Double-layered Membrane Research Articles

Thermosensitive double-membrane neurons and their network dynamics

Abstract Cell membrane of biological neurons has distinct geometric structure, and involvement of diffusive term is suitable to estimate the spatial effect of cell membrane on neural activities. The gradient field diversity between two sides of the cell membrane can be approached by using a double-layer membrane model for the neuron. Therefore, two capacitive variables and diffusive terms are used to investigate the neural activities of cell membrane, and the local kinetics is described by a functional circuit composed of two capacitors. The voltages for the two parallel capacitors describe the inner and outer membrane potentials, and the diffusive effect of ions is considered on the membrane surface. The results reveal that neural activities are relative to the capacitance ratio between the inside and outside of the membrane and diffusive coefficient. High-energy periodic external stimulation induces the target waves to spread uniformly, while low-energy chaotic stimulation results in wave fragmentation. Furthermore, when the capacitance ratio exhibits exponential growth under an adaptive control law, the resulting energy gradient within the network induces stable target waves. That is, energy distribution affects the wave propagation and pattern formation in the neuron. The result indicates that the spatial diffusive effect and capacitance diversity between outer and inner cell membranes are important for selection of firing patterns and signal processing during neural activities. This model is more suitable to estimate neural activities than using generic oscillator-like or map neurons without considering the spatial diffusive effect.

A Double-Layer Polyurethane Electrospun Membrane with Directional Sweat Transport Ability for Use as a Soft Strain Sensor.

Wearable electronics for long-term monitoring of physiological signals should be capable of removing sweat generated during daily motion, which significantly impacts signal stability, human comfort, and safety of the electronics. In this study, we developed a double-layer polyurethane (PU) membrane with sweat-directional transport ability that can be applied for monitoring strain signals. The PU membrane was composed of a hydrophilic, conductive layer and a relatively hydrophobic layer. The double-layer PU composite membrane exhibited varied pore size and opposite hydrophilicity on its two sides, enabling the spontaneous pumping of sweat from the hydrophobic side to the hydrophilic side, i.e., the directional transport of sweat. The membrane can be used as a strain sensor to monitor motion strain over a broad working range of 0% to 250% with high sensitivity (GF = 4.11). The sensor can also detect simple human movements even under sweating conditions. We believe that the strategy demonstrated here will provide new insights into the design of next-generation strain sensors.

Comparing PEMFC state-of-health characteristics obtained by Galvanostatic Charge Method with and without nitrogen flush

Onboard determination of state-of-health (SoH) parameters becomes increasingly important with tightened lifetime requirements for automotive polymer electrolyte membrane (PEM) fuel cell systems. One way to electrochemically characterize SoH parameters like active catalyst surface area (roughness factor, RF), double layer capacitance and membrane permeability is the nitrogen-flush-requiring Galvanostatic Charge Method (GCM). In this publication, a nitrogen-flush-free and thus, onboard-compatible adapted version of GCM (AGCM from Möller et al. (2023)), is directly compared to its original method, GCM. A 20-cell automotive shortstack was frequently characterized with both GCM and AGCM methods as well as standard Cyclic Voltammetry (CV) during a degradation test. Additionally, the evaluation model for AGCM was varied in two aspects: Firstly, modeling the hydrogen partial pressure difference (ΔpH2) responsible for hydrogen crossover and secondly, modeling hydrogen diffusion in the cathode volume with a 0-D transport model. The characterization results prove that all investigated model variations of AGCM can reproduce double layer capacitance results from GCM and CV, as well as the decreasing trend in roughness factor results. RF-values characterized by AGCM agree with either GCM or CV results, depending on the evaluation model. A thorough analysis revealed the neglected short circuit resistance in combination with the chosen modeling approach of ΔpH2 in AGCM as the reason. The two modeling approaches for ΔpH2 base on extreme assumptions about the homogeneity of hydrogen distribution in the anode volume. Neither of them could reproduce the membrane permeability of GCM. Instead, one overestimates, one underestimates it, indicating the truth to be in between the two extreme models. However, AGCM measurement conditions are identified as a lever to improve the AGCM permeability results and their robustness, even if the modeling approaches remain unchanged. Furthermore, this study showed that neglecting hydrogen diffusion in the cathode volume in the AGCM evaluation model leads to overestimation of the membrane permeability.

