Van Der Waals Interactions Research Articles

Synthesis, structure, cytotoxicity, photodynamic reactivities and molecular simulation studies of three [RuNO(Qn)(Pro)Cl] isomeric complexes

Three isomeric nitrosylruthenium complexes [RuCl(Qn)(Pro)(NO)] (1–3) were prepared, where Qn is 8-hydroxyquinoline and Pro is D-proline. The complexes 1–3 were characterized by 1H-NMR, 13C-NMR, ESI-MS, and their crystal structure were further determined with X-ray diffraction techniques. In complexes 1 and 3, the O atom of D-proline coordinated trans to NO, while the O atom of 8-quinolinol coordinated trans to NO in complexes 2, and the complexes 1 and 3 are the Ru-centered enantiomers. The photo induced NO release of the complexes were explored using time-resolved infrared spectroscopy (FT-IR) and electron paramagnetic resonance spectroscopy (EPR) in solution and the released NO was successfully imaged in living cells using a NO selective fluorescent probe. Furthermore, the cytotoxicity of the isomeric complexes against HeLa, HepG2 and A549 cells were evaluated. Among them, the selectivity for HeLa cells is significant (SI ≥ 5) with IC50 values in the range of 1.15–1.94 μM. Moreover, the three complexes spontaneously bind to human serum albumin (HSA) through hydrogen bonding and van der Waals forces, the binding constants Kb of 1–3 are 1.528 × 104, 2.390 × 104 and 2.694 × 104 M−1 at 298 K, respectively. Molecular docking analyses reveals that 1–3 bind within subdomain IB of the protein, which suggest that HSA could be a delivery vehicel for these complexes. This study provides insight into the potential biological and pharmaceutical applications for these isomeric nitrosylruthenium complexes.

The Potential of Clove (Syzygium aromaticum) Essential Oil as Sunscreen and Anti-Aging Agents: An In Vitro and In Silico Study

The earth thermal conditions increase exposure to sunlight, triggering skin damage. The skin has defense mechanisms but needs additional protection to prevent photoaging. Using sunscreen is an effort to reduce the harmful effects of sun exposure. Natural ingredients with antioxidant activity can be developed into sunscreen and antiaging products, including cloves. This study aims to assess the antioxidant, sun protection, and anti-aging properties of essential oils derived from clove leaves and buds. The antioxidant activity was assessed by the DPPH system and then formulated into 5 and 10 % clove leaves cream, as well as 5 and 10 % clove bud cream. The SPF values were assessed using a spectrophotometer and the Mansur formula. The antiaging potential was assessed using the in silico method with MMP-1 protein employing the Auto Dock Vina software, followed by analysis and visualization using BIOVIA Discovery Studio. The essential oils from clove leaves and buds have DPPH IC50 values of 23.09 and 30.31 ppm. The SPF values of clove leaves essential oil, 5 % leaves cream, and 10 % leaves cream are 38.61, 14.32, and 22.15. Meanwhile, the SPF values of clove bud essential oil, 5 % bud cream, and 10 % bud cream are 38.19, 9.32, and 18.16. The in silico test revealed that caryophyllene, eugenol, humulene, and phenol, 2-methoxy-4-(2-propenyl), acetate) have strong interactions because they can interact with the active site of proteins using hydrogen, hydrophobic, and van der Waals bonds. The essential oils from clove leaves and buds exhibit very strong antioxidant activity and offer ultra-protection as a sunscreen. The cream formulations still exhibit sunscreen activity, albeit at a lower level compared to pure essential oil. Caryophyllene, eugenol, humulene, and phenol, 2-methoxy-4-(2-propenyl)-, acetate), have potential as antiaging agents, as indicated by their binding affinity and chemical bond interactions observed in the in silico test. HIGHLIGHTS Clove buds and leaves exhibit antioxidant properties. Essential oil from clove buds and leaves demonstrates a substantial Sun Protection Factor (SPF). The compounds contained in clove essential oil exhibit promise as prospective agents in anti-aging applications. GRAPHICAL ABSTRACT

Gas-Phase Dynamics of Bundle Formation from High-Aspect-Ratio Carbon Nanotubes.

