Amphiphilic Layer Research Articles

Potential of an Amphiphilic Artificial Corneal Endothelial Layer as a Replacement Option for Damaged Corneal Endothelium.

Bullous keratopathy, a condition severely impacting vision and potentially leading to corneal blindness, necessitates corneal transplantation. However, the shortage of donor corneas and complex surgical procedures drive the exploration of tissue-engineered corneal endothelial layers. This study develops a transparent, amphiphilic, and cell-free membrane for corneal endothelial replacement. The membrane, securely attached to the posterior surface of the cornea, is created by mixing hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethylacrylate (EGDMA) in a 10:1 ratio. A 50µL volume is used to obtain a 60µm hydrophobic membrane on both sides, with one side treated with a polyvinylpyrrolidone (PVP) solution. The resulting membrane is transparent, foldable, biocompatible, amphiphilic, and easily handled. When exposed to 20% sulfur hexafluoride (SF6), the hydrophilic side of the membrane adheres tightly to the corneal Descemet's membrane, preventing water absorption into the corneal stroma, and thus treating bullous keratopathy. Histological test confirms its effectiveness, showing normal corneal structure and low inflammation when implanted in rabbits for up to 100 d. This study showcases the potential of this membrane as a viable option for corneal endothelial replacement, offering a novel approach to address donor tissue scarcity in corneal transplantation.

Influence of gamma radiation on self-assembled molecular layers developed on different metals

In this work, self-assembled molecular layers (SAMs), developed from special amphiphilic molecules (undecenyl phosphonic acid) on the top of two types of stainless steels (1.4571 and 1.4841) were in focus. The metal surface was modified by a self-assembled molecular layer with a double bond at the end of the carbon chain. The modification of the structure of the unsaturated hydrophobic chain was done by gamma irradiation to produce a more compact layer. We were interested in the influence of the metal composition on the layer formation. To give answers to these questions SAM layers were deposited on the top of the stainless steels and then the nanolayers were modified by post-treatment (gamma irradiation). The thickness of the surface films was characterized by ellipsometry and the composition of the amphiphilic SAM layers by infrared spectroscopy. Atomic Force Microscope (AFM) visualized the morphological changes due to the layer deposition and the post-treatment; the surfaces were numerically characterized by roughness parameters; contact angle values proved the change in the wettability caused by the metal surface and the gamma irradiation.

Fatty acid-arginine vesicles with prominent encapsulation efficiency and substantial transdermal delivery of sinomenine hydrochloride

In clinical practice, sinomenine hydrochloride (SH) is a valuable and promising medication for rheumatoid arthritis. However, oral administration of SH is less bioavailable with adverse reactions to the digestive system, blood circulation, and nervous system, among which rash, gastric ulcer, gastric haemorrhage and anaphylactic shock are the most common. Owing to a short half-life in the human body (0.791 h), patient compliance is greatly reduced, resulting in frequent administration for patient treatment. Therefore, SH encapsulated in vesicles with amphiphilic layers would be more stable and have fewer side effects. In this study, a transdermal drug delivery system (TDDS) for SH was designed utilizing fatty acid vesicles as carriers. The physicochemical properties and aggregate morphology of two carriers: arginine-oleic acid ([Arg][Ole]) and arginine-decanoic acid ([Arg][Dec]) were investigated, and the SH encapsulation method by the above materials was optimized and verified by single factor and central composite design (CCD) response surface methods. Notably, the encapsulation efficiency (EE) of SH in [Arg][Dec] vesicles was increased to 83.5 % and the centrifugal stability (CS) to 90.4 %. Moreover, as a result of the Conductor-like screening model for real solvents (COSMO-RS) calculation, it was found that the interaction between [Arg][Dec] and SH was stronger than that of [Arg][Ole], aligning with experimental results. In comparison to the sustained release period in water, the in vitro release experiment showed that the [Arg][Ole] and [Arg][Dec] vesicles could be prolonged to 17 hours. Importantly, the cumulative skin permeability of [Arg][Dec] vesicles reached 1665.59 μg·cm−2 after 48 h, which is much higher than the previous literature value of around 663 μg·cm−2. These results suggest that vesicles provide a viable method for transdermal delivery of SH.

