Date of Award:

5-2012

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biological Engineering

Committee Chair(s)

Anhong Zhou

Committee

Anhong Zhou

Committee

Ronald C. Sims

Committee

Timothy A. Gilbertson

Committee

Charles D. Miller

Committee

Lisa M. Berreau

Abstract

Understanding bio-interfaces will help improve the design and application of biomaterials that can interact with biological objects like nucleic acids, molecules, bacteria, and mammalian cells. Currently, there exist instruments to investigate material properties for the electrical, chemical, physical, and mechanical nature of biomaterials or biological samples. Our goal is to use advanced spectroscopic methods and data analysis to find specific properties of biological objects and see how these properties show the biological object’s response to their environment.

My studies of interfacial electron transfer (ET) of DNA coated gold electrodes aided to understand that the density of DNA on the surface is related to the order at which it is added during surface coating. Furthermore, surface coating affects the conductivity of the electrode and I found that guanine and adenine are destroyed through current induced oxidation. Scanning tunneling microscopy (STM) was used to see the height of surface coatings and verify decreased conductivity. I also used Raman microspectroscopy (RM) to obtain Raman peaks and spectral images of DNA coated on the gold surfaces.

For bacteria studies atomic force microscopy (AFM) and scanning electron microscopy (SEM) images showed visually similar features of Gram-positive and Gram-negative bacteria. Data analysis aided to visually separate mixed strains of bacteria and Fourier transform infrared (FTIR) spectroscopy showed specific peaks for Gram-positive bacteria. A combined AFM/RM image showed that there was a relationship between the sample height and the Raman peak intensity.

For mammalian cell studies, RM revealed similarities between two types of breast cancer cell lines. AFM showed increases in biomechanical properties for breast cancer cells that do not metastasize versus those that spread. Fluorescent staining illustrates breast cancer cell physical arrangement of the cytoplasm. Electric cell-substrate impedance sensing (ECIS) revealed that breast cancer cells which do not metastasize, grow more slowly compared to those that do metastasize, and do not spread when wounded (i.e. surgically removed). It was found that for ECIS, diesel exhaust particles (DEP) concentration caused lung cells to either mutate or rapidly die. Resveratrol (RES) showed some protection against DEP before and after exposure and aided in improving injury recovery of airway epithelial cells.

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This work made publicly available electronically on June 4, 2012.

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