Hydrophobic Media Research Articles

Realization for rapid extraction of citric acid from aqueous solutions using deep eutectic solvents

Citric acid is highlighted as a valuable chemical in the pharmaceutical and food industries. We present an extraction technique using hydrophobic deep eutectic solvents (HDES), which has emerged as an efficient and sustainable alternative solvent for the purification and recovery of this important compound from the production environment. HDES systems were formed by combining DL-Menthol as the hydrogen bond donor (HBD) and Tributyl Phosphate (TBP) as the hydrogen bond acceptor (HBA). HDES exhibited excellent performance as a hydrophobic medium for both physical and reactive extraction of citric acid. To demonstrate the effect of HDES composition over-extraction ability, HDESs with various DL-Menthol mole fractions (Xm) were prepared and tested. TOA molar concentration, initial citric acid concentration (CA0), and effect of temperature were also investigated as other effective parameters. The optimized HDES demonstrated remarkable extraction efficiency (E%) of over 90% using tri-n-octylamine (TOA) as the extractant, while offering rapid extraction rates within minutes. Our findings highlight the promising potential of these environmentally conscious HDES for sustainable chemical separation processes.

In English

The use of hydrophobic silicas as medical adsorbents in comparison with hydroxyl silicas allows to increase the adsorption of some toxins on their surface due to the reduction of water adsorption. The purpose of this study was to find a co-adsorbate that, adsorbed on a hydrophobic surface, would allow the preparation of aqueous suspensions of an enterosorbent based on methylsilica, and, once inside the body, would be easily destroyed by the enzymes of the gastrointestinal tract, freeing its surface for the adsorption of toxins on it. The structure of the hydrate shell and the adsorption capacity of composite materials based on methyl silica and gelatin obtained by different methods were investigated by a set of physical and chemical methods. Low-temperature 1H NMR-spectroscopy has been used to study of water clusters bound to composite surface. It has been found that the water in the composite on the basis of hydrophobic methyl silica and gelatin gel is present in the form of clusters with a radius of 0.5–15 nm and is in a strongly associated state when measured in air. When a liquid hydrophobic medium is added, the water partially passes into a weakly associated state. The bound water reacts to the presence of chloroform by changing the radial distribution of the adsorbed water clusters. It has been shown that for the composite system methyl silica AM-1/gelatin (5/1), the introduction of chloroform into the interfacial space leads to a significant decrease in the interfacial energy, which indicates a partial displacement of water by the hydrophobic solvent at the interface. At the same time, for composites made on the basis of dry powders, this effect is not observed and its interfacial energy has an intermediate value between the interfacial energies of methyl silica and gelatin containing the same amount of water. Adsorption of Congo red as the medium molecular weight toxins marker from aqueous solutions on the studied composites was studied in comparison with methylsilica. It has been found that gelatin in the composition of composites contributes to increasing dye adsorption. The amount of adsorbed Congo red depends on the method of preparation of the composite and the ratio of silica to gelatin. It is concluded that AM-1/gelatin composite systems can serve as effective adsorbents for removing medium molecular weight molecules from aqueous solutions.

Design and evaluation of curcumin-loaded poloxamer hydrogels as injectable depot formulations

Poloxamer hydrogels are of interest as injectable depot delivery systems. However, their use for delivering hydrophobic drugs, such as curcumin, is limited due to poor loading capacity. Here, we evaluated the influence of incorporating hydrophobic medium chain triglycerides (MCT) or amphiphilic polyethylene glycol 400 (PEG400) on the physicochemical properties, drug loading, and in vitro compatibility of a curcumin-loaded poloxamer hydrogel.Poloxamer 407 and 188 hydrogel formulations (16:6 w/w) were prepared and MCT and PEG400 (saturated with curcumin) were added to these systems, either alone or in combination, up to a 10 % w/w additive solvent load. Formulation viscoelasticity, gelation behaviour, injectability, morphology and release profiles were assessed. The cytocompatibility of the formulations was also assessed on dermal fibroblasts (HDFn).Both additives increased curcumin loading into the formulation. Addition of MCT to the hydrogel significantly increased its gelation speed, while PEG400 had a less profound impact. Both additive solvents increased the force required to inject the formulation. PEG400 containing systems were single phase, whereas MCT addition created emulsion systems. All formulations released ∼20–30 % of their loaded curcumin in a sustained fashion over 24 h. The modified hydrogel systems showed good biocompatibility on cells when administering up to ∼100–150 µM curcumin into the culture.This study addresses a key limitation in loading hydrophobic drugs into hydrogels and provides a strategy to enhance drug loading and performance of hydrogels by integrating additives such as MCT and PEG400 into the systems.

