Browsing by Author "Spicer, P"

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    Formation of liquid-crystalline structures in the bile salt–chitosan system and triggered release from lamellar phase bile salt–chitosan capsules
    (American Chemical Society, 2014-07-22) Tangso, KJ; Lindberg, S; Hartley, PG; Knott, RB; Spicer, P; Boyd, BJ
    Nanostructured capsules comprised of the anionic bile salt, sodium taurodeoxycholate (STDC), and the biocompatible cationic polymer, chitosan, were prepared to assess their potential as novel tailored release nanomaterials. For comparison, a previously studied system, sodium dodecyl sulfate (SDS), and polydiallyldimethylammonium chloride (polyDADMAC) was also investigated. Crossed-polarizing light microscopy (CPLM) and small-angle X-ray scattering (SAXS) identified the presence of lamellar and hexagonal phase at the surfactant–polymer interface of the respective systems. The hydrophobic and electrostatic interactions between the oppositely charged components were studied by varying temperature and salt concentration, respectively, and were found to influence the liquid-crystalline nanostructure formed. The hexagonal phase persisted at high temperatures, however the lamellar phase structure was lost above ca. 45 °C. Both mesophases were found to dissociate upon addition of 4% NaCl solution. The rate of release of the model hydrophilic drug, Rhodamine B (RhB), from the lamellar phase significantly increased in response to changes in the solution conditions studied, suggesting that modulating the drug release from these bile salt–chitosan capsules is readily achieved. In contrast, release from the hexagonal phase capsules had no appreciable response to the stimuli applied. These findings provide a platform for these oppositely charged surfactant and polymer systems to function as stimuli-responsive or sustained-release drug delivery systems. © 2014, American Chemical Society.
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    QCM-D and neutron reflectometry study of effect of plasma treatment on cellulose-mucin interactions towards ETSA
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2020-11-11) Siddique, A; Gresham, IJ; Davies, J; Ong, H; Traini, D; Nelson, A; Spicer, P; Prescott, SW
    Epidemic thunderstorm asthma (ETSA)[1] is associated with inhalation of airborne pollen grains and aerosolized pollen fragments, causing hypersensitive immune reactions[2] that might lead to an asthma attack. The wall of pollen grains (intine) contains cellulose which is hypothesized to initially interact with the nasal and tracheal mucous layer[3] when inhaled. The air-way mucous layer is comprised of mucin (a major glycosylated proteinaceous element) and water, which serves as a first-line-of-defence against inhaled pollen particles. Although immunological and meteorological studies have been conducted in this regard, the fundamental cause and mechanism of ETSA are under-investigated. This study is focused on unraveling inherent cellulose-mucin interactions employing quartz crystal microbalance with dissipation (QCM-D) and neutron reflectometry (NR) examining the adsorption of mucin on cellulose while mimicking a thunderstorm environment, such as the affect of plasma treatment on cellulose-mucin interactions. Here, we generate air-plasma and plasma-activated water to treat our model cellulose surfaces[4], simulating the ionized surface chemistry of thunderstorm-borne pollen particles and examine subsequent interactions. In this poster, we describe the use of QCM-D and NR to investigate cellulose-mucin interactions and the effect of plasma treatment on these biointerfacial interactions. The advanced molecular and structural data obtained from this study, coupled with immunological and meteorological investigations, will enable the mechanistic understanding, treatment, and prevention of ETSA. © The authors.