The properties of the ternary systems N,N,N',N'-tetramethylurea - N-methylacetamide - water were investigated using Fourier-transform infrared spectroscopy (FTIR), volumetric and compression measurements. Densities and sound velocities were determined in order to obtain the apparent molar volumes (VΦ) and apparent molar isentropic compressions (S,Φ). These values were then extrapolated to infinite dilution. Additionally, interaction parameters were calculated from the McMillan-Mayer theory. The studies were conducted at 288.15, 298.15, and 308.15 K, at atmospheric pressure (0.1 MPa). The concentration ranges of N-methylacetamide were 2, 4, 6, and 8 moles per kilogram of pure water, and for N,N,N',N'-tetramethylurea from 0 to around 0.35 moles per kilogram of solvent. Discrete changes in isentropic compression were observed. This is the result of the alignment of plots of S,Φ0 as a function of NMA concentration. The results for N,N,N',N'-tetramethylurea were compared with analogous data for the system containing n-butylurea, which is an isomeric compound but exhibits different hydration behaviour. Additionally, large volumetric interaction coefficients were observed, indicating strong interactions between urea derivatives and NMA. This suggests the possibility of strong interactions between protein destabilizers and the protein backbone, differing from those observed for protein structure stabilizers. The observation contributes to understanding the mechanism of osmolyte action and their influence on protein stability.
{"title":"Solvation phenomena in ternary system tetramethylurea-methylacetamide-water: Insights from volumetric, compressibility and FTIR analysis","authors":"Jarosław Wawer , Emilia Kaczkowska , Magdalena Tyczyńska , Małgorzata Jóźwiak , Joanna Krakowiak","doi":"10.1016/j.molliq.2024.126436","DOIUrl":"10.1016/j.molliq.2024.126436","url":null,"abstract":"<div><div>The properties of the ternary systems <em>N,N,N',N'</em>-tetramethylurea - <em>N</em>-methylacetamide - water were investigated using Fourier-transform infrared spectroscopy (FTIR), volumetric and compression measurements. Densities and sound velocities were determined in order to obtain the apparent molar volumes (<em>V</em><sub>Φ</sub>) and apparent molar isentropic compressions (<figure><img></figure><sub><em>S</em></sub><sub>,Φ</sub>). These values were then extrapolated to infinite dilution. Additionally, interaction parameters were calculated from the McMillan-Mayer theory. The studies were conducted at 288.15, 298.15, and 308.15 K, at atmospheric pressure (0.1 MPa). The concentration ranges of <em>N</em>-methylacetamide were 2, 4, 6, and 8 moles per kilogram of pure water, and for <em>N,N,N',N'</em>-tetramethylurea from 0 to around 0.35 moles per kilogram of solvent. Discrete changes in isentropic compression were observed. This is the result of the alignment of plots of <figure><img></figure><sub><em>S</em></sub><sub>,Φ</sub><sup>0</sup> as a function of NMA concentration. The results for <em>N,N,N',N'</em>-tetramethylurea were compared with analogous data for the system containing n-butylurea, which is an isomeric compound but exhibits different hydration behaviour. Additionally, large volumetric interaction coefficients were observed, indicating strong interactions between urea derivatives and NMA. This suggests the possibility of strong interactions between protein destabilizers and the protein backbone, differing from those observed for protein structure stabilizers. The observation contributes to understanding the mechanism of osmolyte action and their influence on protein stability.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126436"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.molliq.2024.126409
Mihalj Poša
The Gibbs–Duhem equation results in the independence between the standard Gibbs free energy of micelle formation and the standard Gibbs free energy of monocomponent surfactant’s and cyclodextrin’s (CD’s) inclusion complex formation in aqueous solution. The experimental data show that the surfactant’s critical micellar concentration increases in the presence of CD. At a constant temperature, the standard Gibbs free energy of micelle formation remains constant, irrespective of the presence of parallel competitive processes such as inclusion complex formation. This indicates that the critical micellar concentration remains unchanged at the corresponding concentration scale. As a result, the equilibrium constant for surfactant–CD inclusion complex formation can be determined by changing the critical micellar concentration in the presence and absence of CD. A graphical method for determining the equilibrium constant of the inclusion complex is also presented. An analytical approach for analyzing the influence of the formation of the inclusion complex with CD on the formation of the binary mixed micellar pseudophase is presented. Suppose that different values exist for the equilibrium constants of the formation of the inclusion complex for two surfactants from their binary mixture. In this case, there is a change in the initial mole fraction from the initial mixture of surfactants, which should be considered when applying the regular solution theory protocol when determining the parameters of a binary mixed micelle in the presence of CD.
