Gas Exchange Membrane Research Articles

Is there still aplace for ECCO2R?

The therapeutic target of extracorporeal carbon dioxide removal (ECCO2R) is the elimination of carbon dioxide (CO2) from the blood across agas exchange membrane without influencing oxygenation to aclinically relevant extent. In acute respiratory distress syndrome (ARDS), ECCO2R has been used to reduce tidal volume, plateau pressure, and driving pressure ("ultraprotective ventilation"). Despite achieving these goals, no benefits in outcome could be shown. Thus, in ARDS, the use of ECCO2R to achieve ultraprotective ventilation can no longer be recommended. Furthermore, ECCO2R has also been used to avoid intubation or facilitate weaning in obstructive lung failure as well as to avoid mechanical ventilation in patients during bridging to lung transplantation. Although these goals can be achieved in many patients, the effects on outcome still remain unclear due to lack of evidence. Despite involving less blood flow, smaller cannulas, and smaller gas exchange membranes compared with extracorporeal membrane oxygenation, ECCO2R bears acomparable risk of complications, especially bleeding. Trials to define indications and analyze the risk-benefit balance are needed prior to implementation of ECCO2R as astandard therapy. Consequently, until then, ECCO2R should be used in clinical studies and experienced centers only. This article is freely available.

Characterization of anisotropic pore structure and dense selective layer of capillary membranes for long-term ECMO by cross-sectional ion-milling method.

Since the COVID-19 pandemic of 2020-2023, extracorporeal membrane oxygenator (ECMO) has attracted considerable attention worldwide. It is expected that ECMO with long-term durability is put into practical use in order to prepare for next emerging infectious diseases and to facilitate manufacturing for novel medical devices. Polypropylene (PP) and polymethylpentene (PMP) capillary membranes are currently the mainstream for gas exchange membrane for ECMO. ECMO support days for COVID-19-related acute hypoxemic respiratory failure have been reported to be on average for 14 or 24days. It is necessary to improve opposing functions such that promoting the permeation of oxygen and carbon dioxide and inhibiting the permeation of water vapor or plasma to develop sufficient durability for long-term use. For this purpose, accurately controlling the anisotropy of the pore structure of the entire cross section and functions of capillary membrane is significant. In this study, we focused on the cross-sectional ion-milling (CSIM) method, to precisely clarify the pore structure of the entire cross section of capillary membrane for ECMO, because there is less physical stress on the porous structure applied during the preparation of cross-sectional samples of porous capillary membranes. We attempted to observe the cross sections of commercially available PMP membranes using the CSIM method. As a result, we succeeded in fabricating fine-scale flat cross-sectional samples of PMP capillary membranes. The pore structures and the degree of anisotropy of the cross sections are quantitatively clarified. The achievements and the approaches of this study are being applied to the development of next-generation gas exchange membranes.

Water Deficit Severity during the Preceding Year Determines Plant Tolerance to Subsequent Year Drought Stress Challenges: A Case Study in Damask Rose

Damask rose is an important essential oil crop. In the present study, plants were subjected to three different water deficit levels (70, 40, and 10% available water content) for two periods (June–October). Plant phenology, growth, essential oil yield, gas exchange features, membrane stability and major antioxidant defense elements were monitored across two years. Soil water deficit was related to quicker completion of the growth cycle (up to 7.4 d), and smaller plants (up to 49.7%). Under these conditions, biomass accumulation was jointly constrained by decreased leaf area, chlorophyll content, CO2 intake, and photosynthetic efficiency (up to 82.8, 56.9, 27.3 and 68.2%, respectively). The decrease in CO2 intake was driven by a reduction in stomatal conductance (up to 41.2%), while the decrease in leaf area was mediated by reductions in both number of leaves, and individual leaf area (up to 54.3, and 64.0%, respectively). Although the reactive oxygen species scavenging system was activated (i.e., proline accumulation, and enhanced activity of three antioxidant enzymes) by water deficit, oxidative stress symptoms were still apparent. These effects were amplified, as soil water deficit became more intense. Notably, the adverse effects of water deficit were generally less pronounced when plants had been exposed to water severity during the preceding year. Therefore, exposure to water deficit elicited plant tolerance to future exposure. This phenotypic response was further dependent on the water deficit level. At more intense soil water deficit across the preceding year, plants were less vulnerable to water deficit during the subsequent one. Therefore, our results reveal a direct link between water deficit severity and plant tolerance to future water stress challenges, providing for the first time evidence for stress memory in damask rose.