Simulation analysis of a photonic crystal fiber refractive index sensor based on a double-layer film structure and surface plasmon resonance technology

A photonic crystal fiber surface plasmon resonance sensor based on a double-layer membrane structure is designed and analyzed. In the simple sensing structure with only one air hole size, TiO2 and Au layers with specific thicknesses are sequentially coated on the optical fiber to form a double-layer structure. The sensing characteristics of the double-layer membrane structure are studied by the finite element method. Compared to the single-layer membrane structure, the double-layer membrane sensor has significant sensing properties such as a better wavelength sensitivity and a smaller full width at half maximum in the loss spectrum. In the refractive index range between 1.37 and 1.43, the maximum wavelength sensitivity and average wavelength sensitivity of the sensor are 19,900 nm/RIU and 7417 nm/RIU, respectively, and the resolution can be up to 5.03×10−6RIU. The proposed photonic crystal fiber optic sensor achieves high performance with a simpler sensing structure than previous photonic crystal fiber optic sensors, and eliminates the step of polishing, which will greatly reduce the difficulty of actual fabrication and the error due to uneven polishing. The results show that the photonic crystal fiber optic sensor with a double-layer membrane structure has excellent performance. Due to its high sensitivity and resolution, it has great potential for applications in environmental monitoring, biosensing and chemical sensing.

Fabrication of Electrospun Double Layered Biomimetic Collagen-Chitosan Polymeric Membranes with Zinc-Doped Mesoporous Bioactive Glass Additives.

Several therapeutic approaches have been developed to promote bone regeneration, including guided bone regeneration (GBR), where barrier membranes play a crucial role in segregating soft tissue and facilitating bone growth. This study emphasizes the importance of considering specific tissue requirements in the design of materials for tissue regeneration, with a focus on the development of a double-layered membrane to mimic both soft and hard tissues within the context of GBR. The hard tissue-facing layer comprises collagen and zinc-doped bioactive glass to support bone tissue regeneration, while the soft tissue-facing layer combines collagen and chitosan. The electrospinning technique was employed to achieve the production of nanofibers resembling extracellular matrix fibers. The production of nano-sized (~116 nm) bioactive glasses was achieved by microemulsion assisted sol-gel method. The bioactive glass-containing layers developed hydroxyapatite on their surfaces starting from the first week of simulated body fluid (SBF) immersion, demonstrating that the membranes possessed favorable bioactivity properties. Moreover, all membranes exhibited distinct degradation behaviors in various mediums. However, weight loss exceeding 50% was observed in all tested samples after four weeks in both SBF and phosphate-buffered saline (PBS). The double-layered membranes were also subjected to mechanical testing, revealing a tensile strength of approximately 4 MPa. The double-layered membranes containing zinc-doped bioactive glass demonstrated cell viability of over 70% across all tested concentrations (0.2, 0.1, and 0.02 g/mL), confirming the excellent biocompatibility of the membranes. The fabricated polymer bioactive glass composite double-layered membranes are strong candidates with the potential to be utilized in tissue engineering applications.

Summer and winter performance evaluation of double layered PTFE dome with aerogel-glass wool thermal insulation- field experiments and numerical simulation

Achieving optimal thermal performance in large membrane-enclosed buildings presents a significant challenge. Aerogel mats offer potential for enhanced insulation, but their effectiveness in varying seasonal conditions is yet to be fully determined. The current study investigates the thermal performance of an enclosed dome with double-layered PTFE membrane roof integrated with aerogel-glass wool insulation mats. This research utilizes field experiments to assess indoor thermal comfort and numerical model to evaluate the effectiveness of the dome’s insulation capabilities during summer and winter conditions. The Aerogel integrated areas show a difference of 10.26/3.72 °C for summer/winter while that of 9.36/3.22 °C for glass wool-integrated areas. An online thermal comfort tool utilized maximum indoor temperature values during both seasons obtained from numerical results indicating that winter comfort falls within ASHRAE comfort range with PMV value −0.48 but summer conditions require enhancements. Additionally, the study assessed the insulation’s effectiveness using Maximum Reduction in Temperature (MRT), Decay Factor (DF), and Time Delay (TD) indicators. Results showed significant thermal lag, with peak temperature delays of up to 3.1 h in summer and 2.2 h in winter. Notable temperature differences between the dome’s inner and outer surfaces, alongside 28 % and 27 % DF reductions during summer and winter, respectively, demonstrated the roof insulation’s effectiveness. These findings support the use of both experimental and numerical methods to develop thermal management practices that improve sustainable building design, emphasizing occupant comfort and energy efficiency.

