Influence Of Solvent Research Articles

Exploring the Influence of Various Solvents on the Structural, Optical, and Spectroscopic Properties of MgO

Exploring the Influence of Various Solvents on the Structural, Optical, and Spectroscopic Properties of MgO

Influence of Carbonate Electrolyte Solvents on Voltage and Capacity Degradation in Li‐Rich Cathodes for Li‐ion Batteries

AbstractLithium‐rich cobalt‐free cathodes, such as Li1.2Mn0.6Ni0.2O2 (LMR), are promising next‐generation cathode materials because of their high energy density, cost efficiency, and sustainability. Nevertheless, LMRs suffer from degradation problems such as voltage decay during cycling. Different LMR surface doping and coating strategies are proposed to suppress LMR voltage decay with varying extents of success. Here, the role played by different electrolyte solvents in oxygen loss from the LMR surface is instead investigated. X‐ray absorption spectroscopy (XAS), electron energy loss spectroscopy (EELS), synchrotron XRD, and online electrochemical mass spectrometry (OEMS) results show that ethylene carbonate (EC) leads to accelerated oxygen loss from the LMR surface. As a result, cycling LMR cathodes in EC‐free electrolytes such as pure EMC, improves the capacity retention and reduces voltage decay. This approach provides a new strategy to increase the cycling stability of LMR cathodes, which is important for the development of more sustainable high‐performance batteries.

Employing molecular dynamics simulations and DFT calculations to elucidate the energetic, structural, and spectroscopic attributes of (poly)valines in water solution

In this study, we explored how the growth of peptide chains containing valines impacts nuclear magnetic resonance (NMR) and optical absorption spectra. Results stem from equilibrated configurations in water, reflecting solvent influence and valine vibration. Utilizing fully atomistic molecular dynamics (MD), simulations, and density functional theory (DFT) including TD-DFT, we observe a notable shift in optical absorption towards longer wavelengths with increased valine count. Additionally, carbon atom magnetic signatures unveil distinct peptide bond characteristics. This work sheds light on the spectroscopic behavior of valine-rich peptide chains, crucial for understanding structural and functional properties, particularly in biomolecular contexts.

Influence of Dry-Mixing and Solvent Casting Blending Techniques on the Mechanical and Biological Behavior of Novel Biocompatible Poly(ε-caprolactone)/Alumina-Toughened Zirconia Scaffolds Obtained by 3D Printing

This work focuses on the study and comparison of two mixing methods for the dispersion of Alumina-Toughened Zirconia (ATZ) within the polymer matrix of Poly(ε-caprolactone) (PCL). The dry-mixing method using solvent-free impact milling (M) and the solvent casting method with chloroform (SC) were investigated. Samples were produced by 3D printing, and specimens were printed at increasing ATZ loadings (namely, 10, 20, and 40 wt.%). The chemico-physical, mechanical, and cell interaction characteristics of the materials prepared with both mixing methods were studied. Solvent mixing allowed better dispersion of the ATZ in the polymer matrix with respect to dry mixing. In addition, dry mixing affected the molecular weight of the PCL/ATZ composites much more than the solvent casting method. For these reasons, materials obtained by solid mixing exhibited the worst mechanical performance with respect to those obtained by solvent casting, which showed increased Young’s moduli with increasing ATZ amounts. The in vitro biological response elicited in a mesenchymal stem cell model seemed to be influenced by the mixing method, with a preference for the composites obtained through solvent mixing and containing 20 or 40 wt.% of ATZ.

Molecular structure, optical, first-order hyper polarizability, electronic properties, reactivity (ELF and LOL) − computational analysis using DFT and Multiwfn for 2, 3-diaminopyridinium selenate

