Engineering properties of a camelid antibody affinity sorbent for Immunoglobulin G purification

An IgG-specific camelid antibody matrix (BAC, Naarden, The Netherlands), developed from an immune phage display library, was characterized regarding engineering properties including mass transfer characteristics. Uptake kinetics and equilibrium binding capacity were determined by a finite bath method. Adsorption kinetic parameters were also determined using a real time biosensor. Slightly different properties to conventional Staphylococcal protein A affinity media were shown; especially a 2–2.5 times lower maximal binding capacity with a value of 26 mg/ml polyclonal IgG was obtained. Mass transfer could be described by using a film and pore diffusion model (D_e = 5 × 10⁻⁸ cm²/s). Determined engineering parameters were used to predict breakthrough behaviour in column mode considering film and pore resistances. The dynamic binding capacity at 10% breakthrough did not change when residence time was at least 6 min.