Advances in high-throughput, high-capacity nonwoven membranes for chromatography in downstream processing: A review

: Nonwoven membranes are highly engineered fibrous materials that can be manufactured on a large scale from a wide range of different polymers, and their surfaces can be modified using a large variety of different chemistries and ligands. The fiber diameters, surface areas, pore sizes, total porosities, and thicknesses of the nonwoven mats can be carefully controlled, providing many opportunities for creative approaches for the development of novel membranes with unique properties to meet the needs of the future of downstream processing. Fibrous membranes are already finding use in ultrafiltration, microfiltration, depth filtration, and, more recently, in membrane chromatography for product capture and impurity removal. This article summarizes the various methods of manufacturing nonwoven fabrics, and the many methods available for the modification of the fiber surfaces. It also reviews recent studies focused on the use of nonwoven fabric devices in membrane chromatography and provides some perspectives on the challenges that need to be overcome to increase binding capacities, decrease residence times, and reduce pressure drops so that eventually they can replace resin column chromatography in downstream process operations

Heat Induced Grafting of Poly(glycidyl methacrylate) on Polybutylene Terephthalate Nonwovens for Bioseparations

Polybutylene terephthalate (PBT) nonwovens were successfully grafted with poly(glycidyl methacrylate) (polyGMA) using a heat induced grafting approach with the thermal initiator benzoyl peroxide (Bz2O2). This grafting method resulted in complete, uniform, and conformal grafted layers around the PBT fibers that could be further functionalized as ion exchangers for protein capture. Protein binding capacities as high as 200 mg/g were achieved for ion exchange PBT nonwovens grafted to 20% weight gain using this heat induced grafting method. Compared to UV grafted polyGMA PBT nonwovens, the rates of protein adsorption are several times faster for the heat grafted polyGMA PBT nonwoven, reaching equilibrium within minutes; UV grafted polyGMA ion exchange PBT nonwovens require hours to reach equilibrium. This indicates that polyGMA grafts formed by heat induced grafting are thinner, and therefore more dense, than UV grafted layers with the same % weight gain. To further investigate the structural differences between the two grafting methods, targets of various molecular weights (ATP, lysozyme, BSA, hIgG) were adsorbed to the materials. Increasing the target size resulted in a decrease of target molecules bound for both grafting methods. However, the heat grafted nonwovens exhibited a much stronger dependence of protein molecular weight on protein capture, indicating that heat induced grafting results in a polyGMA layer that has a smaller free volume between chains available for protein binding compared to the UV grafting method. Protein adsorption isotherms for the two grafting methods confirmed that both methods resulted in similar strengths of protein binding, with dissociation constants on the order of Kd = 10-6 M which is consistent with ion exchange binding on polymer brush networks. Heat grafted polyGMA ion exchange PBT nonwovens showed excellent protein binding and elution

Towards implementation of novel single-use devices in integrated processes for biopharmaceuticals

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Nonwoven Ion-Exchange Membranes with High Protein Binding Capacity for Bioseparations

This study presents the preparation and characterization of UV-grafted polybutylene terepthalate (PBT) ion exchange nonwoven membranes for chromatographic purification of biomolecules. The PBT nonwoven was functionalized with sulfonate and secondary amine for cation and anion exchange (CEX and AEX), respectively. The anion exchange membrane showed an equilibrium static binding capacity of 1300 mg BSA/g of membrane, while the cationic membranes achieved a maximum equilibrium binding capacity of over 700 mg hIgG/g of membrane. The CEX and AEX membranes resulted in dynamic binding capacities under flow conditions, with a residence time of 0.1 min, of 200 mg hIgG/mL of membrane and 55 mg BSA/mL of membrane, respectively. The selectivity of the PBT-CEX membranes was demonstrated by purifying antibodies and antibody fragments (hIgG and scFv) from CHO cell culture supernatants in a bind-an-elute mode. The purity of the eluted samples exceeded 97%, with good log removal values (LRV) for both host cell proteins (HCPs) and DNA. The PBT-AEX nonwoven membranes exhibited a DNA LRV of 2.6 from hIgG solutions in a flow-through mode with little loss of product. These results indicate that these membranes have significant potential for use in downstream purification of biologics

Phase Equilibrium Behavior Of The Binary Systems Co 2 + Nonadecane And Co 2 + Soysolv And The Ternary System Co 2 + Soysolv + Quaternary Ammonium Chloride Surfactant

Liquid phase and molar volume data were measured for the binary system CO 2 + soysolv at (298.15, 313.15, 323.15, 333.15, and 343.15) K and the ternary system CO 2 + soysolv + quaternary ammonium chloride surfactant at (298.15, 313.15, and 333.15) K, where the composition of soysolv to the surfactant is 99:1 wt % and 80:20 wt % on a CO 2-free basis. Data were collected stoichiometrically with a high-pressure Pyrex glass cell, where no sampling or chromatographic equipment is required. The accuracy of the experimental apparatus was tested with phase equilibrium measurements for the system CO 2 + nonadecane at 313.15 K. A pressure-decay technique was used to calculate the mass of CO 2 loaded into the equilibrium section of the apparatus, and its accuracy was verified with a blank nitrogen experiment. The generated data show that CO 2 modified soysolv is an effective transport medium for the quaternary ammonium chloride surfactant