A detailed study on the first principle calculations of 2,3-diaminopyridinium selenite (2,3-DAPS) – an organometallic salt has been performed using B3LYP/6–311++G(d,p). Single crystal X-ray diffraction (XRD) analysis confirms that the crystal formed exhibits a monoclinic crystal structure, specifically belonging to the centrosymmetric space group P21/c. The obtained primitives and interfacial angles are as follows: a = 7.4978(15)Å, b = 7.6681(15) Å, c = 14.314(3) Å, α = γ = 90°, β = 93.75(3)°, and the volume of the unit cell V = 821.2(3) (Å)3. The structure was optimized with a global minimum. The natural bonding orbital charge transfer studies between the cation and anion was performed to gain insights into their electronic interactions. Energy gap and other global chemical reactivity descriptors have been computed with the aid of molecular orbital studies. The influence of solvent on the absorption spectra provided the evidence of solvent–solute interactions and their impact on the electronic transitions within the molecule. The presence of electrophilic and nucleophilic reactivity in the chemical is indicated by the molecular electrostatic potential (MEP) map. From the nonlinear optical (NLO) studies, it has been found that the first-order hyperpolarizability value is 30.771 × 10−31 esu, which is 8.252 times that of urea. This suggests that the compound may be a better non-linear optical material and suitable for laser applications. To calculate the proportion of intermolecular interactions and examine the distribution compound's electrostatic potential, a Hirshfeld surface analysis was conducted. The analysis provided insights into the spatial arrangement of molecules and their interactions. Additionally, topology path calculations elucidated the intrinsic connectivity between critical points, shedding light on the bonding characteristics within the compound. The likelihood of electron density at bonding and anti-bonding sites was also determined using the Electron Localization Function (ELF) and Localised Orbital Locator (LOL) plots. These analyses aided in understanding the electron distribution and the nature of chemical bonding within the compound, providing valuable information about its electronic structure and reactivity.

Tailoring Physicochemical Properties of V2O5 Nanostructures: Influence of Solvent Type in Sol-Gel Synthesis.

The influence of different solvents, including aqueous and nonaqueous types, on the physicochemical properties of V2O5 nanostructures was thoroughly investigated. Various characterization techniques, such as XRD, XPS, FTIR, Raman spectroscopy, UV-vis DRS, SEM, TEM, and BET, were employed to analyze the obtained materials. Additionally, the adsorption properties of the synthesized V2O5 nanostructures for methylene blue were examined, and kinetic parameters of adsorption were calculated. The results demonstrate that the morphology of the obtained crystals can be finely controlled by manipulating water concentration in the solution, showcasing its profound impact on both the structural characteristics and adsorption properties of the nanostructures. Furthermore, the structural changes of the resulting V2O5 material induced by solvents show strong impacts on its photocatalytic properties, making it a promising photocatalyst.

Influence of Solvents and Halogenation on ESIPT of Benzimidazole Derivatives for Designing Turn-on Fluorescence Probes.

This work reports a theoretical investigation of the solvent polarity as well as the halogenation of benzimidazole derivatives during excited state intramolecular proton transfer (ESIPT). It details how the environment and halogen substitution may contribute to the efficiency of ESIPT upon keto-enol tautomerism and exploits this effect to design fluorescence sensing. For this purpose, we first examine the conformational equilibrium of benzimidazole derivatives containing different halogen atoms, which results in intramolecular proton transfer, using density-functional theory (DFT) combined with the polarizable continuum model (PCM). Then we evaluate the fluorescence of the benzimidazole derivatives in different dielectric constants within time-dependent DFT (TD-DFT) approaches. Our results quantitatively allow the determination of large Stokes shifts in nonpolar solvents around 100 nm. These theoretical results are in agreement with experimental solvatochromism studies of benzimidazoles. The effect of halogenation, with fluorine, chlorine, and bromine, is less important than solvent polarization when ESIPT takes place. Thus, halogenation can be properly chosen depending on the interest of the synthesis of benzimidazole-based turn-on fluorescence in appropriate solvents.

Microstructure evolution and micromechanical behavior of solvent-modified Cu–Ag composite sintered joints for power electronics packaging at high temperatures

With the increased deployment of power modules in demanding conditions, sintering materials, especially composite sintering materials, have raised growing interest due to their cost-effectiveness and suitability. Therefore, this study explores the viability of Cu–Ag composite sintering material, focusing on solvent influence through microstructure and mechanical behavior analysis. Micron-sized particle-based Cu–Ag composite pastes were designed and compared using eight solvents (four epoxy-free and four epoxy-added) based on fluidity and thermal stability. The sintered joints' performance, assessed through shear strength analysis, showed comparable values to pure silver sintering for both epoxy-free and epoxy-added samples. Optimized samples from each solvent system underwent reliability analysis, demonstrating that Cu–Ag joints with epoxy resin exhibited significantly higher shear strength after high-temperature storage and thermal cycling tests. Micromorphology and elemental composition analysis revealed differences in aging mechanisms, primarily attributed to variations in porosity due to oxide formation and pore filling by epoxy resin under different solvent systems. Further nanoindentation characterization of micromechanical properties, including hardness, modulus, and creep properties, during high-temperature aging, established constitutive models for insights into reliability evolution. In conclusion, the optimized epoxy-added Cu–Ag sintered joints proposed in this study demonstrated exceptional reliability and acceptable micromechanical properties, presenting a promising option for high-temperature power packaging.

