Chemical and Biomolecular Engineering - Research Publications

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    Self-template construction of nanoporous carbon nanorods from a metal-organic framework for supercapacitor electrodes
    Yang, Y-W ; Liu, X-H ; Gao, E-P ; Feng, T-T ; Jiang, W-J ; Wu, J ; Jiang, H ; Sun, B (ROYAL SOC CHEMISTRY, 2018-01-01)
    The morphologies and structures of nanostructured carbons generally influence their catalysis, electrochemical performance and adsorption properties. Metal-organic framework (MOF) nanocrystals usually have various morphologies, and can be considered as a template to construct nanostructured carbons with shaped nanocubes, nanorods, and hollow particles by thermal transformation. However, thermal carbonization of MOFs usually leads to collapse of MOF structures. Here, we report shape-preserved carbons (termed as CNRods) by thermal transformation of nickel catecholate framework (Ni-CAT) nanorods. Supercapacitors of CNRods treated at 800 °C were demonstrated to have enhanced performance due to their structural features that facilitate electron conduction and ion transport as well as abundant O content benefiting the wettability of the carbon materials. This may provide a potential way to explore novel carbon materials for supercapacitors with controllable morphologies and high capacitive performance.
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    A modelling approach to assess the long-term stability of a novel microbial/electrochemical system for the treatment of acid mine drainage.
    Brewster, ET ; Pozo, G ; Batstone, DJ ; Freguia, S ; Ledezma, P (Royal Society of Chemistry (RSC), 2018-05-17)
    Microbial electrochemical processes have potential to remediate acid mine drainage (AMD) wastewaters which are highly acidic and rich in sulfate and heavy metals, without the need for extensive chemical dosing. In this manuscript, a novel hybrid microbial/electrochemical remediation process which uses a 3-reactor system - a precipitation vessel, an electrochemical reactor and a microbial electrochemical reactor with a sulfate-reducing biocathode - was modelled. To evaluate the long-term operability of this system, a dynamic model for the fluxes of 140 different ionic species was developed and calibrated using laboratory-scale experimental data. The model identified that when the reactors are operating in the desired state, the coulombic efficiency of sulfate removal from AMD is high (91%). Modelling also identified that a periodic electrolyte purge is required to prevent the build-up of Cl- ions in the microbial electrochemical reactor. The model furthermore studied the fate of sulfate and carbon in the system. For sulfate, it was found that only 29% can be converted into elemental sulfur, with the rest complexating with metals in the precipitation vessel. Finally, the model shows that the flux of inorganic carbon under the current operational strategy is insufficient to maintain the autotrophic sulfate-reducing biomass. The modelling approach demonstrates that a change in system operational strategies plus close monitoring of overlooked ionic species (such as Cl- and HCO3 -) are key towards the scaling-up of this technology.
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    Flexible C-Mo2C fiber film with self-fused junctions as a long cyclability anode material for sodium-ion battery
    Zhang, W ; Guo, Z ; Liang, Q ; Lv, R ; Shen, W ; Kang, F ; Weng, Y ; Huang, Z-H (ROYAL SOC CHEMISTRY, 2018-01-01)
    Electrospun carbon fiber films have high contact resistance at the fiber junctions, which causes poor cycling stability and limits their further improvement in energy storage performances. To eliminate the contact resistance of the film, we provide a new strategy to fuse the fiber junctions by introducing MoO2 in the fibers, which replaces the C-C interface by a more active C-MoO2-C interface at the fiber junction to promote mass transfer. MoO2 reacts with C matrix to generate Mo2C and form self-fused junctions during the carbonization process. Due to much lower charge transfer and sodium diffusion resistance, the C-Mo2C fiber film with self-fused junctions shows much better cyclability with capacity retention of 90% after 2000 cycles at a constant current density of 1 A g-1. Moreover, the Mo2C particles provide many electrochemically active sites, leading to additional improvement in sodium storage. The C-Mo2C fiber film has a capacity of 134 mA h g-1 at 1 A g-1 and a high capacity of 99 mA h g-1 even at 5 A g-1.
