AVS 52nd International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoP

Paper BI-MoP24
Infrared Spectra of Serum Albumin Immobilized in Porous Alumina

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Biomaterial Interfaces Poster Session
Presenter: L.G. Castro, University of Nebraska-Lincoln
Authors: L.G. Castro, University of Nebraska-Lincoln
S. Sarkar, University of Nebraska-Lincoln
D.W. Thompson, University of Nebraska-Lincoln
J.A. Woollam, University of Nebraska-Lincoln
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While most studies of protein-surface interactions rely on chemistry to obtain specific information about what proteins are present, infrared absorption spectra also contain protein-specific features. Reliable measurement of these spectra could, for example, help identify nonspecific binding. Here porous alumina was used as a capture matrix to increase the detectability of protein infrared spectra. Layers of porous alumina were fabricated electrochemically and fully characterized using visible and mid-infrared (mid-IR) spectroscopic ellipsometry (SE). Pore sizes and center-to-center spacings were engineered to efficiently capture human serum albumin (HSA). The layers were exposed to solutions of HSA in an acetate buffer. The incorporation of the proteins into the matrix was monitored by multiwavelength visible SE. The samples were characterized before and after protein attachment with mid-IR SE. A methodology was developed to obtain the infrared dielectric function @epsilon@ of the adsorbed proteins. Full optical modelling was essential to separate the protein peak signatures from those of the alumina. Strategies to improve capture efficiency and reduce uncertainty of the @epsilon@ spectrum are discussed.