File Download
  Links for fulltext
     (May Require Subscription)
Supplementary

postgraduate thesis: Effects of silver nanoparticles on marine invertebrate larvae

TitleEffects of silver nanoparticles on marine invertebrate larvae
Authors
Issue Date2013
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Chan, Y. [陳映姗]. (2013). Effects of silver nanoparticles on marine invertebrate larvae. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5185920
AbstractSilver nanoparticles (AgNPs) have gained much popularity in consumer products due to their strong antimicrobial ability. The majority of research concerning the biological effects of AgNPs has been limited to humans, mammals and freshwater organisms. Marine organisms, especially invertebrates, have been studied to a lesser extent. The objective of this thesis was to understand the effects of AgNPs on the marine benthic invertebrates. Specifically, we focused on the acute and sub-lethal toxicity of two AgNPs (Oleic acid coated AgNP (OAgNP) and Polyvinylpyrrolidone coated AgNP (PAgNP)) on marine invertebrate larvae across three phyla (i.e. the barnacle Balanus amphitrite, the limpet Crepidula onyx and the polychaete Hydroides elegans) in terms of mortality, growth, development and metamorphosis. Bioaccumulation and biodistribution of silver, as well as apoptosis induction were also investigated. To distinguish the toxic effects derived from nano-silver and aqueous form of silver, larvae were also exposed to silver nitrate (SN) in parallel. In the acute toxicity test, larvae were exposed to OAgNPs and PAgNPs for 48 hours, and the concentration leading to 10 % mortality (〖LC〗_10) were determined and compared. The results indicated that B. amphitrite and H. elegans were more sensitive to OAgNPs (〖LC〗_10: 0.138 and 2.63 × 〖10〗^(-4) μμg L-1, respectively) than PAgNPs (〖LC〗_10: 0.502 and 0.317 μμg L^(-1), respectively). In contrast, C. onyx was more susceptible to PAgNPs (LC10: 38.5 μμg L^(-1)) than OAgNPs (〖LC〗_10: 467 μμg L^(-1)). Among the three taxonomic groups, C. onyx was most tolerant of AgNPs, following by B. amphitrite and H. elegans. The sub-lethal effect of AgNPs resulted in a significant retardation in growth and development, and the reduction of settlement rate of all three species tested. In particular, the settlement rate of H. elegans was significantly lower in AgNPs treatment than in SN treatment, suggesting that toxicity of AgNPs might not be solely evoked by the release of silver ion (Ag+) into the test solution. The three species took up and accumulated silver efficiently from all forms. Importantly, AgNP aggregates were found along the digestive tract of C. onyx and the TEM images further confirmed that AgNPs were able to move across the plasma membrane. In addition, TUNEL assay indicated that AgNPs could induce apoptosis in B. amphitrite and C. onyx. In view of the very low number of detected apoptotic cells and the random occurrence of cell death found, AgNP-induced apoptosis does not appear to be the major toxicity mechanism in causing delayed growth and settlement failure. Unlike the results revealed from acute toxicity test, surface coatings did not affect the sub-lethal toxicity of AgNPs. This research clearly demonstrated that AgNPs exerted toxic effects in a speciesspecific manner, and long-term exposure of AgNPs might allow bioaccumulation of silver, induce apoptosis, and affect growth, development and recruitment of marine invertebrates. This study also highlighted the possibility that toxicity of AgNPs might be mediated through toxic Ag+ as well as the novel modalities of AgNPs.
DegreeMaster of Philosophy
SubjectSilver
Nanoparticles
Marine invertebrates - Larvae
Dept/ProgramBiological Sciences
Persistent Identifierhttp://hdl.handle.net/10722/208175

 

DC FieldValueLanguage
dc.contributor.authorChan, Ying-shan-
dc.contributor.author陳映姗-
dc.date.accessioned2015-02-20T23:07:01Z-
dc.date.available2015-02-20T23:07:01Z-
dc.date.issued2013-
dc.identifier.citationChan, Y. [陳映姗]. (2013). Effects of silver nanoparticles on marine invertebrate larvae. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5185920-
dc.identifier.urihttp://hdl.handle.net/10722/208175-
dc.description.abstractSilver nanoparticles (AgNPs) have gained much popularity in consumer products due to their strong antimicrobial ability. The majority of research concerning the biological effects of AgNPs has been limited to humans, mammals and freshwater organisms. Marine organisms, especially invertebrates, have been studied to a lesser extent. The objective of this thesis was to understand the effects of AgNPs on the marine benthic invertebrates. Specifically, we focused on the acute and sub-lethal toxicity of two AgNPs (Oleic acid coated AgNP (OAgNP) and Polyvinylpyrrolidone coated AgNP (PAgNP)) on marine invertebrate larvae across three phyla (i.e. the barnacle Balanus amphitrite, the limpet Crepidula onyx and the polychaete Hydroides elegans) in terms of mortality, growth, development and metamorphosis. Bioaccumulation and biodistribution of silver, as well as apoptosis induction were also investigated. To distinguish the toxic effects derived from nano-silver and aqueous form of silver, larvae were also exposed to silver nitrate (SN) in parallel. In the acute toxicity test, larvae were exposed to OAgNPs and PAgNPs for 48 hours, and the concentration leading to 10 % mortality (〖LC〗_10) were determined and compared. The results indicated that B. amphitrite and H. elegans were more sensitive to OAgNPs (〖LC〗_10: 0.138 and 2.63 × 〖10〗^(-4) μμg L-1, respectively) than PAgNPs (〖LC〗_10: 0.502 and 0.317 μμg L^(-1), respectively). In contrast, C. onyx was more susceptible to PAgNPs (LC10: 38.5 μμg L^(-1)) than OAgNPs (〖LC〗_10: 467 μμg L^(-1)). Among the three taxonomic groups, C. onyx was most tolerant of AgNPs, following by B. amphitrite and H. elegans. The sub-lethal effect of AgNPs resulted in a significant retardation in growth and development, and the reduction of settlement rate of all three species tested. In particular, the settlement rate of H. elegans was significantly lower in AgNPs treatment than in SN treatment, suggesting that toxicity of AgNPs might not be solely evoked by the release of silver ion (Ag+) into the test solution. The three species took up and accumulated silver efficiently from all forms. Importantly, AgNP aggregates were found along the digestive tract of C. onyx and the TEM images further confirmed that AgNPs were able to move across the plasma membrane. In addition, TUNEL assay indicated that AgNPs could induce apoptosis in B. amphitrite and C. onyx. In view of the very low number of detected apoptotic cells and the random occurrence of cell death found, AgNP-induced apoptosis does not appear to be the major toxicity mechanism in causing delayed growth and settlement failure. Unlike the results revealed from acute toxicity test, surface coatings did not affect the sub-lethal toxicity of AgNPs. This research clearly demonstrated that AgNPs exerted toxic effects in a speciesspecific manner, and long-term exposure of AgNPs might allow bioaccumulation of silver, induce apoptosis, and affect growth, development and recruitment of marine invertebrates. This study also highlighted the possibility that toxicity of AgNPs might be mediated through toxic Ag+ as well as the novel modalities of AgNPs.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.subject.lcshSilver-
dc.subject.lcshNanoparticles-
dc.subject.lcshMarine invertebrates - Larvae-
dc.titleEffects of silver nanoparticles on marine invertebrate larvae-
dc.typePG_Thesis-
dc.identifier.hkulb5185920-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelMaster-
dc.description.thesisdisciplineBiological Sciences-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b5185920-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats