Hydrophobic-hydrophilic Interactions Research Articles

Construction of Slide-Ring Polymers Based on Pillar[5]Arene/Alkyl Chain Host-Guest Interactions.

Slide-ring polymers exhibit distinctive mechanical properties, making them highly promising for applications in emerging fields such as energy storage devices and smart sensing. However, existing slide-ring polymer systems primarily rely on hydrophilic-hydrophobic interactions to achieve ring-axle interlocking in aqueous phases. This reliance limits the construction of slide-ring networks mainly to water-soluble polymers, excluding a diverse range of lipophilic polymers. Therefore, it is crucial to introduce efficient construction strategies that facilitate interpenetration in organic solvents, enabling the development of diverse slide-ring polymers and expanding their range and applications. Herein, by utilizing the pillar[5]arene/alkyl chain host-guest interactions, we successfully facilitated the interpenetration of a pillar[5]arene and poly(caprolactone), enabling the efficient construction of two slide-ring polymer networks in organic solvents. One of these two slide-ring polymers demonstrates a unique network deformation mechanism along with outstanding mechanical properties compared with the control covalently cross-linked polymer network, including maximum stress (4.43 vs 1.98 MPa), maximum strain (1285 vs 330 %), and toughness (35.4 vs 3.92 MJ/m3). More importantly, this strategy of making slide-ring polymers is highly versatile, given the wide range of macrocyclic arenes and alkyl chain-containing polymers it can accommodate.

Unique Crystal Structure of a Self-Assembled Dinuclear Cu Peptoid Reveals an Unusually Long Cu···Cu Distance.

Studies on a series of molecular dicopper peptoid complexes showed that the Cu···Cu distances measured in X-ray single-crystal diffraction are typically in the range of 4.2-6.9 Å. Herein, we designed a new peptoid, L1, having 2,2'-bipyridine, propyl, and pyridyl side chains and discovered that although it forms a typical dicopper self-assembled structure (complex 1), the Cu···Cu distance is exceedingly long -8.043 Å. By analyzing its structure and surface properties in comparison to a control Cu-peptoid complex (2), in which the pyridyl side chain is modified by an ethanolic side chain, we suggest that the long Cu···Cu distance is contributed by the hydrophilic-hydrophobic interaction influenced by the pyridyl side chain and the steric hindrance of the propyl side chain. This result may motivate the use of dinuclear Cu peptoid complexes for wider applications, such as cooperative catalysis and luminescence.

Volumetric, compressibility and viscometric studies on intermolecular interactions of NaC and NaDC with Emtricitabine and Lamivudine in aqueous medium at (298.15–313.15) K

Bile salts are bio-compatible natural amphiphiles having a significant role in pharmaceutical field as a solubility and permeability enhancer and possess a great biological importance for release and transport of nutrients due to dynamic micellization behavior. Hence, to unfold the interactional mystery of drug − bile salt system in the field of anti-retroviral drugs, we have aimed to investigate solute–solute and solute–solvent interactions of bile salts (NaC and NaDC) with anti-HIV drugs (Emtricitabine and Lamivudine) by using various techniques like volumetry, compressibility, and viscometry at temperature range (298.15 K-313.15 K) with a regular variation of 5 K. Experimental density and speed of sound data have been used to evaluate various physicochemical parameters such as apparent molar volume (φv), isentropic compressibility (κs), and apparent molar adiabatic compression (φκ). The CMC values of bile salts in pure water and aqueous solution of ECT and LMV at 298.15 K have also been evaluated from speed of sound data which corroborate well with our earlier conductivity study on these surfactants. The trends of φv, κs and φκ values for both NaC and NaDC with temperature and in presence of drugs (ECT/LMV) indicate strong solute–solvent interactions in studied system. The results are elucidated in terms of electrostatic and hydrophilic-hydrophobic interactions in bile salt-drug-water system which is confirmed by co-sphere overlap model. Comparatively, NaC offers strong interactions with both drugs due to more hydrophilic character than NaDC. Similarly, out of ECT and LMV, ECT shows strong solute–solvent interactions with both bile salts due to more hydrophilic character than LMV. Relative viscosity parameter (ηr) determined from viscosity measurements further supports above results. This interactional knowledge of bile salts with ECT and LMV would be beneficial to develop a better mechanism in pharmacy for enhancing efficacy and permeability of anti-HIV drugs by using bile salts as a drug delivery agent.