Has Extracorporeal Gas Exchange Performance Reached Its Peak?

Extracorporeal gas exchange therapies evolved considerably within the first three-four decades of their appearance, and have since reached a mature stage, where minor alterations and discrete fine-tuning might offer some incremental improvement. A different approach is introduced here, making use of modern, purely diffusive membrane materials, and taking advantage of the elevated concentration gradient ensuing from gas pressure buildup in the gas chamber of the oxygenator. An assortment of silicone membrane gas exchangers were tested in vitro as per a modified protocol in pursuance of assessing their gas exchange efficiency under both regular and high-pressure aeration conditions. The findings point to a stark performance gain when pressurization of the gas compartment is involved; a 40% rise above atmospheric pressure elevates oxygen transfer rate (OTR) by nearly 30%. Carbon dioxide transfer rate (CTR) does not benefit as much from this principle, yet it retains a competitive edge when higher gas flow/blood flow ratios are employed. Moreover, implementation of purely diffusive membranes warrants a bubble-free circulation. Further optimization of the introduced method ought to pave the way for in vivo animal trials, which in turn may potentially unveil new realms of gas exchange performance for therapies associated with extracorporeal circulation.

Roll-to-roll manufacturing of large surface area PDMS devices, and application to a microfluidic artificial lung.

The ability to cost-effectively produce large surface area microfluidic devices would bring many small-scale technologies such as microfluidic artificial lungs (μALs) from the realm of research to clinical and commercial applications. However, efforts to scale up these devices, such as by stacking multiple flat μALs have been labor intensive and resulted in bulky devices. Here, we report an automated manufacturing system, and a series of cylindrical multi-layer lungs manufactured with the system and tested for fluidic fidelity and function. A roll-to-roll (R2R) system to engrave multiple-layer devices was assembled. Unlike typical applications of R2R, the rolling process is synchronized to achieve consistent radial positioning. This allows the fluidics in the final device to be accessed without being unwrapped. To demonstrate the capabilities of the R2R manufacturing system, this method was used to manufacture multi-layer μALs. Gas and blood are engraved in alternating layers and routed orthogonally to each other. The proximity of gas and blood separated by gas permeable PDMS permits CO2 and O2 exchange via diffusion. After manufacturing, they were evaluated using water for pressure drop and CO2 gas exchange. The best performing device was tested with fresh whole bovine blood for O2 exchange. Three μALs were successfully manufactured and passed leak testing. The top performing device had 15 alternating blood and gas layers. It oxygenated blood from 70% saturation to 95% saturation at a blood flow of 3 mL min-1 and blood side pressure drop of 234 mmHg. This new roll-to-roll manufacturing system is suitable for the automated construction of multi-layer microfluidic devices that are difficult to manufacture by conventional means. With some upgrades and improvements, this technology should allow for the automatic creation of large surface area microfluidic devices that can be employed for various applications including large-scale membrane gas exchange such as clinical-scale microfluidic artificial lungs.

Closed airflow system, CUSP, for preventing SARS-CoV-2 infection, promoting health care, and achieving Sustainable Development Goals