An injectable, nanostructured implant for the delivery of adenosine triphosphate: towards long-acting formulations of small, hydrophilic drugs.

While long-acting injectable treatments are gaining increasing interest in managing chronic diseases, the available drug delivery systems almost exclusively rely on hydrophobic matrixes, limiting their application to either hydrophobic drugs or large and hydrophilic molecules such as peptides. To address the technological lock for long-acting delivery systems tailored to small, hydrophilic drugs such as anticancer and antiviral nucleoside/nucleotide analogues, we have synthesized and characterized an original approach with a multi-scale structure: (i) a nucleotide (adenosine triphosphate, ATP) is first incorporated in hydrophilic chitosan-Fe(III) nanogels; (ii) these nanogels are then transferred by freeze-drying and resuspension into a water-free, hydrophobic medium containing PLGA and an organic solvent, N-methyl-2-pyrrolidone. We show that this specific association allows an injectable and homogeneous dispersion, able to form in situ implants upon injection in physiological or aqueous environments. This system releases ATP in vitro without any burst effect in a two-step mechanism, first as nanogels acting as an intermediate reservoir over a week, then as free drug over several weeks. In vivo studies confirmed the potential of such nanostructured implants for sustained drug release following subcutaneous injection to mice hock, opening perspectives for sustained and targeted delivery through the lymphatic system.

Ultrasonication-induced re-dispersion of freeze-dried cellulose nanoparticles for improving strength and durability of PAN polymer matrix

Cellulose nanocrystals (CNCs) have acquired considerable attention owing to their noteworthy properties, including high crystallinity, biodegradability, high specific surface area, and excellent mechanical characteristics that alter the inherent features of the polymer matrix upon reinforcement. Typically, CNCs undergo freeze-drying or spray-drying to facilitate handling and dispersion in a hydrophobic polymer medium. Unfortunately, these drying procedures compromise the intrinsic nano-scale properties of CNCs. Therefore, achieving a uniform re-dispersion of dried CNCs is imperative to attain the desired characteristics in the polymer composite. This study specifically focuses on achieving a homogeneous re-dispersion of freeze-dried CNCs within a waste polyacrylonitrile (PAN) matrix through a simple ultrasonication treatment. The enhanced mechanical properties of the PAN polymer matrix validate the impact of ultrasound energy on re-dispersing CNCs. A noticeable improvement in the tensile properties of the composite polymer film is observed when CNC particles are well-dispersed in the PAN matrix. This observation is substantiated through SEM imaging, XRD, and FTIR data of both neat PAN and PAN–CNC composite films. The results affirm that particle dispersion plays a crucial role in augmenting the tensile properties of PAN composite films.

Overcoming the Low-Stability Bottleneck in the Clinical Translation of Liposomal Pressurized Metered-Dose Inhalers: A Shell Stabilization Strategy Inspired by Biomineralization.

Currently, several types of inhalable liposomes have been developed. Among them, liposomal pressurized metered-dose inhalers (pMDIs) have gained much attention due to their cost-effectiveness, patient compliance, and accurate dosages. However, the clinical application of liposomal pMDIs has been hindered by the low stability, i.e., the tendency of the aggregation of the liposome lipid bilayer in hydrophobic propellant medium and brittleness under high mechanical forces. Biomineralization is an evolutionary mechanism that organisms use to resist harsh external environments in nature, providing mechanical support and protection effects. Inspired by such a concept, this paper proposes a shell stabilization strategy (SSS) to solve the problem of the low stability of liposomal pMDIs. Depending on the shell material used, the SSS can be classified into biomineralization (biomineralized using calcium, silicon, manganese, titanium, gadolinium, etc.) biomineralization-like (composite with protein), and layer-by-layer (LbL) assembly (multiple shells structured with diverse materials). This work evaluated the potential of this strategy by reviewing studies on the formation of shells deposited on liposomes or similar structures. It also covered useful synthesis strategies and active molecules/functional groups for modification. We aimed to put forward new insights to promote the stability of liposomal pMDIs and shed some light on the clinical translation of relevant products.

