Affinity ligands for immunoglobulins based on the multicomponent Ugi reaction

FYWHCLDE-based affinity chromatography of IgG: Effect of ligand density and purifications of human IgG and monoclonal antibody

DNA binding during expanded bed adsorption and factors affecting adsorbent aggregation

This work describes the synthesis of two poly(lactic acid)-b-poly(ethylene glycol) copolymers (PLA-b-PEG), one containing folic acid, a targeting ligand, and the other containing fluorescein, a marker, both important in drug delivery systems. The copolymerization was carried out using the Ugi multicomponent reaction, which is a one pot reaction that involves the condensation of four components, an aldehyde or ketone, an amine, a carboxylic acid and an isocyanide. For this, poly(lactic acid) was functionalized with an aldehyde group (PLA-CHO) and poly(ethylene glycol) with an amine (PEG-NH2) and a carboxylic acid group (PEG-COOH), to be used in the Ugi reactions. From Fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1 H NMR) and ultraviolet-visible (UV-Vis) analyses, it was possible to confirm the synthesis of the block copolymers, in addition to the presence of both folic acid and fluorescein in the chemical structure of the materials. The work demonstrates that the Ugi reaction is an effective method to obtaining copolymers with different functionalities, and these materials have the potential to prepare micro and nanoparticles to be used in the controlled release of drugs.

The Ugi reaction constructs α-acylaminoamide compounds by combining an aldehyde or ketone, an amine, a carboxylic acid, and an isocyanide in a single flask. Its appealing features include inherent atom and step economy together with the potential to generate products of broad structural diversity. However, control of the stereochemistry in this reaction has proven to be a formidable challenge. We describe an efficient enantioselective four-component Ugi reaction catalyzed by a chiral phosphoric acid derivative that delivers more than 80 α-acylaminoamides in good to excellent enantiomeric excess. Experimental and computational studies establish the reaction mechanism and origins of stereoselectivity.

Evaluation of hydrophobic charge-induction ligand efficiency for protein adsorption in one single cycle

Surface extenders and an optimal pore size promote high dynamic binding capacities of antibodies on cation exchange resins

Bio-based membranes are becoming highly-desired low-cost, environmentally friendly, and readily available supports for the separation and purification of biomacromolecules. In this work, weak cation-exchange and highly (> 95%) microporous (> 80 μm) cellulose-based membranes were prepared from different weight ratios of carboxymethyl cellulose (CMC) as anionic polymer and cellulose nanofibrils (CNFs) as a stabilizing and structural filler, by the freeze-casting process and citric-acid (CA) mediated in situ cross-linking (esterification). It was ascertained that mono-esterified/grafted CA also contributes to the total carboxylic groups (1.7–2.6 mmol/g), while the CMC-induced CNF orientation affected the membrane’s morphology and lysozyme (Lys) binding capacity. A static binding capacity (SBC) between 370 and 1080 mg/g, and equilibrium within 3.3 h for 1 g/mL Lys was thus achieved with increasing the total solid and CMC content by forming more isotropic microporous structures. The selected membranes were then packed in a chromatographic housing, analyzed for pressure drop, and evaluated for dynamic binding capacity (DBC), depending on the process performance (flow rates, Lys concentration). A DBC in the 165–417 mg/g range was determined at a throughput of 0.5 mL/min, and elution yield of 78–99% with > 95% recovery. The Lys adsorption and transfer were reduced by the increasing flow rate and membrane density due to compressibility issues, resulting in smaller and irregularly distributed pores and the unavailability of carboxylic groups. Although the DBC was still comparable with the commercial CIM® monoliths, the convection-based transport of molecules inside the membrane and the membrane stiffness needs to be improved in further research.Graphical abstract

Process intensification of immobilized metal affinity chromatography with longitudinal and oscillatory transverse electric fields

Development of high-productivity, strong cation-exchange adsorbers for protein capture by graft polymerization from membranes with different pore sizes

Efficient Development of Nanobody-Based Affinity Chromatography for AAV8 Purification

Engineering of novel Staphylococcal Protein A ligands to enable milder elution pH and high dynamic binding capacity

Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.

Sulfadoxine derivatization through multicomponent reactions to obtain new antiplasmodial compounds.

The performance of weak and strong anion- and cation-exchange membrane adsorbents with a grafted gel layer (Sartobind Q, D, S, and C) was investigated using six proteins: bovine serum albumin, human serum albumin, α-lactalbumin, β-lactoglobulin, lysozyme, and myoglobin. Static binding experiments were used to assess the effect of pH and buffer concentration and to determine the adsorption isotherms for selected membrane/protein combinations. The equilibrium data were duly described either by the Langmuir or Freundlich isotherms. Dynamic binding experiments were carried out for the same membrane/protein combinations in a broad range of linear flow velocity. Both the dynamic binding capacity at 10 % breakthrough and the final binding capacity at complete breakthrough were independent of the flow velocity despite strong dispersion of the adsorption zone. A good match between the equilibrium data from static and dynamic experiments was obtained for the anion exchangers. The correlation between the dynamic binding capacity and protein molecule size was observed for the strong cation exchanger. This was due to the different accessibility of the gel layer for the protein molecules.

Fabrication of claviform fluorescent polymeric nanomaterials containing disulfide bond through an efficient and facile four-component Ugi reaction.