable roll-to-roll printing of environmentally friendly, mechanically flexible and cost-effective photovoltaic devices. Nevertheless, many high-performing systems show best power conversion efficiencies (PCEs) with a thin active layer (thickness is ∼100 nm) that is difficult to translate to roll-to-roll processing with high reproducibility. Here we report a new molecular donor, benzodithiophene terthiophene rhodanine (BTR), which exhibits good processability, nematic liquid crystalline behaviour and excellent optoelectronic properties. A maximum PCE of 9.3% is achieved under AM 1.5G solar irradiation, with fill factor reaching 77%, rarely achieved in solution-processed OPVs. Particularly promising is the fact that BTR-based devices with active layer thicknesses up to 400nm can still afford high fill factor of ∼70% and high PCE of ∼8%. Together, the results suggest, with better device architectures for longer device lifetime, BTR is an ideal candidate for mass production of OPVs.

Journal article

Gregory M, Yin MX, McConville MJ, Williams E, Bullock AN, Conway SJ, Burgess AW, Catimel B, Holmes ABet al., 2015, Synthesis of highly water-soluble adamantyl phosphoinositide derivatives, Australian Journal of Chemistry, Vol: 68, Pages: 543-548, ISSN: 0004-9425

Phosphatidylinositol phosphates are key regulators of cell signalling pathways and membrane trafficking in eukaryotic cells, and there is a need for new chemical probes to further understand how they interact with lipid-binding proteins. Here, the synthesis of phosphatidylinositol phosphate analogues containing adamantyl carboxylic ester groups, in place of the natural lipid side chains, is described. These derivatives are considerably more soluble in water than analogues containing other lipid side chains and do not form large aggregates such as liposomes or micelles. These adamantyl analogues bind to known phosphoinositide-binding proteins with similar affinities to native ligands and will facilitate future studies on the substrate specificities of these proteins involving cocrystallisation studies with proteins.

Journal article

Xiao Z, Subbiah J, Sun K, Jones DJ, Holmes AB, Wong WWHet al., 2014, Synthesis and photovoltaic properties of thieno[3,2-b]thiophenyl substituted benzo[1,2-b:4,5-b′]dithiophene copolymers, Polymer Chemistry, Vol: 5, Pages: 6710-6717, ISSN: 1759-9954

A new benzo[1,2-b:4,5-b′]dithiophene (BDT) building block with 4,8-disubstitution using 2-(2-ethylhexyl)-3-hexylthieno[3,2-b]thiophene as the substituent has been designed and synthesized. The new building block has been copolymerized with benzothiadiazole (BT) and 5,6-difluorobenzothiadiazole (fBT) by Suzuki and Stille coupling polymerization to synthesize donor-acceptor conjugated polymers. The optical and electrochemical properties of the synthesized copolymers were studied. Bulk heterojunction solar cells were fabricated using the donor-acceptor copolymers in conjunction with PC71BM and exhibited up to 4.20% power conversion efficiency.

Journal article

Hooper JF, White JM, Holmes AB, 2014, Development of the claisen rearrangement/organocatalytic diels-alder approach for the synthesis of eunicellins, Australian Journal of Chemistry, Vol: 67, Pages: 1189-1194, ISSN: 0004-9425

The intramolecular Diels-Alder approach to synthesizing eunicellins has proved to be a powerful method for the synthesis of this class of natural products. The key to the success of this strategy is control over the endo/exo selectivity of the cycloaddition reaction, which we have addressed through an organocatalytic reaction employing the MacMillan imidazolidinone catalyst. This approach has been further developed to address the issue of functionality at the C8 position, and a novel scalable method for the extension of the medium-ring lactone has been developed. © 2014 CSIRO.

Journal article

Bleher O, Schindler A, Yin M-X, Holmes AB, Luppa PB, Gauglitz G, Proll Get al., 2014, Development of a new parallelized, optical biosensor platform for label-free detection of autoimmunity-related antibodies., Anal Bioanal Chem, Vol: 406, Pages: 3305-3314

Autoimmune diseases are characterized by the presence of autoantibodies in serum of affected patients. The heterogeneity of autoimmune relevant antigens creates a variety of different antibodies, which requires a simultaneous detection mode. For this reason, we developed a tool for parallelized, label-free, optical detection that accomplishes the characterization of multiple antigen-antibody interactions within a single measurement on a timescale of minutes. Using 11-aminoundecyltrimethoxysilane, we were able to immobilize proteinogenic antigens as well as an amino-functionalized cardiolipin on a glass surface. Assay conditions were optimized for serum measurements with a single spot antigen chip on a single spot 1-λ detection system. Minimized background signal allows a differentiation between patients and healthy controls with a good sensitivity and specificity. Applying polarized imaging reflectometric interference spectroscopy, we evaluated samples from three APS patients and three control subjects for this proof-of-principle and already obtained good results for β2-glycoprotein I and cardiolipin.