根据吉布斯-杜恒方程，胶束形成的标准吉布斯自由能与单组分表面活性剂和环糊精（CD）在水溶液中形成包合物的标准吉布斯自由能之间是独立的。实验数据表明，表面活性剂的临界胶束浓度会随着 CD 的存在而增加。在恒温条件下，胶束形成的标准吉布斯自由能保持不变，而与包合物形成等平行竞争过程无关。这表明临界胶束浓度在相应的浓度范围内保持不变。因此，可以通过改变存在和不存在 CD 时的临界胶束浓度来确定表面活性剂-CD 包合物形成的平衡常数。此外，还介绍了一种确定包合复合物平衡常数的图形方法。还提出了一种分析方法，用于分析与 CD 形成的包合物对形成二元混合胶束假相的影响。假设两种表面活性剂二元混合物形成包合物的平衡常数存在不同值。在这种情况下，初始表面活性剂混合物的初始摩尔分数会发生变化，在确定存在 CD 的二元混合胶束的参数时，应用常规溶液理论规程时应考虑到这一点。
{"title":"Parallel (competitive) reactions of micelle formation and cyclodextrin–surfactant inclusion complex formation in aqueous solution: A consequence of the Gibbs–Duhem equation—invariance of the mass action law and the possibility of determining the equilibrium constant of the inclusion complex","authors":"Mihalj Poša","doi":"10.1016/j.molliq.2024.126409","DOIUrl":"10.1016/j.molliq.2024.126409","url":null,"abstract":"<div><div>The Gibbs–Duhem equation results in the independence between the standard Gibbs free energy of micelle formation and the standard Gibbs free energy of monocomponent surfactant’s and cyclodextrin’s (CD’s) inclusion complex formation in aqueous solution. The experimental data show that the surfactant’s critical micellar concentration increases in the presence of CD. At a constant temperature, the standard Gibbs free energy of micelle formation remains constant, irrespective of the presence of parallel competitive processes such as inclusion complex formation. This indicates that the critical micellar concentration remains unchanged at the corresponding concentration scale. As a result, the equilibrium constant for surfactant–CD inclusion complex formation can be determined by changing the critical micellar concentration in the presence and absence of CD. A graphical method for determining the equilibrium constant of the inclusion complex is also presented. An analytical approach for analyzing the influence of the formation of the inclusion complex with CD on the formation of the binary mixed micellar pseudophase is presented. Suppose that different values exist for the equilibrium constants of the formation of the inclusion complex for two surfactants from their binary mixture. In this case, there is a change in the initial mole fraction from the initial mixture of surfactants, which should be considered when applying the regular solution theory protocol when determining the parameters of a binary mixed micelle in the presence of CD.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126409"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.molliq.2024.126426
Tanishka Mehta, Bhupesh Goyal
Type 2 diabetes (T2D) is linked to the apoptosis of insulin-producing β-cells due to the aberrant fibrillation of the human islet amyloid polypeptide (hIAPP or amylin) to cytotoxic aggregates. Profit et al. generated conjugates (C1–C7) by appending benzene carboxylic acids of varying charges to the N-terminal of hIAPP22-29 fragment peptide NFGAILSS to modulate hIAPP fibrillation and cytotoxicity. C5 (4 µM) derived by conjugating low-cost, commercially available benzene-1,2,4,5-tetracarboxylic acid known as pyromellitic acid to NFGAILSS completely abolishes the hIAPP (40 µM) self-assembly as noted in the thioflavin T (ThT) fluorescence assay. The circular dichroism (CD) spectra highlighted that C5 stabilized hIAPP in a distinctive conformation and blocked its conformational switching to amyloidogenic β-sheet structure. C5 possessing a charge-dense pyromellitic acid moiety appended on the N-terminal region of self-recognition hIAPP fragment sequence NFGAILSS created significant interest as it effectively inhibited hIAPP fibrillation and possessed lower molecular mass, smaller size, and charge as compared to hIAPP aggregation inhibitor EEEENFGAILSS (P10). However, it remains unclear how C5 traps hIAPP into a unique conformation that abolishes its self-aggregation propensity. Thus, molecular dynamics (MD) simulations have been employed to illuminate the conformational transitions and structural changes in hIAPP on the inclusion of C5. C5 displayed high-affinity binding interactions to hIAPP (ΔGbinding = −37.11 ± 3.72 kcal/mol) with major contributions from the van der Waals and electrostatic interactions. Furthermore, residue-specific binding free energy analysis depicted high-affinity binding interactions of C5 with Phe15, His18, Asn21, and Tyr37 of hIAPP that play a crucial role in hIAPP fibrillation. The negatively charged carboxylate groups of pyromellitic acid moiety of C5 displayed interactions with the key residues of hIAPP as noted in the conformational clustering analysis. Notably higher sampling of helix from 24.00 ± 0.84 % in hIAPP to 34.20 ± 1.92 % in hIAPP–C5 is consistent with the CD studies, which depicted that C5 trapped hIAPP monomer in a conformation that blocked its self-association. MD simulations illuminated the molecular mechanism and atomistic details of the C5 interactions with hIAPP, which are responsible for its inhibitory activity against hIAPP fibrillation and alleviating hIAPP aggregates-induced cytotoxicity.
