Synthesis of biodegradable polymer-mesoporous silica composite microspheres for DNA prime-protein boost vaccination

DNA vaccines or proteins are capable of inducing specific immunity; however, the translation to the clinic has generally been problematic, primarily due to the reduced magnitude of immune response and poor pharmacokinetics. Herein we demonstrate a composite microsphere formulation, composed of mesoporous silica spheres (MPS) and poly(d,l-lactide-co-glycolide) (PLGA), enables the controlled delivery of a prime-boost vaccine via the encapsulation of plasmid DNA (pDNA) and protein in different compartments. Method with modified dual-concentric-feeding needles attached to a 40 kHz ultrasonic atomizer was studied. These needles focus the flow of two different solutions, which passed through the ultrasonic atomizer. The process synthesis parameters, which are important to the scale-up of composite microspheres, were also studied. These parameters include polymer concentration, feed flowrate, and volumetric ratio of polymer and pDNA-PEI/MPS-BSA. This fabrication technique produced composite microspheres with mean D[4,3] ranging from 6 to 34 μm, depending upon the microsphere preparation. The resultant physical morphology of composite microspheres was largely influenced by the volumetric ratio of pDNA-PEI/MPS-BSA to polymer, and this was due to the precipitation of MPS at the surface of the microspheres. The encapsulation efficiencies were predominantly in the range of 93-98% for pDNA and 46-68% for MPS. In the in vitro studies, the pDNA and protein showed different release kinetics in a 40 day time frame. The dual-concentric-feeding in ultrasonic atomization was shown to have excellent reproducibility. It was concluded that this fabrication technique is an effective method to prepare formulations containing a heterologous prime-boost vaccine in a single delivery system.

Large-volume methacrylate monolith for plasmid purification : process engineering approach to synthesis and application

The extent of exothermicity associated with the construction of large-volume methacrylate monolithic columns has somewhat obstructed the realisation of large-scale rapid biomolecule purification especially for plasmid-based products which have proven to herald future trends in biotechnology. A novel synthesis technique via a heat expulsion mechanism was employed to prepare a 40 mL methacrylate monolith with a homogeneous radial pore structure along its thickness. Radial temperature gradient was recorded to be only 1.8 °C. Maximum radial temperature recorded at the centre of the monolith was 62.3 °C, which was only 2.3 °C higher than the actual polymerisation temperature. Pore characterisation of the monolithic polymer showed unimodal pore size distributions at different radial positions with an identical modal pore size of 400 nm. Chromatographic characterisation of the polymer after functionalisation with amino groups displayed a persistent dynamic binding capacity of 15.5 mg of plasmid DNA/mL. The maximum pressure drop recorded was only 0.12 MPa at a flow rate of 10 mL/min. The polymer demonstrated rapid separation ability by fractionating Escherichia coli DH5α-pUC19 clarified lysate in only 3 min after loading. The plasmid sample collected after the fast purification process was tested to be a homogeneous supercoiled plasmid with DNA electrophoresis and restriction analysis.

Process engineering approach to large-volume methacrylate monolith synthesis for plasmid purification

The construction of large?volume methacrylate monolithic columns for preparative-scale plasmid purification is obstructed by the enormous release of exotherms, thus introducing structural heterogeneity in the monolith pore system. A remarkable radial temperature gradient develops along the monolith thickness, reaching a terminal temperature that supersedes the maximum temperature required for the preparation of a structurally homogeneous monolith. A novel heat expulsion technique is employed to overcome the heat build-up during the synthesis process. The enormous heat build-up is perceived to encompass the heat associated with initiator decomposition and the heat released from free radical-monomer and monomer-monomer interactions. The heat resulting from the initiator decomposition was expelled along with some gaseous fumes before commencing polymerisation in a gradual addition fashion. Characteristics of a 50 mL monolith synthesized using this technique showed an improved uniformity in the pore structure radially along the length on the monolith. Chromatographic characterization of this adsorbent displayed a persistent binding capacity of 14.5 mg pDNA/mL of the adsorbent. The adsorbent was able to fractionate a clarified bacteria lysate in only 3 min (after loading) into RNA, protein and pDNA respectively. The pDNA fraction obtained was analyzed to be a homogeneous supercoiled pDNA.

