Preliminary assessment of the modification of polystyrene-divinylbenzene resin with lipid-tethered ligands for selective separations

Abstract

Functionalized lipid tethered ligands use physical adsorption to anchor reactive head groups to hydrophobic supports. We previously demonstrated the use of these species adsorbed onto polypropylene capillary-channeled polymer fibers. The general use of lipid tethered ligands on other hydrophobic chromatographic supports is demonstrated here for polystyrene-divinylbenzene. Evaluation of ligand adsorption conditions was performed using a fluorescein isocyanate head group to quantify the extent of loading by UV-Vis absorbance and by fluorescence microscopy. Selective protein capture was demonstrated by the detection of Texas Red labeled streptavidin (using fluorescence microscopy imaging, with quantification assessed through the depletion of solution-phase protein using UV-Vis absorbance. A second demonstration of the coupling involved an iminodiacetic acid head group lipid tethered ligand to capture the cationic dye, methylene blue. Two common means of alleviating nonspecific binding, adsorption in detergent media and use of a bovine serum albumin block, were evaluated. The first was found to cause release of the ligands, while the second was nominally effective. Indeed, the lipid tethered ligands itself may be most effective at impeding nonspecific binding. While further optimization and chromatographic evaluation is required, the general viability of this ligand immobilization method onto this common polymer support is demonstrated.

Keywords: Affinity separations; Lipid-tethered ligand; Polystyrene-divinylbenzene; Surface modification.