{"title":"Unveiling molecular mechanism underlying inhibition of human islet amyloid polypeptide fibrillation by benzene carboxylic acid-peptide conjugate","authors":"Tanishka Mehta, Bhupesh Goyal","doi":"10.1016/j.molliq.2024.126426","DOIUrl":"10.1016/j.molliq.2024.126426","url":null,"abstract":"<div><div>Type 2 diabetes (T2D) is linked to the apoptosis of insulin-producing β-cells due to the aberrant fibrillation of the human islet amyloid polypeptide (hIAPP or amylin) to cytotoxic aggregates. Profit et al. generated conjugates (C1–C7) by appending benzene carboxylic acids of varying charges to the N-terminal of hIAPP<sub>22-29</sub> fragment peptide NFGAILSS to modulate hIAPP fibrillation and cytotoxicity. C5 (4 µM) derived by conjugating low-cost, commercially available benzene-1,2,4,5-tetracarboxylic acid known as pyromellitic acid to NFGAILSS completely abolishes the hIAPP (40 µM) self-assembly as noted in the thioflavin T (ThT) fluorescence assay. The circular dichroism (CD) spectra highlighted that C5 stabilized hIAPP in a distinctive conformation and blocked its conformational switching to amyloidogenic β-sheet structure. C5 possessing a charge-dense pyromellitic acid moiety appended on the N-terminal region of self-recognition hIAPP fragment sequence NFGAILSS created significant interest as it effectively inhibited hIAPP fibrillation and possessed lower molecular mass, smaller size, and charge as compared to hIAPP aggregation inhibitor EEEENFGAILSS (P10). However, it remains unclear how C5 traps hIAPP into a unique conformation that abolishes its self-aggregation propensity. Thus, molecular dynamics (MD) simulations have been employed to illuminate the conformational transitions and structural changes in hIAPP on the inclusion of C5. C5 displayed high-affinity binding interactions to hIAPP (Δ<em>G</em><sub>binding</sub> = −37.11 ± 3.72 kcal/mol) with major contributions from the van der Waals and electrostatic interactions. Furthermore, residue-specific binding free energy analysis depicted high-affinity binding interactions of C5 with Phe15, His18, Asn21, and Tyr37 of hIAPP that play a crucial role in hIAPP fibrillation. The negatively charged carboxylate groups of pyromellitic acid moiety of C5 displayed interactions with the key residues of hIAPP as noted in the conformational clustering analysis. Notably higher sampling of helix from 24.00 ± 0.84 % in hIAPP to 34.20 ± 1.92 % in hIAPP–C5 is consistent with the CD studies, which depicted that C5 trapped hIAPP monomer in a conformation that blocked its self-association. MD simulations illuminated the molecular mechanism and atomistic details of the C5 interactions with hIAPP, which are responsible for its inhibitory activity against hIAPP fibrillation and alleviating hIAPP aggregates-induced cytotoxicity.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"416 ","pages":"Article 126426"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.molliq.2024.126347
Oleg V. Kashurin , Nikolay D. Kondratyuk , Alexander V. Lankin , Genri E. Norman
To accelerate the development of liquid ion-selective barriers based on ethers, we compare the all-atom force fields GAFF, OPLS-AA with charge correction 1.14*CM1A (OPLS-AA/CM1A), CHARMM version 36 (CHARMM36), and COMPASS for diisopropyl ether (DIPE) to determine the most appropriate model for further simulations of liquid membranes. Utilizing the selected force fields, we calculate the density and shear viscosity of DIPE across a temperature range of 243–333 K. Furthermore, we use CHARMM36 with mTIP3P water model and COMPASS with its own water model to evaluate the mutual solubility and interfacial tension between DIPE and water, estimate the partition coefficients of ethanol in DIPE + Ethanol + Water systems. Based on our comparative study, we conclude that CHARMM36 is the most suitable force field for modeling ether-based liquid membranes.