Fluorescence visualization of CO2-responsive phase transfer materials targeting at the heterogeneous interfacial reactions in advanced oxidation of naphthenic acid in wastewater

Treatment of naphthenic acids (NAs) in wastewater is necessary due to its high toxicity and difficult degradation. In the heterogeneous Fenton-like advanced oxidation of organic pollutant system, the insufficient accessibility of oxidizing agent and NAs greatly hamper the reaction efficiency. CO2-responsive phase transfer materials derived from polyethylene glycol (PEG)-based deep eutectic solvents were specific targeted at the immiscible-binary phase system. The NAs oxidative degradation process was optimized including the kinds of catalyst (Molecular weight of PEG, constitute of DESs, and dosage.), temperature, flow rate of CO2, et al. With the help of fluorescence properties of catalyst, the hydrophilic-hydrophobic interaction was visual-monitored and further studied. The amphipathic property of PEG-200/Sodium persulfate/Polyether amine 230 (PEA230) greatly reduced the aqueous/organic phase transfer barrier between sodium persulfate and NAs (up to 84 %), thus accreting oxidation rate. The surface tension decreased from 35.364 mN/m to 28.595 mN/m. To control the reaction rate, the CO2 respond structure of amido played an important role. In addition, the interfacial transfer intermediates and oxidation pathways were also explored by nuclear magnetic resonance, flourier transform infrared spectroscopy, surface tension, and radical inhibition experiments. The mechanism of advanced oxidation of NAs catalyzed by CO2-responsive phase transfer catalyst was proposed, which would made up for the deficiency of the system theory of heterogeneous chemical oxidation of organic pollutants.

Donor-Acceptor Assembly of Amphiphilic Molecules Based on 9,10-Distyrylanthracene Derivatives with Terminal Naphthalene Groups.

Amphiphilic rod-coil compounds have excellent photophysical properties and can be assembled into supramolecular nanostructures of different sizes in water or polar solvents. Herein, we synthesized the amphiphilic compounds 2N-DSA, 4N-DSA, and 6N-DSA with 9,10-distyrylanthracene (DSA) as the core and a naphthalene unit as the terminal group that connected DSA through a tetraethylene glycol chain. These compounds have excellent aggregation-induced emission (AIE) properties in aqueous solution and are assembled into worm-like fragments or different sizes of spherical assemblies, defending the volume ratio of the rod to coil segments. Notably, the donor-acceptor interaction between DSA and electron- deficient compounds 2,4,6-trinitrophenol (TNP), 2,4,5,7-tetranitrofluorenone (TNF), and tetraethylene glycol dinitrobenzoate (TGDNB) forms a charge transfer complex, which can be used as a nanoreactor to improve the yield of the Suzuki coupling reaction about 8-10 times. The experimental results reveal that the synergy effect of the donor-acceptor, intermolecular π-π stacking, and hydrophobic-hydrophilic interactions significantly influences the morphology of aggregates and the efficiency of the nanoreactor.

Aggregation behavior and thermodynamic parameters of biosurfactants (NaC/NaDC) in aqueous medium of Emtricitabine and Lamivudine (anti-HIV drugs)

Abstract This paper investigates the interactions and aggregation behavior of biosurfactants, sodium cholate (NaC) and sodium deoxycholate (NaDC) in aqueous solutions of Emtricitabine and Lamivudine (anti-HIV drugs). The study uses conductometry and UV–visible spectroscopy techniques to evaluate the critical micelle concentration (CMC) at different temperatures ranging from 298.15 K to 313.15 K with a variation of 5 K. The temperature dependence of the CMC was examined, and the stability of micelles was analyzed in light of the hydrophobic-hydrophilic interactions involved in this system. The CMC obtained from both the methods are in agreement. Various thermodynamic parameters, such as ∆ H m 0 ${\increment}{H}_{m}^{0}$ , ∆ S m 0 ${\increment}{S}_{m}^{0\hspace{0.17em}}$ and ∆ G m 0 ${\increment}{G}_{m}^{0}$ have been estimated using a “pseudo-phase separation model” to understand the contribution of the chemical and de-solvation part in the micellization process. Furthermore, the enthalpy-entropy compensation plots validate the micellar stability of the studied systems.

Chiral aggregates of rod-coil molecules inside nanopores as efficient nanoreactors for asymmetric synthesis.