Thorough analytical investigation is made on an open airflow system, on which conventional clean rooms are based, and on a closed airflow system realized by a clean unit system platform (CUSP) combined with a gas exchange membrane (GEM). The air pressure inside the CUSP is exactly the same as that outside. Thanks to this equal pressure in and outside of the room, there is no airflow coming and going across the GEM, resulting in a closed airflow system. In the CUSP/GEM system, fresh air is introduced, not by mechanical ventilation that conventional clean rooms are based upon, but by diffusion-based molecular ventilation, in which O2, CO2, and other molecules come and go across the GEM depending on the molecule concentration gradient across the GEM. Since there is no airflow exchanged between the inside and outside, together with the fact that microbes, having roughly two orders of magnitude larger size than molecules, are too large to diffuse across the GEM, the CUSP/GEM system can be an ideal, extremely safe place in which to protect people from SARS-CoV-2 or any other viruses floating in the air outside. The CUSP is an ideal place in which patients can be treated while staying in very clean air — importantly, with zero risk of any harm coming to people outside of the space. Based on this system, we have succeeded in demonstrating that CUSP can provide the opportunity of correlation analysis in sleep assessment with CO2 production while patients are sleeping in the CUSP. The unique features of the CUSP/GEM system, that make the inside of the room completely decoupled from the outside, mean that it can effectively be used for various applications. In the near future, diffusion-based molecular ventilation, or molecular ventilation in short, will prevail with CUSP systems wherever fresh clean air is needed for any closed space.

Dynamics of Mineral Uptake and Plant Function during Development of Drug-Type Medical Cannabis Plants

Recent studies have demonstrated dose-responses of the cannabis plant to supply of macronutrients. However, further development of precision nutrition requires a high-resolution understanding of temporal trends of plant requirements for nutrients throughout the developmental progression, which is currently not available. As plant function changes during development, temporal information on nutrient uptake should be considered in relation to gradients in developmental-related physiological activity. Therefore, the present study investigated tempo-developmental trends of nutritional demands in cannabis plants, and in relation to physiological performance. Three cultivars differing in phenotype and chemotype were analyzed to evaluate genotypic variability. The results demonstrate that nutrient acquisition and deposition rates change dramatically during plant development. Uptake of individual minerals generally increased with the progression of both vegetative and reproductive development and the increase in plant biomass, while the deposition rates into the plant demonstrated nutrient specificity. The average concentrations of N, P, and K in the shoots of the different cultivars were 2.33, 4.90, and 3.32 times higher, respectively, at the termination of the reproductive growth phase, compared to the termination of the vegetative growth phase. Surprisingly, the uptake of Ca was very limited during the second part of the reproductive growth phase for two cultivars, revealing a decrease in Ca demand at this late developmental stage. Root-to-shoot translocation of most nutrients, including P, K, Mg, Mn, and Zn, as well as Na, is higher during the reproductive than the vegetative growth phase, and Fe, Mn, Zn, Cu, and Na displayed very little root-to-shoot translocation. The physiological characteristics of the plants, including gas exchange parameters, membrane leakage, osmotic potential, and water use efficiency, changed over time between the vegetative and the reproductive phases and with plant maturation, demonstrating a plant-age effect. The revealed tempo-developmental changes in nutritional requirements of the cannabis plant are a powerful tool required for development of a nutritional protocol for an optimal ionome.

BIO27: Automated PDMS Engraving and Assembly of a Prototype Microfluidic Artificial Lung