{"title":"Force field comparison for molecular dynamics simulations of liquid membranes","authors":"Oleg V. Kashurin , Nikolay D. Kondratyuk , Alexander V. Lankin , Genri E. Norman","doi":"10.1016/j.molliq.2024.126347","DOIUrl":"10.1016/j.molliq.2024.126347","url":null,"abstract":"<div><div>To accelerate the development of liquid ion-selective barriers based on ethers, we compare the all-atom force fields GAFF, OPLS-AA with charge correction 1.14*CM1A (OPLS-AA/CM1A), CHARMM version 36 (CHARMM36), and COMPASS for diisopropyl ether (DIPE) to determine the most appropriate model for further simulations of liquid membranes. Utilizing the selected force fields, we calculate the density and shear viscosity of DIPE across a temperature range of 243–333 K. Furthermore, we use CHARMM36 with mTIP3P water model and COMPASS with its own water model to evaluate the mutual solubility and interfacial tension between DIPE and water, estimate the partition coefficients of ethanol in DIPE + Ethanol + Water systems. Based on our comparative study, we conclude that CHARMM36 is the most suitable force field for modeling ether-based liquid membranes.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"416 ","pages":"Article 126347"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Currently, it is still lacking of deep understanding of the alternative of benzohydroxamic acid (BHA) on smithsonite and calcite flotation. We hypothesize that the presence of hydration films plays a significant role. Therefore, this paper aims to uncover the impact of hydration on the alternative flotation of smithsonite and calcite with BHA, utilizing flotation experiments, DFT calculations, Zeta potential tests, FTIR measurements, and XPS analyses. The results of the flotation experiments confirmed the effective separation of smithsonite from calcite with BHA. DFT calculations innovatively discovered that Zn on the surface of smithsonite can interact with BHA− but the Ca on the surface of calcite was easier to interact with the H2O instead of BHA−, thus BHA was incapable of repelling the hydrated layer from the surface of calcite to interact with the calcium ions. Zeta potential tests, FTIR measurements, and XPS analyses further provided experimental support that BHA was selectively chemically adsorbed onto the surface of smithsonite via forming Zn-BHA complex, whereas no such interaction occurred with the surface of calcite by generating Ca-BHA complex, which validated the DFT calculation results. This study provides valuable insights into the role of hydration in the beneficiation of smithsonite and calcite.