Synthesis of novel interlocked architectures in solution and solid phase

Mechanically interlocked molecules, such as catenanes and rotaxanes, are fascinating due to their unique sensing and catalytic properties and their potential to act as molecular motors or switches. Traditionally their synthesis has been laborious and expensive, however this research project endeavoured to overcome this challenge by exploring novel ways of preparing mechanically interlocked molecules both in solution and on surfaces. A series of disulfide-linked macrocycles, [2]catenanes and [2]rotaxanes were synthesised in solution using reversible dynamic covalent chemistry. Subsequently, the interlocked architectures were adapted into solid-tethered systems via attachment to swelling polystyrene resins.

Bayesian networks for information synthesis in complex systems

This thesis introduces a method of applying Bayesian Networks to combine information from a range of data sources for effective decision support systems. It develops a set of techniques in development, validation, visualisation, and application of Complex Systems models, with a working demonstration in an Australian airport environment. The methods presented here have provided a modelling approach that produces highly flexible, informative and applicable interpretations of a system's behaviour under uncertain conditions. These end-to-end techniques are applied to the development of model based dashboards to support operators and decision makers in the multi-stakeholder airport environment. They provide highly flexible and informative interpretations and confidence in these interpretations of a system's behaviour under uncertain conditions.

The synthesis, characterization, X-ray structure and magnetism of dinuclear-based bis[μ-(1,1,3,3-tetracyano-2-ethoxypropenido-κ2N,N′) (1,1,3,3-tetracyano-2-ethoxypropenido-κN)(2,2′-bipyridine)copper(II)] organized in alternating chains via semi-coordinating Cu–N distances

The monoanionic ligand 1,1,3,3 tetracyano-2 ethoxypropenide (tcnoet) is reported with its Cu(II)–bpy complex of formula [Cu2(µ-tcnoet)2(tcnoet)2(bpy)2]. The structure has been determined using X-ray diffraction and features an alternating chain with bridging tcnoet ligands. One ligand acts as a bidentate, dinucleating ligand with one short Cu–N and one medium Cu–N bond, whereas the other tcnoet is largely monodentate, albeit with a very weak interdimer Cu–N bond. Despite the arrangement in dinuclear units, further arranged into linear chains through the non-bridging tcnoet ligand, the compound shows no significant magnetic exchange, as deduced from magnetic susceptibility down to 4 K. Ligand-field, IR and EPR spectra in the solid state and in frozen solution are reported and are consistent with the overall structure.

Design and synthesis of a screening library using the natural product scaffold 3-chloro-4-hydroxyphenylacetic acid

The fungal metabolite 3-chloro-4-hydroxyphenylacetic acid (1) was utilized in the generation of a unique drug-like screening library using parallel solution-phase synthesis. A 20-membered amide library (3–22) was generated by first converting 1 to methyl (3-chloro-4-hydroxyphenyl)acetate (2), then reacting this scaffold with a diverse series of primary amines via a solvent-free aminolysis procedure. The structures of the synthetic analogues (3–22) were elucidated by spectroscopic data analysis. The structures of compounds 8, 12, and 22 were confirmed by single X-ray crystallographic analysis. All compounds were evaluated for cytotoxicity against a human prostate cancer cell line (LNCaP) and for antiparasitic activity toward Trypanosoma brucei brucei and Plasmodium falciparum and showed no significant activity at 10 μM. The library was also tested for effects on the lipid content of LNCaP and PC-3 prostate cancer cells, and it was demonstrated that the fluorobenzyl analogues (12–14) significantly reduced cellular phospholipid and neutral lipid levels.