In floating catalyst chemical vapor deposition (FCCVD), high-aspect-ratio carbon nanotubes (CNTs) are produced in the gas phase at high number concentrations and undergo collision and agglomeration, eventually giving rise to a macroscale aerogel, enabling functional material forms such as fibers or mats to be obtained directly from the synthesis process. The self-assembly behavior between high-aspect-ratio CNTs dictates the resulting morphology at the nanoscale and subsequently the bulk properties of the CNT product. Reorientation between CNTs after collision is a critical step that results in bundle formation and precedes aerogel formation. However, it has been challenging to study the phenomenon with existing methods as it spans multiple time and length scales. In this study, a physics-based semi-analytical model was developed to study the gas-phase reorientation dynamics of high-aspect-ratio CNTs and their bundles, with ±10% accuracy compared with mesoscale molecular dynamics simulations, but at <0.1% the computational cost. It was revealed that the reorientation time scale is dictated by the interplay among the van der Waals potential, drag, and the geometric configuration of CNTs upon collision. This then allows the time scale of reorientation (i.e., bundle formation) to be compared with other gas-phase dynamics in a typical FCCVD reactor and offers new insights into the self-assembly behavior of 1D nanoparticles in the gas phase.

COPOLYMER BASED ON [(3-METHACRYLOYLAMINO)PROPYL] TRIMETHYLAMMONIUM CHLORIDE AS A FLOCCULANT FOR INDUSTRIAL WATER TREATMENT

The using of polymeric flocculants in the development of the oil industry in Kazakhstan is one of the innovative tasks. Therefore, the creation of new effective flocculants based on available industrial monomers with structure-forming is an urgent task. The mechanism of action of flocculants is based on the phenomenon of adsorption of flocculant molecules on the surface of colloidal particles, the formation of a network structure of flocculant molecules, and the adhesion of colloidal particles due to van der Waals and other forces. New polymeric flocculant with different molar composition was synthesized by radical copolymerization [(3-methacryloylamino)propyl]trimethylammonium chloride (TMAPMACh) with N,N-dimethyl-acrylamide (DMAA) at 333 K in the presence of ammonium persulfate, (NH4)2S2O8 as an initiator. The molar composition of the synthesized TMAPMACh-DMAA copolymer was determined by FTIR and NMR spectroscopy and conductometric titration with AgNO3 solution. The flocculation properties of the copolymers were studied by measuring the sedimentation of dispersed particles of bentonite suspension in the presence of the flocculant. Sedimentation degree was determined by measuring the optical density of the suspension. It was found that TMAPMACh-DMAA copolymers had a flocculating effect and could be used for industrial wastewater treatment. Thermogravimetric analysis showed that this copolymer was thermally stable up to 270°C. Therefore, it can be used in deep well drilling to regulate the properties of drilling fluids.

DFT, Structure Activity Relationship, Fukui, Wave Function, NBO, NLO, Spectral and Hole-Electron Analyses of Dexmethylphenidate

Dexmethylphenidate (DMP) is used to treat attention deficit hyperactivity disorder (ADHD) and belongs to the central nervous system (CNS) stimulant group of medicines. The physical properties of DMP were analyzed under the DFT/B3LYP/6-311++G(d,p) basis set. The ESP study reveals the electrophilic attack is possible, while FMO analysis shows that the molecule is hard, stable and an electron donor. The non-covalent interaction (NCI) study explains that van der Waals and steric repulsion forces are observed. The HEI studies indicated that this molecule has CT excitation in the S0→S5 state. The shaded surface map analysis reveals the presence of electron depletion regions in this molecule. The UV-Vis spectral analysis was carried out in various solvents. The Fukui function analysis conveys that 7C is the best domain for electrophilic attack. Theoretical IR determinations and NLO properties were also performed. The structure-activity relationship findings were performed in order to improve the docking score.

