title: Generalized ellipsometry in-situ quantification of organic adsorbate attachment within slanted columnar thin films.
abstract: We apply generalized ellipsometry, well-known to be sensitive to the optical properties of                     anisotropic materials, to determine the amount of fibronectin protein that                     adsorbs onto a Ti slanted columnar thin film from solution. We find that the                     anisotropic optical properties of the thin film change upon organic adsorption.                     An optical model for ellipsometry data analysis incorporates an anisotropic                     Bruggeman effective medium approximation. We find that differences in                     experimental data from before and after fibronectin adsorption can be solely                     attributable to the uptake of fibronectin within the slanted columnar thin film.                     Simultaneous, in-situ generalized ellipsometry and quartz                     crystal microbalance measurements show excellent agreement on the amount and                     rate of fibronectin adsorption. Quantitative characterization of organic                     materials within three-dimensional, optically anisotropic slanted columnar thin                     films could permit their use in optical sensor applications.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, 207 Othmer Hall, Lincoln, NE 68588, USA. kbrod@engr.unl.edu
authors.forename: Keith B
authors.initials: KB
authors.lastname: Rodenhausen
authors.forename: Daniel
authors.initials: D
authors.lastname: Schmidt
authors.forename: Tadas
authors.initials: T
authors.lastname: Kasputis
authors.forename: Angela K
authors.initials: AK
authors.lastname: Pannier
authors.forename: Eva
authors.initials: E
authors.lastname: Schubert
authors.forename: Mathias
authors.initials: M
authors.lastname: Schubert
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005353:Fibronectins / Q000032:analysis*; D008567:Membranes, Artificial; D012031:Refractometry / Q000295:instrumentation*
chemical_list: D005353:Fibronectins; D008567:Membranes, Artificial