Exploration of the effect of NaCl/urea on aggregation process of imipramine hydrochloride drug and TX-165 mixture: A surface tension and UV–visible study

In this research, mixed micellization analysis of imipramine hydrochloride (IMP), an antidepressant drug with nonionic TX-165 surfactant has been investigated entirely via tensiometry and UV–visible techniques. Influence of distinct solvents of certain concentration (aqueous/50 mmol.kg−1 NaCl/500 mmol.kg−1 urea) was also detected on mixed association behavior of IMP+TX-165 mixtures. As compared to the aqueous system, higher nonideality in IMP+TX-165 in NaCl solution was detected while in the urea system was found less i.e., the interaction between IMP and TX-165 in different solvents was found as follows: NaCl > aqueous > urea. The fraction of TX-165 in mixed micelles (X1m) was found to be higher than IMP caused by the high hydrophobicity of TX-165 than IMP. The attained interaction parameter (βm) for bulk mixed systems was negative in each case depicting the synergism or attractive interaction amid IMP and TX-165. Numerous evaluated thermodynamic parameters demonstrated that IMP+TX-165 mixed micelles formation is viable along with spontaneous and among all employed solvents, spontaneity was found higher in NaCl solvent and lower in urea solvent than aqueous solution. Interaction of IMP with TX-165 was also detected by UV–visible analysis as an increase in absorbance was attained. Overall, results might be helpful in the development of the drug delivery system.

Selective conversion of furfural to furfuryl alcohol by heterogeneous TiO2 photocatalysis

Selective synthesis of furfuryl alcohol from furfural conversion via semiconductor photocatalytic route has appeared as a promising solution for transforming biomass into high‐value‐added products under mild temperature and pressure conditions. Titanium dioxide (TiO2) photocatalysts were prepared by a simple sol‐gel method followed by a calcination treatment of 500 – 1000 ºC, resulting in materials with distinct physicochemical properties. The photocatalytic efficiency of the TiO2 samples was examined in the selective production of furfuryl alcohol from furfural under UV‐LED irradiation. The influence of various organic solvents, including ethanol, methanol, 2‐propanol, and acetonitrile, was evaluated to optimise the selectivity towards furfuryl alcohol production. Photocatalysts with larger anatase to rutile ratio and increased density of oxygen vacancies (defects) exhibited superior performance for furfuryl alcohol production. The presence of these defects on the catalyst surface leads to a significant enhancement in the photocatalytic efficiency by acting as crucial active sites. Among the TiO2 samples, the highest conversion of furfural into furfuryl alcohol was observed with the TiO2 sample calcined under an air atmosphere at 600 ºC (TiO2‐600), achieving 85% yield and 100% selectivity for furfural after 30 min reaction using ethanol as solvent.

Rational construction of ZnFe2O4 decorated hollow carbon cloth towards effective electromagnetic wave absorption

As typical magnetic materials, ferrites and their composites play dominant roles in the design of high-performance electromagnetic wave (EW) absorber. Solvent thermal method is the most popular route for synthesizing ferrites, while systematical comparison research about the influence of reaction solvents of solvent thermal process on ferrite based material's EW absorption performance has rarely been carried out. Thus in this work, we adopted cotton fabric as raw material, and synthesized two kinds of zinc ferrite decorated hollow carbon cloth (CC@ZnFe2O4) composites through solvent thermal reaction where deionized water and ethylene glycol was adopted as reaction solvents, respectively. After comprehensive and detailed comparison of the structures and performances of these two ferrite composites, the CC@ZnFe2O4 synthesized in deionized water phase possesses an ideal optimal absorption efficiency for EW, that is the minimum reflection loss (RL min) of −46 dB, while the effective absorption bandwidth of CC@ZnFe2O4 composites synthesized in ethylene glycol phase is wider (4.9 GHz). The synergistic effect of impedance matching, interface polarization, magnetic resonance, and multiple reflections co-determined the ideal EW absorption performances of these two samples. The research can not only provide new guidance for the secondary utilization of waste textiles, but also become an important reference for the preparation of ferrite based high-performance EW absorbers through solvent thermal method.