Journal article

Wong WWH, Subbiah J, White JM, Seyler H, Zhang B, Jones DJ, Holmes ABet al., 2014, Single isomer of indene-C<inf>70</inf> bisadduct - Isolation and performance in bulk heterojunction solar cells, Chemistry of Materials, Vol: 26, Pages: 1686-1689, ISSN: 0897-4756

Indene-C70 bisadduct (IC70BA) is a high performance electron acceptor material consisting of a mixture of regioisomers. A single isomer of the IC70BA was isolated by careful chromatographic separation. The structure of this isomer was confirmed by various analytical techniques including single crystal X-ray analysis. The isomer showed superior performance to other isomer mixtures of IC70BA in bulk heterojunction solar cells using poly(3-hexylthiophene) as the donor material. © 2014 American Chemical Society.

Journal article

Xiao Z, Subbiah J, Sun K, Ji S, Jones DJ, Holmes AB, Wong WWHet al., 2014, Thiazolyl substituted benzodithiophene copolymers: Synthesis, properties and photovoltaic applications, Journal of Materials Chemistry C, Vol: 2, Pages: 1306-1313, ISSN: 2050-7534

Three new conjugated polymers based on 5-decylthiazol-2-yl substituted benzodithiophene have been synthesized by Stille cross-coupling polymerization. 1,3-Dibromo-5-octylthieno[3,4-c]pyrrole-4,6-dione (M1), 2,5-diethylhexyl-3,6- bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]-pyrrole-1,4-dione (M2) and 4,6-dibromo-thieno[3,4-b]thiophene-2-dodecyl carboxylate (M3) were used as acceptor building blocks for the synthesis of conjugated donor-acceptor polymers. The thermal, optical, electrochemical, and photovoltaic properties of the synthesized polymers were studied. © 2014 The Royal Society of Chemistry.

Journal article

Wong WWH, Subbiah J, Puniredd SR, Pisula W, Jones DJ, Holmes ABet al., 2014, Benzotriazole-based donor-acceptor conjugated polymers with a broad absorption in the visible range, Polymer Chemistry, Vol: 5, Pages: 1258-1263, ISSN: 1759-9954

A series of benzodithiophene-benzotriazole push-pull copolymers were synthesised and characterised and their performance in bulk heterojunction solar cells devices was assessed. By incorporating strong electron acceptor units, such as benzothiadiazole and pyridylthiadiazole, into the polymer backbone, significant absorption across the entire visible range (300 nm to 750 nm) was observed for the random copolymers. The importance of investigating photophysical as well as bulk material properties of the polymers was demonstrated with a correlation of properties with device performance. © The Royal Society of Chemistry.

Journal article

Dryza V, Nguyen JL, Kwon T-H, Wong WWH, Holmes AB, Bieske EJet al., 2013, Photophysics and aggregation effects of a triphenylamine-based dye sensitizer on metal-oxide nanoparticles suspended in an ion trap., Phys Chem Chem Phys, Vol: 15, Pages: 20326-20332

The photophysical behaviour of a triphenylamine-based organic dye sensitizer (Carbz-PAHTDTT) attached to alumina and titania nanoparticles (labelled Carbz-Al and Carbz-Ti, respectively) is examined in the absence and presence of the chenodeoxycholic acid (CDCA) coadsorber. The experiments are conducted in vacuo by suspending the target dye-sensitized nanoparticles within a quadrupole ion trap, where they are probed with laser radiation to obtain emission spectra and time-resolved excited state decay curves. For Carbz-Al, the dye's emission band is blue-shifted and the excited state lifetime is increased upon the coabsorption of CDCA, effects attributed to reduced dye aggregation. Compared to Carbz-Al, the Carbz-Ti excited state lifetimes are significantly shorter due to excited dye molecules injecting electrons into the titania conduction band. For Carbz-Ti, the electron injection quantum yields for the surfaces with CDCA (CDCA : dye = 25 : 1) and without CDCA are estimated to be 0.87 and 0.71, respectively. The gas-phase results demonstrate that Carbz-PAHTDTT dye aggregates are detrimental to the performance of a dye-sensitized solar cell.

