Chitosan-based membrane chromatography for protein adsorption and separation

Bioseparation using membrane chromatography: Innovations, and challenges

The resin-based column continues to be the dominant incumbent in bioprocess chromatography. While alternative formats such as membrane-, monolith- and fiber-based chromatography are more visible than before, each still plays minor roles. The reasons for this are complex and some of these are explained in this paper. However, the fact remains that membrane chromatography has come a long way since its early days of development. The main advantage of membrane chromatography continues to be its convection dominant transport mechanism, the resultant benefit being fast and scalable separation. Also, resolution obtained with properly designed devices could be comparable or even better than resin-based chromatography. Significant progress has been made in new membrane development, membrane characterization, device design and novel applications development. A wider range of new membrane matrices, ligands, and ligand-matrix linking chemistries are now available. New membrane modules, formats, and process configurations have also helped improve membrane performance. However, some significant challenges still exist, and these need to be addressed if membrane chromatography is to become more mainstream in the field of bioprocessing. Also, membrane chromatography has significant potential for application in analytical separations and this space has hardly been explored. In this paper, the advances in the areas of membrane preparation, device design and process development are reviewed. A high-level cost analysis is presented and the role of process design in membrane chromatography is discussed.

Assessment of membrane-based downstream purification processes as a replacement to traditional resin bead for monoclonal antibody purification

Membrane chromatography devices are a viable alternative to packed-bed resins and enable highly productive purification cascades for monoclonal antibodies and Fc-fusion proteins. In this study, ion exchange and protein A membrane chromatography performances were assessed and compared with their resin counterparts. Protein A dynamic binding capacities were higher than 50 g/L for two of the tested membranes and with a residence time of 0.2 min. For polishing, it was observed that aggregate clearance was generally less performant with membrane separation when compared to resins with similar ligands. However, the comparable yield and increased productivity of membranes could be enough to consider their implementation. In addition, lifetime studies demonstrated that the performance of membranes remained robust over cycles. One hundred cycles were reached for most of the tested membranes with no impact on the process performance nor product quality. Finally, purification cascades were fully operated with membranes, from capture to polishing, reaching good levels of host cells proteins (less than 50 ppm) and aggregates (equal to or less than 1%). The outcome of this study demonstrated that resin chromatography could be fully replaced by membranes for monoclonal antibody and Fc-fusion protein purification processes.

Affinity purification/immobilization of poly histidine-tagged proteins by nickel-functionalized porous chitosan membranes

Although immobilized metal ion affinity chromatography (IMAC) is one of the most effective methods for purifying his-tagged proteins, it has limitations such as expensive commercial resins and non-specific binding of unwanted proteins to the nickel immobilized on the resin. In this study, biocompatible chitosan and porous chitosan membranes as alternative resins were synthesized for protein immobilization and purification, but finally porous chitosan membrane was selected due to its higher porosity and consequently higher nickel adsorption. Once the membrane was functionalized with nickel ions and its metal adsorption confirmed by EDS and ICP methods, it was used to immobilize and purify recombinant β-NGF as a protein model with his-tag tail in batch-fashion. Protein binding and purification were also approved by FTIR and UV-Vis spectroscopy and SDS-PAGE technique. Our results indicated that the protein of interest could bind to the nickel-functionalized porous chitosan membrane with high efficiency at pH=7. Furthermore, for protein purification, the pH value of 6 and an imidazole concentration of 750 mM were suggested for the final elution buffer. In conclusion, nickel-functionalized porous chitosan membrane could be a suitable alternative to IMAC for low cost and specific protein immobilization and purification.

Recent development and application of membrane chromatography

Membrane chromatography is mainly used for the separation and purification of proteins and biological macromolecules in the downstream processing process, also applications in sewage disposal. Membrane chromatography is recognized as an effective alternative to column chromatography because it significantly improves chromatography from affinity, hydrophobicity, and ion exchange; the development status of membrane chromatography in membrane matrix and membrane equipment is thoroughly discussed, and the applications of protein capture and intermediate purification, virus, monoclonal antibody purification, water treatment, and others are summarized. This review will provide value for the exploration and potential application of membrane chromatography.

Freezing-triggered gelation of quaternized chitosan reinforced with microfibrillated cellulose for highly efficient removal of bilirubin

The highly efficient removal of bilirubin from blood by hemoperfusion for liver failure therapy remains a challenge in the clinical field due to the low adsorption capacity and poor hemocompatibility of currently used carbon-based adsorbents. Polysaccharide-based cryogels seem to be promising candidates for hemoperfusion adsorbents owing to their inherited excellent hemocompatibility. However, the weak mechanical strength and relatively low adsorption capacity of polysaccharide-based cryogels limited their application in bilirubin adsorption. In this work, we presented a freezing-triggered strategy to fabricate QCS/MFC cryogels, which were formed by quaternized chitosan (QCS) crosslinked with divinylsulfonyl methane (BVSM) and reinforced with microfibrillated cellulose (MFC). Ice crystal exclusions triggered the chemical crosslinking to generate the cryogels with dense pore walls. The obtained QCS/MFC cryogels were characterized by FTIR, SEM, stress-strain test, and hemocompatibility assay, which exhibited interconnected macroporous structures, excellent shape-recovery and mechanical performance, and outstanding blood compatibility. Due to the quaternary ammonium functionalization of chitosan, the QCS/MFC showed a high adsorption capacity of 250 mg g^-1 and a short adsorption equilibrium time of 3 h. More importantly, the QCS/MFC still exhibited high adsorption efficiency (over 49.7%) in the presence of 40 g L^-1 albumin. Furthermore, the QCS/MFC could also maintain high dynamic adsorption efficiency in self-made hemoperfusion devices. This facile approach provides a new avenue to develop high-performance hemoperfusion adsorbents for bilirubin removal, showing great promise for the translational therapy of hyperbilirubinemia.

