"Modified" Liquid⁻Liquid Displacement Porometry and Its Applications in Pd-Based Composite Membranes

Automated Liquid-Liquid Displacement Porometry (LLDP) for the Non-Destructive Characterization of Ultrapure Water Purification Filtration Devices

This scientific publication presents a novel modification of the liquid-liquid displacement porosimetry (LLDP) method, aiming for the non-destructive automated analysis of water purification membrane filtration devices in the microfiltration (MF) and ultrafiltration (UF) range. The technical adaptation of LLDP enables the direct in-line porosimetric analysis of commercial filtration devices, avoiding the filtration devices' destruction. Six commercially available filtration devices with polyethersulfone (PES) and polysulfone (PS) membranes were studied using an improved device developed by the IFTS, which was based on a commercial LLDP instrument. The filtration devices were evaluated in three different configurations: flat disks, hollow fibers, and pleated membranes. The results obtained using the proposed method were compared with other characterization techniques, including submicronic efficiency retention, image analysis of scanning electron microscopy (SEM), and gas-liquid displacement porosimetry (GLDP). The comparison of the results demonstrated that the proposed method accurately determined the porosimetric characteristics of the filters. It proved to be a precise technique for the non-destructive in-line evaluation of filter performance, as well as for periodic quality control and the fouling degree assessment of commercial filtration devices. This modified LLDP approach offers significant potential for the advanced characterization and quality assessment of water purification membrane filtration devices, contributing to improved understanding and optimization of their performance.

Development of electrospun keratin/coenzyme Q10/poly vinyl alcohol nanofibrous scaffold containing mupirocin as potential dressing for infected wounds

Background

Nanostructured wound dressings produced by electrospinning biocompatible polymers possess great potential because they resemble the natural extracellular matrix and support cell adhesion, proliferation, and differentiation. This study seeks to fabricate mupirocin, keratin, and coenzyme Q10 (Co Q10)-loaded PVA electrospun scaffolds intended for wound healing application and to characterize their morphology, physical properties, antibacterial activity, and biocompatibility. Polyvinyl alcohol (PVA) (10% w/v), various concentrations of keratin/Co Q10 fibrous scaffolds (electrospun at a voltage of 50 kV, flow rate of 4 mL/h), and 2% mupirocin was designed and fabricated to activate keratinocytes in the wound bed, stimulate cell proliferation, and increase antimicrobial penetration.

Results

The diameters of the scaffolds were observed to be in the nanoparticulate range 2.11 ± 0.20 to 3.27 ± 0.10 nm. By 30 min, all the scaffolds had more than 50% of the cumulative concentration of mupirocin released with 51.06 ± 2.104% to 74.66 ± 1.72% of mupirocin released. At 1 h, 80% of the mupirocin in the scaffold was seen to have diffused out of the scaffold. Release of mupirocin was modulated; an initial burst release was followed by sustained release over 2 h. Electrospun keratin/Co Q10/PVA scaffold containing mupirocin showed excellent antimicrobial activity against all the clinical isolates of 2586, Staphylococcus aureus 2590, 2583, 2587, 2555. All the electrospun scaffolds showed higher cell viability values than the control at 48 and 72 h, with the optimized CoQ10 scaffold concentration being 0.05% w/w.

Conclusion

Electrospun nanofibers combining the biocompatibility potential of PVA with the bioactive nature of keratin (0.01% w/w) and CoQ10 (0.5% w/w) and the antibacterial property of mupirocin as a new potential for proper wound care was successfully developed. The cell line studies on this electrospun scaffold (PKCM 3) showed their ability to support the growth of keratinocytes hence the potential of developed scaffolds as a wound dressing. In vivo studies to further investigate the applications of the electrospun keratin/Co Q10/PVA nanofibrous scaffold as a wound dressing is however required.

Safety and function of a new pre-vascularized bioartificial pancreas in an allogeneic rat model

Cell encapsulation could overcome limitations of free islets transplantation but is currently limited by inefficient cells immune protection and hypoxia. As a response to these challenges, we tested in vitro and in vivo the safety and efficacy of a new macroencapsulation device named MailPan^®. Membranes of MailPan^® device were tested in vitro in static conditions. Its bio-integration and level of oxygenation was assessed after implantation in non-diabetic rats. Immune protection properties were also assessed in rat with injection in the device of allogeneic islets with incompatible Major Histocompatibility Complex. Finally, function was assessed in diabetic rats with a Beta cell line injected in MailPan^®. In vitro, membranes of the device showed high permeability to glucose, insulin, and rejected IgG. In rat, the device displayed good bio-integration, efficient vascularization, and satisfactory oxygenation (>5%), while positron emission tomography (PET)-scan and angiography also highlighted rapid exchanges between blood circulation and the MailPan^®. The device showed its immune protection properties by preventing formation, by the rat recipient, of antibodies against encapsulated allogenic islets. Injection of a rat beta cell line into the device normalized fasting glycemia of diabetic rat with retrieval of viable cell clusters after 2 months. These data suggest that MailPan^® constitutes a promising encapsulation device for widespread use of cell therapy for type 1 diabetes.

Pd-Based Membranes: Overview and Perspectives

Palladium (Pd)-based membranes have received a lot of attention from both academia and industry thanks to their ability to selectively separate hydrogen from gas streams. Integration of such membranes with appropriate catalysts in membrane reactors allows for hydrogen production with CO₂ capture that can be applied in smaller bioenergy or combined heat and power (CHP) plants, as well as in large-scale power plants. Pd-based membranes are, therefore, regarded as a Key Enabling Technology (KET) to facilitate the transition towards a knowledge-based, low carbon and resource-efficient economy. This Special Issue of the journal Membranes on “Pd-based Membranes: Overview and Perspectives” contains nine peer-reviewed articles. Topics include manufacturing techniques, understanding of material phenomena, module and reactor design, novel applications, and demonstration efforts and industrial exploitation.