Stabilization of weakly associated water forms by the surface of compacted methylsilica and its composites with Betulin

A complex of physicochemical methods was used to study the morphology and structure of the surface of methylsilica AM-1. Hydration of methylsilica was carried out by mechanochemical activation in the presence of water. The structure of the hydrate layer was studied using low-temperature 1H NMR spectroscopy. It has been established that adsorbed water is present in the form of nanosized clusters with a radii R = 0.4–20 nm, some of which are in a strongly associated state (SAW), and the other in a weakly associated state (WAW). The properties of the weakly associated state of water are similar to the supercritical state, which exists at high temperatures and pressures in the form of nanosized surface clusters. A method has been developed for the formation of a hydrated composite system AM-1/Betulin, which provides it possible for a significant amount of weakly associated water forms to exist in the surface layer. The contact of composite particles with a liquid hydrophobic medium (modeling hydrophobic areas of the gastrointestinal mucosa) further increases the amount of WAW even more. The binding energy of water and the size of adsorbed water clusters depend on the method of hydration. In the case of soft hydration by shaking with water, large clusters of SAW are formed on the surface, localized on the molecules of adsorption-fixed Betulin. During hard hydration (grinding with water in a porcelain mortar), water penetrates into the gaps between hydrophobic particles of methylsilica or methylsilica with immobilized Betulin and forms clusters of WAW, the radii of which can be 0.4–8 nm. This type of interfacial water exists in a wide temperature range, its amount increases with increasing temperature. Thus, a new type of composites has been created, promising for use as antiviral and anticancer drugs.

Scalable absorber with tuneable water supply fabricated via centrifugal spinning for highly efficient and stable solar-driven interfacial desalination

Although realising tuneable water supply in photothermal evaporation is an effective way to boost solar-driven interfacial evaporation for water desalination, simultaneously achieving continuous water transport and appropriate water content in evaporators remains a significant challenge. To address this challenge, centrifugal spinning technology is proposed herein to fabricate a scalable, flexible and stable photothermal evaporator from a hydrophilic (polyacrylonitrile, (PAN)) and hydrophobic polymer medium (polyurethane, (PU)). Efficient water management can be realised by tuning the parameters of polymer materials to permit vapour escape and achieve salt resistance. In addition, the arched design of the evaporator allows for omnidirectional evaporation, which enhances the photothermal conversion efficiency. The scalable centrifugal spinning nonwoven membrane-based arched evaporator prepared at the optimal hydrophilic–hydrophobic polymer ratio (21 wt% PAN and 2 wt% PU) after polypyrrole modification (PPy/21PAN/2PU CSMAE) offers a highly efficient evaporation rate of 1.82 kg m−2 h−1 with photothermal efficiency of 97.33 % under 1-sun illumination and excellent salt resistance against high-salinity brine (10 wt%). Thus, the unique properties of centrifugal spinning technology enable the large-scale preparation application of multicomponent polymeric materials for realising tuneable water supply in solar-driven interfacial evaporation and desalination.

Absorbent bioactive aerogels based on germinated wheat starch and grape skin extract

This study aimed to produce water-absorbent bioactive aerogels using biodegradable raw materials, wheat starch and poly ethylene oxide (PEO), and derived from agro-industrial residues (grape skin) obtained in the wine industry. The aerogels were produced using germinated wheat starch (GWS), with and without PEO, and incorporating grape skin extract (GSE) at concentrations of 5 and 10 % (w/w). The GSE was evaluated for total and individual phenolic compounds, anthocyanins, and antioxidant activity. The starch aerogels were characterized for morphology, density, porosity, functional groups by FT-IR, relative crystallinity and diffraction pattern, water absorption capacity, antioxidant activity, and in vitro release profile of phenolic compounds in food simulant medium. The total phenolic compounds in GSE was 226.25 ± 0.01 mg equivalent of gallic acid/g GSE. The aerogels showed low density and high porosity. All aerogels demonstrated high water absorption capacity (581.4 to 997.5 %). The antioxidant activity of the aerogels increased with increasing GSE concentration and the addition of PEO. The aerogels could release GSE gradually for up to 120 days in the hydrophilic simulant medium and 240 h for the hydrophobic medium. Starch-based aerogels with GSE showed potential to be applied as exudate absorbers with antioxidant activity to develop active food packaging.