Uni-directional release of ibuprofen from an asymmetric fibrous membrane enables effective peritendinous anti-adhesion

Drug-loaded porous membranes have been deemed to be effective physicochemical barriers to separate postoperative adhesion-prone tissues in tendon healing. However, cell viability and subsequent tissue regeneration might be severely interfered with the unrestricted release and the locally excessive concentration of anti-inflammatory drugs. Herein, we report a double-layered membrane with sustained and uni-directional drug delivery features to prevent peritendinous adhesion without hampering the healing outcome. A vortex-assisted electrospinning system in combination with ibuprofen (IBU)-in-water emulsion was utilized to fabricate IBU-loaded poly-ʟ-lactic-acid (PLLA) fiber bundle membrane (PFB-IBU) as the anti-adhesion layer. The resultant highly porous structure, oleophilic and hydrophobic nature of PLLA fibers enabled in situ loading of IBU with a concentration gradient across the membrane thickness. Aligned collagen nanofibers were further deposited at the low IBU concentration side of the membrane for regulating cell growth and achieving uni-directional release of IBU. Drug release kinetics showed that the release amount of IBU from the high concentration side reached 79.32% at 14 d, while it was only 0.35% at the collagen side. Therefore, fibroblast proliferation at the high concentration side was successfully inhibited without affecting the oriented growth of tendon-derived stem cells at the other side. In vivo evaluation of the rat Achilles adhesion model confirmed the successful peritendinous anti-adhesion of our double-layered membrane, in that the macrophage recruitment, the inflammatory factor secretion and the deposition of pathological adhesion markers such as α-SMA and COL-III were all inhibited, which greatly improved the peritendinous fibrosis and restored the motor function of tendon.

3D-printed porous zinc scaffold combined with bioactive serum exosomes promotes bone defect repair in rabbit radius.

Currently, the repair of large bone defects still faces numerous challenges, with the most crucial being the lack of large bone grafts with good osteogenic properties. In this study, a novel bone repair implant (degradable porous zinc scaffold/BF Exo composite implant) was developed by utilizing laser melting rapid prototyping 3D printing technology to fabricate a porous zinc scaffold, combining it under vacuum conditions with highly bioactive serum exosomes (BF EXO) and Poloxamer 407 thermosensitive hydrogel. The electron microscope revealed the presence of tea saucer-shaped exosomes with a double-layered membrane structure, ranging in diameter from 30-150 nm, with an average size of 86.3 nm and a concentration of 3.28E+09 particles/mL. In vitro experiments demonstrated that the zinc scaffold displayed no significant cytotoxicity, and loading exosomes enhanced the zinc scaffold's ability to promote osteogenic cell activity while inhibiting osteoclast activity. In vivo experiments on rabbits indicated that the hepatic and renal toxicity of the zinc scaffold decreased over time, and the loading of exosomes alleviated the hepatic and renal toxic effects of the zinc scaffold. Throughout various stages of repairing radial bone defects in rabbits, loading exosomes reinforced the zinc scaffold's capacity to enhance osteogenic cell activity, suppress osteoclast activity, and promote angiogenesis. This effect may be attributed to BF Exo's regulation of p38/STAT1 signaling. This study signifies that the combined treatment of degradable porous zinc scaffolds and BF Exo is an effective and biocompatible strategy for bone defect repair therapy.

Preparation of a membrane-sealed cell for studying catalyst nanoparticles in flowing gas with high vacuum x-ray photoelectron spectrometer.