Effects of Solvents on the Material Properties of Screen‐Printed Electrodes and a Polydimethylsiloxane Dielectric for Dielectric Elastomer Transducers

Dielectric elastomer transducers (DETs), namely, highly stretchable dielectric membranes sandwiched between two compliant electrodes, allow to develop sensors, actuators, and generator systems. DET performance is strongly influenced by the material properties of dielectric and electrodes, as well as the type of manufacturing process. For instance, when manufacturing the electrodes via screen‐printing, significant amounts of solvents are needed to adjust the printing materials’ viscosity, but they potentially alter DET properties. The investigation of this effect, however, is largely unexplored. Addressing this issue, this article investigates the influence of various solvents on a DET consisting of a polydimethylsiloxane (PDMS) membrane with PDMS/carbon black electrodes. Physical and chemical interactions between dielectric and solvents are characterized by infrared‐spectroscopy (IR), optical investigations, and light microscopy. Different solvents used for screen‐printing are analyzed in terms of their effects on the electrode electrical resistance, screen‐print image, and breakdown strength. Even though the solvent strongly affects the electrodes’ electrical resistance (ranging from ≈22 kΩ to >MΩ), it does not modify the breakdown strength of the pure dielectric (113 V μm−1). In the IR, no chemical aging is found. The obtained results provide systematic guidelines for the choice of solvents in DET electrode manufacturing.

Influence of DMSO Non-Toxic Solvent on the Mechanical and Chemical Properties of a PVDF Thin Film

Influence of DMSO Non-Toxic Solvent on the Mechanical and Chemical Properties of a PVDF Thin Film

Effects of solvent composition on agglomerate structure in catalyst ink for polymer electrolyte fuel cells

The solvent composition of the catalyst ink profoundly impacts both the porous structure and the efficiency of the mass-production process of the catalyst layer for polymer electrolyte fuel cells. However, the underlying mechanism remains far from elucidated. Here, we present the size of aggregate and the fractal dimension of the agglomerate structure as determined by ultra-small X-ray scattering (USAXS) of the catalyst inks with varied solvent composition. By examining the correlations between the structural properties provided by USAXS, rheological properties, and the quantity of ionomer adsorbed on the Pt/C, we elucidate the solvent's influence on the agglomerate structure. In highly polar solvents, akin to water, a considerable number of amphiphilic ionomers adsorb to the Pt/C particles, resulting in the formation of dispersed Pt/C aggregate particles approximately 200 nm in size that cannot be subdivided further into smaller particles even with the use of a homogenizer. As the polarity diminishes with the addition of alcohol content, ionomers desorb, and the affinity between the aggregates and the solvent decreases, leading to the evolution of agglomerates. The observed solvent effect can be rationally characterized by one of Hansen's solubility parameters, which specifies the polar interaction.

Biological control of Pseudomonas aeruginosa (ATCC-27853) by isolated lytic bacteriophage

Background Pseudomonas aeruginosa is a common bacterial species; it can grow in all fields, even in distilled water. One of the obvious characteristics of P. aeruginosa species is its low antibiotic susceptibility (antibiotic-multi-resistant species); this reflects the urgent need for alternative strategies. Unconventionally, we try to use an alternative destructive antibacterial agent, phage. phage application in our environmental fields (engineering relevance) is a promising safe avenue for replacing chemical biocides. Objective To isolate a lytic phage as a bio-control agent for Pseudomonas aeruginosa (ATCC-27853), evaluate the ability of the isolated phage to inhibit or suppress the growth of the target bacteria. We study phage stability while performing biological and physical characterization, optimizing phage action against bacteria. Materials and methods We use an activated, purified young culture of Pseudomonas aeruginosa (ATCC-27853) as the target bacteria to isolate a specific lytic bacteriophage from a mixture of Enriched sewage and marine water through a sequence of experiments: a Broth clearing assay using nutrient broth and a spot assay test by using nutrient agar medium, both for the detection of phage presence and its lytic action. For the purification of phage, the plaque assay test was performed in many successive subcultures by using the serial dilution method on a semisolid medium. The high-titer lysate obtained from the confluent plates was investigated by TEM to determine its morphology and taxonomy. We performed biological characterization of the isolated phage: one-step growth curve, Phage adsorption rate, host range (using nutrient double layer agar), as well as a bacterial challenge test (using nutrient broth, based on the optical densities). Also, we performed physical characterization of the phage to determine phage Stability, pH, thermal stability, and the influence of UV and organic solvents on the lytic action of the phage. Results and conclusion Pyocyanin and pyoverdin pigments (both fluorescent under UV illumination) are secreted by P. aeruginosa (ATCC-27853), also their ability to thrive at 42°C. After spotting P. aeruginosa plates with enriched sewage filtrate, the results indicated lytic area (+ve). Plaques have a pin tip and are translucent. The lytic profile of bacteria after phage infection revealed that the bacteria was reduced to a MOI of 10 in 4 h. However, the multiplicity of infection(MOI) of 1 and 0.01, respectively, was longer (10, 22/h). The electron microscopy revealed that the phage is a member of the podoviridae family, with a noncontractile short tail (18 nm) and a polyhedral (heptagonal) head (45 nm) in diameter and a phage length of 63 nm. The adsorption rate of the phage was greatest at 20 min. Our goal with the phage application is to replace harmful chemical biocides with lytic bacteriophages in various environmental systems (Phage for Biological Control). Phage bio-control treatment thus holds promise for eliminating the requirement for hazardous chemical biocides.