An amphiphilic interface for constructing a uniform composite solid-state electrolyte towards long-life all-solid-state sodium metal batteries

A polydopamine amphiphilic compatibility layer was applied to meliorate filler dispersion, and enhance the electrochemical performance and stability of all-solid-state sodium metal batteries.

Effect of ion to ligand ratio on the aqueous to organic relative solubility of a lanthanide-ligand complex.

In the solvent extraction of rare earth elements, mechanistic aspects remain unclear regarding where and how extractant molecules coordinate metal ions and transport them from the aqueous phase into the organic phase. Molecular dynamics simulations were used to examine how unprotonated di(2-ethylhexyl)phosphoric acid (DEHP-) ligands that coordinate the Gd3+ ion can transfer the ion across the water-organic interface. Using the umbrella sampling technique, potential of mean force profiles were constructed to quantify the relative solubility of the Gd3+ ion coordinated to 0-3 DEHP- ligands in either water, 1-octanol, or hexane solvents and at the water-organic interfaces. The simulations show the Gd-DEHP- complexes, at varying Ln-ligand ratios, preferentially solvate on water-organic interfaces. While the Gd(DEHP-)3 complex will diffuse past the aqueous-organic interface into the octanol solvent, it is thermodynamically preferred for the Gd(DEHP-)3 complex to remain in the water-hexane interface when there is no amphiphilic layer of excess ligand.

Constructing amphipathic molecular layer to assists de-solvation process for dendrite-free Zn anode

Due to the excellent safety feature, substantial theoretical capacity and abundant zinc reserves in the earth's crust, Aqueous Zn-ion batteries (AZIBs) are promising as the next generation energy storage system. However, the problem of dendrite growth and the related side reactions in Zn surface limit their further development and application. Herein, an amphipathic molecular layer (Polyacrylic Acid, named as PAA) is constructed on Zn surface to hinder the side reactions and zinc dendrites by intervening the de-solvation process. It is found that the rich hydroxyl group in polyacrylic acid is very hydrophilic. On the contrary, hydrocarbon group on the other side is nearly hydrophobic. The amphiphilic PAA molecular layer on Zn surface results in lower de-solvation energy barrier, thus inhibits the decomposition of water and related side reactions. Additionally, the accumulate abundant negative charge at the interface of polyacrylic acid and Zn surface can attract homogeneous deposition of Zn atoms. Using only 0.01 M PAA as additive in 2.0 M ZnSO4 electrolyte. Zn||Zn symmetric cells expresses a superior cycling stability of 4643 h (5 mA cm−2, 1 mAh cm−2). This study provides new insights into the long-life AZIBs modulated by amphipathic molecular layer.

Fabrication of silver nanoparticle-containing electrospun polycaprolactone membrane coated with chitosan oligosaccharides for skin wound care

An ideal wound dressing should have several qualities to protect the wound from infection and other adverse factors. This study aimed to fabricate a wound care membrane combining the two well-known bioactive agents silver nanoparticles (AgNPs) and chitosan oligosaccharides (COS). In specific, this multilayer membrane (PCL-Ag/POX/COS) consisted of (1) the electrospun basement layer of poly(ε-caprolactone) (PCL) and AgNPs; (2) the intermediate amphiphilic layer of PCL and poloxamer 407 (POX); and (3) the coating layer of COS and poly(N-vinyl pyrrolidone) (PVP). Several characterisation tests showed that the membrane was successfully coated with COS and owned suitable characteristics as a wound dressing, including proper tensile strength (more significant than the typical value of the skin), the hydrophilic and fluid-absorbable innermost surface, the waterproof outermost basement, vapour permeability, rapid COS release, and gradual AgNP release. In vitro experiments proved its haemostatic effect and antibacterial activities. Though its 100% extract solution reduced in vitro fibroblast viability, through the skin-defected mouse model experiment, PCL-Ag/POX/COS was compatible with the wound tissue and exhibited several positive effects on wound healing. In conclusion, PCL-Ag/POX/COS was proven for its potential for wound care, but it needs further investigations to allow translation from bench to bedside.

