Native poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers have been used as the stationary phase for high-performance liquid chromatography (HPLC) of proteins via reversed-phase and ion-exchange processes. Functionalization can be used to bring about greater selectivity through surface modification. PET fibers were treated with ethylenediamine to generate primary amine groups on the fiber surface, enabling subsequent covalent attachment of ligands. The ninhydrin test for primary amines revealed surface densities of 13.9–60.0 μmol m−2 for PET fibers exposed for periods of 3–12 min. Here, 8-amino-3,6-dioxaoctanoic acid was linked to the EDA-treated PET fiber surface as a hydrophilic spacer, and then d-biotin was attached on the end of the spacer as an affinity ligand. The streptavidin binding capacity and binding homogeneity were studied on the biotin-functionalized PET C-CP fiber microbore column. The selectivity of the biotin surface functionalization was assessed by spiking lysate with Texas Red-labeled streptavidin and enhanced green fluorescent protein. Greater than 99 % selectivity was realized. This ligand-coupling strategy from standard solid-phase peptide synthesis used in stationary phase functionalization creates great potential for PET C-CP fiber-packed HPLC columns to perform a variety of chromatographic separations.