Impact of Salts and Linear Carbonates on the Performance of Layered Oxide/Hard Carbon Sodium-Ion Pouch Cells with Alkyl Carbonate Electrolytes

This study examines the influence of electrolyte salts and solvents on the performance of O3 layered oxide NaMn0.39Fe0.31Ni0.22Zn0.08O2/hard carbon sodium-ion pouch cells with polyethylene terephthalate (PET) jellyroll tape. A significant enhancement in cell performance between 2.0 and 3.8 V was observed across various temperatures (20, 40, and 55 °C) by substituting NaPF6 with NaFSI, including reduced impedance growth, minimized gas generation, and supressed jellyroll tape decomposition. Ultra-high precision coulometry revealed that the use of NaPF6 resulted in increased unwanted parasitic reactions associated with tape decomposition, e.g., capacity fade and charge endpoint capacity slippage. Teardown of sodium-ion pouch cells after cycling in DMC-based electrolytes revealed a severe decomposition of the PET tape with NaPF6 but not with NaFSI. Gas chromatography shows significantly more electrolyte decomposition products with NaPF6 as opposed to NaFSI. DEC-based electrolyte showed less capacity fade, less electrolyte decomposition products, and less tape decomposition after cycling than DMC-based electrolyte. The electrolyte additive DTD can prevent parasitic reactions in DMC- and NaPF6-based electrolyte. Overall, the choice of salts and linear carbonates in alkyl carbonate electrolytes plays a crucial role in determining the overall cycling performance of the layered oxide/hard carbon sodium-ion cells with PET jellyroll tape.

A new novel series of vanillin-based hexaimine-Schiff bases: Synthesis, characterization and investigation of chromic and fluorescence properties

Here, new symmetrical diimines D1 and D2 were prepared by the condensation reaction of o-vanillin with 2-nitro-p-phenylenediamine or 4-nitro-o-phenylenediamine, respectively. Diimines were reduced selectively to their amino derivatives, and reacted with terephthaldehyde to obtain of a novel symmetrical hexaimines (H1 and H2). Their structures were identified on the basis of microanalyses, IR, 1H/13C NMR, HRMS and UV–vis spectroscopy. The enol–keto tautomeric equilibrium in these Schiff bases were elucidated by chromically and fluorescence spectra with respect to the influence of solvent, acid–base and light. They acted non-emissive in the solid state (λexc = 365 nm). Diimines displayed a weak green, bluish-green/blue emission in basic DMSO and DMF solution (v/v, 1:1), but they were non-fluorescent in other media. In contrast to this, hexaimines emitted a strong greenish-blue fluorescence in pure, bluish-green/greenish-blue fluorescence in acidic, and purplish-blue/blue fluorescence in basic aqueous DMSO and DMF media.Mass spectrum of Schiff bases exhibited the ion peaks as following positions: (D1): m/z (RI%) = 447.1329 (100 %), 424.1517 (60 %), 322.1454 (20 %), 288.0988 (30 %), 102.1277 (55 %) (Fig. S7). (D2): m/z (RI%) = 422.1361 (20 %), 288.0996 (100 %) (Fig. 6). (H1): m/z (RI%) = 883.4259 (10 %), 528.2244 (100 %), 510.2038 (20 %), 392.1605 (10 %), 102.1276 (10 %) (Fig. S8). (H2): m/z (RI%) = 882.3320 (10 %) [M + 2H]+, 434.1278 (40 %), 392.1710 (50 %), 374.1588 (100 %), 322.1523 (10 %), 256.1142 (15 %), 102.1297 (15 %) (Fig. S9). Mass spectral pattern of D1 displayed [M + 3H]+ ion peak at m/z 424.1517. The base peak was observed at m/z 447.1329, which may be due to [M + 3H+Na]+ ion. And the following fragment ion appeared at m/z 288.0988, which may be due to [C14H14N3O4]+ ion (4-((2‑hydroxy-3-methoxybenzylidene)amino)-3-nitrobenzenaminium)). D2 showed [M + H]+ molecular ion at m/z 422.1361. The similar fragmentation was observed at m/z 288.0996. This base peak may be due to fragment [C14H14N3O4]+ ion (2-((2‑hydroxy-3-methoxybenzylidene)amino)-4-nitrobenzenaminium)). H1 exhibited [M + 3H]+ molecular ion at m/z 883.4259. The base peak was observed at m/z 528.2244, which may be due to [C35H24N6]+ ion (3,3′-(((2-((4-(((2-amino-5-(methyleneamino)phenyl)imino)methyl)benzylidene)amino)-1,4-phenylene) bis(azanylylidene))bis(methanylylidene))bis(benzene-1,2-diylium)). In the case of H2, [M + 2H]+ ion peak was seen at m/z 882.3320. The following fragmentation was observed at m/z 434.1278, which may be belonged to fragment [C30H18N4]+ ion (3,3′-(((4-((4-((vinylimino)methyl)benzylidene)amino)1,2phenylene)bis(azanylylidene))bis(methanylylidene))bis(benzene-1,2-diylium)). The base peak was recorded at m/z 374.1588, which may be due to fragment [C26H208N3]+ ion (3,3′-(((4-((2-vinylbut-2-en-1-ylidene)amino)-1,2-phenylene)bis(azanylylidene))bis(methanylylidene))bis(benzene-1-ylium)).