An important subject of porous organic materials is their capacity to access enantioselectivity due to their high surface area, controllable pore size, and ease of functionalization. However, recyclability of enantio-separation is a challenge, mainly due to the complex procedures of recovery and refreshing from enantiomers. For the first time, we combined nanochannel technology and supramolecular chiral assembly to achieve efficient enantioselectivity. Fine-designed amphiphilic chiral rod-coil molecules 1-3 were immobilized to SBA-15 pore walls to form SA-M1-3 (abbreviation for amino-functionalized SBA-15 connected to molecules 1-3), which commenced chiral aggregation inside the channels. The experimental results indicated that the strong π-π stacking interaction between the rigid terphenyl groups, as well as hydrophilic-hydrophobic interaction of the amphiphiles, assisted in chiral arrangement in aqueous solution, and was accompanied by amplification of chirality. As a result, porous chiral channels exhibiting enhanced efficiency in asymmetric synthesis were manufactured, where enantioselectivity can be controlled by the initial structural design of amphiphiles that induce chiral aggregation behaviors. The chiral centers of SA-M1 and SA-M2 are located on hydrophobic and hydrophilic coils, respectively, while SA-M3 possesses both chiral coils. The SA-M materials proceeded with chiral aggregation and behaved efficiently for enantioselectivity. SA-M3, which contained the most chiral centers, showed the most optimal enantioselectivity with an enantiomeric excess (ee) value up to 71.75%, which occurred because of the strongly driven chiral aggregation of the hydrophobic and hydrophilic chiral coils. The covalent hybrid structures of the SA-M materials can be easily refreshed simply through washing, and exhibited excellent recyclability with negligible loss of efficiency. Therefore, the SA-M materials have the ability to provide sustainable and reliable application value for enantiomer separation.

Lessons Learned in Interfacial Tension Prediction Using a Mixture of Sulfonate- and Ethoxylate-based Surfactants in a Waxy Oil-brine System

The chemical-enhanced oil recovery (CEOR) method is applied to change reservoir rock or fluid characteristics by injecting alkaline, surfactant, and polymer or a combination of two or three of the compounds. Surfactant flooding improves oil recovery by reducing the interfacial tension between oil and water. Selecting reservoir surfactants, especially microemulsions, requires careful screening. This study predicted waxy oil system interfacial tension using surfactant mixtures at below- and above-optimum salinity. To predict the interfacial tension, microemulsion types, HLB, ideal salinity, and HLD were used. The study predicted oil-surfactant-water interfacial tension using SAE, FEO, and their mixtures. We improved the Huh equation by adding a fitting parameter, β, to accommodate the transition from type III to type II microemulsions as salinity increases. With increasing salinity, anionic surfactant’s hydrophilic-hydrophobic interactions change, affecting the values and surfactant layer thickness. This study improved hydrophilic-lipophilic deviation (HLDN) by establishing a fixed interval for nonionic surfactants. Van der Waals attraction, values and interface surfactant layer thickness are connected, reflecting the fact that lower values reduce interfacial tension better. This study also found that surfactant packing at the oil-water interface increases the order of the oil-solution ratio and the microemulsion values with polarity.

Curcumin and resveratrol delivery from multi-functionalized calcium phosphate scaffold enhances biological properties

Natural medicinal compounds (NMCs) can assist effectively in treating bone disorders. NMC release kinetics from a ceramic bone tissue engineering scaffold can be tailored. However, inferior physicochemical properties halt their therapeutic applications and need a carrier system for delivery. We developed a multi-functionalized scaffold to understand the effect of curcumin (Cur) and resveratrol (Rsv) on in vitro biological properties. Polycaprolactone (PCL) nanoparticles encapsulated resveratrol in the polymeric matrix. Nanoparticles showed a hydrodynamic diameter of about 180 nm, −16 mV zeta potential, and up to ∼65 % encapsulation efficiency. Scaffolds made of zinc-doped tricalcium phosphate (Zn-TCP) were coated with curcumin followed by either resveratrol (Cur-Rsv) or resveratrol nanoparticles (Cur-Rsv-NP). NMC-loaded scaffolds exhibited a biphasic release pattern over 60 days. Solubility and hydrophobic-hydrophilic interactions affected the NMC release profile. Resveratrol showed rapid release as compared to curcumin. The treated scaffold increased the cell viability of human fetal osteoblast (hFOB) by 1.8-fold as compared to the control. It exhibited a 6-fold increase in cytotoxicity toward osteosarcoma (MG-63) cells as compared to the untreated scaffold. NMCs loaded scaffold effectively inhibited Staphylococcus aureus from colonizing over the scaffold. Zinc doping enhanced osteoblast growth and prevented bacterial colony formation. Such design principle provided a direction for developing multi-functionalized calcium phosphate (CaP) scaffolds against bone diseases for orthopedic applications.