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    Polysulfides made from re-purposed waste are sustainable materials for removing iron from water
    Lundquist, NA ; Worthington, MJH ; Adamson, N ; Gibson, CT ; Johnston, MR ; Ellis, AV ; Chalker, JM (ROYAL SOC CHEMISTRY, 2018-01-01)
    Water contaminated with Fe3+ is undesirable because it can result in discoloured plumbing fixtures, clogging, and a poor taste and aesthetic profile for drinking water. At high levels, Fe3+ can also promote the growth of unwanted bacteria, so environmental agencies and water authorities typically regulate the amount of Fe3+ in municipal water and wastewater. Here, polysulfide sorbents-prepared from elemental sulfur and unsaturated cooking oils-are used to remove Fe3+ contaminants from water. The sorbent is low-cost and sustainable, as it can be prepared entirely from waste. The preparation of this material using microwave heating and its application in iron capture are two important advances in the growing field of sulfur polymers.
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    Self-assembly of "patchy" nanoparticles: a versatile approach to functional hierarchical materials
    Lunn, DJ ; Finnegan, JR ; Manners, I (ROYAL SOC CHEMISTRY, 2015-01-01)
    The solution-phase self-assembly or "polymerization" of discrete colloidal building blocks, such as "patchy" nanoparticles and multicompartment micelles, is attracting growing attention with respect to the creation of complex hierarchical materials. This approach represents a versatile method with which to transfer functionality at the molecular level to the nano- and microscale, and is often accompanied by the emergence of new material properties. In this perspective we highlight selected recent examples of the self-assembly of anisotropic nanoparticles which exploit directional interactions introduced through their shape or surface chemistry to afford a variety of hierarchical materials. We focus in particular on the solution self-assembly of block copolymers as a means to prepare multicompartment or "patchy" micelles. Due to their potential for synthetic modification, these constructs represent highly tuneable building blocks for the fabrication of a wide variety of functional assemblies.
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    The within-day behaviour of 6 minute rainfall intensity in Australia
    Western, AW ; Anderson, B ; Siriwardena, L ; Chiew, FHS ; Seed, A ; Bloeschl, G (COPERNICUS GESELLSCHAFT MBH, 2011-01-01)
    Abstract. The statistical behaviour and distribution of high-resolution (6 min) rainfall intensity within the wet part of rainy days (total rainfall depth >10 mm) is investigated for 42 stations across Australia. This paper compares nine theoretical distribution functions (TDFs) in representing these data. Two goodness-of-fit statistics are reported: the Root Mean Square Error (RMSE) between the fitted and observed within-day distribution; and the coefficient of efficiency for the fit to the highest rainfall intensities (average intensity of the 5 highest intensity intervals) across all days at a site. The three-parameter Generalised Pareto distribution was clearly the best performer. Good results were also obtained from Exponential, Gamma, and two-parameter Generalized Pareto distributions, each of which are two parameter functions, which may be advantageous when predicting parameter values. Results of different fitting methods are compared for different estimation techniques. The behaviour of the statistical properties of the within-day intensity distributions was also investigated and trends with latitude, Köppen climate zone (strongly related to latitude) and daily rainfall amount were identified. The latitudinal trends are likely related to a changing mix of rainfall generation mechanisms across the Australian continent.