Enzybiotic-mediated antimicrobial functionalization of polyhydroxyalkanoates.

Polymeric nanoparticles (NPs) present some ideal properties as biomedical nanocarriers for targeted drug delivery such as enhanced translocation through body barriers. Biopolymers, such as polyhydroxyalkanoates (PHAs) are gaining attention as nanocarrier biomaterials due to their inherent biocompatibility, biodegradability, and ability to be vehiculized through hydrophobic media, such as the lung surfactant (LS). Upon colonization of the lung alveoli, below the LS layer, Streptococcus pneumoniae, causes community-acquired pneumonia, a severe respiratory condition. In this work, we convert PHA NPs into an antimicrobial material by the immobilization of an enzybiotic, an antimicrobial enzyme, via a minimal PHA affinity tag. We first produced the fusion protein M711, comprising the minimized PHA affinity tag, MinP, and the enzybiotic Cpl-711, which specifically targets S. pneumoniae. Then, a PHA nanoparticulate suspension with adequate physicochemical properties for pulmonary delivery was formulated, and NPs were decorated with M711. Finally, we assessed the antipneumococcal activity of the nanosystem against planktonic and biofilm forms of S. pneumoniae. The resulting system displayed sustained antimicrobial activity against both, free and sessile cells, confirming that tag-mediated immobilization of enzybiotics on PHAs is a promising platform for bioactive antimicrobial functionalization.

Emulgel: An Effective Drug Delivery System

When emulgel comes to administering hydrophobic medications, many of the benefits of gels are also severe disadvantages. An emulsion-based strategy is adapted to bypass barriers, giving even a hydrophobic medicinal component to take advantage of the special features of gels. Emulgel is a dosage form that combines gels and emulsions. The utilization of novel polymers has sparked a lot of curiosity in recent years. The direct convenience of the skin as a target organ for diagnostic and therapeutic objectives distinguishes dermatological pharmacology. Both hydrophilic and hydrophobic chemicals are blocked by this barrier is created by combining hydrophilic horn cells with a hydrophobic intercellular medium. Within the primary group of semi-solid preparations, the use of opaque gels in cosmetics and pharmaceutical preparations has grown. By lowering surface and interfacial tensions while raising aqueous phase viscosity, these chemicals allow the formation of stable emulsions and creams. An emulgel is created by adding a gelling ingredient to a conventional emulsion's aqueous phase. In various ways, these emulsifiers exceed both novel vesicular systems and traditional systems. Using various permeation enhancers, emulsifiers could be used as better topical medication delivery systems than they are today. The use of emulsifiers can be expanded to include analgesics and antifungals. Analgesics and antifungals can both benefit from emulsifiers. We discuss the types, advantages, marked emulgel, formulation of emulgel, emulgel preparation, and characterization.

Gamma radiation induced synthesis of double network hydrophilic cryogels at low pH loaded with AuNPs for fast and efficient degradation of Congo red

