Contribution of the "Click Chemistry" Toolbox for the Design, Synthesis, and Resulting Applications of Innovative and Efficient Separative Supports: Time for Assessment

Preparation of Protein A Membrane Adsorbers Using Strain-Promoted, Copper-Free Dibenzocyclooctyne (DBCO)-Azide Click Chemistry

Protein A chromatography is the preferred unit operation for purifying Fc-based proteins. Convective chromatography technologies, like membrane adsorbers, can perform the purification rapidly and improve throughput dramatically. While the literature reports the preparation of Protein A membrane adsorbers utilizing traditional coupling chemistries that target lysine or thiol groups on the Protein A ligand, this study demonstrates a new approach utilizing copper-free dibenzocyclooctyne (DBCO)-azide click chemistry. The synthetic pathway consists of three main steps: bioconjugation of Protein A with a DBCO-polyethylene glycol (PEG) linker, preparation of an azide-functionalized membrane surface, and click reaction of DBCO-Protein A onto the membrane surface. Using polyclonal human immunoglobulins (hIgG) as the target molecule, Protein A membranes prepared by this synthetic pathway showed a flowrate-independent dynamic binding capacity of ~10 mg/mL membrane at 10% breakthrough. Fitting of static binding capacity measurements to the Langmuir adsorption isotherm showed a maximum binding (qmax) of 27.48 ± 1.31 mg/mL and an apparent equilibrium dissociation constant (Kd) of value of 1.72 × 10-1 ± 4.03 × 10-2 mg/mL. This work represents a new application for copper-less click chemistry in the membrane chromatography space and outlines a synthetic pathway that can be followed for immobilization of other ligands.

Metallic Nanoparticles Adsorbed at the Pore Surface of Polymers with Various Porous Morphologies: Toward Hybrid Materials Meant for Heterogeneous Supported Catalysis

Hybrid materials consisting of metallic nanoparticles (NPs) adsorbed on porous polymeric supports have been the subject of intense research for many years. Such materials indeed gain from intrinsic properties, e.g., high specific surface area, catalytic properties, porous features, etc., of both components. Rational design of such materials is fundamental regarding the functionalization of the support surface and thus the interactions required for the metallic NPs to be strongly immobilized at the pore surface. Herein are presented some significant scientific contributions to this rapidly expanding research field. This contribution will notably focus on various examples of such hybrid systems prepared from porous polymers, whatever the morphology and size of the pores. Such porous polymeric supports can display pores with sizes ranging from a few nanometers to hundreds of microns while pore morphologies, such as spherical, tubular, etc., and/or open or closed, can be obtained. These systems have allowed some catalytic molecular reactions to be successfully undertaken, such as the reduction of nitroaromatic compounds or dyes, e.g., methylene blue and Eosin Y, boronic acid-based C–C homocoupling reactions, but also cascade reactions consisting of two catalytic reactions achieved in a row.