Nylon 6 capillary-channeled polymer (C-CP) fibers are investigated as an alternative support/stationary phase for downstream processing of macromolecules. Ionizable amine and carboxylic acid end groups on the native fiber surface allow for ion exchange chromatography (IEC). The low cost and ability to operate at high linear velocities and low back pressures are practical advantages of C-CP fibers for preparative-scale macromolecule separations. The lack of fiber porosity ensures facile adsorption/desorption that is conducive to high throughput and recoveries/yields. Described here is a preliminary investigation of the processing characteristics of lysozyme on nylon 6 fibers with an eye toward downstream processing applications. Fibers were packed into microbore (0.8 mm i.d.) and analytical-size (2.1 mm i.d.) columns for the evaluation of the role of linear velocity on pressure drop, frontal throughput, and yield. Protein isolation by frontal development involved three steps: loading of the column to breakthrough, an aqueous wash, and a salt wash to recover the protein. Frontal throughput was evaluated with different salt concentrations (0-1000 mM NaCl) and different linear velocities (6-24 mm s(-1)). The observed throughput values are in the range of 0.12-0.20 mg min(-1) when 0.25 mg mL(-1) lysozyme (in 20 mM Tris-HCl) is loaded onto 78 mg of C-CP fiber in 0.52 mL volume analytical columns. Increased throughput and yield were found when protein was loaded and eluted at high linear velocity. Results of this study lend credence to the further development of C-CP fibers for biomacromolecule processing on larger scales. (c) 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1222-1229, 2013