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Materials Science at Oregon State University

ToF-SIMS Study of Orientation of Fibronectin Fragment on Self-Assembled Monolayers

Date: Thursday, Oct 6th
Presenter: Dr. Liney Arnadottir, OSU Chemical Engineering


Fibronectin (FN) is an extra-cellular matrix protein that is involved in many cell processes such as adhesion, migration, and growth. The orientation and conformation of FN adsorbed onto surfaces can therefore have a critical effect on cell-surface interactions. Advanced experimental techniques, such as Time of flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS), have been proven successful in evaluating a wide range of surface phenomena, ranging from engineered composites to biological media. In this study the adsorbed orientation of the 9-10 fragment of fibronectin was studied on three different model surface (self-assembled monolayers (SAM) of C11 alkanethiols on Au, -CH3, -NH2, and -COOH terminated SAMs.) The fibronectin fragment naturally has a significant asymmetry in its amino acid distribution. ToF-SIMS and XPS was used to study the different orientation on the three different surfaces taking advantage of the shallow sampling depth of ToF-SIMS and the asymmetry of the amino acid distribution within the fragment. Comparing the two charged surfaces –COOH and –NH2 indicates that the fragment is oriented with the cell-binding site in opposite direction on the two surfaces. Time allowing, the use of ToF-SIMS chemical imaging for patterned SAMs and chemical bounding of thin film organo-phosphonate SAM/AlOx/SiO2 for hybrid dielectrics devices will also be discussed.

Líney Árnadóttir graduated with a bachelor’s degree in Chemistry from the University of Iceland in 2001 with an emphasis on physical chemistry. Líney received her Ph.D. in Chemical Engineering from the University of Washington in December 2007 where she studied methanol oxidation on platinum at elevated temperatures via cyclic voltammetry and potential step experiments in Prof. Eric Stuve’s laboratory. Along with the experimental studies she worked with Prof. Hannes Jónsson on density functional theory calculations of water-platinum interactions and the effect of water on methanol oxidation intermediates and reaction pathways. After her Ph.D. she worked as a postdoctoral fellow in the surface analysis laboratory (NESAC/Bio) at the University of Washington were she applied various surface analysis techniques such as ToF-SIMS spectroscopy and X-ray photoelectron spectroscopy to studying model surfaces of self-assembly monolayers and biomaterials. She joined the faculty of the School of Chemical, Biological, and Environmental Engineering as an Assistant Professor (Senior Research) in fall 2011.