Electrophoretic elution and adsorption: Investigations using microporous membrane immunoadsorbents

This report describes an initial investigation into electrophoretic elution and adsorption techniques which employ microporous membrane adsorbents. To probe the mechanism of elution, electrophoretic elution rates were measured as a function of key process parameters. The elution rate trends qualitatively obeyed the reaction-migration theory developed previously for packed column adsorbents. A quantitative theoretical description of the process is presented. Electrophoretic elution was observed to preserve the activity of a chemically-sensitive monoclonal antibody immunoadsorbent: when eluted using glycine buffer at pH 2.5, anti-bovine serum albumin immunomembranes lost 85% of their antigen binding capacities within three cycles, but essentially full binding capacity was retained over 15 cycles of electrophoretic elution. Electrophoretic adsorption is a technique whereby an electric field is used to facilitate adsorption. Compared with crossflow adsorption, electrophoretic adsorption increased antigen adsorption yields 10-fold (67% vs. 6.6%) while reducing adsorption times by a factor of eight (45 min vs. 6 hr). Adsorption data were interpreted using the numerical reaction-migration theory. Process scale-up and optimization strategies are discussed.