Search Results (385)

Nanocarriers have found numerous applications in pharmaceutical and food sectors due to their unique physical and chemical properties. In particular, liposomes are the most extensively studied kind of nanoparticles for these applications. They are spherical colloidal systems characterized by lipid membranes enclosing an aqueous core. This versatile structure enables the incorporation of hydrophilic, hydrophobic, and amphiphilic molecules, making them optimal candidates for the controlled release of drugs and enzymes. Despite numerous promising applications, liposomes face challenges such as low colloidal stability, inefficient drug encapsulation, and high production costs for large-scale applications. For this reason, innovative methods, such as microfluidics, electroporation, and supercritical CO₂, are currently being investigated to overcome these limitations. This review examines the recent applications of liposomes in enzyme encapsulation within the pharmaceutical and food sectors, emphasizing production challenges and emerging technological developments. Full article

Background/Objectives: A nanostructured membrane of polycaprolactone (a synthetic polymer) was synthesized using an electrospinning technique aiming to enhance its hydrophilicity and rate of degradation by surface modification via aminolysis. Since polycaprolactone nanofibrous films are naturally hydrophobic and with slow degradation, which restricts their use in biological systems, amino groups were added to the fiber surface using the aminolysis technique, greatly increasing the wettability of the membranes. Methods: Polycaprolactone nanofibrous membranes were synthesized via the electrospinning technique and surface modification by aminolysis. Trypsin, pepsin, and pancreatin were conjugated onto the aminolyzed PNF surface to further strengthen biocompatibility by enhancing the hydrophilicity, porosity, and biodegradation rate. SEM, FTIR, EDX, and liquid displacement method were performed to investigate proteolytic efficiency and morphological and physical characteristics such as hydrophilicity, porosity, and degradation rates. Results: Enzyme activity tests, which showed a zone of clearance, validated the successful enzyme conjugation and stability over a wide range of pH and temperatures. Scanning electron microscopy (SEM) confirms the smooth morphology of nanofibers with diameters ranging from 150 to 950 nm. Fourier transform infrared spectroscopy (FTIR) revealed the presence of O–H, C–O, C=O, C–N, C–H, and O–H functional groups. Energy-dispersive X-ray (EDX) elemental analysis indicates the presence of carbon, oxygen, and nitrogen atoms owing to the presence of peptide and amide bonds. The liquid displacement technique and contact angle proved that Pepsin-PNFs possess notably increased porosity (88.50% ± 0.31%) and hydrophilicity (57.6° ± 2.3 (L), 57.9° ± 2.5 (R)), respectively. Pancreatin-PNFs demonstrated enhanced enzyme activity and degradation rate on day 28 (34.61%). Conclusions: These enzyme-conjugated PNFs thus show improvements in physicochemical properties, making them ideal candidates for various biomedical applications. Future studies must aim for optimization of enzyme conjugation and in vitro and in vivo performance to investigate the versatility of these scaffolds. Full article

Hypothesis: Structural optimization of crosslinkers within a reactive glycerol-based hexagonal lyotropic liquid crystal (HLLC) system is proposed to enhance the interfacial stability of hexagonal mesophases and improve the hexagonal structure retention during polymerization. This targeted modification is anticipated to significantly improve the water filtration efficiency of HLLC-templated nanofiltration. Experiments: The effect of crosslinkers on the interfacial stability of glycerol-based hexagonal mesophases was studied by evaluating their concentration accommodation within the mesophases using ¹³C solid NMR, FTIR and SAXS. Findings: A hydrophilic crosslinker consisting of ten ethylene glycol units shows less interference with the interfacial stability of hexagonal mesophases, therefore contributing to a higher concentration accommodation compared to the one with three ethylene glycol units. This long-chain crosslinker, despite having a low content of reactive groups, effectively connects the cylinders and better retains the hexagonal structures during polymerization than the hydrophobic crosslinker with shorter ethylene glycol units but a higher content of reactive groups. The retained hexagonal nanofiltration membranes show a remarkable pure water permeability of 40 L m⁻² h⁻¹ bar⁻¹ µm, resulting from the strong hygroscopic effect of glycerol and the crumpled surface of membranes due to the flexible nature of the system plasticized by glycerol. Full article

