Non-invasive sensing tools to study mechanisms of toxicity: A case study with silver nanoparticles
Abstract
The field of environmental toxicology is continuously adapting to emerging contaminants and rediscovering legacy chemicals by developing more sensitive endpoints to achieve the goal of protecting the environment and those that are part of it. In an endeavor to address these needs, we have developed and incorporated a series of techniques to target developmental and physiological endpoints in the cosmopolitan, aquatic invertebrate, Daphnia magna. While a variety of chemicals are investegated, this dissertation is in great part a case study on the toxicity of silver nanoparticles Ag NPs, the most rapidly growing class of nano-enhanced products. Ag NPs are of great interest toxicologically because unclear mechanisms of toxicity have prevented sound regulations regarding their use. The focus on Ag NPs is two-fold: to address its mechanistic toxicity and to demonstrate the applicability of novel techniques to this prominent emerging contaminant. In this work, we have developed a difference imaging technique demonstrated with cyanide, ionic silver, and Ag NPs as a highly sensitive, non-invasive technique of monitoring embryo development. We have used advanced imaging and biosensing techniques to outline a mechanism of toxicity that is unique to Ag NPs, centering on direct membrane damage caused to mitochondria. The last stage of this research was to develop a biological early warning system for detecting changes in water quality from changes in organismal health, capable of detecting low levels of ionic silver and Ag NPs in water samples. Within each of these studies is both innovation and significant advancement in each field that is addressed, that is developmental, mechanistic and applied toxicology. This dissertation represents the interdisciplinary work of engineers, chemists, and biologists to make significant contributions to environmental toxicology.
Degree
Ph.D.
Advisors
Sepulveda, Purdue University.
Subject Area
Toxicology|Surgery|Environmental Health
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