Purpose: The ability to cost-effectively produce high-surface area microfluidic devices would bring many small-scale technologies from the realm of research to clinical and commercial applications. In particular microfluidic artificial lungs (µALs) promise improved gas exchange efficiency through micron-scale feature sizes. However, most µALs have only a single layer which limits their rated flows. Efforts to scale up these devices, such as by stacking multiple flat µALs have been labor intensive and resulted in bulky devices. Here, we present an automated roll-to-roll (R2R) manufacturing system and a cylindrical multi-layer µAL. Methods: The R2R system (Fig 1A) begins with a roll of biocompatible silicone rubber (Silpuran 2030). A heavily-modified CO2 laser engraver (Omtech K40 with custom vacuum engraving bed, N2 purge, and custom motherboard) creates patterns in the silicone sheet (Fig 1B). The sheet is then plasma-activated using two CeraPlas F-series cold-plasma wands to bond the PDMS to itself in an irreversible bond. Finally, it is rerolled into a processed device around a 30 mm PDMS core. This entire process from unrolling to rerolling is performed simultaneously and synchronously, allowing the creation of very large area microfluidic devices. Further, it is automated (Arduino Mega 1680), eliminating human error over this repetitive process. Results: Using our automated manufacturing system, we fabricated a 27-layer cylindrical prototype µAL, consisting of 1) an 8-layer base, 2) 11 layers of alternating blood and gas channels, and 3) an 8-layer protective cover. Laser-engraved fluidic channels were triangular, 60 µm deep and 180 µm wide (Fig 1B). If unrolled, the microfluidic part of this system would stretch 1.1 m, and the total length would stretch 2.7 m. This was placed into a custom 3D printed housing which routes blood and gas to their respective microfluidic channels (Fig 2A,B; filled with dyed water for visualization). Empirical pressure drop data were gathered for flows from 1 mL/min to 10 mL/min, which were similar to theoretical values (Fig 3). While the R2R manufacturing system successfully created the prototype 27-layer µAL, the device exhibited some internal fluid pooling and layer-to-layer leaks during fluidic testing. Both issues are believed to be caused by inadequate localized layer-to-layer adhesion. We plan to remedy these issues in the coming months. Conclusion: This roll-to-roll manufacturing system is designed to manufacture the first large surface-area microfluidic devices that are impractical to manufacture by conventional means. This can be employed for large-scale membrane gas exchange such as human-scale µALs.Figure 1. (A) An automated roll to roll manufacturing system for silicone. The path of the silicone is shown in green. The silicone comes on a protective PET backing, which is removed and highlighted in cyan. (B) Confocal scan of engraved Silpuran 2030. Channels were 60 µm deep, and 180 µm wide.Figure 2. (A) Finished device, with custom housing (B) Device with colored water being routed through. Red arrows depict blood connections, and blue arrows depict gas connections. Two of the blood outlets filled with blue dye, and there is a dark blue region indicating imperfect layer-to-layer bonding resulting in leaking.Figure 3. Experimental vs theoretical pressure drop across the μAL (water)

Extracorporeal membrane oxygenators with light-diffusing fibers for treatment of carbon monoxide poisoning: Experiments, mathematical modeling, and performance assessment with unit cells.

Two small unit-cell p-ECMO devices consisted of a plastic capillary with a length and inside diameter of 10 cm and 1.15 mm, respectively. Either five (4-1 device) or seven (6-1 device) gas exchange tubes were placed in the plastic capillary and a light-diffusing fiber was inserted into one of the gas exchange tubes. Light from lasers emitting either 635 nm or 465 nm wavelengths was coupled into the light-diffusing fiber as oxygen flowed through the gas exchange membranes. To assess the ability of the device to remove CO from blood in vitro, the percent COHb reduction in a single pass through the device was assessed with and without light. The Navier Stokes equations, Carreau-Yesuda model, Boltzman equation for light distribution, and hemoglobin kinetic rate equations, including photo-dissociation, were combined in a mathematical model to predict COHb elimination in the experiments. For the unit-cell devices, the COHb removal rate increases with increased 635 nm laser power, increased blood time in the device, and greater gas exchange membrane surface-to-blood volume ratio. The 6-1 device COHb half-life versus that of the 4-1 device with 4 W at 635 nm light was 1.5 min versus 4.25 min, respectively. At 1 W laser power, 635 nm and 465 nm exhibited similar CO removal rates. The COHb half-life times of the 6-1 device were 1.25, 2.67, and 8.5 min at 635 nm (4 W), 465 nm (1 W), and 100% oxygen only, respectively. The mathematical model predicted the experimental results. An analysis of the in vivo COHb half-life of oxygen respiration therapy versus an adjunct therapy with a p-ECMO device and oxygen respiration shows a reduction from 90 min to as low as 10 min, depending on the device design. In this study, we experimentally studied and developed a mathematical model of a small unit-cell ECMO device integrated with a light-diffusing fiber illuminated with laser light. The unit-cell device forms the basis for a larger device and, in an adjunct therapy with oxygen respiration, has the potential to remove COHb at much higher rates than oxygen therapy alone. The mathematical model can be used to optimize the design in practical implementations to quickly and efficiently remove CO from CO-poisoned blood.