Unraveling the Influence of Solvent on Side Reactions between Formamidinium Lead Triiodide and Methylammonium Cations.

Formamidinium lead triiodide (FAPbI3) perovskite thin films are commonly deposited through a solution process, often incorporating a specific amount of methylammonium halide to stabilize the α-phase or enhance their crystallinity. The precursor solution for such coatings significantly influences the fabrication of perovskite solar cells (PSCs), involving time-dependent aging and byproduct formation. The chemical principle underlying this behavior is believed to be related to the deprotonation of methylamine cations (MA+) and subsequent chemical reactions with FA+ to generate N-methylformamidinium. Nevertheless, the role of the solvent in the side reactions between these organic cations remains unclear. This work systematically investigates the reaction reactivity in three protic solvents and three aprotic solvents. We uncover the hidden role of dimethylamine from the hydrolysis products of N,N-dimethylformamide, promoting the reaction between FA+ and MA+. Additionally, we elucidate the impact of environmental factors, such as water and oxygen, in stabilizing precursor solutions. This work establishes a basic concept and scientific direction for rationalizing high-efficiency, reproducible, and long-term-stable PSCs.

Development of a novel human stratum corneum mimetic phospholipid ­vesicle-based permeation assay models for in vitro permeation studies

Objectives To develop and evaluate a novel human stratum corneum (SC) mimetic phospholipid vesicle-based permeation assay (PVPASC) model for in vitro permeation studies. Significance Due to the increasing restrictions on the use of human and animal skins, artificial skin models have attracted substantial interest in pharmaceuticals and cosmetic industries. In this study, a modified PVPASC model containing both SC lipids and proteins was developed. Methods The PVPASC model was optimized by altering the lipid composition and adding keratin in the formulation of large liposomes. The barrier properties were monitored by measuring the electrical resistance (ER) and permeability of Rhodamine B (RB). The modified PVPASC model was characterized in terms of the surface topography, solvent influence and storage stability. The permeation studies of the active components in Compound Nanxing Zhitong Plaster (CNZP) were performed to examine the capability of PVPASC in the application of skin penetration. Results The ER and P app values of RB obtained from the optimized PVPASC model indicated a similar barrier property to porcine ear skin. Scanning electron microscope analysis demonstrated a mimic ‘brick-and-mortar’ structure. The PVPASC model can be stored for three weeks at −20 °C, and withstand the presence of different receptor medium for 24 h. The permeation studies of the active components demonstrated a good correlation (r 2 = 0.9136) of P app values between the drugs’ permeation through the PVPASC model and porcine ear skin. Conclusion Keratin contained composite phospholipid vesicle-based permeation assay models have been proven to be potential skin tools in topical/transdermal permeation studies.

Insight into the influence of natural deep eutectic solvents on the extraction of phenolic compounds from poplar type propolis: Composition and in vitro biological activity

Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.