Effect of Oligomers and Polymers of Ethylene Glycols on Micellar Characteristics of Aqueous Solutions of Sodium Pentadectyl Sulfonate

The influence of oligomers and polymers of ethylene glycols with a different molecular mass on the structural transformations of aqueous solutions of surfactant, sodium pentadecylsulfonate, studied by viscometry and light scattering methods depending on their content in the system. It established that ethylene glycol with a molecular mass of 2,000 and 40,000 does not affect the structure of the system. For ethylene glycol with a molecular mass of 4,000, 6,000, and 20,000, a clearly expressed complex course of the dependence of the intrinsic viscosity of the micelle system on the polymer content was established. It assumed that with the changes in the concentration of ethylene glycols in the system, micelles are compacted due to a change in the balance of hydrophobic-hydrophilic interactions. In parallel with the change in apparent micelle masses and asymmetry coefficients determined by the light scattering method, the intrinsic viscosity also changes depending on the system's composition. The practical application of this research is that it allows the performance properties of sodium pentadecyl sulfonate (SPDS) to be adjusted, thereby expanding and improving its applications.

One-step preparation of a biphasic monolithic separation media for enriching and purifying lupeol in medicine plants

In this study, a monolith consisted of two materials with different separation modes were prepared by a one-step method at both ends of a column. Acrylic acid and 2-hydroxyethyl methacrylate (HEMA) were used as monomers for hydrophilic and hydrophobic parts, respectively. The total pore volumes and porosities of hydrophilic and hydrophobic materials were 3.1098 mL/g and 75.2535 %, 4.4380 mL/g and 72.5317 %, respectively. The prepared monolithic columns had excellent mechanical strength and good permeability, and can bear high flow rates up to 5 mL/min. The biphasic monolith functioned in two retention modes: hydrophilic interaction chromatography (HILIC) and hydrophobic interaction chromatography (HIC), and the dual-mode were realized by switching the ratio of acetonitrile in the mobile phase. The biphasic monolithic column was used as solid phase extraction (SPE) adsorbent for on-line enrichment and purification of lupeol in Chinese herbal medicines (CHM), which showed good adsorption performance and excellent reproducibility. The spiked recoveries were from 88.52 % to 93.68 % under the optimal experimental conditions; the repeatability could reach 100 times. The method showed good linearity in the range of 0.13 ∼ 2.00 × 103 μg /mL with a correlation coefficient of r = 0.9991; the limit of detection (LOD) was 0.023 μg/mL and the limit of quantification (LOQ) was 0.076 μg/mL; the intra-day and inter-day precisions were both less than 1.05 %.

Ultra-short columns for the chromatographic analysis of large molecules

Today, reverse phase liquid chromatography (RPLC) analysis of proteins is almost exclusively performed on conventional columns (100–150 mm) in gradient elution mode. However, it was shown many years ago that large molecules present an on/off retention mechanism, and that only a very short inlet segment of the chromatographic column retains effectively the large molecules. Much shorter columns - like only a few centimetres or even a few millimetres - can therefore be used to efficiently analyse such macromolecules.The aim of this review is to summarise the historical and more recent works related to the use of very short columns for the analysis of model and therapeutic proteins. To this end, we have outlined the theoretical concepts behind the use of short columns, as well as the instrumental limitations and potential applications.Finally, we have shown that these very short columns were also possibly interesting for other chromatographic modes, such as ion exchange chromatography (IEX), hydrophilic interaction chromatography (HILIC) or hydrophobic interaction chromatography (HIC), as analyses in these chromatographic modes are performed in gradient elution mode.