Photosynthesis of plants of shade-tolerant ecotype of Paubrasilia echinata are more tolerance to drought than the sun-tolerant ecotype

Frequent and prolonged droughts are predicted for the Northeast region of Brazil until the end of this century. How the sun-tolerant and shade-tolerant tree species of the tropical forests in this region of the planet will respond to this climate scenario is a matter of global interest. To clarify this issue, we used plants of the shade-tolerant ecotype and the sun-tolerant ecotype of Paubrasilia echinata as a biological model. One batch of each ecotype was subjected to water suspension (drought simulation) for 17 days followed by water restitution (rainfall simulation) for 36 days. In the initial, intermediate, and final time of drought (7, 12, and 17 days, respectively) and rain (5, 12, and 36 days, respectively), we analyzed the water potential (Ψwp), electrolyte leakage (EL), net assimilation of CO2 (A), stomatal conductance (gs), transpiration (E), water use efficiency (A/E), the internal concentration of CO2 (Ci), instantaneous carboxylation efficiency (A/Ci), and fluorescence parameters of the chlorophyll a, among which are the photochemical performance indices (PIABS and PITOTAL). The photosynthetic activity and Ψwp of the shade-tolerant ecotype were more tolerance to the short dry period than the sun-tolerant one. Even so, the two ecotypes withstood water scarcity with 100% survival. The restitution of water, after a period of drought, allowed some of the gas exchange variables (E, A/E, and Ci), the Ψwp, and membrane damage (EL), from both ecotypes, to completely recover their values ​​to those at time zero, reaching the values of their respective controls. On the other hand, the variables most closely associated with CO2 assimilation (A, gs, and A/Ci) and ATP and NADPH production (PITotal and PIABS) did not fully recover from drought damage. We conclude that, if the droughts intensify in the northeast region of Brazil by the end of this century, the CO2 assimilation, and the photochemical efficiency of photosynthesis of the shade-tolerant species will possibly suffer greater impacts than the sun-tolerant ones. Predictably, this can affect the plant production of shade-tolerant species.

Influence of Aerosolization on Endothelial Cells for Efficient Cell Deposition in Biohybrid and Regenerative Applications

The endothelialization of gas exchange membranes can increase the hemocompatibility of extracorporeal membrane oxygenators and thus become a long-term lung replacement option. Cell seeding on large or uneven surfaces of oxygenator membranes is challenging, with cell aerosolization being a possible solution. In this study, we evaluated the endothelial cell aerosolization for biohybrid lung application. A Vivostat® system was used for the aerosolization of human umbilical vein endothelial cells with non-sprayed cells serving as a control. The general suitability was evaluated using various flow velocities, substrate distances and cell concentrations. Cells were analyzed for survival, apoptosis and necrosis levels. In addition, aerosolized and non-sprayed cells were cultured either static or under flow conditions in a dynamic microfluidic model. Evaluation included immunocytochemistry and gene expression via quantitative PCR. Cell survival for all tested parameters was higher than 90%. No increase in apoptosis and necrosis levels was seen 24 h after aerosolization. Spraying did not influence the ability of the endothelial cells to form a confluent cell layer and withstand shear stresses in a dynamic microfluidic model. Immunocytochemistry revealed typical expression of CD31 and von Willebrand factor with cobble-stone cell morphology. No change in shear stress-induced factors after aerosolization was reported by quantitative PCR analysis. With this study, we have shown the feasibility of endothelial cell aerosolization with no significant changes in cell behavior. Thus, this technique could be used for efficient the endothelialization of gas exchange membranes in biohybrid lung applications.

Advances in lung bioengineering: Where we are, where we need to go, and how to get there.

Lung transplantation is the only potentially curative treatment for end-stage lung failure and successfully improves both long-term survival and quality of life. However, lung transplantation is limited by the shortage of suitable donor lungs. This discrepancy in organ supply and demand has prompted researchers to seek alternative therapies for end-stage lung failure. Tissue engineering (bioengineering) organs has become an attractive and promising avenue of research, allowing for the customized production of organs on demand, with potentially perfect biocompatibility. While breakthroughs in tissue engineering have shown feasibility in practice, they have also uncovered challenges in solid organ applications due to the need not only for structural support, but also vascular membrane integrity and gas exchange. This requires a complex engineered interaction of multiple cell types in precise anatomical locations. In this article, we discuss the process of creating bioengineered lungs and the challenges inherent therein. We summarize the relevant literature for selecting appropriate lung scaffolds, creating decellularization protocols, and using bioreactors. The development of completely artificial lung substitutes will also be reviewed. Lastly, we describe the state of current research, as well as future studies required for bioengineered lungs to become a realistic therapeutic modality for end-stage lung disease. Applications of bioengineering may allow for earlier intervention in end-stage lung disease and have the potential to not only halt organ failure, but also significantly reverse disease progression.

