DOI
https://doi.org/10.25772/12NY-3M68
Author ORCID Identifier
https://orcid.org/0000-0003-1723-3997
Defense Date
2018
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Engineering
First Advisor
Dr. Nastassja Lewinski
Abstract
The toxicology of aerosols in occupational settings is often performed through particle collection on a filter followed by reconstitution into cell culture media which can alter the biological effects. Current in vitro exposure systems require additional instruments to control temperature and humidity, making the system bulky and difficult to take to the field. The Portable In Vitro Exposure Cassette (PIVEC) was designed for personal monitoring, characterized using copper nanoparticles, tested with alveolar cells, and set-up for real-time monitoring. Three differently sized copper nanoparticles, 40-800 nm, were dispersed as a dry aerosol and measured gravimetrically and on a number concentration basis to determine the deposition efficiency of the PIVEC. A549 cells, a human alveolar adenocarcinoma epithelial line, were exposed to the aerosols and oxidative stress and cell viability were monitored post-exposure. The deposition efficiency ranged from 0.5% to 18% depending on method of analysis and size of particle. Oxidative stress increased within the first two hours post exposure, however there was no significant difference in cell viability at the four hour time point at deposited doses up to 1.63 mg/cm2.
Validation of the PIVEC was done in the laboratory using diesel exhaust. Metal oxide fuel additives are used to reduce emissions; however, additives have been shown to increase emitted nanoparticles. The PIVEC was used to determine the potential cytotoxicity and oxidative activity changes in A549 cells after exposure to either model particles or exhaust generated with or without a commercial, nano-cerium oxide based additive. Acellular experiments suggest a correlation between the deposition and the type of fuel used for the newly designed PIVEC. Cellular results suggest a decrease in cytotoxicity and no statistically significant effect on reactive oxygen species generation with the use of the nano-cerium oxide additive.
Rapid monitoring of oxidative stress was performed using an enzyme-based biosensor. The functionalized biosensor uses cytochrome c to measure reactive oxygen species through electrochemical detection during aerosol exposures. When compared to a traditional biological assay, the biosensor response was similar. The PIVEC is a unique device, designed to monitor aerosols using air-liquid interface in vitro techniques including a real-time monitor for oxidative stress.
Rights
© Lynn Secondo
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
1-14-2019