Quantification of the total neuronal structure of the fear conditioning circuit of the lateral amygdala of the rat

During Pavlovian auditory fear conditioning a previously neutral auditory stimulus (CS) gains emotional significance through pairing with a noxious unconditioned stimulus (US). These associations are believed to be formed by way of plasticity at auditory input synapses on principal neurons in the lateral nucleus of the amygdala (LA). In order to begin to understand how fear memories are stored and processed by synaptic changes in the LA, we have quantified both the entire neural number and the sub-cellular structure of LA principal neurons.We first used stereological cell counting methods on Gimsa or GABA immunostained rat brain. We identified 60,322+/-1408 neurons in the LA unilaterally (n=7). Of these 16,917+/-471 were GABA positive. The intercalated nuclei were excluded from the counts and thus GABA cells are believed to represent GABAergic interneurons. The sub-nuclei of the LA were also independently counted. We then quantified the morphometric properties of in vitro electrophysiologically identified principal neurons of the LA, corrected for shrinkage in xyz planes. The total dendritic length was 9.97+/-2.57mm, with 21+/-4 nodes (n=6). Dendritic spine density was 0.19+/-0.03 spines/um (n=6). Intra-LA axon collaterals had a bouton density of 0.1+/-0.02 boutons/um (n=5). These data begin to reveal the finite cellular and sub-cellular processing capacity of the lateral amygdala, and should facilitate efforts to understand mechanisms of plasticity in LA.

Synthesis of organoclays: A critical review and some unresolved issues

The synthesis of organoclays (OC) by intercalation of quaternary ammonium cation (QAC) into expanding clay minerals, notably montmorillonite (Mt), has attracted a great deal of attention during the past two decades. The OC have also found applications in the manufacture of clay polymer nanocomposites (CPN) and environmental remediation. Despite the wealth of information that exists on the formation and properties of OC, some problems remain to be resolved. The present contribution is an attempt at clarifying two outstanding issues, based on the literature and experimental data obtained by the authors over the past years. The first issue concerns the relationship between the cation exchange capacity (CEC) of the Mt and the basal spacing of the OC which, in turn, is dependent on the concentration and the nature of the added QAC. At a concentration less than 1 CEC, organo-Mt (OMt) formed using the QAC with a short alkyl chain length with nc < 16 (e.g., dodecyl trimethylammonium) gives basal spacings of 1.4–1.6 nm that are essentially independent of the CEC. However, for long-chain QAC with nc ≥ 16 (e.g., hexadecyl trimethylammonium), the basal spacing varies with the QAC concentration. For Mt with a CEC of 80–90 meq/100 g, the basal spacing of the OC increases gradually with the CEC and shows a sudden (stepwise) increase to 3.2–3.8 nm at a QAC concentration of 1.5 CEC and to 3.5–4.0 nm at a concentration of 2.0 CEC. The second issue pertains to the “locking” effect in QAC- and silane-modified pillared interlayered clays (PILC) and Mt. For silylated Mt, the “locking” effect results from the covalent bonding of silane to two adjacent layers within a single clay mineral particle. The same mechanism can operate in silane-grafted PILC but in this case, the “locking” effect may primarily be ascribed to the pillaring of adjacent basal surfaces by metal hydr(oxides).

Oral liquid nutritional supplements for people with dementia in residential aged care facilities

AIM: This systematic review investigated the prescription, administration and effectiveness of oral liquid nutritional supplements (OLNS) for people with dementia in residential aged care facilities (RACF). METHODS: A comprehensive search of relevant databases, hand searching and cross-referencing found 15 relevant articles from a total of 2910 possible results. Articles which met the inclusion criteria were critically appraised by two independent reviewers using the relevant Joanna Briggs Institute (JBI) appraisal checklist. Data were extracted using the relevant JBI extraction instruments. No data synthesis was possible due to clinical and methodological heterogeneity. RESULTS: Included studies examined a range of strategies, issues and results related to OLNS for persons with dementia in RACFs; however there appear to be significant gaps in the current body of research, particularly in relation to examinations of effectiveness. CONCLUSIONS: This review was unable to produce a definitive finding regarding effectiveness. OLNS may improve the nutritional state of residents with dementia and help prevent weight loss, and there is some suggestion that it may slow the rate of cognitive decline. However, in order for OLNS to be effective, nursing and care staff need to ensure that sufficient attention is paid to the issues of prescription and administration.