Structural and functional changes on polyhydroxy alcohol-mediated curing pork myofibrillar protein: Experimental and molecular simulation investigations

This study aimed to investigate the structural and functional changes in polyhydroxy alcohol-mediated curing on pork myofibrillar proteins (MP). The results obtained from total sulfhydryl groups, surface hydrophobicity, fluorescence and Raman spectroscopies, and solubility demonstrated that the polyhydroxy alcohols (especially xylitol) significantly modified the MP tertiary structure, making this structure more hydrophobic and tighter. However, no significant differences were detected in the secondary structure. Furthermore, the thermodynamic analysis revealed that polyhydroxy alcohols could develop an amphiphilic interfacial layer on the MP surface, significantly increasing the denaturation temperature and enthalpy of denaturation (P < 0.05). On the other hand, the molecular docking and dynamics simulations showed that polyhydroxy alcohols interact with actin mainly through hydrogen bonds and van der Waals forces. Therefore, this could help reduce the effect of high-content salt ions on MP denaturation and improve the cured meat quality.

Magnetic-driving giant multilayer polyelectrolyte microcapsules for intelligent enhanced oil recovery

With the worldwide energy crisis breaking out, the global demand for petroleum is increasing tremendously. However, it is still a major challenge to improve oil recovery from oil reservoirs in the petroleum industry. Here, the multilayer giant polyelectrolyte microcapsules (PEM), sodium dodecyl benzene sulfonate-Fe3O4 @ (polyacrylamine hydrochloride/polystyrene sulfonate)3-poly(N-isopropylacrylamide-co-diallyl dimethyl ammonium chloride) (SFe@(PAH/PSS)3-PND), were prepared through electrostatic self-assembly technique. PND was polymerized from N-isopropylacrylamide (NIPAM) and dimethyl diallyl ammonium chloride (DMDAAC). The oil recovery efficiency of the polyelectrolyte microcapsules was all higher than 50 %, and which was significantly increased to over 70 % after heating above the lower critical solution temperature (LCST). Attributed to the temperature-adjusted intelligent mechanisms of the NIPAM molecular in PND, the contraction of NIPAM molecular chains affected with high temperature, coupled with the reduction of microcapsule volume, led to expansion of the pores in the capsule walls, which significantly increased the permeability of SDBS. Meanwhile, oil droplets combined with SDBS were encapsuled with the hydrophobic PND layer based on hydrophobic interaction, part of which entered into amphiphilic phospholipid core layer. Inspired by cellular cytokinesis, the SFe@ (PAH/PSS)3-PND was capable of intelligently capturing and carrying oil droplets driven with magnetism. The oil recovery efficiency of SFe@ (PAH/PSS)3-PND significantly improved and were all more than 78 % after heating above the LCST With magnetron drive, which is much higher than the traditional method. Hence, this work revealed the novel approaches in potential applications for intelligent enhanced oil recovery (EOR) in the petroleum industry.

Heat transport and magnetohydrodynamic hybrid micropolar ferrofluid flow over a non-linearly stretching sheet