{"title":"Innovative discovery on the impact of hydration on the alternative flotation of smithsonite and calcite under benzohydroxamic acid system","authors":"Yuanjia Luo, Wei Sun, Shuai He, Jian Peng, Feng Jiang","doi":"10.1016/j.molliq.2024.126433","DOIUrl":"10.1016/j.molliq.2024.126433","url":null,"abstract":"<div><div>Currently, it is still lacking of deep understanding of the alternative of benzohydroxamic acid (BHA) on smithsonite and calcite flotation. We hypothesize that the presence of hydration films plays a significant role. Therefore, this paper aims to uncover the impact of hydration on the alternative flotation of smithsonite and calcite with BHA, utilizing flotation experiments, DFT calculations, Zeta potential tests, FTIR measurements, and XPS analyses. The results of the flotation experiments confirmed the effective separation of smithsonite from calcite with BHA. DFT calculations innovatively discovered that Zn on the surface of smithsonite can interact with BHA<sup>−</sup> but the Ca on the surface of calcite was easier to interact with the H<sub>2</sub>O instead of BHA<sup>−</sup>, thus BHA was incapable of repelling the hydrated layer from the surface of calcite to interact with the calcium ions. Zeta potential tests, FTIR measurements, and XPS analyses further provided experimental support that BHA was selectively chemically adsorbed onto the surface of smithsonite via forming Zn-BHA complex, whereas no such interaction occurred with the surface of calcite by generating Ca-BHA complex, which validated the DFT calculation results. This study provides valuable insights into the role of hydration in the beneficiation of smithsonite and calcite.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126433"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.molliq.2024.126430
Victoria Varchenko, Kateryna Bryleva, Zinaida Bunina, Konstantin Belikov
The clouding behavior of Triton X-100 solutions was investigated in the presence of resorcinol or β-naphthol. Both agents can effectively decrease the cloud point of Triton X-100 solutions. Resorcinol is active over a wider pH range, while β-naphthol is required at concentrations 10–50 times lower than resorcinol. It was also shown that about 60–70 % of β-naphthol transfers to the micellar phase, whereas resorcinol barely enters the micellar phase (about 10–15 %). Thermodynamic parameters of the clouding process were also calculated, revealing no significant differences between thermodynamic parameters for these two substances studied. Based on the results obtained, we assume different mechanisms of phase separation by these agents. Using the systems studied, mercury cloud point extraction was successfully carried out with 8-hydroxyquinoline as a ligand. The optimal parameters for extraction were determined as follows: pH of 8 (β-naphthol) and 6 (resorcinol), ligand concentration of 0.03–0.26 mmol L−1, and surfactant concentration of 1.7 g L−1.
{"title":"Clouding of Triton X-100 solutions in the presence of resorcinol or β-naphthol and their application for mercury cloud point extraction","authors":"Victoria Varchenko, Kateryna Bryleva, Zinaida Bunina, Konstantin Belikov","doi":"10.1016/j.molliq.2024.126430","DOIUrl":"10.1016/j.molliq.2024.126430","url":null,"abstract":"<div><div>The clouding behavior of Triton X-100 solutions was investigated in the presence of resorcinol or β-naphthol. Both agents can effectively decrease the cloud point of Triton X-100 solutions. Resorcinol is active over a wider pH range, while β-naphthol is required at concentrations 10–50 times lower than resorcinol. It was also shown that about 60–70 % of β-naphthol transfers to the micellar phase, whereas resorcinol barely enters the micellar phase (about 10–15 %). Thermodynamic parameters of the clouding process were also calculated, revealing no significant differences between thermodynamic parameters for these two substances studied. Based on the results obtained, we assume different mechanisms of phase separation by these agents. Using the systems studied, mercury cloud point extraction was successfully carried out with 8-hydroxyquinoline as a ligand. The optimal parameters for extraction were determined as follows: pH of 8 (β-naphthol) and 6 (resorcinol), ligand concentration of 0.03–0.26 mmol L<sup>−1</sup>, and surfactant concentration of 1.7 g L<sup>−1</sup>.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"416 ","pages":"Article 126430"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.molliq.2024.126427
Elison Lepore , Gianluca Ciancaleoni , Diego Romano Perinelli , Giulia Bonacucina , Serena Gabrielli , Gaia de Simone , Rosita Gabbianelli , Laura Bordoni , Matteo Tiecco
Deep Eutectic Solvents (DESs) are emerging in the recent literature as promising environmentally friendly liquids in different topics, finding fruitful applications as substitutes to common volatile organic solvents.
In this work a study of cluster formation of water-based DESs in water dilutions is presented. The three analysed mixtures are: glycolic acid/water (GA/H2O); betaine/water (TMG/H2O), choline chloride/water (ChCl/H2O). Ionic conductivity, viscosity, ultrasound spectroscopy and NMR techniques showed the presence of aggregates of aquoDESs in water dilutions. These aggregates are present in the solutions until values about 50 % w/w of added water, showing the presence of water-in-water structured systems. Moreover, taking into account the convenient disposal as water dilution of a DES, the cytotoxicity of these dilutions was evaluated on Caco2 model cells, showing the effect to be related only to the non-water components of these liquids. The water dilutions of water-based DESs have a great relevance for their applications, because their physical properties can be modulated as needed preserving their DESs’ identities.