The inherent hydrophobic nature of PVDF material renders it challenging to establish a stable aqueous hydration layer, thereby limiting its suitability as a substrate for the preparation of nanofiltration (NF) membranes. In this study, we developed a novel modification approach that effectively enhances the hydrophilicity of PVDF substrates through the incorporation of sulfonic acid-doped polyaniline (SPANI) and hyperbranched polyester (HPE) into the PVDF casting solution, followed by cross-linking with trimesoyl chloride (TMC). The introduction of SPANI and HPE, which contain reactive polar amino and hydroxyl groups, improved the hydrophilicity of the substrate, while the subsequent cross-linking with TMC effectively anchored these components within the substrate through the covalent linking between TMC and the reactive sites. Additionally, the hydrolysis of TMC yielded non-reactive carboxyl groups, which further enhanced the hydrophilicity of the substrate. As a result, the modified PVDF substrate exhibited improved hydrophilicity, facilitating the construction of an intact polyamide layer. In addition, the fabricated TFC NF membrane demonstrated excellent performance in the advanced treatment of tap water, achieving a total dissolved solid removal rate of 57.9% and a total organic carbon removal rate of 85.3%. This work provides a facile and effective route to modify PVDF substrates for NF membrane fabrication. Full article

Polyethersulfone (PES) membranes are essential in separation processes; however, their inherent hydrophobicity can limit their effectiveness in water-intensive applications. This study aims to enhance PES membranes by modifying them with a NiFe₂O₄–nanoclay composite nanoparticle to improve both their hydrophilicity and photocatalytic potential as a photocatalytic membrane. The nanoparticles were synthesized using the sol–gel auto-combustion method and incorporated into PES membranes through mixed-matrix embedding (1 wt% and 3 wt%) and surface coating. X-ray diffraction confirmed the cubic spinel structure of the composite nanoparticles, which followed the second order kinetic reaction during the photodegradation–adsorption of crystal violet. The mixed-matrix membranes displayed a remarkable 170% increase in water flux and a 25% improvement in mechanical strength, accompanied by a slight decrease in contact angle at 1 wt% of nanoparticle loading. In contrast, the surface-coated membranes demonstrated a significant reduction in contact angle to 18°, indicating a highly hydrophilic surface and increased roughness. All membranes achieved high dye removal rates of 98–99%, but only the coated membrane system exhibited approximately 50% photocatalytic degradation, following mixed kinetics. These results highlight the critical importance of surface modification in advancing PES membranes, as it significantly reduces fouling and enhances water–material interaction qualities essential for future filtration and photocatalytic applications. Exploring hybrid strategies that combine both embedding and coating approaches may yield even greater synergies in membrane functionality. Full article

Aim: The aim of this study was to evaluate the adhesion of oral microorganisms on the surfaces of polytetrafluoroethylene (PTFE) membranes used in guided bone regeneration (GBR) procedures. Materials and Methods: In this study, three oral microorganisms (Streptococcus mutans, Porphyromonas gingivalis, and Candida albicans) were used, and six PTFE membranes were characterized by their surface roughness, contact angle (CA), and surface free energy (SFE). Microbial hydrophobicity was investigated, and adhesion was examined via DNA extraction and quantitative real-time PCR. Results: Significant differences were noted amongst the membranes with respect to SFE, CA, and roughness (p < 0.001). S. mutans was the most hydrophobic microorganism, followed by C. albicans and P. gingivalis. SEM analyses confirmed that the microorganisms adhered to all membranes, with Surgitime being the membrane that attracted the highest number of S. mutans (p < 0.001) and P. gingivalis (p < 0.001). By contrast, OsseoGuard-TXT was one of the membranes that attracted the lowest number (p < 0.001) of all three tested species. Conclusions: The results showed that microbial adhesion to PTFE membranes was affected by the membrane surface roughness and SFE, as well as the characteristics of the microorganisms. The most hydrophilic bacteria adhered the least to all the tested membranes, whereas membranes with a low surface roughness and high SFE attracted the lowest number of all the tested microbes. These results may guide the selection of an appropriate GBR membrane. Full article