&lt;abstract&gt; &lt;p&gt;A stable colloid called ferrofluid is made up of tiny magnetic particles, often magnetite (Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;), that have been bonded with an amphiphilic dispersion layer and are then suspended in a suitable liquid solvent carrier. Current industrial uses for ferrofluid include dynamic sealing, inertial and viscous damping, magnetic drug targeting, liquid microrobots, etc. In this article, we studied the heat transfer and MHD micropolar ferrofluid flow caused by non-linearly stretching surface. The results are presented for hybrid alumina- copper/ethylene glycol (${Al}_2 {O}_3$-Cu/EG) nanofluid. The governing non-linear equations describing flow are transformed into a system of ordinary differential equations using similarity transformations. Using the BVp4c method, the microstructure and inertial properties of a magnetite ferrofluid across a non-linear stretched sheet are studied. The influence of relevant parameters on stream function, velocity, micro-rotation velocity, and temperature are obtained and represented graphically. The computed results are original, and it has been observed that if we increase the magnetic parameter, the stream function and the velocity decrease, while the temperature and micro-rotation velocity increase. As the Prandtl number increases, the temperature profile decreases. It has been observed that the Nusselt number or heat transfer rate of hybrid nanofluid is better as compared to nanofluid flow.&lt;/p&gt; &lt;/abstract&gt;

Multidimensional Self-Propelled Motion Based on Nonlinear Science

Self-propelled objects, which exhibit characteristic features of motion, are proposed based on nonlinear science. At first, a self-propelled object with length like undulatory swimming is designed, i.e., the phase of oscillation at several points on the object is propagated in the opposite direction of motion. Second, the vertical oscillation of a camphor disk is created at an amphiphilic molecular layer developed on water. The proposed systems suggest that nonlinearity can enhance the autonomy of self-propelled objects as multidimensional motion.

Self-Propelled Motion Sensitive to the Chemical Structure of Amphiphilic Molecular Layer on an Aqueous Phase.

Two novel amphiphiles, N-(3-nitrophenyl)stearamide (MANA) and N,N′-(4-nitro-1,3-phenylene)distearamide (OPANA), were synthesized by reacting nitroanilines with one or two equivalents of stearic acid. We investigated how the molecular structures of these compounds influenced the characteristics of a self-propelled camphor disk placed on a monolayer of the synthesized amphiphiles. Three types of motion were observed at different surface pressures (Π): continuous motion (Π < 4 mN m−1), deceleration (4 mN ≤ Π ≤ 20 mN m−1), and no motion (Π > 20 mN m−1). The speed of the motion of the camphor disks was inversely related to Π for both MANA and OPANA at the temperatures tested, when Π increased in the respective molecular layers under compression. The spectroscopic evidence from UV-Vis, NMR, and ESI-TOF-MS revealed that the dependence of the speed of the motion on Π originates from the intermolecular interactions that are present in the monolayers. This study suggests that it is possible to control the self-propelled motion by manipulating contributing factors at the molecular level.

Polyimide-free liquid crystal devices with carbon nanotube-based electrodes

A novel type of polyimide-free liquid crystal (LC) device has been fabricated using layer-by-layer (LBL) deposition of carbon nanotube-based electrodes and in situ formation of self-aligning amphiphilic graft copolymer layer. The LBL-processed organic electrodes showed high transparency comparable to indium tin oxide (ITO) and the self-aligned layer of amphiphilic graft copolymer on organic electrodes provided a stable vertical alignment of LCs. Moreover, the proposed LC device resulted in voltage-dependent driving characteristics suitable for display application. This functional organic electrode layer has potential for application in a flexible display to replace conventional ITO electrode and polyimide alignment layer.

Printing zwitterionic self-assembled thin film composite membranes: Tuning thickness leads to remarkable permeability for nanofiltration

Zwitterionic copolymer self-assembled membranes have been shown to have impressive selectivity for nanofiltration applications. Conventional approaches used to fabricate these asymmetric membranes, such as casting followed by phase inversion, typically result in thick selective layers being formed that can limit permeance. In this work, we evaluate the use of electrospray to print thin layers of amphiphilic zwitterionic selective layers onto UF membrane substrates. Dyes are used to probe the rejection of these membranes while their thickness is reduced by orders of magnitude compared to casting methods. As thickness is decreased, water permeance was found to proportionally increase while dye rejection was maintained for some dyes. It was found that a threshold minimum thickness was required to maintain rejection for some dye molecules while the intrinsic permeability of the polymer films changed as a function of thickness. Annealing the membranes was found to increase permeance as well without a significant loss of rejection. Notably, one of our annealed ultra-thin TFC membranes was found to exhibit a water permeance value of 180 LMH/bar and a chlorophyllin rejection at 99.67%. Interestingly, this permeance is indistinguishable from the supporting UF membrane permeance, suggesting that even higher permeance without rejection loss is possible with more permeable support layers.