Here a sealing-style x-ray photoelectron spectroscopy study of the surface of a 1.0 wt. %Ni/TiO2 nanoparticle catalyst in a flowing mixture of CO and O2 at 1bar was performed with a graphene membrane-sealed Si3N4 window-based miniature cell. We report the details on how a commercial Si3N4 window is modified before assembling a graphene membrane, how single-layer graphene membranes are transferred from their metal supports to the modified Si3N4 window, how a modified Si3N4 window covered with a double-layer graphene membrane is assembled onto a blank cell cap, how a nanoparticle catalyst is introduced to the cell cap and then the cell cap is installed onto a cell body to form a complete reaction cell, and how a complete cell is interfaced with a high vacuum chamber of an XPS system before an XPS study of 1.0 wt. %Ni/TiO2 catalyst surface in a flowing mixture for 0.2bar CO and 0.8bar O2 is performed. How the characterization of a catalyst using this type of graphene membrane-sealed Si3N4 window-based miniature cell is relevant to the finding of the actual surface chemistry of a catalyst during catalysis is discussed.

Biological Roles and Clinical Applications of Exosomes in Breast Cancer: A Brief Review.

Breast cancer (BC) is a global health risk for women and has a high prevalence rate. The drug resistance, recurrence, and metastasis of BC affect patient prognosis, thus posing a challenge to scientists. Exosomes are extracellular vesicles (EVs) that originate from various cells; they have a double-layered lipid membrane structure and contain rich biological information. They mediate intercellular communication and have pivotal roles in tumor development, progression, and metastasis and drug resistance. Exosomes are important cell communication mediators in the tumor microenvironment (TME). Exosomes are utilized as diagnostic and prognostic biomarkers for estimating the treatment efficacy of BC and have the potential to function as tools to enable the targeted delivery of antitumor drugs. This review introduces recent progress in research on how exosomes influence tumor development and the TME. We also present the research progress on the application of exosomes as prognostic and diagnostic biomarkers and drug delivery tools.

Functionalizable bacterial cellulose composite membrane for guided tissue regeneration

This research aims to develop guided tissue regeneration (GTR) membranes from bacterial cellulose (BC), a natural polysaccharide-based biopolymer. A double-layered BC composite membrane was prepared by coating the BC membrane with mixed carboxymethyl cellulose/poly(ethylene oxide) (CMC/PEO) fibers via electrospinning. The CMC/PEO-BC membranes were then characterized for their chemical and physical characteristics. The 8 % (wt/v) CMC/PEO (1:1) aqueous solution yielded well-defined electrospun CMC/PEO nanofibers (125 ± 10 nm) without beads. The CMC/PEO-BC membranes exhibited good mechanical and swelling properties as well as good cytocompatibility against human periodontal ligament cells (hPDLs). Its functionalizability via carboxyl entities in CMC was tested using the calcium-binding domain of plant-derived recombinant human osteopontin (p-rhOPN-C122). As evaluated by enzyme-linked immunosorbent assay, a 98–99 % immobilization efficiency was achieved in a concentration-dependent manner over an applied p-rhOPN-C122 concentration range of 7.5–30 ng/mL. The biological function of the membrane was assessed by determining the expression levels of osteogenic-related gene transcripts using quantitative real-time reverse-transcriptase polymerase chain reaction. Mineralization assay indicated that the p-rhOPN-C122 immobilized CMC/PEO-BC membrane promoted hPDLs osteogenic differentiation. These results suggested that the developed membrane could serve as a promising GTR membrane for application in bone tissue regeneration.

Flexible cellulose nanofibers/MXene bilayer membrane humidity sensor with a synergistic effect of force and hygroscopic expansion

A double layer membrane humidity sensor was designed with a synergistic effect of force and hygroscopic expansion, capitalizing on the high sensitivity demonstrated by MXene material. This sensitivity was achieved through the modulation of resistance change associated with layer spacing of MXene. The double layer structure of sensor was made by vacuum filtration, with an inner layer of MXene for conductivity and an outer layer of cellulose nanofibers (CNF) for moisture absorption, which is rooted in the MXene through the CNFs, similar to the biomimetic structure of hairs rooted in the skin. The synergistic effect of humidity sensitivity is achieved by trapping and dissociating water molecules through the CNF layer generating a change in MXene stress and disrupting the conductive pathway of MXene upon swelling. The CNF/MXene humidity sensor showed a resistance change rate of 117.93 % from 11 % RH to 98 % RH, accompanied by a response time of 319s and a recovery time of 132s. Stable sensing performance is maintained even after 5 times adsorption and desorption cycling, prolonged exposure (7 days) or bending and folding. CNF/MXene bilayer membrane also has good electrical heating performance, reaching about 80 °C at 7V and maintaining stable performance under 5 cycles of heating and 10 min of long heating, respectively. The CNF/MXene membrane humidity sensor can monitor human respiration monitoring, fingertip humidity, pipeline leakage and artifact dehumidification, and combined with the function of electric heating can realize the cycle of dehumidification and humidity monitoring, which has a wide range of application prospects in flexible equipment.