A prime role of biological membranes is to form barriers for material transport into and out of cells. Membranes consist of phospholipids with polar heads, which are presented to the aqueous solutions, and hydrophobic tails that form the membrane core. This construct prevents the permeation of hydrophilic, well-solvated molecules across the lipid hydrophobic barrier. The barrier is not absolute, and several approaches are available for efficient translocation. Channels and pumps enable selective and efficient transport across membranes. Another transport mechanism is passive permeation, in which permeants, without assistance, directly transport across membranes. Passive transport is coupled to transient defects in the membrane structure that make crossing the hydrophobic bilayer easier—for example, displacements of head groups from aqueous solution–membrane interface into the membrane core. The defects, in turn, are rare unless assisted by passively permeating molecules such as cell-penetrating peptides that distort the membrane structure. One possible defect is a phospholipid molecule with a head pointing to the hydrophobic core. This membrane distortion allows head group flipping from one layer to the other. We show computationally, using atomically detailed simulations and the Milestoning theory, that the presence of a cell-penetrating peptide in a membrane greatly increases phospholipid flip-flop rate and hence defect formation and the permeability of membranes. Full article

Graphene oxide (GO) films have attracted significant attention due to their potential in separation and filtration applications. Based on their unique lamellar structure and ultrathin nature, GO films are difficult to maintain in a free-standing form and typically require substrate support. Consequently, understanding their film formation behavior and mechanisms on substrates is of paramount importance. This work employs commonly used nonwoven fibrous membranes as substrates and guided by the coffee-ring theory, systematically investigates the film formation behaviors, film morphology, and underlying mechanisms of GO films on fibrous membranes with varying wettability. Fibrous membranes with different wetting properties—hydrophilic, hydrophobic, and superhydrophobic—were prepared via electrospinning and initiated chemical vapor deposition (iCVD) surface modification techniques. The spreading behaviors, deposition dynamics, capillary effects, and evaporation-induced film formation mechanisms of GO suspensions on these substrates were thoroughly examined. The results showed that GO formed belt-like, ring-like, and circular patterns on the three fibrous membranes, respectively. GO films encapsulated more than the upper half, approximately the upper half, and the top portion of fibers, respectively. Pronounced wrinkling of GO films was observed except for those on the hydrophilic fibrous membrane. This work demonstrates that tuning the wettability of fibrous substrates enables precise control over GO film morphology, including fiber encapsulation, wrinkling, and coverage area. Furthermore, it deepens the understanding of the interactions between 1D nanofibers and 2D GO sheets at low-dimensional scales, laying a foundational basis for the optimized design of membrane engineering. Full article

Membrane technology has received great attention in the desalination and water treatment sectors over the last few decades. However, membrane fouling remains a critical issue that affects membrane performance, a phenomenon common in membrane bioreactors (MBRs). This major drawback can be overcome by the preparation of antifouling membranes using an electrospinning technique that generates a hydrophilic modification of membranes. In this study, nanocomposite polyvinylidene fluoride (PVDF) and cellulose acetate (CA) polymer was fabricated to mitigate membrane fouling. Surface and mechanical characterization of the electrospun membrane was performed to assess morphology, chemical composition, and hydrophilic/hydrophobic properties. Anti-fouling performance of the composite PVDF/CA membrane was evaluated versus a neat PVDF membrane through bench-scale experiments. The PVDF/CA nanofiber membrane displayed a more hydrophilic nature, demonstrated by a lower water contact angle (101° vs. 115°) and increased wastewater flux (190 L/m²·h. vs. 160 L/m²·h), although the composite membrane demonstrated lower tensile strength (2.0 ± 0.1 MPa vs. 1.7 ± 0.1 MPa). The new material demonstrated greater anti-fouling performance compared to the neat PVDF membrane. Results suggest that this nanofiber material shows promise as an enhanced antifouling membrane that can overcome membrane fouling limitations. Full article

