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

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dc.contributor.advisorColvin, Vicki L.en_US
dc.contributor.committeeMemberWilson, Lon J.en_US
dc.contributor.committeeMemberZhong, Weiweien_US
dc.creatorContreras, Elizabethen_US
dc.date.accessioned2013-06-05T14:47:25Zen_US
dc.date.accessioned2013-06-05T14:48:09Zen_US
dc.date.available2013-06-05T14:47:25Zen_US
dc.date.available2013-06-05T14:48:09Zen_US
dc.date.created2012-12en_US
dc.date.issued2013-06-05en_US
dc.date.submittedDecember 2012en_US
dc.date.updated2013-06-05T14:48:09Zen_US
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.en_US
dc.format.mimetypeapplication/pdfen_US
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>.en_US
dc.identifier.slug123456789/ETD-2012-12-323en_US
dc.identifier.urihttps://hdl.handle.net/1911/71273en_US
dc.language.isoengen_US
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.en_US
dc.subjectC. elegansen_US
dc.subjectCadmiumen_US
dc.subjectQuantum dotsen_US
dc.subjectSilveren_US
dc.subjectNanoparticlesen_US
dc.subjectMultigenerationen_US
dc.subjectToxicityen_US
dc.subjectCytotoxicityen_US
dc.subjectIn vitroen_US
dc.subjectIn vivoen_US
dc.subjectHuman cellsen_US
dc.subjectROSen_US
dc.subjectFullerenesen_US
dc.subjectAssaysen_US
dc.subjectReviewen_US
dc.titleInvestigating the biological impacts of nanoengineered materials in Caenorhabditis elegans and in vitroen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemistryen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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