Amphiphilic Ti porous transport layer for highly effective PEM unitized regenerative fuel cells.

Polymer electrolyte membrane unitized regenerative fuel cells (PEM-URFCs) require bifunctional porous transport layers (PTLs) to play contradictory roles in a single unitized system: hydrophobicity for water drainage in the fuel cell (FC) mode and hydrophilicity for water supplement in the electrolysis cell (EC) mode. Here, we report a high-performance amphiphilic Ti PTL suitable for both FC and EC modes, thanks to alternating hydrophobic and hydrophilic channels. To fabricate the amphiphilic PTL, we used a shadow mask patterning process using ultrathin polydimethylsiloxane (PDMS) brush as a hydrophobic surface modifier, which can change the Ti PTL's surface polarity without decreasing its electrical conductivity. Consequently, performance improved by 4.3 times in FC (@ 0.6 V) and 1.9 times in EC (@ 1.8 V) from amphiphilic PTL. To elucidate reason for performance enhancement, discrete gas emission through the hydrophobic channels in amphiphilic PTL was verified under scanning electrochemical microscopy.

Langmuir-Blodgett monolayers holding a wound healing active compound and its effect in cell culture. A model for the study of surface mediated drug delivery systems

Langmuir and Langmuir-Blodgett films holding a synthetic bioinspired wound healing active compound were used as drug-delivery platforms. Palmitic acid Langmuir monolayers were able to incorporate 2-methyltriclisine, a synthetic Triclisine derivative that showed wound healing activity. The layers proved to be stable and the nanocomposites were transferred to solid substrates. Normal human lung cells (Medical Research Council cell strain 5, MRC-5) were grown over the monomolecular Langmuir-Blodgett films that acted as a drug reservoir and delivery system. The proliferation and migration of the cells were clearly affected by the presence of 2-methyltriclisine in the amphiphilic layers. The methodology is proposed as a simple and reliable model for the study of the effects of bioactive compounds over cellular cultures.

In situ amphiphilic modification of thin film composite membrane for application in aqueous and organic solvents

Conventional support (uncrosslinked) based polyamide (PA) thin film composite (TFC) membranes are indispensable for desalination and purification of water. In addition to water purification, an emerging application of TFC membrane is the nanofiltration of organic solvents if the support layer is solvent resistant. However, solvent resistant PA TFC membranes show good permeate flux of polar solvents but low flux of non-polar solvents. We report that amphiphilic PA barrier layer is required to obtain good permeate flux of polar and nonpolar solvents. Herein, a facile approach for the in situ amphiphilic modification of PA layer of TFC membrane for application in aqueous and organic (polar and non-polar) medium is reported. Amphiphilic PA layers have been fabricated on conventional polysulfone (PSf) and solvent resistant polyimide (PI) supports. Interfacial polymerization (IP) between mixture of m-phenylenediamine (MPD) and MPD-capped polyethylene glycol (MPD-PEG-MPD) and mixture of trimesoyl chloride (TMC) and TMC-capped polydimethylsiloxane (TMC-PDMS-TMC) produces amphiphilic TFC membranes. Hydrophobic TFC membranes have been prepared by the IP between MPD and mixture of TMC and TMC-PDMS-TMC. The TFC membranes exhibit tunable water wetting behavior (water contact angle = 61-110o) depending on the composition of the organic phase. Amphiphilic TFC membranes show surface rearrangement/reconstruction behavior in contact with water and non-polar solvent. The amphiphilic membranes show good antifouling property with reduction of flux to about 14% and recovery in the flux to about 97% during desalination of water containing bovine serum albumin. The hydrophobic and amphiphilic TFC membranes (solvent resistant) showed significant improvement in the permeate flux of toluene and hexane. Particularly, amphiphilic solvent resistant membranes are suitable for application in water and nanofiltration of polar and non-polar solvents.