Journal article

Yan C, Cadby AJ, Parnell AJ, Tang W, Skoda MWA, Mohamad D, King SP, Reynolds LX, Haque SA, Wang T, Parnell SR, Holmes AB, Jones RAL, Jones DJet al., 2013, Photophysics and Morphology of a Polyfluorene Donor-Acceptor Triblock Copolymer for Solar Cells, JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, Vol: 51, Pages: 1705-1718, ISSN: 0887-6266

Journal article

McCluskey GE, Watkins SE, Holmes AB, Ober CK, Lee JK, Wong WWHet al., 2013, Semi-perfluoroalkyl polyfluorene with varying fluorine content: Synthesis and photophysical properties, Polymer Chemistry, Vol: 4, Pages: 5291-5296, ISSN: 1759-9954

Deposition of multilayer organic electronic devices by solution processing often requires clever material design to avoid intermixing of the various layers. The use of orthogonal solvents for multilayer processing is a simple and effective method to solve this problem. However, the introduction of fluorous substituents to materials normally functionalised with aliphatic side chains has been shown to affect the device performance of these materials. In this study, a series of 9,9-disubstituted polyfluorenes containing varying ratios of semi-perfluoroalkyl to alkyl side chains have been synthesised and characterised. The effect of the semi-perfluoroalkyl chains on photophysical, electrochemical and thermal properties of the polymers was examined. The results indicate that the semi-perfluoroalkyl chains have varying influence on these properties and this is reflected in the previously reported electroluminescent device performances. © 2013 The Royal Society of Chemistry.

Journal article

Seyler H, Subbiah J, Jones DJ, Holmes AB, Wong WWHet al., 2013, Controlled synthesis of poly(3-hexylthiophene) in continuous flow, Beilstein Journal of Organic Chemistry, Vol: 9, Pages: 1492-1500

There is an increasing demand for organic semiconducting materials with the emergence of organic electronic devices. In particular, large-area devices such as organic thin-film photovoltaics will require significant quantities of materials for device optimization, lifetime testing and commercialization. Sourcing large quantities of materials required for the optimization of large area devices is costly and often impossible to achieve. Continuous-flow synthesis enables straight-forward scale-up of materials compared to conventional batch reactions. In this study, poly(3-hexylthiophene), P3HT, was synthesized in a bench-top continuous-flow reactor. Precise control of the molecular weight was demonstrated for the first time in flow for conjugated polymers by accurate addition of catalyst to the monomer solution. The P3HT samples synthesized in flow showed comparable performance to commercial P3HT samples in bulk heterojunction solar cell devices. © 2013 Seyler et al.

Journal article

Kumar RJ, Churches QI, Subbiah J, Gupta A, Ali A, Evans RA, Holmes ABet al., 2013, Enhanced photovoltaic efficiency via light-triggered self-assembly., Chem Commun (Camb), Vol: 49, Pages: 6552-6554

Light-initiated, radical and hydrogen-bond induced self-assembly of bis-acetamido-functionalized triarylamines is demonstrated to occur in strongly dipolar "push-pull" molecules. This self-assembly process results in the formation of self-assembled nanostructures which in turn increase the efficiency of organic photovoltaic devices.

Journal article

Kumar RJ, Subbiah J, Holmes AB, 2013, Enhancement of efficiency in organic photovoltaic devices containing self-complementary hydrogen-bonding domains, Beilstein Journal of Organic Chemistry, Vol: 9, Pages: 1102-1110

Self-complementary hydrogen-bonding domains were incorporated as the electron deficient unit in "push-pull", p-type small molecules for organic photovoltaic active layers. Such compounds were found to enhance the fill factor, compared with similar non-self-organized compounds reported in the literature, leading to higher device efficiencies. Evidence is presented that the ability of these molecules to form one-dimensional hydrogen-bonded chains and subsequently exhibit hierarchical self-assembly into nanostruc-tured domains can be correlated with improved device efficiency. © 2013 Kumar et al; licensee Beilstein-Institut.