γ−radiation is a clean, fast and efficient synthetic route for polymeric materials. it is very powerful tool to generate free radicals during polymerization without any need of initiator and accelerator in both hydrophilic and hydrophobic media. Here in this work, for the first time, we fabricated acrylamide-methyl-propane sulfonic acid based-single and double network hydrophilic cryogels via γ−radiation at low pH. pH highly effects the synthesis of acrylamide-methyl-propane sulfonic acid based cryogels using redox initiation method. Along with pH, the effect of radiation time and radiation dose rate on cryo-polymerization was also studied. Gold hybrid cryogels (single and double network) were fabricated via self-reduction method at ambient conditions. Fourier transform infrared spectroscopy was implemented for chemical structure analysis of the synthesized material. The surface morphology of single and double network cryogels was observed via scanning electron microscopy. For the hybrid cryogels materials analysis x-ray diffraction, thermal gravimetric analysis, energy dispersive x-ray analysis, x-ray photoelectron spectroscopy and transmission electron microscopy and was used to confirm the presence of nanoparticles in the polymer network. The fabricated hybrid cryogels (0.15 g) were used for the degradation of Congo red (50 mL) as model dye in the presence of NaBH4 (0.02 g) with efficient and fast degradation activity. The apparent rate constant value (Kapp) for single and double network hybrid cryogels was 0.3652 min−1 and 0.2268 min−1, respectively. The activation energy, enthalpy and entropy was calculated (34.44 kJ.mol−1, –30.85 kJ.mol−1 and –146.30 J·mol−1k−1, respectively) using Arrhenius and Eyring equations for the fabricated catalyst. The catalyst was tasted in the tap water system and its efficiency was satisfied in real world too. The fabricated double wall hybrid catalyst will have a significant importance in the environmental field.

Bis(2,4,6-trichlorophenyl)oxalate-based chemically initiated electron exchange chromogenic reaction system for colorimetric detection of fentanyl and norfentanyl

Bioenzymes or nanoenzymes-involved aqueous chromogenic systems play a central role in colorimetric analysis. A lack of high and general chromogenic reactions that work in a hydrophobic medium has hampered the development of colorimetric methods for the detection of many hydrophobic analytes. To address this challenge, a series of chemically initiated electron exchange chromogenic (CIEEC) reaction systems are presented that functions in an ethanol–water mixture solvent. The resulting CIEEC systems are based on the oxidation capacity of biradical intermediate produced by the reaction between bis(2,4,6-trichlorophenyl)oxalate (TCPO) and H2O2, and it oxidizes various chromogenic substrates such as 3, 3′, 5, 5′-tetramethylbenzidine (TMB), o-phenylenediamine, diazoaminobenzene, and 2,2ʹ-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) to create colored products. Taking advantage of the catalytic effect of fentanyl (FTN) and norfentanyl (NFTN), we fabricate a visual colorimetric assay based on the TCPO-H2O2-TMB CIEEC reaction system, and the resulting sensitivity is comparable to that of the reported colorimetric assays for FTN. Moreover, the present assay is capable of detecting both FTN and NFTN in human urine samples.

A Closed-Form Equation for Capillary Pressure in Porous Media for All Wettabilities

A saturation–capillary pressure relationship is proposed that is applicable for all wettabilities, including mixed-wet and oil-wet or hydrophobic media. This formulation is more flexible than existing correlations that only match water-wet data, while also allowing saturation to be written as a closed-form function of capillary pressure: we can determine capillary pressure explicitly from saturation, and vice versa. We propose Pc=A+Btanπ2-πSeCfor0≤Se≤1,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_{{\ ext{c}}} = A + B\ an \\left( {\\frac{\\pi }{2} - \\pi S_{e}^{C} } \\right)\\,{\ ext{for}}\\,0 \\le S_{{\ ext{e}}} \\le 1,$$\\end{document}where S_{{text{e}}} is the normalized saturation. A indicates the wettability: A>0 is a water-wet medium, A<0 is hydrophobic while small A suggests mixed wettability. B represents the average curvature and pore-size distribution which can be much lower in mixed-wet compared to water-wet media with the same pore structure if the menisci are approximately minimal surfaces. C is an exponent that controls the inflection point in the capillary pressure and the asymptotic behaviour near end points. We match the model accurately to 29 datasets in the literature for water-wet, mixed-wet and hydrophobic media, including rocks, soils, bead and sand packs and fibrous materials with over four orders of magnitude difference in permeability and porosities from 20% to nearly 90%. We apply Leverett J-function scaling to make the expression for capillary pressure dimensionless and discuss the behaviour of analytical solutions for spontaneous imbibition.