Highly fluorescent composite of boron nitride quantum dots decorated on cellulose nanofibers for detection and removal of Hg(II) ions from waste water

To address the challenge of heavy-metal ions in wastewater, boron nitride quantum dots (BNQDs) were synthesized in-situ on rice straw derived cellulose nanofibers (CNFs) as substrate. The composite system exhibited strong hydrophilic-hydrophobic interactions, as corroborated by FTIR, integrated the extraordinary fluorescence properties of BNQDs with fibrous-network of CNFs (BNQD@CNFs) yielding a surface of 35.147 m2 g−1 of luminescent fibers. Morphological studies revealed uniform distribution of BNQDs on CNFs due to hydrogen bonding, according high thermal stability with peak degradation occurring at 347.7 °C and quantum yield of 0.45. The nitrogen-rich surface of BNQD@CNFs exhibited strong affinity for Hg(II), quenching the fluorescence intensity due to combined inner-filter effect and photo-induced electron transfer. The limit of detection (LOD) and limit of quantification (LOQ) were 4.889 nM and 11.1 5 nM, respectively. BNQD@CNFs concomitantly exhibited adsorption of Hg(II) owing to strong electrostatic interactions, confirmed by X-ray photon spectroscopy. Presence of polar BN bonds favoured 96 % removal of Hg(II) at 10 mg L−1 with maximum adsorption capacity of 314.5 mg/ g. Parametric studies corresponded to pseudo-second order kinetics and Langmuir isotherm with R2 ≈ 0.99. BNQD@CNFs exhibited recovery rate between 101.3 %–111 % for real water samples and recyclability upto 5 cycles, demonstrating high potential in wastewater remediation.

Multifunctional Dendritic Au@SPP@DOX Nanoparticles Integrating Chemotherapy and Low-Dose Radiotherapy for Enhanced Anticancer Activity.

Combined chemoradiotherapy can improve antitumor efficiency and reduce the side effects of monotherapy. In this study, we aimed to construct dendritic peptide-based multifunctional nanoparticles (Au@SPP@DOX) for a prolonged circulation time, enhanced cellular uptake, and targeted cancer therapy. Amphiphilic micelle PEG-polylysine-SA (SPP) is composed of polylysine combined with hydrophilic poly(ethylene glycol) (PEG) and hydrophobic stearic acid (SA). Doxorubicin (DOX) is loaded via the hydrophilic-hydrophobic interaction of SPP, and gold nanoparticles (AuNPs) are loaded via the electrostatic interaction with SPP. Au@SPP@DOX showed good biocompatibility and could be successfully accumulated at tumor sites through the enhanced permeability and retention (EPR) effect. Then, lysosomes could be ruptured due to the proton sponge effect. DOX became protonated in response to tumor extracellular acidity and was then released from SPP. Under the action of low-dose radiation, Au@SPP@DOX could promote the production of reactive oxygen species (ROS), increase mitochondrial dysfunction, block cell division, and ultimately promote tumor cell apoptosis to achieve a better antitumor effect. This study highlighted the benefit of chemoradiotherapy and suggested that Au@SPP@DOX might serve as a high-efficiency codelivery system for cancer combination therapy in the future.

Construction the hierarchical architecture of molybdenum disulfide/MOF composite membrane via electrostatic self-assembly strategy for efficient molecular separation

• Electrostatic LBL self-assembly strategy is firstly employed to integrate MoS 2 with CMOF. • Superior rejection rates are increased above 27–55% more than that of monomer membranes for FQs. • Synergy of size exclusion, electrostatic repulsion, and hydrophilic interaction is explained. • High stability in harsh environments for 72 h and over 90% rejection against FQs in the real sample. Developing a novel nanofiltration membrane for effectively purifying antibiotic wastewater has been a daunting challenge in recent years. However, a convenient and controllable strategy for constructing membranes with two-dimensional nanomaterials (2DNMs) and metal–organic frameworks (MOFs) needs to be further studied. Herein, a loosely hierarchical architecture composite membrane has been fabricated, utilizing an electrostatic layer-by-layer (LBL) self-assembly method to intercalate chitosan crosslinked UiO-66-NH 2 MOFs (CMOF) into MoS 2 laminates. Through regulating the CMOF content, lower hydraulic-resisted channels and precise separation regions have been formed in the hierarchical architecture. The well-designed MoS 2 /CMOF composite membrane exhibited enhanced water permeance (78.98 ± 1.45 L·m -2 h −1 bar −1 ) and superior antibiotic rejection capability (98.01 ± 1.12% for ciprofloxacin and 94.31 ± 0.68% for ofloxacin), which are increased by 27–55% more than monomer membranes. Detailed analysis results indicate the nanofiltration performance of the MoS 2 /CMOF composite membrane depends heavily on the synergistic mechanism, including the molecular sieving effect (size exclusion), electrostatic repulsion, and hydrophilic-hydrophobic interaction. Besides, the MoS 2 /CMOF composite membrane has emerged with excellent antifouling ability and long-term stability, which could maintain favorable rejection efficiency in continuous nanofiltration for 72 h under an alkaline and acidic environment. Furthermore, it presents over 90% antibiotic rejection rates for real water samples obtained from the municipal domestic sewage and livestock wastewater along the Xiangjiang River in China, indicating its good availability. In general, this work provides a new vision and a reasonable design strategy to construct 2DNMs/MOFs-based nanofiltration membranes with hierarchical architecture, further expanding their application in wastewater treatment and reclamation, in harmony with the global trend of green and low-carbon development.