Exosomes miRNA-499a-5p targeted CD38 to alleviate anthraquinone induced cardiotoxicity: experimental research.

The purpose of this study was to investigate the effects of cardiac homing peptide (CHP) engineered bone marrow mesenchymal stem cells (BMMSc) derived exosomes (B-exo) loaded miRNA-499a-5p on doxorubicin (DOX) induced cardiotoxicity. miRNA chip analysis was used to analyze the differences between DOX induced H9c2 cells and control group. CHP engineering was performed on BMMSc derived exosomes to obtain C-B-exo. miRNA-499a-5p mimic was introduced into C-B-exo by electroporation technology to obtain C-B-exo-miRNA-499a-5p. DOX was used to establish a model of cardiotoxicity to evaluate the effects of C-B-exo- miRNA-499a-5p in vivo and in vitro . Western blot, immunohistochemistry, immunofluorescence, and other molecular biology methods were used to evaluate the role and mechanism of C-B-exo-miRNA-499a-5p on DOX induced cardiotoxicity. miRNA chip analysis revealed that miRNA-499a-5p was one of the most differentially expressed miRNAs and significantly decreased in DOX induced H9c2 cells as compared to the control group. Exo-and B-exo have a double-layer membrane structure in the shape of a saucer. After engineering the CHP of B-exo, the results showed that the delivery of miRNA-499a-5p significantly increased and significantly reached the target organ (heart). The experimental results showed that C-B-exo-miRNA-499a-5p significantly improved electrocardiogram, decreased myocardial enzyme, serum and cardiac cytokines, improved cardiac pathological changes, inhibited CD38/MAPK/NF-κB signal pathway. In this study, C-B-exo-miRNA-499a-5p significantly improved DOX-induced cardiotoxicity via CD38/MAPK/NF-κB signal pathway, providing a new idea and method for the treatment of DOX induced cardiotoxicity.

A Microchip For Exosome Isolation That Can Be Impregnated With Imatinib Simultaneously: An In Vitro Analysis

Background and Aims — Exosomes, which are tiny double-layered membranes originating from eukaryotic cells, have been recognized as a valuable natural vehicle for delivering substances because of their optimal size, compatibility with living organisms, strong structure, ability to carry a large amount of cargo, and capacity to be modified on their surface. Methods — Various strategies have been employed to isolate exosomes due to the challenges associated with maintaining their high purity. The current investigation utilized a soft lithography technique to fabricate channels for exosome separation, incorporating immunoaffinity capabilities. Both biochemical and biophysical assays were conducted to assess the quality of isolated exosomes from various sources (serum, cell supernatant, and urine) and compared with a commercially available kit. Results — The current investigation employed a microfluidic method to capture CD63-conjugated magnetic beads, resulting in a very effective separation of exosomes. Based on the data, there were no notable variations in miRNAs that were statistically significant. This demonstrates that the engineered chip successfully achieved the separation of the exosome while preserving the integrity of its nucleic acid components. Conclusion — The results shown that the current methodology effectively isolated exosomes with a high yield rate, purity, and minimal time requirement. The imatinib laden exosomes demonstrated anticancer efficacy against the KYO-1 cell line in all of their forms.

Extracellular vesicles as carriers for noncoding RNA-based regulation of macrophage/microglia polarization: an emerging candidate regulator for lung and traumatic brain injuries.