Curcumin exhibits compromised bioavailability upon oral administration due to its inherent limitations, including low aqueous solubility, poor membrane permeability, and chemical instability. Inspired by the efficient mechanism by which viruses penetrate mucus and cells, we constructed an electrically neutral and hydrophilic nanocarrier (C60-CPP5/Pser@CUR) using fullerene C60 as the matrix modified with cell-penetrating peptides and phosphoserine. CPP5 facilitates efficient cellular internalization of therapeutic agents, while the incorporation of phosphoserine serves as a charge reversal strategy. This design enables dynamic surface charge modulation to enhance curcumin’s trans-barrier delivery efficiency. Systematic in vitro and in vivo evaluations demonstrated that the synthesized carrier significantly improved the synergistic effects of mucus penetration and cellular uptake. The Caco-2 cellular uptake of curcumin-loaded carriers was 2.26 times higher than that of free drugs. In a single-pass intestinal perfusion study in rat models, this nanocarrier significantly enhanced the absorption of curcumin in the duodenal and colonic regions. In the in vivo experiments, compared with free curcumin, its C_max and AUC_0–t achieved improvements of 2.60 times and 14.70 times, respectively. This virus-mimetic platform dynamically adapts to micro-environmental demands through charge reversal mechanisms, effectively overcoming sequential biological barriers and providing a robust strategy for oral delivery of hydrophobic therapeutics. Full article

Wood-based membranes have garnered increasing attention due to their structural advantages and durability in the efficient treatment of oily kitchen wastewater. However, conventional fabrication methods often rely on toxic chemicals or synthetic processes, generating secondary pollutants and suffering from fouling, which reduces performance and increases resource loss. In this study, an innovative bilayer membrane was developed from balsa wood by combining a hydrophilic longitudinal layer for water transport with a polydimethylsiloxane (PDMS)-impregnated carbonized transverse layer to enhance hydrophobicity, resulting in increased separation efficiency and a reduction in fouling by 98.38%. The results show a high permeation flux of 1176.86 Lm^–2 h^–1 and a separation efficiency of 98.60%, maintaining low fouling resistance (<3%) over 20 cycles. Mechanical tests revealed a tensile strength of 10.92 MPa and a fracture elongation of 10.42%, ensuring robust mechanical properties. Wettability measurements indicate a 144° contact angle and a 7° sliding angle with water on the carbonized side, and a 163.7° contact angle with oil underwater and a 5° sliding angle on the hydrophilic side, demonstrating excellent selective wettability. This study demonstrates the potential of carbonized wood-based membranes as a sustainable, effective alternative for large-scale wastewater treatment. Full article

Solar-driven interfacial evaporation has emerged as a sustainable and highly efficient technology for seawater desalination, attracting considerable attention for its potential to address global water scarcity. However, challenges such as low evaporation rates and salt accumulation significantly hinder the performance and operational lifespan of evaporators. Here, we present an innovative Janus-structured evaporator featuring distinct operational mechanisms through the integration of a hydrophobic PVDF-HFP@PPy photothermal membrane and a hydrophilic PVA-CF@TA-Fe³⁺ hydrogel, coupled with a unidirectional flow configuration. Distinct from conventional Janus evaporators that depend on interfacial water transport through asymmetric layers, our design achieves two pivotal innovations: (1) the integration of a lateral fluid flow path with the Janus architecture to enable sustained brine replenishment and salt rejection and (2) the creation of dual vapor escape pathways (hydrophobic and hydrophilic layers) synergized with hydrogel-mediated water activation to elevate evaporation kinetics. Under 1 sun illumination, the evaporator achieves a maximum evaporation rate of 2.26 kg m⁻² h⁻¹ with a photothermal efficiency of 84.6%, in both unidirectional flow and suspension modes. Notably, the evaporation performance remains stable across a range of saline conditions, demonstrating remarkable resistance to salt accumulation. Even during continuous evaporation of highly saline water (10% brine), the evaporator maintains an evaporation rate of 2.10 kg m⁻² h⁻¹ without observable salt precipitation. The dual anti-salt strategies—enabled by the Janus structure and unidirectional flow design—underscore the evaporator’s capability for sustained high performance and long-term stability in saline environments. These findings provide valuable insights into the development of next-generation solar evaporators that deliver high performance, long-term stability, and robustness in saline and hypersaline environments. Full article