Childhood to adulthood: Accounting for age dependence in healthy-reference distributions in 129 Xe gas-exchange MRI.

Xenon-129 (129 Xe) gas-exchange MRI is a pulmonary-imaging technique that provides quantitative metrics for lung structure and function and is often compared to pulmonary-function tests. Unlike such tests, it does not normalize to predictive values based on demographic variables such as age. Many sites have alluded to an age dependence in gas-exchange metrics; however, a procedure for normalizing metrics has not yet been introduced. We model healthy reference values for 129 Xe gas-exchange MRI against age using generalized additive models for location, scale, and shape (GAMLSS). GAMLSS takes signal data from an aggregated heathy-reference cohort and fits a distribution with flexible median, variation, skewness, and kurtosis to predict age-dependent centiles. This approach mirrors methods by the Global Lung Function Initiative for modeling pulmonary-function test data and applies it to binning methods widely used by the 129 Xe MRI community to interpret and quantify gas-exchange data. Ventilation, membrane-uptake, red blood cell transfer, and red blood cell:membrane gas-exchange metrics were collected on 30 healthy subjects over an age range of 5 to 68years. A GAMLSS model was fit against age and compared against widely used linear and generalized-linear binning 129 Xe MRI analysis schemes. All 4 gas-exchange metrics had significant skewness, and membrane-uptake had significant kurtosis compared to a normal distribution. Age has significant impact on distribution parameters. GAMLSS-binning produced narrower bins compared to the linear and generalized-linear binning schemes and distributed signal data closer to a normal distribution. The proposed "proof-of-concept" GAMLSS-binning approach can improve diagnostic accuracy of 129 Xe gas-exchange MRI by providing a means of modeling voxel distribution data against age.

Profiling of time-dependent human plasma protein adsorption on non-coated and heparin-coated oxygenator membranes.

Patients with severe lung diseases are highly dependent on lung support systems. Despite many improvements, long-term use is not possible, mainly because of the strong body defence reactions (e.g. coagulation, complement system, inflammation and cell activation). The systematic characterization of adsorbed proteins on the gas exchange membrane of the lung system over time can provide insights into the course of various defence reactions and identify possible targets for surface modifications. Using comprehensive mass spectrometry analyses of desorbed proteins, we were able to identify for the first time binding profiles of over 500 proteins over a period of six hours on non-coated and heparin-coated PMP hollow fiber membranes. We observed a higher degree of remodeling of the protein layer on the non-coated membrane than on the coated membrane. In general, there was a higher protein binding on the coated membrane with exception of proteins with a heparin-binding site. Focusing on the most important pathways showed that almost all coagulation factors bound in higher amounts to the non-coated membranes. Furthermore, we could show that the initiator proteins of the complement system bound stronger to the heparinized membranes, but the subsequently activated proteins bound stronger to the non-coated membranes, thus complement activation on heparinized surfaces is mainly due to the alternative complement pathway. Our results provide a comprehensive insight into plasma protein adsorption on oxygenator membranes over time and point to new ways to better understand the processes on the membranes and to develop new specific surface modifications.

PDMS membrane-based flexible bi-layer microfluidic device for blood oxygenation

We report the fabrication and experimental study of a flexible bi-layer microfluidic device for blood oxygenation, mimicking the thin alveolar exchange barrier constituting a lung. A facile technique is employed to fabricate the device by sandwiching a thin polymeric membrane as the gas exchange layer between two flexible microchannels. A numerical model coupling the mass, momentum, and species transport equations, is used to simulate oxygen diffusion between the blood and oxygen channels across the gas exchange membrane. The oxygen saturation is experimentally measured at different locations in the blood channel along the flow direction and compared against the simulation results, which show a very good agreement. The effect of blood and oxygen flow rates, channel height, and membrane thickness on the variations in oxygen concentration in the blood and oxygen channels and the diffusion membrane are studied. The outcome of the present study may find relevance in the development of organ-on-chip devices for blood oxygenation.