Aggregation behaviors of gradient and diblock copoly(2-oxazoline) monolayers at the air-water interface

This study reveals the different behavior of amphiphilic gradient and diblock copolymers based on aliphatic and aromatic 2-oxazolines. The copolymers were synthesized by the polymerization of hydrophilic 2-ethyl-2-oxazoline with hydrophobic 2-(4-octyloxyphenyl)-2-oxazoline. The aggregation behavior of gradient and diblock copolymers with different ratios between hydrophilic and hydrophobic units was explored. Surface pressure (Π)–surface area ( A ) isotherms were measured at the air-water interface. The gradient copolymers produced higher surface pressures and smaller limiting areas, while the diblock copolymers exhibit relatively flexible behaviors. Langmuir–Blodgett monolayers were transferred on the hydrophilic silicon wafer substrates at various surface pressure levels, and the nanostructure of the films was investigated by using atomic force microscopy and X-ray reflectivity measurements. It was observed that the morphologies of gradient and diblock copolymers were similar, indicating that the films form a uniform monolayer. The diblock copolymers produced relatively small changes in thickness upon the compression, compared to the changes in gradient copolymer monolayer films. The thickness of the gradient copolymers which have a high hydrophilic ratio at low surface pressure increases by increasing surface pressure and hydrophobic ratio. But the diblock copolymers do not change the thickness by increasing the surface pressure and hydrophobic ratio. The results indicate that the gradient copolymer monolayers have relatively rigid domains where hydrophilic and hydrophobic parts are smeared. On the other hand, the diblock copolymer has a flexible hydrophilic cushioning effect. This study provides insights into the development of novel materials based on hydrophilic-hydrophobic interactions. • The different behavior of amphiphilic gradient and diblock copolymers based on aliphatic and aromatic 2-oxazolines. • The aggregation behavior of gradient and diblock copolymers with different ratios between hydrophilic and hydrophobic units was explored. • The gradient copolymer monolayers have relatively rigid domains where hydrophilic and hydrophobic parts are smeared. • The diblock copolymer has a flexible hydrophilic cushioning effect.

Catalytic Etherification of ortho-Phosphoric Acid for the Synthesis of Polyurethane Ionomer Films.

The etherification reaction of ortho-phosphoric acid (OPA) with polyoxypropylene glycol in the presence of tertiary amines was studied. The reaction conditions promoting the catalytic activity of triethanolamine (TEOA) and triethylamine (TEA) in the low-temperature etherification of OPA were established. The catalytic activity of TEOA and TEA in the etherification reaction of phosphoric acid is explained by the hydrophobic-hydrophilic interactions of TEA with PPG, leading, as a result of collective interactions, to a specific orientation of polyoxypropylene chains around the tertiary amine. When using triethylamine, complete etherification of OPA occurs, accompanied by the formation of branched OPA ethers terminated by hydroxyl groups and even the formation of polyphosphate structures. When triethanolamine is used as a catalyst, incomplete etherification of OPA with polyoxypropylene glycol occurs and as a result, part of the phosphate anions remain unreacted in the composition of the resulting aminoethers of ortho-phosphoric acid (AEPA). In this case, the hydroxyl groups of triethanolamine are completely involved in the OPA etherification reaction, but the catalytic activity of the tertiary amine weakens due to a decrease in its availability in the branched structure of AEPA. The kinetics of the etherification reaction of OPA by polyoxypropylene glycol catalyzed by TEOA and TEA were studied. It was shown that triethanolamine occupies a central position in the AEPA structure. The physico-mechanical and thermomechanical properties of polyurethane ionomer films obtained on the basis of AEPA synthesized in a wide temperature range were studied.