深共晶溶剂（DESs）作为有前途的环境友好型液体在最近的文献中出现在不同的主题中，作为常见挥发性有机溶剂的替代品找到了富有成效的应用。分析的三种混合物是：乙醇酸/水（GA/H2O）、甜菜碱/水（TMG/H2O）和氯化胆碱/水（ChCl/H2O）。离子电导率、粘度、超声波谱和核磁共振技术表明，在水稀释液中存在含水沉积物的聚集体。这些聚集体一直存在于溶液中，直到添加水的重量百分比达到 50%左右，这表明存在水包水结构系统。此外，考虑到以水稀释的方式处理 DES 比较方便，还在 Caco2 模型细胞上对这些稀释液的细胞毒性进行了评估，结果表明这种影响只与这些液体中的非水成分有关。水基 DES 的水稀释液对其应用具有重要意义，因为它们的物理特性可以根据需要进行调节，从而保持 DES 的特性。
{"title":"Cluster aggregation of water-based deep eutectic solvents in water and evaluation of their cytotoxicity","authors":"Elison Lepore , Gianluca Ciancaleoni , Diego Romano Perinelli , Giulia Bonacucina , Serena Gabrielli , Gaia de Simone , Rosita Gabbianelli , Laura Bordoni , Matteo Tiecco","doi":"10.1016/j.molliq.2024.126427","DOIUrl":"10.1016/j.molliq.2024.126427","url":null,"abstract":"<div><div>Deep Eutectic Solvents (DESs) are emerging in the recent literature as promising environmentally friendly liquids in different topics, finding fruitful applications as substitutes to common volatile organic solvents.</div><div>In this work a study of cluster formation of water-based DESs in water dilutions is presented. The three analysed mixtures are: glycolic acid/water (GA/H<sub>2</sub>O); betaine/water (TMG/H<sub>2</sub>O), choline chloride/water (ChCl/H<sub>2</sub>O). Ionic conductivity, viscosity, ultrasound spectroscopy and NMR techniques showed the presence of aggregates of <em>aquo</em>DESs in water dilutions. These aggregates are present in the solutions until values about 50 % w/w of added water, showing the presence of water-in-water structured systems. Moreover, taking into account the convenient disposal as water dilution of a DES, the cytotoxicity of these dilutions was evaluated on Caco2 model cells, showing the effect to be related only to the non-water components of these liquids. The water dilutions of water-based DESs have a great relevance for their applications, because their physical properties can be modulated as needed preserving their DESs’ identities.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126427"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pepsin and trypsin are noteworthy for the digestion of proteins in the human body. Trilobatin is a dihydrochalone that has anti-obesity, antioxidant, and anti-diabetes functions. The interaction of trilobatin and pepsin or trypsin is not currently being explored. Therefore, in this research multiple methods involving fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) and molecular docking were employed for studying the interaction between trilobatin and pepsin or trypsin. During the interaction between trilobatin and pepsin or trypsin, the quenching type was static quenching and a single binding site existed. The binding constants (Ka) values were 2.177 and 3.028 × 104 L/mol in trilobatin-pepsin and trilobatin-trypsin system at 298 K, respectively. However, the presense of metal ions (Zn2+, Ca2+ and K+) decreased the binding of trilobatin to pepsin and trypsin. The complex between trilobatin and pepsin was generated typically through hydrogen bonding and van der Waals force (ΔH° < 0 and ΔS° < 0), in comparison the complex between trilobatin and trypsin was established chiefly through hydrogen bond and hydrophobic force (ΔH° > 0 and ΔS° > 0). The data from UV–Vis, synchronous fluorescence, FT-IR and CD spectra indicated that trilobatin reduced the hydrophobicity of Tyrosine (Tyr) residues of pepsin and trypsin. Furthermore, trilobatin altered the secondary structures of pepsin and trypsin. Meanwhile, trilobatin changed the conformation of pepsin and trypsin so that the viscosity of the interaction systems decreased with increased of trilobatin concentration. The molecular docking modeling identified that the trilobatin interacted with amino acid residues around pepsin and trypsin. This work consistently showed the interaction between trilobatin and pepsin or trypsin, in addition to offering valuable information for the application of trilobatin.
