Nano-Biophysical Approaches for Assessing Nanoparticle Interactions with Biological Systems

Understanding interactions between nanoparticles and biological systems is fundamental for the development of emerging nano-biotechnology applications. In this thesis, I present an investigation of zinc oxide (ZnO) nanoparticles interactions with biomolecules in two separate studies. The first section of my thesis covers tracking and detection of ZnO nanoparticles using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). ZinkicideTM is a bactericidal ZnO nanoparticle which has been developed for agriculture. The characterization of Zinkicide in biological media and in solution has been difficult due to its high dispersibility and ultra-small size. SDS-PAGE is considered a golden standard for protein qualitative interpretations. In this study, we have modified this typical protein assay and developed protocols for quantifying Zinkicide concentration, fluorescence intensity, and relative molecular weight changes in aqueous solutions. We found that SDS-PAGE is a novel and fundamental approach for assessing ZnO nanoparticles. The second part of my thesis is focused on investigating biological toxicity induced by nanoparticles. Recent studies have shown that nanoparticles have the capabilities to induce abnormalities on cellular networks including actin cytoskeleton. We have studied the effects of ZnO nanoparticles on filamentous actin assembly dynamics utilizing total internal reflection fluorescence (TIRF) microscopy imaging and biophysical analysis. The combination of these studies has provided pertinent information for the future development of nanoparticles designed for biological applications