Interactions of Fibrillar Insulin with Proteins: A Molecular Docking Study

During the last decades growing attention has been paid to ascertaining the factors responsible for the toxic potential of particular protein aggregates, amyloid fibrils, whose formation is associated with a range of human pathologies, including the neurodegenerative diseases, systemic amyloidosis, type II diabetes, etc. Despite significant progress in elucidating the mechanisms of cytotoxic action of amyloid fibrils, the role of fibril-protein interactions in determining the amyloid toxicity remains poorly understood. In view of this, in the present study the molecular docking techniques has been employed to investigate the interactions between the insulin amyloid fibrils (InsF) and three biologically important multifunctional proteins, viz. serum albumin, lysozyme and insulin in their native globular state. Using the ClusPro, HDOCK, PatchDock and COCOMAPS web servers, along with BIOVIA Discovery Studio software, the structural characteristics of fibril-protein complexes such as the number of interacting amino acid residues, the amount of residues at fibril and protein interfaces, the contributions of various kinds of interactions, buried area upon the complex formation, etc. It was found that i) hydrophilic-hydrophilic and hydrophilic-hydrophobic interactions play dominating role in the formation of fibril-protein complexes; ii) there is no significant differences between the investigated proteins in the number of fibrillar interacting residues; iii) the dominating hydrogen bond forming residues are represented by glutamine and asparagine in fibrillar insulin, lysine in serum albumin and arginine in lysozyme; iv) polar buried area exceeds the nonpolar one upon the protein complexation with the insulin fibrils. The molecular docking evidence for the localization of phosphonium fluorescent dye TDV at the fibril-protein interface was obtained.

An off-line three-dimensional liquid chromatography/Q-Orbitrap mass spectrometry approach enabling the discovery of 1561 potentially unknown ginsenosides from the flower buds of Panax ginseng, Panax quinquefolius and Panax notoginseng

To comprehensively elucidate the herbal metabolites is crucial in natural products research to discover new lead compounds. Ginsenosides are an important class of bioactive components from the Panax plants exerting the significant tonifying effects. However, to identify new ginsenosides by the conventional strategies trends to be more and more difficult because of the large spans of acid-base property (the neutral and acidic saponins), molecular mass (400–1400 Da), and rather low content. Herein, an off-line multidimensional chromatography/high-resolution mass spectrometry approach was presented: ion exchange chromatography (IEC) as the first dimension of separation, hydrophilic interaction chromatography (HILIC) in the second dimension, and reversed-phase chromatography (RPC) for the third dimension which was hyphenated to a Q Exactive Q-Orbitrap mass spectrometer. By applying to the flower buds of P. ginseng (PGF), P. quinquefolius (PQF), and P. notoginseng (PNF), IEC using a PhenoSphereTM SAX column could fractionate the total extracts into the neutral (unretained) and acidic (retained) fractions, while HILIC (an XBridge Amide column) and RPC (BEH Shield RP18 column) achieved the hydrophilic interaction and hydrophobic interaction separations, respectively. Q-Orbitrap mass spectrometry offered rich structural information and complementary resolution to the co-eluting components, particular to those minor ones by including precursor ion lists in data-dependent acquisition. We could characterize 803 ginsenosides from PGF, 795 from PQF, and 833 from PNF, and 1561 thereof are potentially unknown. These results can indicate the great potential of this multidimensional approach in the ultra-deep characterization of complex herbal samples supporting the efficient discovery of potentially novel natural compounds.

Roles of Surfactants in Oriented Immobilization of Cellulase on Nanocarriers and Multiphase Hydrolysis System.

Surfactants, especially non-ionic surfactants, play an important role in the preparation of nanocarriers and can also promote the enzymatic hydrolysis of lignocellulose. A broad overview of the current status of surfactants on the immobilization of cellulase is provided in this review. In addition, the restricting factors in cellulase immobilization in the complex multiphase hydrolysis system are discussed, including the carrier structure characteristics, solid-solid contact obstacles, external diffusion resistance, limited recycling frequency, and nonproductive combination of enzyme active centers. Furthermore, promising prospects of cellulase-oriented immobilization are proposed, including the hydrophilic-hydrophobic interaction of surfactants and cellulase in the oil-water reaction system, the reversed micelle system of surfactants, and the possible oriented immobilization mechanism.