{"title":"Investigation on the interaction mechanism of trilobatin with pepsin and trypsin by multi-spectroscopic and molecular docking methods","authors":"Yaping Li, Yuqing Zhang, Yuhan Zhai, Guorui Yang, Haifang Xiao, Yuanda Song","doi":"10.1016/j.molliq.2024.126424","DOIUrl":"10.1016/j.molliq.2024.126424","url":null,"abstract":"<div><div>Pepsin and trypsin are noteworthy for the digestion of proteins in the human body. Trilobatin is a dihydrochalone that has anti-obesity, antioxidant, and anti-diabetes functions. The interaction of trilobatin and pepsin or trypsin is not currently being explored. Therefore, in this research multiple methods involving fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) and molecular docking were employed for studying the interaction between trilobatin and pepsin or trypsin. During the interaction between trilobatin and pepsin or trypsin, the quenching type was static quenching and a single binding site existed. The binding constants (K<sub>a</sub>) values were 2.177 and 3.028 × 10<sup>4</sup> L/mol in trilobatin-pepsin and trilobatin-trypsin system at 298 K, respectively. However, the presense of metal ions (Zn<sup>2+</sup>, Ca<sup>2+</sup> and K<sup>+</sup>) decreased the binding of trilobatin to pepsin and trypsin. The complex between trilobatin and pepsin was generated typically through hydrogen bonding and van der Waals force (ΔH° < 0 and ΔS° < 0), in comparison the complex between trilobatin and trypsin was established chiefly through hydrogen bond and hydrophobic force (ΔH° > 0 and ΔS° > 0). The data from UV–Vis, synchronous fluorescence, FT-IR and CD spectra indicated that trilobatin reduced the hydrophobicity of Tyrosine (Tyr) residues of pepsin and trypsin. Furthermore, trilobatin altered the secondary structures of pepsin and trypsin. Meanwhile, trilobatin changed the conformation of pepsin and trypsin so that the viscosity of the interaction systems decreased with increased of trilobatin concentration. The molecular docking modeling identified that the trilobatin interacted with amino acid residues around pepsin and trypsin. This work consistently showed the interaction between trilobatin and pepsin or trypsin, in addition to offering valuable information for the application of trilobatin.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126424"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.molliq.2024.126432
Lu Wang , Langyuan Cao , Jianhua Fan , Zonghao Li , Zhiwu Han , Dan Liu
A large number of oil spills and oily wastewater are discharged, in the modern industrial production process, resulting in serious water pollution. Oily wastewater can be extremely harmful to ecosystems and human health. Oil-water separation has become a major challenge at present, and membrane separation has aroused more and more concern in recent years due to its high economic efficiency. This paper fabricated PES filtration membranes using the novel nanoparticles based on both metal–organic frameworks-5 (MOF-5) and polydopamine (PDA) layers as dopants, and then adequately explored the porosity, morphology, separation, hydrophilicity, and fouling-resistant performance of the resultant membranes. In addition, the prepared membranes were used for oil–water separation, including soybean-in-water, petroleum ether-in-water, and gasoline-in-water emulsions. MOF@PDA membranes exhibit high separation efficiency of up to 99.8%. Subsequently, membrane fouling mechanisms were investigated using the Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and the molecular mode of interaction with the three oil–water emulsions with the membrane was compared. Newly prepared MOF@PDA membranes have better stability, fouling-resistant, and self-cleaning properties. Finally, an optimal machine learning model for oil–water separation efficiency was developed with a high prediction accuracy of 98%. The obtained results indicate that mixed matrix membranes exhibit excellent oil–water separation performance, demonstrating great application prospects in the remediation of oily wastewater.