Hierarchical Surface Inspired by Geminized Cationic Amphiphilic Polymer Brushes for Super-Antibacterial and Self-Cleaning Properties.

Pathogenic bacteria adhesion and formation of biofilm on the implant are the most common reasons for healthcare-associated device failure. Cationic amphiphilic polymer brushes containing covalently linked quaternary ammonium salts (QASs) are considered to be the most promising bactericidal materials, but these surfaces still suffer from incomplete bactericidal ability and serious microorganism accumulation. With this in mind, a novel kind of hierarchical surface integrating both geminized cationic amphiphilic antibacterial upper layer and zwitterionic antifouling sublayer has been developed in this study. Measurements of X-ray photoelectron spectroscopy, spectroscopic ellipsometry, atomic force microscopy, water contact angle, and surface ζ-potential were performed to investigate the surface functionalization process. The thicknesses and grafting densities of the pAGC8 upper blocks have been optimized to avert the mutual interference among different components. The optimal hierarchical surface exhibits an ultrahigh antibacterial activity and a potent self-cleaning functionality against both Staphylococcus aureus and Escherichia coli bacteria, as well as a certain protein repellence ability. Such a novel hierarchical architecture provides innovative guidance for the construction of super-antibacterial and self-cleaning brushes in many biomedical applications.

Cross-Link-Functionalized Nanoparticles for Rapid Excretion in Nanotheranostic Applications.

Most NIR-IIb fluorophores are nanoparticle-based probes with long retention (≈1 month or longer) in the body. Here, we applied a novel cross-linked coating to functionalize core/shell lead sulfide/cadmium sulfide quantum dots (PbS/CdS QDs) emitting at ≈1600 nm. The coating was comprised of an amphiphilic polymer followed by three crosslinked amphiphilic polymeric layers (P3 coating), imparting high biocompatibility and >90 % excretion of QDs within 2 weeks of intravenous administration. The P3 -QDs were conjugated to an engineered anti-CD8 diabody (Cys-diabody) for in vivo molecular imaging of CD8+ cytotoxic T lymphocytes (CTLs) in response to anti-PD-L1 therapy. Two-plex molecular imaging in combination with down-conversion Er nanoparticles (ErNPs) was performed for real-time in vivo monitoring of PD-L1 positive tumor cells and CTLs with cellular resolution by non-invasive NIR-IIb light sheet microscopy. Imaging of angiogenesis in the tumor microenvironment and of lymph nodes deep in the body with a signal-to-background ratio of up to ≈170 was also achieved using P3 -QDs.

Cross‐Link‐Functionalized Nanoparticles for Rapid Excretion in Nanotheranostic Applications

AbstractMost NIR‐IIb fluorophores are nanoparticle‐based probes with long retention (≈1 month or longer) in the body. Here, we applied a novel cross‐linked coating to functionalize core/shell lead sulfide/cadmium sulfide quantum dots (PbS/CdS QDs) emitting at ≈1600 nm. The coating was comprised of an amphiphilic polymer followed by three crosslinked amphiphilic polymeric layers (P3 coating), imparting high biocompatibility and &gt;90 % excretion of QDs within 2 weeks of intravenous administration. The P3‐QDs were conjugated to an engineered anti‐CD8 diabody (Cys‐diabody) for in vivo molecular imaging of CD8+ cytotoxic T lymphocytes (CTLs) in response to anti‐PD‐L1 therapy. Two‐plex molecular imaging in combination with down‐conversion Er nanoparticles (ErNPs) was performed for real‐time in vivo monitoring of PD‐L1 positive tumor cells and CTLs with cellular resolution by non‐invasive NIR‐IIb light sheet microscopy. Imaging of angiogenesis in the tumor microenvironment and of lymph nodes deep in the body with a signal‐to‐background ratio of up to ≈170 was also achieved using P3‐QDs.