Synoeca‐MP: New insights into its mechanism of action by using NMR and molecular dynamics simulations approach

AbstractSynoeca‐MP is a 14‐residue amidated peptide, belongs to the mastoparan family and it is found in the venom of the wasp Synoeca surinama and has antibacterial and antifungal activity. The low cytotoxicity of the peptide also makes it an excellent candidate for drug development. To better understand its selectivity and interaction with the membrane, the peptide behavior in membrane‐like environments was studied here and the peptide structure in SDS micelles was determined by NMR spectroscopy. The behavior of the peptide in hydrophobic media and in different pH ranges was studied by CD spectroscopy. The incorporation of residues into the anionic micelles was studied by hydrogen‐deuterium exchange. The peptide stability and insertion in the micelles was studied by molecular dynamics simulations. Synoeca‐MP, bound to SDS micelles, exhibits a partial α‐helix conformation, with the first five residues and the last two unfolded. H/D exchange showed that the peptide has a slow exchange rate. After 164 h, four residues had not yet completed H/D substitution, suggesting parallel alignment of the peptide with the micelle, mainly due to the hydrophobic interface. This may indicate a carpet interaction model of the peptide with micelles. The molecular simulation study of peptide showed that the peptide consists of a well‐folded alpha‐helix core and unfolded extremities, which are responsible for the nature of the peptide interaction. The biophysical analyses can improve the atomic understanding of the mode of action of the peptide and help in future improvements of the peptide for clinical usage.

Investigating water/oil interfaces with opto-thermophoresis

Charging of interfaces between water and hydrophobic media is a mysterious feature whose nature and origin have been under debate. Here, we investigate the fundamentals of the interfacial behaviors of water by employing opto-thermophoretic tweezers to study temperature-gradient-induced perturbation of dipole arrangement at water/oil interfaces. With surfactant-free perfluoropentane-in-water emulsions as a model interface, additional polar organic solvents are introduced to systematically modify the structural aspects of the interface. Through our experimental measurements on the thermophoretic behaviors of oil droplets under a light-generated temperature gradient, in combination with theoretical analysis, we propose that water molecules and mobile negative charges are present at the water/oil interfaces with specific dipole arrangement to hydrate oil droplets, and that this arrangement is highly susceptible to the thermal perturbation due to the mobility of the negative charges. These findings suggest a potential of opto-thermophoresis in probing aqueous interfaces and could enrich understanding of the interfacial behaviors of water.

Wetting Dynamics of Nanoparticle Dispersions: From Fully Spreading to Non-sticking and the Deposition of Nanoparticle-Laden Surface Droplets.

Controlled transport of liquid droplets on solid surfaces is critical in many practical applications, such as self-cleaning surfaces, coating, drug delivery, and agriculture. Non-adhesive liquid drops levitate on solid surfaces; therefore, they are highly mobile and directed toward desired locations by external stimuli. Although research on liquid-repellent surfaces has proliferated, the existing methods are still limited to creating surface roughness or coating the liquid droplets. Here, we create non-contact aqueous drops on hydrophilic surfaces in an oleic environment and use them to deposit submicrometer droplets encapsulating nanoparticles on solid surfaces. A glass surface is buried under an oil phase that contains a high concentration of Span 80 surfactants, and a drop of silica nanoparticle dispersion is released on the solid surface. We study the effect of surfactant concentration in oil and nanoparticle concentration in water on wetting dynamics and report a plethora of droplet spreading regimes from fully wetting to non-wetting. We find a threshold Span 80 concentration above which surfactant assemblies are formed on the solid and prevent the direct contact of the drop with the surface. At the same time, water-in-oil emulsions are generated at the drop-oil interface. The drop moves and leaves a trace of emulsions with encapsulated nanoparticles on the solid. We demonstrate the possibility of local surface coating with hydrophilic nanoparticles in a hydrophobic medium. The developed methodology in this study is a generic approach facilitating the droplet patterning in numerous applications, from pharmaceutical polymetric carriers to the formulation of cosmetics, insecticides, and biomedical diagnoses.

Adsorption Equilibria, Kinetics, and Column Dynamics of L-Tryptophan on Mixed-Mode Resin HD-1.