Journal article

Catimel B, Kapp E, Yin M-X, Gregory M, Wong LS-M, Condron M, Church N, Kershaw N, Holmes AB, Burgess AWet al., 2013, The PI(3)P interactome from a colon cancer cell., J Proteomics, Vol: 82, Pages: 35-51

A comprehensive analysis of the phosphoinositide interactome has been performed using an ω-amino analogue of phosphatidylinositol 3-phosphate (PI(3)P immobilised onto Affi-10 beads for use as an affinity absorbent for cytosolic, membrane and nuclear extracts from the LIM1215 colonic carcinoma cell line. Affinity/LC/MS/MS experiments allowed the identification of 681 proteins/protein complexes which interact with PI(3)P. Protein domain enrichment analysis identified proteins possessing PI(3)P (e.g., FYVE, PX, PH), PIP and PIP/phospholipid binding domains along with small GTPases, GTPase regulators, kinases and SH2/SH3 containing proteins. Functional and pathway enrichment analyses highlighted the major role of PI(3)P in endocytosis dynamics and vesicular trafficking, intracellular cell signalling regulation, cell division and cytokinesis. BIOLOGICAL SIGNIFICANCE: This study provides an initial detailed assessment of the phosphatidylinositol 3-phosphate (PI(3)P) interactome, highlights the major role of PI(3)P in endocytosis dynamics and vesicular trafficking, cell intracellular regulation, signalling and cytokinesis and suggests potential PI(3)P specificity for further biochemical and biological characterisation.

Journal article

Seyler H, Haid S, Kwon TH, Jones DJ, Bäuerle P, Holmes AB, Wong WWHet al., 2013, Continuous flow synthesis of organic electronic materials-case studies in methodology translation and scale-up, Australian Journal of Chemistry, Vol: 66, Pages: 151-156, ISSN: 0004-9425

The continuous flow synthesis of functional thiophene derivatives was examined. Methodology for the lithiation of thiophene building blocks was developed using a commercial bench-top flow reactor. In addition, the advantages of flow processing were demonstrated in the synthesis of a high performance organic dye in gram scale. © 2013 CSIRO.

Journal article

Schlichtiger A, Baier C, Yin M-X, Holmes AB, Maruyama M, Strasser R, Rant U, Thaler M, Luppa PBet al., 2013, Covalent attachment of functionalized cardiolipin on a biosensor gold surface allows repetitive measurements of anticardiolipin antibodies in serum., Anal Bioanal Chem, Vol: 405, Pages: 275-285

Antiphospholipid antibodies (aPL) are a relevant serological indicator of antiphospholipid syndrome (APS). A solid-state surface with covalently bound ω-amine-functionalized cardiolipin was established and the binding of β2-glycoprotein I (β2-GPI) was investigated either by use of surface plasmon resonance (SPR) biosensor, by electrically switchable DNA interfaces (switchSENSE) and by scanning tunneling microscopy (STM). STM could clearly visualize the attachment of β2-GPI to the cardiolipin surface. Using the switchSENSE sensor, β2-GPI as specific ligand could be identified by increased hydrodynamic friction. The binding of anti-cardiolipin antibodies (aCL) was detected against the ω-amine-functionalized cardiolipin-modified SPR biosensor (aCL biosensor) using sera from healthy donors, APS patients and syphilis patients. Our results showed that the aCL biosensor is a much more sensitive diagnostic device for APS patients compared to previous methods. The specificity between β2-GPI-dependent autoimmune- and β2-GPI-independent infection-associated types of aPLs was also studied and they can be distinguished by the different binding kinetics and patterns.

Journal article

Hodges AJ, Adams JP, Bond AD, Holmes AB, Press NJ, Roughley SD, Ryan JH, Saubern S, Smith CJ, Turnbull MD, Newton AFet al., 2012, Intramolecular nitrone dipolar cycloadditions: control of regioselectivity and synthesis of naturally-occurring spirocyclic alkaloids., Org Biomol Chem, Vol: 10, Pages: 8963-8974

The intramolecular nitrone dipolar cycloaddition of in situ-generated nitrones such as compound 26 has been used for the synthesis of cyclic isoxazolidines 27 and 29. The regioselectivity of the intramolecular cycloaddition depends on the nature of the terminal substituent on the dipolarophile. The influence of the substituent on the regioselectivity of the cycloaddition has been examined using several model systems and two methods of nitrone formation. These studies demonstrated that the cyano-substituent plays a special role in favouring the formation of the 6,6,5-ring fused adduct 27 under thermodynamically controlled conditions. The utility of the cyclo-adduct 57 (see Scheme 12) as a precursor for the naturally occurring histrionicotoxins is illustrated by the synthesis of three "unsymmetrical" (i.e. with each side chain bearing different functional groups) members of the histrionicotoxin family HTX-259A, HTX-285C and HTX-285E (2, 3 and 4 respectively).

Journal article

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