On the Performance of a Ready-to-Use Electrospun Sulfonated Poly(Ether Ether Ketone) Membrane Adsorber

Motivated by the need for efficient purification methods for the recovery of valuable resources, we developed a wire-electrospun membrane adsorber without the need for post-modification. The relationship between the fiber structure, functional-group density, and performance of electrospun sulfonated poly(ether ether ketone) (sPEEK) membrane adsorbers was explored. The sulfonate groups enable selective binding of lysozyme at neutral pH through electrostatic interactions. Our results show a dynamic lysozyme adsorption capacity of 59.3 mg/g at 10% breakthrough, which is independent of the flow velocity confirming dominant convective mass transport. Membrane adsorbers with three different fiber diameters (measured by SEM) were fabricated by altering the concentration of the polymer solution. The specific surface area as measured with BET and the dynamic adsorption capacity were minimally affected by variations in fiber diameter, offering membrane adsorbers with consistent performance. To study the effect of functional-group density, membrane adsorbers from sPEEK with different sulfonation degrees (52%, 62%, and 72%) were fabricated. Despite the increased functional-group density, the dynamic adsorption capacity did not increase accordingly. However, in all presented cases, at least a monolayer coverage was obtained, demonstrating ample functional groups available within the area occupied by a lysozyme molecule. Our study showcases a ready-to-use membrane adsorber for the recovery of positively charged molecules, using lysozyme as a model protein, with potential applications in removing heavy metals, dyes, and pharmaceutical components from process streams. Furthermore, this study highlights factors, such as fiber diameter and functional-group density, for optimizing the membrane adsorber's performance.</p

Intracellular Galectin-9 Controls Dendritic Cell Function by Maintaining Plasma Membrane Rigidity

Biological Sciences; Molecular Biology; Cell BiologyEndogenous extracellular Galectins constitute a novel mechanism of membrane protein organization at the cell surface. Although Galectins are also highly expressed intracellularly, their cytosolic functions are poorly understood. Here, we investigated the role of Galectin-9 in dendritic cell (DC) surface organization and function. By combining functional, super-resolution and atomic force microscopy experiments to analyze membrane stiffness, we identified intracellular Galectin-9 to be indispensable for plasma membrane integrity and structure in DCs. Galectin-9 knockdown studies revealed intracellular Galectin-9 to directly control cortical membrane structure by modulating Rac1 activity, providing the underlying mechanism of Galectin-9-dependent actin cytoskeleton organization. Consequent to its role in maintaining plasma membrane structure, phagocytosis studies revealed that Galectin-9 was essential for C-type-lectin receptor-mediated pathogen uptake by DCs. This was confirmed by the impaired phagocytic capacity of Galectin-9-null murine DCs. Together, this study demonstrates a novel role for intracellular Galectin-9 in modulating DC function, which may be evolutionarily conserved

Proteolytic Processing of Interleukin-1 Family Cytokines: Variations on a Common Theme

Members of the extended interleukin-1 (IL-1) cytokine family, such as IL-1, IL-18, IL-33, and IL-36, play a pivotal role in the initiation and amplification of immune responses. However, deregulated production and/or activation of these cytokines can lead to the development of multiple inflammatory disorders. IL-1 family members share a broadly similar domain organization and receptor signaling pathways. Another striking similarity between IL-1 family members is the requirement for proteolytic processing in order to unlock their full biological potential. Although much emphasis has been put on the role of caspase-1, another emerging theme is the involvement of neutrophil- and mast cell-derived proteases in IL-1 family cytokine processing. Elucidating the regulation of IL-1 family members by proteolytic processing is of great interest for understanding inflammation and immunity. Here, we review the identity of the proteases involved in the proteolytic processing of IL-1 family cytokines and the therapeutic implications in inflammatory disease

Self-assembling liquid crystals as building blocks to design nanoporous membranes suitable for molecular separations

The transition from the current “linear” economy to a “circular” economy with a strong focus on the recovery and reuse of materials and resources undoubtedly necessitates efficient and effective separation technologies. Membrane technology will play an important role in this transition to a circular economy. In that perspective, separation at the molecular level to separate and fractionate e.g. individual ions and small molecules for reuse is especially essential. Unfortunately, conventional membrane materials and their fabrication methods mostly lack design and control over pore size and selectivity at a true molecular level. In view of this challenge, nanostructured polymer membranes based on self-assembled materials are gaining more and more interest. Using the self-assembly properties of polymerizable liquid crystal molecules ensures control at a molecular level and gives rise to narrow pore size distributions, high pore densities and control of pore size and functionality. In this review, the potential of liquid crystal materials and their self-assembly properties to fabricate nanoporous membranes for water purification, desalination and selective recovery is presented. The basic principles of liquid crystals, the self-assembling characteristics and methods to control pore size and functionality are discussed in the perspective of membrane properties and applications. Efforts reported in the literature highlighting advances and pointing out important limitations for different pore morphologies are discussed. The versatility of liquid crystal based membranes is highlighted by exploring approaches for post-modification of the nanopores to further tune the pore size and control the pore functionality after polymerization of the liquid crystals. The work provides readers with a thorough understanding of the design and fabrication of nanoporous liquid crystal membranes combined with a perspective on the potential of liquid crystal membranes. Next to recent advances, future challenges are presented as well, with the most crucial two: 1) The formation of thin, defect-free nanoporous liquid crystal layers supported on a microporous support; 2) Large-scale production combined with alignment control over longer length scales

Antibodies and tuberculosis

Tuberculosis (TB) remains a major public health problem internationally, causing 9.6 million new cases and 1.5 million deaths worldwide in 2014. The Bacillus Calmette-Guérin vaccine is the only licensed vaccine against TB, but its protective effect does not extend to controlling the development of infectious pulmonary disease in adults. The development of a more effective vaccine against TB is therefore a pressing need for global health. Although it is established that cell-mediated immunity is necessary for the control of latent infection, the presupposition that such immunity is sufficient for vaccine-induced protection has recently been challenged. A greater understanding of protective immunity against TB is required to guide future vaccine strategies against TB. In contrast to cell-mediated immunity, the human antibody response against M.tb is conventionally thought to exert little immune control over the course of infection. Humoral responses are prominent during active TB disease, and have even been postulated to contribute to immunopathology. However, there is evidence to suggest that specific antibodies may limit the dissemination of M.tb, and potentially also play a role in prevention of infection via mucosal immunity. Further, antibodies are now understood to confer protection against a range of intracellular pathogens by modulating immunity via Fc-receptor mediated phagocytosis. In this review, we will explore the evidence that antibody-mediated immunity could be reconsidered in the search for new vaccine strategies against TB