Developing an oral fibrous barrier membrane that prevents bacterial invasion while possessing antibacterial properties and facilitating fluid decompression remains a significant clinical and scientific challenge. In this study, we developed a novel Janus membrane by modifying a polypropylene (PP) fibrous membrane with dopamine and zinc oxide nanoparticles (ZnO-NPs). Fabricated via a simple floating immersion method, this asymmetric bilayer structure consists of a hydrophobic PP layer and a hydrophilic PP/dopamine@30 nm ZnO layer, providing both antibacterial properties and enhanced fluid filtration. The mechanical properties of the PP/ZnO membrane were significantly enhanced, with an increase in the Young’s modulus and ultimate tensile strength, indicating improved strength. Antibacterial activity against Streptococcus mutans (S. mutans) demonstrated a significant reduction in biofilm formation on the PP/dopamine@30 nm ZnO surface compared to unmodified PP. Water flux tests confirmed a stable, high filtration rate, with increased permeability under rising pressure. In vivo experiments with miniature pigs confirmed reduced bacterial presence on the sterile side of the membrane. These findings highlight the potential of the membrane for oral exudate filtration, extending filtration time and minimizing infection risks under strict sterility conditions. Further improvements in barrier properties are necessary to optimize its clinical performance. Full article

Janus nanorods are a special class of nanorods composed of two distinct surface regions, one hydrophilic and one hydrophobic. This amphiphilic characteristic makes them promising candidates for stabilizing water–oil interfaces. Oily wastewater (OWW) contamination, resulting from industrial activities such as petroleum extraction and refining and vegetable oil processing, poses significant risks to ecosystems, water resources, and public health. Traditional surfactants used in enhanced oil recovery (EOR) and wastewater treatment often introduce secondary pollution due to their persistence and toxicity. In this work, we investigate the interfacial behavior of Janus NRs under two different conditions: a thin oil film surrounded by water and a nanoconfined system with purely repulsive walls. Using dissipative particle dynamics (DPD) simulations, we analyze how nanorod length and confinement influence interfacial tension and self-assembly. In bulk systems, shorter NRs (dimers and quadrimers) effectively reduce interfacial tension by adsorbing at the oil–water interface, while longer NRs (hexamers) exhibit bulk aggregation, limiting their surfactant efficiency. In contrast, under nanoconfinement, all NR sizes increase interfacial tension due to steric constraints, with longer NRs preferentially adsorbing onto the solid–liquid interface. These results pave the way for the rational design of nanostructured materials for applications in enhanced oil recovery, wastewater treatment, and membrane filtration. Full article

This study focused on synthesizing polyvinyl alcohol (PVA) utilizing glutaraldehyde (GA) as a crosslinking agent and silicon dioxide (SiO₂) nanopowder with titanium dioxide (TiO₂) nanopowder to reduce or prevent the hydrophilic property of PVA. Integrating SiO₂ and TiO₂ into the PVA boosted the hydrophobicity, thermal properties, and self-cleaning of the PVA film. The characteristic properties of PVA/GA, PVA/SiO₂/GA, and PVA/SiO₂/TiO₂/GA nanocomposites polymer membranes were investigated by gel content, swelling capacity, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction patterns (XRD), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and contact angle. The resulting PVA/5%SiO2/1%TiO₂/GA nanocomposite exhibits much better physical properties than PVA/GA hydrogel (water absorbency from 3.1 g/g to 0.07 g/g and contact angel from 0° to 125°). In addition, the nanocomposite retains very low swelling properties. These prepared nanocomposites are promising in a variety of applications such as sand soil stabilizers, construction, and building works where they exhibit excellent water resistance performance. This study introduces a novel approach for creating hydrophobic polymeric membranes from hydrophilic polymeric materials to stabilize sandy soil effectively. Full article