{"title":"Polydopamine-incorporated MOF membrane with hydrophilicity for effective oil/water separation and fouling-resistant model analysis and prediction","authors":"Lu Wang , Langyuan Cao , Jianhua Fan , Zonghao Li , Zhiwu Han , Dan Liu","doi":"10.1016/j.molliq.2024.126432","DOIUrl":"10.1016/j.molliq.2024.126432","url":null,"abstract":"<div><div>A large number of oil spills and oily wastewater are discharged, in the modern industrial production process, resulting in serious water pollution. Oily wastewater can be extremely harmful to ecosystems and human health. Oil-water separation has become a major challenge at present, and membrane separation has aroused more and more concern in recent years due to its high economic efficiency. This paper fabricated PES filtration membranes using the novel <span><span>nanoparticles</span><svg><path></path></svg></span> <!-->based on both metal–organic frameworks-5 (MOF-5) and polydopamine (PDA) layers as dopants, and then adequately explored the porosity, morphology, separation, hydrophilicity, and fouling-resistant performance of the resultant membranes. In addition, the prepared membranes were used for oil–water separation, including soybean-in-water, petroleum ether-in-water, and gasoline-in-water emulsions. MOF@PDA membranes exhibit high separation efficiency of up to 99.8%. Subsequently, membrane fouling mechanisms were investigated using the Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and the molecular mode of interaction with the three oil–water emulsions with the membrane was compared. Newly prepared MOF@PDA membranes have better stability, fouling-resistant, and self-cleaning properties. Finally, an optimal machine learning model for oil–water separation efficiency was developed with a high prediction accuracy of 98%. The obtained results indicate that mixed matrix membranes exhibit excellent oil–water separation performance, demonstrating great application prospects in the remediation of oily wastewater.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126432"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.molliq.2024.126435
Yibo Kong , Jincheng Liu , Hang Lu , Xuesong Yang , Bobo Zhou , Yaowen Xing , Zhe Li , Xiahui Gui
Low-rank coal (LRC) is difficult to float using conventional oily collectors due to the rich oxygen-containing functional groups and abundant pores on its surface. In this study, an effective nanocarrier collector containing both nanoemulsion and nanoparticle with droplet size of 10–70 nm was developed, through diesel-beeswax mixture and AEO-7 using low-energy shearing and rapid cooling emulsification to enhance the LRC flotation. The surface morphology and elemental compositions of LRC were firstly characterized using SEM and EDS, identifying its difficult-to-float mechanisms. Then, the macroscopic appearance and microscopic size distribution of nanocarriers, and flotation tests were conducted to determine the optimum formula of nanocarrier collector for LRC. The results indicated that the recovery rate of combustibles was first increased and then decreased, by increasing the mass ratio of beeswax to diesel. When the mass ratio of diesel, beeswax, and AEO-7 was 2:3:5, the recovery rate of combustibles could be achieved to 92.98 %. Finally, the BET specific surface area, water adsorption, contact angle and wrap angle experiments were conducted to clarifying the synergistic enhancing LRC flotation mechanisms of nanocarriers collector. The nanocarriers could permeate into and seal the LRC surface pores, thereby reducing the both surface pore volumes and specific surface area. In addition, the mixtures of diesel and beeswax synergistically improved the surface hydrophobicity. Consequently, this research provides new insight into the development of effective collectors for LRC flotation.
{"title":"Synergistic enhancing low-rank coal flotation mechanisms using nanocarrier collector through pore sealing and surface hydrophobicity","authors":"Yibo Kong , Jincheng Liu , Hang Lu , Xuesong Yang , Bobo Zhou , Yaowen Xing , Zhe Li , Xiahui Gui","doi":"10.1016/j.molliq.2024.126435","DOIUrl":"10.1016/j.molliq.2024.126435","url":null,"abstract":"<div><div>Low-rank coal (LRC) is difficult to float using conventional oily collectors due to the rich oxygen-containing functional groups and abundant pores on its surface. In this study, an effective nanocarrier collector containing both nanoemulsion and nanoparticle with droplet size of 10–70 nm was developed, through diesel-beeswax mixture and AEO-7 using low-energy shearing and rapid cooling emulsification to enhance the LRC flotation. The surface morphology and elemental compositions of LRC were firstly characterized using SEM and EDS, identifying its difficult-to-float mechanisms. Then, the macroscopic appearance and microscopic size distribution of nanocarriers, and flotation tests were conducted to determine the optimum formula of nanocarrier collector for LRC. The results indicated that the recovery rate of combustibles was first increased and then decreased, by increasing the mass ratio of beeswax to diesel. When the mass ratio of diesel, beeswax, and AEO-7 was 2:3:5, the recovery rate of combustibles could be achieved to 92.98 %. Finally, the BET specific surface area, water adsorption, contact angle and wrap angle experiments were conducted to clarifying the synergistic enhancing LRC flotation mechanisms of nanocarriers collector. The nanocarriers could permeate into and seal the LRC surface pores, thereby reducing the both surface pore volumes and specific surface area. In addition, the mixtures of diesel and beeswax synergistically improved the surface hydrophobicity. Consequently, this research provides new insight into the development of effective collectors for LRC flotation.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":"415 ","pages":"Article 126435"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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