Antibody-Imprinted Membrane Adsorber via Two-Step Surface Grafting

Abstract

In this work, a recently established, novel two-step imprinting strategy combining surface imprinting and scaffold imprinting was applied successfully to prepare a molecularly imprinted polymer (MIP) adsorber for immunoglobulin G (IgG). Track-etched polyethylene terephthalate (PET) membranes with previously introduced aliphatic C-Br groups as initiator on the pore surface were used to prepare first a functional polymer scaffold, grafted poly(methacrylic acid), via surface-initiated atom transfer radical polymerization (SI-ATRP). After template protein (IgG) binding to the scaffold, UV-initiated cross-linking copolymerization of acrylamide and methylenebisacrylamide (MBAA) as second step lead to a grafted MIP hydrogel layer. The influences of the three independent parameters, scaffold chain length by SI-ATRP time, degree of cross-linking of the MIP layer by MBAA content, and grafted MIP layer thickness by UV irradiation time, were studied to optimize protein binding capacity and selectivity. The results were also compared to previously obtained data for lysozyme imprinting using the same method, and significant effects of protein size on imprinting efficiency could be identified. The best IgG MIP membrane adsorber was then used to separate IgG from mixtures with human serum albumin (HSA), demonstrating IgG binding capacities and eluted IgG purities, which were almost independent of the excess of HSA. The results of this study are a significant extension of the scope of molecular imprinting toward large target bionanoparticles. The transfer of the approach from the model PET to other base membranes with higher specific surface area is straightforward, and the resulting affinity materials would, in principle, be suited for "capturing" of an antibody from a complex mixture.

Nanoporous membranes generated from self‐assembled block polymer precursors: Quo Vadis?

“…using Cu 2+ coordination, are able to be flushed of proteins and, in the case of copper, regenerated, without loss of their high binding capacity . Membrane adsorbers have been designed using a combination of layers and post‐synthesis modification to create polymer chains that recognize the target molecule through coordination or charge‐exchange . On the other hand, and despite promising initial results demonstrating proof of the concept, membrane adsorbers based on track‐etched membranes as the separation platform demonstrate relatively low binding capacities.…”

Novel pitaya-inspired well-defined core–shell nanospheres with ultrathin surface imprinted nanofilm from magnetic mesoporous nanosilica for highly efficient chloramphenicol removal

“…Molecularly imprinted polymers (MIPs) have been proposed to solve the problem of the poor selectivity for conventional adsorbents [17]. Especially, surface molecularly imprinted materials had the large adsorption capacity, fast removal kinetics, easy access to binding sites, high selectivity, and complete template extraction, which established imprinted recognition sites onto the surface or approximately surface of arbitrary solid matrices [18,19]. Very recently, mesoporous silica was functionalized with MIPs, which had the advantages of both porous inorganic materials as well as the organic MIPs [20][21][22].…”

Functionalizing Microporous Membranes for Protein Purification and Protein Digestion

“…These authors also developed an IgG-imprinted membrane to separate IgG from human serum albumin, a major contaminating protein in antibody downstream processing. The binding capacity for IgG was 8 mg/mL, and the IgG/human serum albumin selectivity was 5 (67). Further improvements in binding capacity and selectivity are needed to make separations with imprinted membranes competitive with techniques such as antibody capture with protein A columns.…”