Macrophage/microglia function as immune defense and homeostatic cells that originate from bone marrow progenitor cells. Macrophage/microglia activation is historically divided into proinflammatory M1 or anti-inflammatory M2 states based on intracellular dynamics and protein production. The polarization of macrophages/microglia involves a pivotal impact in modulating the development of inflammatory disorders, namely lung and traumatic brain injuries. Recent evidence indicates shared signaling pathways in lung and traumatic brain injuries, regulated through non-coding RNAs (ncRNAs) loaded into extracellular vesicles (EVs). This packaging protects ncRNAs from degradation. These vesicles are subcellular components released through a paracellular mechanism, constituting a group of nanoparticles that involve exosomes, microvesicles, and apoptotic bodies. EVs are characterized by a double-layered membrane and are abound with proteins, nucleic acids, and other bioactive compounds. ncRNAs are RNA molecules with functional roles, despite their absence of coding capacity. They actively participate in the regulation of mRNA expression and function through various mechanisms. Recent studies pointed out that selective packaging of ncRNAs into EVs plays a role in modulating distinct facets of macrophage/microglia polarization, under conditions of lung and traumatic brain injuries. This study will explore the latest findings regarding the role of EVs in the progression of lung and traumatic brain injuries, with a specific focus on the involvement of ncRNAs within these vesicles. The conclusion of this review will emphasize the clinical opportunities presented by EV-ncRNAs, underscoring their potential functions as both biomarkers and targets for therapeutic interventions.

Isolation and usage of exosomes in central nervous system diseases.

Exosomes are vesicles secreted by all types of mammalian cells. They are characterized by a double-layered lipid membrane structure. They serve as carriers for a plethora of signal molecules, including DNA, RNA, proteins, and lipids. Their unique capability of effortlessly crossing the blood-brain barrier underscores their critical role in the progression of various neurological disorders. This includes, but is not limited to, diseases such as Alzheimer's, Parkinson's, and ischemic stroke. Establishing stable and mature methods for isolating exosomes is a prerequisite for the study of exosomes and their biomedical significance. The extraction technologies of exosomes include differential centrifugation, density gradient centrifugation, size exclusion chromatography, ultrafiltration, polymer coprecipitation, immunoaffinity capture, microfluidic, and so forth. Each extraction technology has its own advantages and disadvantages, and the extraction standards of exosomes have not been unified internationally. This review aimed to showcase the recent advancements in exosome isolation techniques and thoroughly compare the advantages and disadvantages of different methods. Furthermore, the significant research progress made in using exosomes for diagnosing and treating central nervous system (CNS) diseases has been emphasized. The varying isolation methods result in differences in the concentration, purity, and size of exosomes. The efficient separation of exosomes facilitates their widespread application, particularly in the diagnosis and treatment of CNS diseases.

Phosphotungstic acid-coated glass fibre with thin Pd-sputtered films enhances fuel cell performance and durability in proton exchange membrane fuel cells (PEMFCs)

This study investigated the potential utilization of glass microfiber filters (GMFs) reinforced with hetero polyacid (12-phosphotungstic acid, H3PW12O40; PWA) in hydrogen fuel cells. Nano-sized PWA powders were confirmed through XRD and Raman spectra. Several analytical techniques confirmed the preservation of the Keggin structure of PWA following the absorption (interfacial contact) procedure using the dip-coating wetness method with water as the solvent. Proton conductivity under wet conditions exhibited a proportional increase with temperature. The research comprehensively explored the impact of the PWA membrane on microstructure, physicochemical properties, proton conductivity, and fuel cell performance. It was observed that the incorporation of Pd-decorated PWA enhances membrane mechanical strength, improves durability, and prevents membrane reduction from water contact, addressing PWA's high water solubility. Hydrogen fuel cells were constructed using both a pristine PWA membrane and a double-layered membrane (PWA/Pd). The PWA/Pd membrane demonstrated superior hydrogen fuel cell performance, achieving a higher maximum power density (MPD) of 16 mW cm−2 at a current density of 50 mA cm−2, compared to pristine PWA (1.03 mW cm−2) under identical conditions at 40 °C.