Versatile antibacterial surface with amphiphilic quaternized chitin-based derivatives for catheter associated infection prevention

Microbial colonization of catheter surfaces is responsible for most healthcare-associated infections. Quaternized chitin and chitosan have excellent antimicrobial and biocompatible properties and can be used to provide safe and prolonged protection for biomedical catheters. Herein, we prepared quaternized β-chitin derivative (QC)- and quaternized chitosan derivative (QCS)-based antimicrobial surfaces. The quaternized polysaccharides modified TPU surfaces exhibited hydrophilicity, good biocompatibility. Among these, QCS2-modified TPU exhibited excellent antibacterial properties against Gram-positive and Gram-negative bacteria, and prevented the adherence of bacteria compared with pristine TPU. The antibacterial activity of QCS2-modified surfaces maintained for 8 weeks under the condition of immersion in serum. An in vivo subcutaneous implantation experiment revealed 99.87% reduction of bacteria and reduced expression of inflammation-related factors in the surrounding tissue five days after implantation with QCS2-modified TPU. Therefore, quaternized polysaccharide-modified surfaces have promising potential in preventing medical catheter-associated infections.

G protein-coupled receptor-in-paper, a versatile chromatographic platform to study receptor-drug interaction

High-performance affinity chromatography is limited by its high cost and high pressure. Paper is made up of porous fiber networks and has the properties of low cost, ease of fabrication, and biodegradable. Due to these advantages, herein, we immobilized beta2-adrenoceptor (β₂-AR) onto the surface of the polytetrafluoroethylene membrane, a paper-based material, and constructed a G protein-coupled receptor (GPCR)-in-paper chromatographic platform. This platform was characterized by Fourier transform infrared spectroscopy, fluorescence analysis, X-ray photoelectron spectroscopy, and chromatographic studies. These morphological and elemental analysis showed that β₂-AR was successfully immobilized on the paper surface. The specific drugs have good retentions on the GPCR-in-paper chromatographic platform. The association constants of salbutamol, terbutaline and bambuterol to β₂-AR were calculated to be 2.02 × 10⁴ M^-1, 1.15 × 10⁴ M^-1, 1.75 × 10⁴ M^-1 by adsorption energy distribution, which were in good line with the values from frontal analysis, zonal elution and previous literatures. We demonstrated that the GPCR-in-paper platform was cost-effective, easy to be modified for protein immobilization, and applicable in the receptor-drug interaction analysis. We believe such a platform sheds new light on paper chromatography for receptor-drug interaction analysis and other applications.

Protein adsorption and desorption behavior of a pH-responsive membrane based on ethylene vinyl alcohol copolymer

The pH-responsive protein adsorption and desorption of a poly(DMAEMA)-grafted EVAL membrane was observed.

Scalable Fabrication of Electrospun Nanofibrous Membranes Functionalized with Citric Acid for High-Performance Protein Adsorption

Fabricating protein adsorbents with high adsorption capacity and appreciable throughput is extremely important and highly desired for the separation and purification of protein products in the biomedical and pharmaceutical industries, yet still remains a great challenge. Herein, we demonstrate the synthesis of a novel protein adsorbent by in situ functionalizing eletrospun ethylene-vinyl alcohol (EVOH) nanofibrous membranes (NFM) with critic acid (CCA). Taking advantage of the merits of large specific surface area, highly tortuous open-porous structure, abundant active carboxyl groups introduced by CCA, superior chemical stability, and robust mechanical strength, the obtained CCA-grafted EVOH NFM (EVOH-CCA NFM) present an excellent integrated protein (take lysozyme as the model protein) adsorption performance with a high capacity of 284 mg g(-1), short equilibrium time of 6 h, ease of elution, and good reusability. Meanwhile, the adsorption performance of EVOH-CCA NFM can be optimized by regulating buffer pH, ionic strength, and initial concentration of protein solutions. More importantly, a dynamic binding efficiency of 250 mg g(-1) can be achieved driven solely by the gravity of protein solution, which matches well with the demands of the high yield and energy conservation in the actual protein purification process. Furthermore, the resultant EVOH-CCA NFM also possess unique selectivity for positively charged proteins which was confirmed by the method of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Significantly, the successful synthesis of such intriguing and economic EVOH-CCA NFM may provide a promising candidate for the next generation of protein adsorbents for rapid, massive, and cost-effective separation and purification of proteins.