Fourier transform infrared spectroscopy/attenuated total reflection studies of protein adsorption in flowing systems: Approaches for bulk correction and compositional analysis of adsorbed and bulk proteins in mixtures

Abstract

We have been investigating the usefulness of Fourier transform infrared (FT-IR) spectroscopy coupled with attenuated total reflection (ATR) optics as a method for monitoring blood-surface interactions. These studies have included the determination of the kinetics of the plasma protein adsorption process, the description of the adsorbed film composition on various biopolymers, and interpretation of the structural features of the adsorbed protein layer. This paper describes some of our most recent results of studies with two of the important plasma proteins, albumin and the γ-globulins. Algorithms are presented for the correction of the FT-IR/ATR spectra for the protein in the bulk (nonadsorbed) solution and for the analysis of the composition of the adsorbed protein layer. The real-time kinetics of adsorption of albumin and the γ-globulins from both single-component systems and from mixtures is described. Results of flow experiments with physiological concentrations of albumin and γ-globulins onto a commercial polyurethane, while preliminary and somewhat variable, illustrate the data analysis algorithms and suggest a higher affinity for albumin compared to control germanium surfaces.