Graduation Year

2004

Document Type

Thesis

Degree

M.S.E.E.

Degree Granting Department

Electrical Engineering

Major Professor

Schlaf, Rudiger

Keywords

bio-materials, gold, HOPG, electrospray, x-ray photospectroscopy(XPS)

Abstract

The objective of this master s thesis is the preparation and characterization of ribonucleic acid (RNA)/inorganic material interfaces by electrospray deposition and photoemission spectroscopy. This was done through investigation of the chemical and electronic structure of the surface of Highly Ordered Pyrolytic Graphite (HOPG) and gold before and after multiple steps of RNA thin film deposition by electrospray. Great interest has been shown by researchers into RNA due to its self-assembling ability. A series of experiments was conducted depositing RNA Poly adenosine, RNA Poly cytidine, and (for control purposes) DI water on HOPG. RNA Poly adenosine was also deposited on Gold. Gold is a more practical surface for use with RNA, but HOPG is useful for this study because it allows the precise determination of the density of states (DOS) of RNA.

X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) were used to characterize the RNA-interfaces. The work function, high binding energy cutoff, and HOMO energies were determined. The clean, in-vacuum deposition of RNA was carried out using an electrospray thin film deposition device. The HOPG and gold substrates were prepared by in-situ cleavage and sputtering respectively. The electrospray method can be used for many different types of molecules including Polymers, metal-organics, crystals, and biological materials including RNA or DNA. These measurements provided data that will be helpful in determining the electronic properties of biological and substrate interfaces.

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