Brassinosteroid application increases tomato tolerance to salinity by changing the effects of stress on membrane integrity and gas exchange

Salinity is one of the environmental stresses that most cause losses in agricultural systems, including tomato production. Brassinosteroids, such as epibrassinolide (EBL), have multiple actions in essential processes in plants. Thus, the objective of this study was to evaluate the contributions of EBL to the growth, physiology, and production of tomato plants under salinity. The experiment was conducted in a factorial scheme, with five levels of water salinity (0.5 [the control], 1.5, 3.0, 4.5, and 6.0 dS m-1) and two concentrations of EBL (0 and 10-6 M). Salt stress reduced tomato growth, relative water content, membrane integrity, gas exchange, and fruit production. However, the exogenous application of EBL attenuated the adverse effects, partially improving these characteristics at all salinity levels. EBL reduced electrolyte leakage and increased membrane integrity and relative water content in control and stressed plants. Additionally, it increased the content of photosynthetic pigments, stomatal conductance, transpiration, and photosynthesis, which led to higher leaf dry mass production, fruit transverse diameter, and production per plant. Therefore, our results confirmed that foliar application of EBL improved the characteristics of stressed and non-stressed tomato plants.

Soaking Maize Seeds in Zeatin-Type Cytokinin Biostimulators Improves Salt Tolerance by Enhancing the Antioxidant System and Photosynthetic Efficiency.

There is an urgent need for innovative strategies to raise the performance of environmentally stressed plants. The seeds of single-cross yellow Zea mays (L.) hybrid Giza-168 were soaked in Cis-(c-Z-Ck) or trans-zeatin-type cytokinin (t-Z-Ck) solutions at a concentration of 50 or 40 µM, respectively. Salinity stress was imposed at 0, 75 or 150 mM NaCl in the Hoagland nutrient solution (full strength) used for irrigation. The total carotenoids content was negatively affected by only 150 mM NaCl, while both 75 and 150 mM NaCl negatively affected the growth and yield components, relative water content, membrane stability index, photochemical activity, gas exchange, K+ and chlorophyll contents, K+/Na+ ratio, and photosynthetic efficiency. However, all of these traits were significantly improved by c-Z-Ck pretreatment and further enhanced by t-Z-Ck pretreatment compared with the corresponding controls. Furthermore, the contents of proline, soluble sugars, ascorbate, and glutathione, as well as enzymatic antioxidant activities, were significantly elevated by both salt stress concentrations and increased more by both biostimulators compared to the control. Compared to c-Z-Ck, t-Z-Ck was superior in mitigating the harmful effects of the high H2O2 levels caused by salt stress on the levels of malondialdehyde and ion leakage compared to the control. Under normal or stress conditions, t-Z-Ck pretreatment was better than c-Z-Ck pretreatment, while both positively affected maize hormonal contents. As a result, t-Z-Ck is recommended to enhance the growth and productivity of maize plants by suppressing the effects of oxidative stress caused by saline water irrigation.

Superamphiphobic blood-repellent surface modification of porous fluoropolymer membranes for blood oxygenation applications

