Negatively Charged Composite Nanofibrous Hydrogel Membranes for High-Performance Protein Adsorption

Fabrication of highly carboxylated nanofibrous aerogels under mild conditions and their protein adsorption performance

The development of high-performance media for protein adsorption in bio-purification is highly desired, particularly in biological pharmaceuticals. In this study, we demonstrate a simple, versatile and mild strategy to construct a nanofibrous aerogel (NFA)-based adsorption media for protein purification. Pyromellitic dianhydride (PMDA) was selected to in-situ graft onto poly(ethylene-co-vinyl alcohol) (PE-co-PVA) nanofibers in aerogels through liquid phase grafting. The obtained PE-co-PVA/PMDA NFAs (PPNAs) possessed superb underwater elasticity, compression fatigue resistance and shape-memory performance. With an open porous network, abundant adsorption ligands, and surface hydrophilicity, the PPNAs exhibited a significant adsorption capacity of 1019.71 mg/g and a short equilibrium time of 3.0 h, surpassing that of commercial and reported nanofiber-based adsorbents. Additionally, the PPNAs demonstrated good dynamic adsorption performance for protein driven solely by gravity. Furthermore, the PPNAs showed reusability, selectivity, acid and alkaline resistance, and practical potential of extracting lysozyme form egg white solution. The successful scale-up of such aerogel-based adsorbents can open up new way for the development and design of next-generation protein adsorption media for bio-purification applications.

Facile Fabrication of Zeolitic Imidazolate Framework-8@Regenerated Cellulose Nanofibrous Membranes for Effective Adsorption of Tetracycline Hydrochloride

The excessive utilization of antimicrobials in humans and animals has resulted in considerable environmental contamination, necessitating the development of high-performance antibiotic adsorption media. A significant challenge is the development of composite nanofibrous materials that are both beneficial and easy to fabricate, with the aim of improving adsorption capacity. Herein, a new kind of zeolitic imidazolate framework-8 (ZIF-8)-modified regenerated cellulose nanofibrous membrane (ZIF-8@RC NFM) was designed and fabricated by combining electrospinning and in situ surface modification technologies. Benefiting from its favorable surface wettability, enhanced tensile strength, interconnected porous structure, and relatively large specific surface area, the resulting ZIF-8@RC NFMs exhibit a relatively high adsorption capacity for tetracycline hydrochloride (TCH) of 105 mg g-1 within 3 h. Moreover, a Langmuir isotherm model and a pseudo-second-order model have been demonstrated to be more appropriate for the description of the TCH adsorption process of ZIF-8@RC-3 NFMs. Additionally, this composite fibrous material could keep a relatively stable adsorption capability under various ionic strengths. The successful fabrication of the novel ZIF-8@RC NFMs may shed light on the further development of wastewater adsorption treatment materials.

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.