Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material
<p>Form, mobility, toxicity and the eventual fate of engineered nanomaterials in environmental ecosystems are currently not well defined and are needed to improve risk assessment and legislation. The present study subjected uncoated zinc oxide (ZnO) nanoparticles (30nm and 200nm) and coated si...
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| Format: | Thesis |
| Language: | English |
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2014
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| _version_ | 1797050930580946944 |
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| author | Taylor, C |
| author2 | Crossley, A |
| author_facet | Crossley, A Taylor, C |
| author_sort | Taylor, C |
| collection | OXFORD |
| description | <p>Form, mobility, toxicity and the eventual fate of engineered nanomaterials in environmental ecosystems are currently not well defined and are needed to improve risk assessment and legislation. The present study subjected uncoated zinc oxide (ZnO) nanoparticles (30nm and 200nm) and coated silver (Ag) nanoparticles (Paraffin: 3-8nm and citrate/PVP: 50nm) to different ionic strength media and different types of algal/bacterial extracellular-polymeric species (EPS) at long (6 months) and short (2 weeks) timescales. Changes in particle size distribution and stability were examined using a multi-method approach. Sample concentration and sample polydispersity are important factors when selecting techniques. Uncoated ZnO nanoparticles aggregated heavily in water at high concentrations (1000mg/L). However silver nanoparticles (1-10mg/L) remained stable at all ionic strengths and EPS in this study due to the steric component of their coatings. Nano-toxicological experiments involving cyanobacteria <em>S.leopoliensis</em> and green algae <em>C.reinhardtii</em> showed size-dependent toxicity from coated nanosilver particles. Smaller nanoparticles (3-8nm) showed greater dissolution over 72h and greater toxicity to both species than 50nm particles indicating silver ions are an important toxicity mechanism. Nanoparticle coatings were likely important in controlling dissolution levels. Cell viability and production of reactive oxygen species (ROS) were shown to be important mechanisms of toxicity to phycological species. Species specific effects were noted for both silver nanoparticles. EPS from <em>S.leopoliensis</em> were noted to remove ionic silver from suspension and different types of <em>C.reinhardtii</em> EPS were produced when particles underwent different levels of toxic stress indicating that EPS could both affect particle toxicity and be affected by it. This work has demonstrated that coated nanoparticles could remain stable under various ionic strengths and with exposure to algal organic matter for timescales up to 6 months. This could result in adverse effects to aquatic organisms were they to reach environmental systems and is of concern to nanomaterial risk assessors.</p> |
| first_indexed | 2024-03-06T18:12:30Z |
| format | Thesis |
| id | oxford-uuid:03810528-de65-4094-907c-8c0d4e0386c8 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:12:30Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | oxford-uuid:03810528-de65-4094-907c-8c0d4e0386c82022-03-26T08:46:37ZCharacterisation of engineered nanoparticles and their interaction with natural biological and non-biological materialThesishttp://purl.org/coar/resource_type/c_db06uuid:03810528-de65-4094-907c-8c0d4e0386c8Materials SciencesEnglishOxford University Research Archive - Valet2014Taylor, CCrossley, AGrovenor, C<p>Form, mobility, toxicity and the eventual fate of engineered nanomaterials in environmental ecosystems are currently not well defined and are needed to improve risk assessment and legislation. The present study subjected uncoated zinc oxide (ZnO) nanoparticles (30nm and 200nm) and coated silver (Ag) nanoparticles (Paraffin: 3-8nm and citrate/PVP: 50nm) to different ionic strength media and different types of algal/bacterial extracellular-polymeric species (EPS) at long (6 months) and short (2 weeks) timescales. Changes in particle size distribution and stability were examined using a multi-method approach. Sample concentration and sample polydispersity are important factors when selecting techniques. Uncoated ZnO nanoparticles aggregated heavily in water at high concentrations (1000mg/L). However silver nanoparticles (1-10mg/L) remained stable at all ionic strengths and EPS in this study due to the steric component of their coatings. Nano-toxicological experiments involving cyanobacteria <em>S.leopoliensis</em> and green algae <em>C.reinhardtii</em> showed size-dependent toxicity from coated nanosilver particles. Smaller nanoparticles (3-8nm) showed greater dissolution over 72h and greater toxicity to both species than 50nm particles indicating silver ions are an important toxicity mechanism. Nanoparticle coatings were likely important in controlling dissolution levels. Cell viability and production of reactive oxygen species (ROS) were shown to be important mechanisms of toxicity to phycological species. Species specific effects were noted for both silver nanoparticles. EPS from <em>S.leopoliensis</em> were noted to remove ionic silver from suspension and different types of <em>C.reinhardtii</em> EPS were produced when particles underwent different levels of toxic stress indicating that EPS could both affect particle toxicity and be affected by it. This work has demonstrated that coated nanoparticles could remain stable under various ionic strengths and with exposure to algal organic matter for timescales up to 6 months. This could result in adverse effects to aquatic organisms were they to reach environmental systems and is of concern to nanomaterial risk assessors.</p> |
| spellingShingle | Materials Sciences Taylor, C Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title | Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title_full | Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title_fullStr | Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title_full_unstemmed | Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title_short | Characterisation of engineered nanoparticles and their interaction with natural biological and non-biological material |
| title_sort | characterisation of engineered nanoparticles and their interaction with natural biological and non biological material |
| topic | Materials Sciences |
| work_keys_str_mv | AT taylorc characterisationofengineerednanoparticlesandtheirinteractionwithnaturalbiologicalandnonbiologicalmaterial |