Service Interface Synthesis in Business Networks

Mismatches between services needing to interoperate have been addressed through the adaptation of structural and behavioural interfaces of services, which in practice incur long lead time through manual, coding effort. We propose a framework, complementary to con- ventional service adaptation, to synthesise service interfaces in the open setting of business networks, allowing consumers to introspect service interfaces and formulate service invocations. The framework also allows evolved service requests, as new features of service capabilities are discov- ered, through interactions with other, similar services. Finally the frame- work fosters reuse of adaptation efforts through normalisation of struc- tural and behavioural interfaces of similar services. This paper provides a first exposition of the service interface synthesis framework, describing patterns containing novel requirements for unilateral service adaptation and detailing the interface synthesis technique. Complex examples of ser- vices drawn from commercial logistic systems are then used to validate the synthesis technique and identify open challenges and future research directions.

Visible light photocatalytic synthesis of fine organic chemicals with new photocatalysts

This project was a step forward in developing new recyclable photocatalysts for chemical reactions. These new photocatalysts can facilitate reactions by using visible light under moderate reaction conditions which is suitable for a sustainable, green and eco-friendly modern chemical industry. The outcome of the study greatly extended our understanding in metal nanoparticle photocatalysis, which reveals new photocatalytic mechanisms for the controlled transformation of chemical reactions. The prospect of sunlight irradiation driving chemical reactions may provide opportunity for the organic synthesis via a more controlled, simplified, and greener process in the future.

Investigation of structural requirements of anticancer activity at the paclitaxel/tubulin binding site using CoMFA and CoMSIA

CoMFA and CoMSIA analysis were utilized in this investigation to define the important interacting regions in paclitaxel/tubulin binding site and to develop selective paclitaxel-like active compounds. The starting geometry of paclitaxel analogs was taken from the crystal structure of docetaxel. A total of 28 derivatives of paclitaxel were divided into two groups—a training set comprising of 19 compounds and a test set comprising of nine compounds. They were constructed and geometrically optimized using SYBYL v6.6. CoMFA studies provided a good predictability (q2 = 0.699, r2 = 0.991, PC = 6, S.E.E. = 0.343 and F = 185.910). They showed the steric and electrostatic properties as the major interacting forces whilst the lipophilic property contribution was a minor factor for recognition forces of the binding site. These results were in agreement with the experimental data of the binding activities of these compounds. Five fields in CoMSIA analysis (steric, electrostatic, hydrophobic, hydrogen-bond acceptor and donor properties) were considered contributors in the ligand–receptor interactions. The results obtained from the CoMSIA studies were: q2 = 0.535, r2 = 0.983, PC = 5, S.E.E. = 0.452 and F = 127.884. The data obtained from both CoMFA and CoMSIA studies were interpreted with respect to the paclitaxel/tubulin binding site. This intuitively suggested where the most significant anchoring points for binding affinity are located. This information could be used for the development of new compounds having paclitaxel-like activity with new chemical entities to overcome the existing pharmaceutical barriers and the economical problem associated with the synthesis of the paclitaxel analogs. These will boost the wide use of this useful class of compounds, i.e. in brain tumors as the most of the present active compounds have poor blood–brain barrier crossing ratios and also, various tubulin isotypes has shown resistance to taxanes and other antimitotic agents.

Synthesis and applications of carbon nanomaterials for energy generation and storage

The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Carbon, one of the most abundant materials found on earth, and its allotrope forms have been proposed in this project for novel energy generation and storage devices. This studied investigated the synthesis and properties of these carbon nanomaterials for applications in organic solar cells and supercapacitors.