Events & Media

The Bren School of Environmental Science & Management
at the University of California, Santa Barbara

Presents

A PhD DEFENSE

"Bacterial exposure to TiO2 nanoparticles:
methods, physical interactions, and biological effects"

Allison Horst
Doctoral Student
Bren School of Environmental Science & Management

Thursday, May 31, 2012
8:30 a.m.
Bren Hall Dean's Conference Room

Patricia Holden, Faculty Advisor
Jeff Dozer and Galen Stucky, Committee Members

Abstract
Nanotechnology is a major endeavor of this century, with proposed applications in fields ranging from agriculture to energy to medicine. Nanoscale titanium dioxide (nano-TiO2) is among the most widely produced nanoparticles worldwide, and will inevitably transport into the environment via consumer or industrial waste. Effects of nano-TiO2 on environmental organisms, however, are largely unknown. Bacteria are ideal organisms for nanotoxicology research because they are environmentally important, respond rapidly to intoxication, and provide evidence for effects in higher organisms.

Allison's doctoral work describes outcomes of bacterial exposure to nano-TiO2 in aqueous media, with specific focus on: a) bacterial dispersion of nano-TiO2 agglomerates; b) a method and a general framework for dispersing nanoparticles in aqueous culture medium; c) an assessment of fluorescence- and absorbance-based assays to rapidly study nanoparticle ROS generation and effects on bacterial membranes; and d) influences of primary particle size and iron-doping on nano-TiO2 effects on E. coli growth and membranes in the dark.

Generally, this research is toward: better understanding outcomes of interactions between nanoparticles and bacteria, advancing methods in the relatively new field of nanotoxicology that are transferable to other nanoparticle and media chemistries, and improving our understanding of structure-activity relationships (e.g. size and doping effects) leading to intoxication in environmental organisms.