Highly selective recovery of palladium using innovative double-layer adsorptive membranes

Palladium (Pd) recovery from secondary resources is urgently needed to meet the rising demands for precious metals for sustainable development and environmental protection. To achieve the goal of simple, efficient, and selective recovery of precious metal Pd, we reported an innovative strategy that utilized a double-layer adsorptive membrane based on polydopamine (PDA) modification and polymethacryloxyethyltrimethyl ammonium chloride (PDMC) grafting. The adsorption results suggested that the adsorptive membrane exhibited an excellent adsorption capacity of 61.5 mg g−1 towards Pd(II) at pH 2.0 and the adsorption capacity remained stable after six cycles. Moreover, the adsorption processes of Pd(II) were fitted to pseudo second-order kinetic models and the Langmuir isotherm models. Density functional theory (DFT) simulation, and FTIR, XPS analysis indicated the adsorption mechanisms were ion exchange from the PDMC layer and chelation and ion exchange from the PDA layer. In the presence of other metal ions (Ni(II), Cu(II), Zn(II), Ca(II), Mg(II), K(I) and Na(I)), the separation factor of adsorptive membrane for Pd(II) was in the range of 50–529. The remarkable selectivity was due to the mechanism of the combination of electrostatic attraction and coordination interaction to Pd(II) while the electrostatic repulsion to other metal cations. Furthermore, membrane filtration results suggested that Pd(II) was effectively adsorbed and rejected and the leakage risk could be reduced by dual adsorption from the double-layer membrane. This study not only offers an innovative strategy to precisely and effectively recover Pd(II) and other platinum group metals, but also provides valuable insights for the future implementation of adsorptive membranes in recycling low-concentration wastewater in an efficient and friendly way.

Harmonizing Thickness and Permeability in Bone Tissue Engineering: A Novel Silk Fibroin Membrane Inspired by Spider Silk Dynamics.

Guided bone regeneration gathers significant interest in the realm of bone tissue engineering; however, the interplay between membrane thickness and permeability continues to pose a challenge that can be addressed by the water-collecting mechanism of spider silk, where water droplets efficiently move from smooth filaments to rough conical nodules. Inspired by the natural design of spider silk, an innovative silk fibroin membrane is developed featuring directional fluid transportation via harmoniously integrating a smooth, dense layer with a rough, loose layer; conical microchannels are engineered in the smooth and compact layer. Consequently, double-layered membranes with cone-shaped microporous passageways (CSMP-DSF membrane) are designed for in situ bone repair. Through extensive in vitro testing, it is noted that the CSMP-DSF membrane guides liquid flow from the compact layer's surface to the loose layer, enabling rapid diffusion. Remarkably, the CSMP-DSF membrane demonstrates superior mechanical properties and resistance to bacterial adhesion. When applied in vivo, the CSMP-DSF membrane achieves results on par with the commercial Bio-Gide collagen membranes. This innovative integration of a cross-thickness wetting gradient structure offers a novel solution, harmonizing the often-conflicting requirements of material transport, mechanical strength, and barrier effectiveness, while also addressing issues related to tissue engineering scaffold perfusion.

Folic Acid-Modified Long-Circulating Liposomes Loaded with Sulfasalazine For Targeted Induction of Ferroptosis in Melanoma.

Melanoma is a malignant tumor that originates from melanocytes. The incidence of melanoma is increasing worldwide, partially because of its insensitivity to radiotherapy or chemotherapy. Therefore, effective treatments for melanoma are urgently required. In this study, we employed folic acid-modified sulfasalazine long-circulating liposomes (FA-SSZ-Lips) to precisely target drug delivery to melanoma cells, eliciting ferroptosis effectively. The synthesized FA-SSZ-Lips were characterized as small spheres of a double-layer membrane, a particle size of 110.1 nm, and a ζ-potential of -22.8 ± 0.66 mV. FA-SSZ-Lips are effective drug carriers with SSZ-loading ratio and SSZ release rate of 6.2 ± 0.10%, and 72.63 ± 1.40%, respectively. The liposomes enhanced SSZ solubility, and the folic acid modifications increased the liposome targeting to melanoma cells. Compared with SSZ alone, FA-SSZ-Lips more strongly inhibited B16F10 cell growth, significantly disrupted the intracellular redox balance, and induced ferroptosis. After treatment, considerable differences were observed in the tumor volumes between FA-SSZ-Lips and phosphate-buffered saline control groups. The tumor growth-inhibition value of the FA-SSZ-Lips group reached 70.09%. Thus, FA-SSZ-Lips exhibited favorable antitumor effects in vitro and in vivo and are a promising strategy for melanoma treatment.