Biomedical gas exchange membranes used for blood oxygenation, including extracorporeal membrane oxygenators (ECMO) and artificial lung technology, have suffered from the insufficient hemocompatibility of membrane materials. Despite over 50 years of membrane oxygenation (MO) technology development, a few hydrophobic membrane materials are now available on the market. Since the hydrophobic nature of the membrane promotes protein fouling which causes thrombus formation, various anti -thrombogenic and anti-fouling coating techniques have been applied to improve the hemocompatibility and lifetime of membranes for long-term MO and implanted artificial lung applications. Here, for the first time, we have developed a superamphiphobic blood-repellent structure on a porous fluoropolymer (PVDF-HFP) based membrane for blood MO application. The PVDF-HFP nanoparticles were electrosprayed on the porous membrane surface and thermally fused to secure physical stability followed by perfluoro-silane coating with a biocompatible adhesive. A soot-like re-entrance structure was successfully generated on the membrane surface, resulting in high water, blood, and hexadecane contact angles over 150°. The modified membranes have excellent anti-fouling properties with competitive blood oxygen performance, implying promising surface properties for long-term MO and artificial lung applications. • The porous PVDF-HFP membrane surface was modified to have amphiphobicity. • A soot-like re-entrance nanostructure coated with perfluorocarbon silane showed liquid repellent properties. • The modified amphiphobic membrane showed resistance to fouling and wetting in contact with blood. • Competitive gas exchange performance were confirmed by a blood oxygenation test.

Insights into Gradient and Anisotropic Pore Structures of Capiox® Gas Exchange Membranes for ECMO: Theoretically Verifying SARS-CoV-2 Permeability.

When using the extracorporeal capillary membrane oxygenator (sample A) for ECMO treatments of COVID-19 severely ill patients, which is dominantly used in Japan and worldwide, there is a concern about the risk of SARS-CoV-2 scattering from the gas outlet port of the membrane oxygenator. Terumo has launched two types of membranes (sample A and sample B), both of which are produced by the microphase separation processes using polymethylpentene (PMP) and polypropylene (PP), respectively. However, the pore structures of these membranes and the SARS-CoV-2 permeability through the membrane wall have not been clarified. In this study, we analyzed the pore structures of these gas exchange membranes using our previous approach and verified the SARS-CoV-2 permeation through the membrane wall. Both have the unique gradient and anisotropic pore structure which gradually become denser from the inside to the outside of the membrane wall, and the inner and outer surfaces of the membrane have completely different pore structures. The pore structure of sample A is also completely different from the other membrane made by the melt-extruded stretch process. From this, the pore structure of the ECMO membrane is controlled by designing various membrane-forming processes using the appropriate materials. In sample A, water vapor permeates through the coating layer on the outer surface, but no pores that allow SARS-CoV-2 to penetrate are observed. Therefore, it is unlikely that SARS-CoV-2 permeates through the membrane wall and scatter from sample A, raising the possibility of secondary ECMO infection. These results provide new insights into the evolution of a next-generation ECMO membrane.

Utilization and outcomes of extracorporeal CO2 removal (ECCO2 R): Systematic review and meta-analysis of arterio-venous and veno-venous ECCO2 R approaches.

Extracorporeal carbon dioxide removal (ECCO2 R) provides respiratory support to patients suffering from hypercapnic respiratory failure by utilizing an extracorporeal shunt and gas exchange membrane to remove CO2 from either the venous (VV-ECCO2 R) or arterial (AV-ECCO2 R) system before return into the venous site. AV-ECCO2 R relies on the patient's native cardiac function to generate pressures needed to deliver blood through the extracorporeal circuit. VV-ECCO2 R utilizes a mechanical pump and can be used to treat patients with inadequate native cardiac function. We sought to evaluate the existing evidence comparing the subgroups of patients supported on VV and AV-ECCO2 R devices. A literature search was performed to identify all relevant studies published between 2000 and 2019. Demographic information, medical indications, perioperative variables, and clinical outcomes were extracted for systematic review and meta-analysis. Twenty-five studies including 826 patients were reviewed. 60% of patients (497/826) were supported on VV-ECCO2 R. The most frequent indications were acute respiratory distress syndrome (ARDS) [69%, (95%CI: 53%-82%)] and chronic obstructive pulmonary disease (COPD) [49%, (95%CI: 37%-60%)]. ICU length of stay was significantly shorter in patients supported on VV-ECCO2 R compared to AV-ECCO2 R [15 (95%CI: 7-23) vs. 42 (95%CI: 17-67) days, p=0.05]. In-hospital mortality was not significantly different [27% (95%CI: 18%-38%) vs. 36% (95%CI: 24%-51%), p=0.26]. Both VV and AV-ECCO2 R provided clinically meaningful CO2 removal with comparable mortality.