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Title: Investigation into the availability of man-made nanoparticles and their interaction with exposed sea urchin (Paracentrotus lividus)
Author: Piticharoenphun, Sunthon
ISNI:       0000 0004 5353 7725
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2014
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Due to the environmental issues concerning the toxicity of silver nanoparticles (AgNPs), this work will study the interaction between silver nanoparticles (AgNPs) and exposed sea urchins. Paracentrotus lividus sea urchins were exposed to citrate-stabilized AgNPs (5-35 nm in diameter) and Ag+ ions (using AgNO3 as Ag+ ion source). AgNPs cause dose dependent developmental defects at the concentration of 0.3 mg/L. It has been observed that AgNPs induce stronger defects than Ag+ ions at equivalent concentrations. The effect of sea water on AgNPs was studied and the results show that sea water causes AgNPs to agglomerate. However, small amounts of AgNPs persisted in sea water at over 48 h after mixing. X-ray fluorescence (XRF) maps show the agglomerated AgNPs in the sea urchin at 51 h of growth after exposure to 0.3 mg/L AgNPs. The agglomerated AgNPs in the exposed sea urchins were confirmed using the X-ray absorption near edge structure (XANES) technique. In addition, XANES results indicate that the agglomerated AgNPs in sea urchins were assigned to oxidized Ag species complexed with S and O/N ligands. The result from the fourier transform infrared (FTIR) technique implies that there was a calcite loss in the AgNPexposed sea urchin. Furthermore, the FTIR result illustrates that excess sulphur-containing compounds in AgNP-exposed sea urchin were noticed and are suggested to be a biological response of the exposed sea urchins to reduce the toxicity of AgNPs. Photoluminescence (PL) of AgNPs was observed from the upper part of the exposed sea urchin body. The exposure to alkylated silicon nanocrystals (alkylated SiNCs) was also carried out in Paracentrotus lividus sea urchins, while the exposure to silica-coated iron oxide nanoparticles (Si-coated IONPs) was carried out in Arbacia lixula sea urchins. The XRF results showed that agglomerated alkylated SiNCs and Si-coated IONPs were observed in exposed sea urchins ii at 51 h of alkylated SiNC exposure and at 48 h of Si-coated IONP exposure. In addition, the distribution of several elements over the body of exposed sea urchins, such as O, Ni, Cu, Fe, Mg, Na, N and C, can be obtained via XRF maps. The FTIR results suggested that a low level of calcite loss occurred in the sea urchin exposed to alkylated SiNCs and Si-coated IONPs. Furthermore, the FTIR results indicate that excess sulphur-containing compounds were also noticed as a result of a biological response of the exposed sea urchins to protect against the toxicity of alkylated SiNCs and Sicoated IONPs. Organic compounds such as amino acids and membrane lipids, which are produced during sea urchin fertilization, were observed over the scanned area of alkylated SiNC and Si-coated IONP-exposed sea urchins, using the FTIR technique.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available