Investigating the biological impacts of nanoengineered materials in Caenorhabditis elegans and in vitro

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dc.contributor.advisorColvin, Vicki L.
dc.contributor.committeeMemberWilson, Lon J.
dc.contributor.committeeMemberZhong, Weiwei
dc.creatorContreras, Elizabeth
dc.date.accessioned2013-06-05T14:47:25Z
dc.date.accessioned2013-06-05T14:48:09Z
dc.date.available2013-06-05T14:47:25Z
dc.date.available2013-06-05T14:48:09Z
dc.date.created2012-12
dc.date.issued2013-06-05
dc.date.submittedDecember 2012
dc.date.updated2013-06-05T14:48:09Z
dc.description.abstractIn nematode Caenorhabditis elegans, the chronic and multi-generational toxicological effects of commercially relevant engineered nanoparticles (ENPs), such as quantum dots (QDs) and silver (AgNP) caused significant changes in a number of physiological endpoints. The increased water-solubility of ENPs in commercial products, for example, makes them increasingly bioavailable to terrestrial organisms exposed to pollution and waste in the soil. Since 2008, attention to the toxicology of nanomaterials in C. elegans continues to grow. Quantitative data on multiple physiological endpoints paired with metal analysis show the uptake of QDs and AgNPs, and their effects on nematode fitness. First, C. elegans were exposed for four generations through feeding to amphiphilic polymer coated CdSe/ZnS (core-shell QDs), CdSe (core QDs), and different sizes of AgNPs. These ENPs were readily ingested. QDs were qualitatively imaged in the digestive tract using a fluorescence microscopy and their and AgNP uptake quantitatively measured using ICP-MS. Each generation was analyzed for changes in lifespan, reproduction, growth and motility using an automated computer vision system. Core-shell QDs had little impact on C. elegans due to its metal shell coating. In contrast, core QDs lacked a metal shell coating, which caused significant changes to nematode physiology. In the same way, at high concentrations of 100 ppm, AgNP caused the most adverse effect to lifespan and reproduction related to particle size, but its adverse effect to motility had no correlation to particle size. Using C. elegans as an animal model allowed for a better understanding of the negative impacts of ENPs than with cytotoxicity tests. Lastly, to test the toxicity of water-dispersed fullerene (nanoC60) using human dermal fibroblast cells, this thesis investigated a suite of assays and methods in order to establish a standard set of cytotoxicity tests. Ten assays and methods assessed nanoC60 samples of different purities to show differences in cytotoxic effects. Washed samples of fullerenes, with negligible traces of THF and other impurities, rendered the solution nontoxic. Even when exposed to UV-irradiation, washed nanoC60 were not photosensitized and did not cause cellular death. This work characterizes ENPs and investigates their impact in C. elegans and cells to assess toxicity risks to the environment and to human health.
dc.format.mimetypeapplication/pdf
dc.identifier.citationContreras, Elizabeth. "Investigating the biological impacts of nanoengineered materials in Caenorhabditis elegans and in vitro." (2013) Diss., Rice University. <a href="https://hdl.handle.net/1911/71273">https://hdl.handle.net/1911/71273</a>.
dc.identifier.slug123456789/ETD-2012-12-323
dc.identifier.urihttps://hdl.handle.net/1911/71273
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectC. elegans
dc.subjectCadmium
dc.subjectQuantum dots
dc.subjectSilver
dc.subjectNanoparticles
dc.subjectMultigeneration
dc.subjectToxicity
dc.subjectCytotoxicity
dc.subjectIn vitro
dc.subjectIn vivo
dc.subjectHuman cells
dc.subjectROS
dc.subjectFullerenes
dc.subjectAssays
dc.subjectReview
dc.titleInvestigating the biological impacts of nanoengineered materials in Caenorhabditis elegans and in vitro
dc.typeThesis
dc.type.materialText
thesis.degree.departmentChemistry
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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