Flowing systems, protein adsorption

Summarizing this short discussion it has to be stated, that up to now experiments providing absolute numbers of kf during protein adsorption in fluidized beds are not available, the interpretations are based on correlations derived for small ions. As ion exchange with fluidized resins is performed at much higher Reynolds numbers and mostly is not limited by particle side transport, the validity of the correlations for proteins has to be proven. Nevertheless, the influence of bed expansion at increased linear flow rate cannot be neglected and fluid side mass transport should be considered as a system parameter governing the sorption process in a fluidized bed under certain conditions. 

The flow system is mounted by connecting the peristaltic pump to the injection valve and this one to the cell flow inlet by using Teflon tubes. The length of the tubes should be reduced as much as possible to avoid losses associated with the adsorption of protein on the tube walls and the dispersion effects of two different fluids inside the tube. The loop of the injection valve has the suitable length for injecting a solution volume of 200 pL. An extra tube is used from the cell oudet to the waste glassware see Fig. 4A, B). 

Application of a quantity of solution, in this case protein solution, to a column filled with appropriate substrate, leads to an exchange between the solute and the surface, and movement with the solvent front such that the emerging solute profile contains complete information concerning the kinetics of adsorption/desorption. Apart from the interaction of solute with surface, concurrent three-dimensional diffusion often occurs, and perhaps occlusion, if the substrate is porous. Nevertheless, the option of deducing interfacial kinetics from the elution profile in a flowing system has a certain elegance and relevance to the performance of blood plasma proteins in vivo. 

The transmission FTIR studies of aqueous protein solutions indicate how structural and conformational differences in a protein can be related to spectral changes, and that spectral features can be used to identify proteins in mixtures. However, these studies involve static systems, and our goal was to study flowing systems and the adsorption of proteins onto various surfaces. 

Fourier Transform Infrared Spectroscopic and Attenuated Total Reflectance Studies of Protein Adsorption in Flowing Systems... 

Dynamic (agitators, centrifugation systems, flow chambers, Chandlerloops, closed loops) Protein adsorption (fluorescent fibrinogen absorption assay)... 

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