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    Enhancing dendritic cell activation and HIV vaccine effectiveness through nanoparticle vaccination
    Glass, JJ ; Kent, SJ ; De Rose, R (TAYLOR & FRANCIS LTD, 2016-01-01)
    Novel vaccination approaches are needed to prevent and control human immunodeficiency virus (HIV) infection. A growing body of literature demonstrates the potential of nanotechnology to modulate the human immune system and generate targeted, controlled immune responses. In this Review, we summarize important advances in how 'nanovaccinology' can be used to develop safe and effective vaccines for HIV. We highlight the central role of dendritic cells in the immune response to vaccination and describe how nanotechnology can be used to enhance delivery to and activation of these important antigen-presenting cells. Strategies employed to improve biodistribution are discussed, including improved lymph node delivery and mucosal penetration concepts, before detailing methods to enhance the humoral and/or cellular immune response to vaccines. We conclude with a commentary on the current state of nanovaccinology.
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    Human immune cell targeting of protein nanoparticles - caveospheres
    Glass, JJ ; Yuen, D ; Rae, J ; Johnston, APR ; Parton, RG ; Kent, SJ ; De Rose, R (ROYAL SOC CHEMISTRY, 2016-01-01)
    Nanotechnology has the power to transform vaccine and drug delivery through protection of payloads from both metabolism and off-target effects, while facilitating specific delivery of cargo to immune cells. However, evaluation of immune cell nanoparticle targeting is conventionally restricted to monocultured cell line models. We generated human caveolin-1 nanoparticles, termed caveospheres, which were efficiently functionalized with monoclonal antibodies. Using this platform, we investigated CD4+ T cell and CD20+ B cell targeting within physiological mixtures of primary human blood immune cells using flow cytometry, imaging flow cytometry and confocal microscopy. Antibody-functionalization enhanced caveosphere binding to targeted immune cells (6.6 to 43.9-fold) within mixed populations and in the presence of protein-containing fluids. Moreover, targeting caveospheres to CCR5 enabled caveosphere internalization by non-phagocytic CD4+ T cells--an important therapeutic target for HIV treatment. This efficient and flexible system of immune cell-targeted caveosphere nanoparticles holds promise for the development of advanced immunotherapeutics and vaccines.
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    Tuning the properties of pH responsive nanoparticles to control cellular interactions in vitro and ex vivo
    Mann, SK ; Dufour, A ; Glass, JJ ; De Rose, R ; Kent, SJ ; Such, GK ; Johnston, APR (ROYAL SOC CHEMISTRY, 2016-01-01)
    Engineering the properties of nanoparticles to limit non-specific cellular interactions is critical for developing effective drug delivery systems. Differences between interactions with cultured cells and human blood highlights the need for appropriate assays
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    Recombinant influenza virus expressing HIV-1 p24 capsid protein induces mucosal HIV-specific CD8 T-cell responses
    Tan, H-X ; Gilbertson, BP ; Jegaskanda, S ; Alcantara, S ; Amarasena, T ; Stambas, J ; McAuley, JL ; Kent, SJ ; De Rose, R (ELSEVIER SCI LTD, 2016-02-24)
    Influenza viruses are promising mucosal vaccine vectors for HIV but their use has been limited by difficulties in engineering the expression of large amounts of foreign protein. We developed recombinant influenza viruses incorporating the HIV-1 p24 gag capsid into the NS-segment of PR8 (H1N1) and X31 (H3N2) influenza viruses with the use of multiple 2A ribosomal skip sequences. Despite the insertion of a sizable HIV-1 gene into the influenza genome, recombinant viruses were readily rescued to high titers. Intracellular expression of p24 capsid was confirmed by in vitro infection assays. The recombinant influenza viruses were subsequently tested as mucosal vaccines in BALB/c mice. Recombinant viruses were attenuated and safe in immunized mice. Systemic and mucosal HIV-specific CD8 T-cell responses were elicited in mice that were immunized via intranasal route with a prime-boost regimen. Isolated HIV-specific CD8 T-cells displayed polyfunctional cytokine and degranulation profiles. Mice boosted via intravaginal route induced recall responses from the distal lung mucosa and developed heightened HIV-specific CD8 T-cell responses in the vaginal mucosa. These findings demonstrate the potential utility of recombinant influenza viruses as vaccines for mucosal immunity against HIV-1 infection.