AVS 50th International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThM

Paper BI-ThM11
Infrared and Visible Spectroscopy of Anisotropic Spin-cast Chitosan Films

Thursday, November 6, 2003, 11:40 am, Room 318/319

Session: Biosensors
Presenter: W.H. Nosal, University of Nebraska, Lincoln
Authors: W.H. Nosal, University of Nebraska, Lincoln
S. Sarkar, University of Nebraska, Lincoln
A. Subramanian, University of Nebraska, Lincoln
D.W. Thompson, University of Nebraska, Lincoln
J.A. Woollam, University of Nebraska, Lincoln
Correspondent: Click to Email
Chemical modification of chitosan is postulated as a way to control thrombosis at the surface of biomedical implants. Recent interest in performing surface modification of biomaterials has led to chitosan as a candidate to improve biocompatibility, due to the relative ease with which the amine groups can be chemically modified. As a way to evaluate surface modification effectiveness, spin-cast films of chitosan on silicon wafers were characterized using both infrared and visible spectroscopic ellipsometry (SE). Infrared SE data was modeled using a set of harmonic oscillators to represent the chemical bonds of the chitosan molecule. Visible SE data was modeled using an anisotropic uniaxial Cauchy dispersion model. In-plane vs. Out-of-plane optical anisotropy was detected in both the Infrared and visible wavelength data. This work shows there is a preferred orientation of the molecule, likely a result of spin casting. Visible ellipsometry surface mapping was used to determine anisotropy as a function of position on the wafer. This work discusses anisotropy and orientation of identified chemical bonds in a biomolecular film by spectroscopic ellipsometry.