The adsorption amount and selectivity of L-tryptophan (l-Trp) on the hydrophobic interaction and ion exchange mixed-mode chromatography medium HD-1 were studied as well as the salt resistance of the resin via adsorption equilibrium experiments. The adsorption mechanisms of l-Trp were illuminated by combining adsorption equilibria and a kinetics analysis. The separation effect was studied by dynamic separation experiments in a fixed-bed. The results indicate that an increase of the concentration proportion of l-Trp zwitterion benefits the adsorption of l-Trp. The resin shows a high adsorption selectivity for l-Trp at different pH values. The adsorption amount of l-Trp is not affected significantly by NaCl. Various groups play a role in the adsorption of l-Trp. An adsorption energy lower than 8 kJ/mol indicates that the adsorption of l-Trp is mainly based on non-electrostatic interactions, with an electrostatic interaction as a supplement. The adsorption equilibrium model considering the dissociation equilibrium of the resin and l-Trp proposed in this work can simulate the adsorption equilibrium data of l-Trp at different pH values as well. The mass transfer rate of l-Trp is controlled by intraparticle and liquid film diffusion simultaneously. The fixed-bed packed with resin HD-1 can separate l-Trp with the purity of l-Trp higher than 99%, recovery rate higher than 95%, and concentration of 4.69 × 10–3 mol/L.

Oxidative effects of glyphosate on the lipophobic intracellular environment in the microalgae

The studied hypothesis is that the herbicide glyphosate (GLY) can affect the oxidative balance in the hydrophobic intracellular medium in non-target Chlorella vulgaris cells. Analytical GLY and RoundUp (RUP) supplementation, affected the growth profile. A significant 42% decrease in the cellular biomass in stationary (St) phase was observed in cultures supplemented with either 5 µM of GLY or RUP, as compared to control cultures. The treatment with 0.3 µM of GLY generated non-significant effects on the oxidation rate of 2’, 7’ dichlorofluorescein diacetate (DCFH-DA), neither in exponential (Exp) nor in St phase of development, as compared to control cultures. However, the treatment with either 5 µM GLY or 0.3 and 5 µM RUP lead to a significant decrease in the DCFH-DA oxidation rate, as compared to control cultures. The lipid radical (LR●) generation rate, detected by Paramagnetic Resonance Spectroscopy (EPR), was significantly increased in the presence of RUP, in Lag and Exp phase of growth. The non-enzymatic antioxidants, α-Tocopherol (α-T) and β-Carotene (β-C), are aimed to protect membranes against the damage produced by the radical reactions. The content of β-C was not significantly affected, as compared to control cultures, by any of the treatments, in both growth phases of cellular development. The content of α-T was significantly decreased by the supplementation with either 0.3 or 5 µM of RUP or 5 µM GLY. The LR●/α-T ratio, used as indicator of the oxidative balance in the hydrophobic cellular media, was significantly different between samples obtained from control and RUP-exposed microalgae in both, Exp and St phase of development, with either 0.3 or 5 μM RUP. The data presented here showed evidence that suggested that oxidative balance in the hydrophobic environment was affected by either GLY or RUP.

In Ukrainian

Composite systems with certain cytotoxic (AM1/lectin) and adsorption (AM1/gelatin) activity have been developed on the basis of methyl silica and protein molecules – lectin and gelatin. For both types of composites, mechanisms of water binding to the surface and methods of transferring of hydrophobic materials into the aquatic environment have been investigated. The state of interfacial water in air, organic and acid media was studied. It has been found that the presence of a hydrophobic component in composites stabilizes of surface water in a weakly associated state, when a significant part of water molecules does not form hydrogen bonds. Liquid hydrophobic medium enhances this effect, and the strong acid (trifluoroacetic), added to it, promotes the transition of water to a strongly associated state. It has been shown that the redistribution of water in the interparticle intervals of AM1 with protein molecules immobilized on their surface changes under the influence of mechanical loads. Mechanoactivated samples are characterized by the possibility of water penetration into the spaces between the primary particles of methyl silica. It has been shown that immobilization of lectin on the surface of AM1 is accompanied by an increase in the interfacial energy gS from 4.1 to 5.2 J/g. This is due to an increase in the concentration of strongly bound water. If we analyze the changes in the distributions of radii R of the clusters of adsorbed water, we can state that in the water adsorbed by native lectin molecules, there are two main maxima at R = 1 and 3 nm. In the immobilized state, the maximum at R = 1 nm is present in both types of water (of different order), but the second maximum is observed only for more ordered associates.