Chitosan/La catalyzed synthesis of novel ferrocenated spiropyrrolizidines: Green synthesis, crystallographic, DFT and Hirshfeld surface studies

A novel polymeric catalytic system, utilizing chitosan-bounded lanthanum (chitosan/La), facilitated the formation of spiropyrrolizidine hybrids in higher yield. These hybrids were synthesized via one-pot three component 1,3-dipolar cycloaddition reaction involving ferrocenated chalcones, and azomethine ylides. The chemical structures were elucidated using various spectroscopic techniques and further confirmed via X-ray crystallography of a compound 3. Density functional theory (DFT) calculations executed followed by Gaussian 09 and GaussView 5.0 software provided insights into the optimal structure of molecular compounds. The computational analysis employed the 6–311G++ (d,p) higher-order basis set and the B3LYP method. Additionally, Hirshfeld surface analysis was utilized to predict crystallographic shapes, revealing van der Waals interaction contributing to crystal stabilization.

From single tube to multi-channel configuration: Constructing nanofiltration membranes with superior adhesion strength on the ceramic support by interfacial polymerization

Ceramic membranes with multi-channel configurations exhibit superior mechanical strength, high packing density, and high separation efficiency, making them more suitable for industrial applications than single tube and hollow fiber membranes. However, the preparation of thin-film composite (TFC) membranes on multi-channel ceramic supports remains a challenge because of the poor compatibility between organic and inorganic materials and their special configuration. In this study, nanofiltration membranes with a stabilized structure supported by 19-channel ceramic membranes were successfully prepared with improved adhesion strength and dynamic interfacial polymerization. TFC membranes with different channels exhibited uniform microstructure and stable performance. Specifically, polyethyleneimine, which served as a polymerization reactant, can be tightly wound on the surface of ceramic membranes via hydrogen bonding and van der Waals forces during interfacial polymerization. Owing to the enhanced cross-linked network interactions between the support and separation layers, the adhesion strength was significantly improved. Consequently, the optimized membranes maintained excellent rejection to MgCl2 of ∼94 % after the back-flush test under the pressure of 4 bar. Additionally, the multi-channel TFC membranes exhibited stable performance, with a pure water permeance of ∼14.9 LMH/bar and a molecular weight cut-off of 450 Da. When filtering sunset yellow for 10 h, the prepared membranes exhibited stable permeance and excellent rejection performance.

Molecular Interactions Governing the Rat Aryl Hydrocarbon Receptor Activities of Polycyclic Aromatic Compounds and Predictive Model Development.

Polycyclic aromatic compounds (PACs) exhibit rat aryl hydrocarbon receptor (rAhR) activities, leading to diverse biological or toxic effects. In this study, the key amino residues and molecular interactions that govern the rAhR activity of PACs were investigated using in silico strategies. The homology model of rAhR was first docked with 90 PACs to yield complexes, and the results of the molecular dynamics simulations of 16 typical complexes showed that the binding energies of the complexes range from -7.37 to -26.39 kcal/mol. The major contribution to the molecular interaction comes from van der Waals forces, and Pro295 and Arg316 become the key residues involved in most complexes. Two QSAR models were further developed to predict the rAhR activity of PACs (in terms of log IEQ for PACs without halogen substitutions and log%-TCDD-max for halogenated PACs). Both models have good predictive ability, robustness, and extrapolation ability. Molecular polarizability, electronegativity, size, and nucleophilicity are identified as the important factors affecting the rAhR activity of PACs. The developed models could be employed to predict the rAhR activity of other reactive PACs. This work provides insight into the mechanisms and interactions of the rAhR activity of PACs and assists in the assessment of their fate and risk in organisms.

Adsorption of phenolic compounds on polymeric ionic liquids: Adsorption isotherms interpretation and thermodynamic study

This study describes the thermodynamic assessment and steric interpretation of the 4-nitrophenol (4-NP) and 4-chlorophenol (4-CP) adsorption on polymeric ionic liquids (PILs) using advanced statistical physics model. A monolayer model with a single energy level was employed to elucidate the adsorption mechanisms of these phenolic compounds. The results showed that the orientation of 4-NP and 4-CP on the surface of this adsorbent was a combination of parallel and non-parallel configurations at the tested adsorption temperatures. The values of the adsorption capacities at saturation were 484.7 and 406.7 mg/g for4-NP and 4-CP, respectively. The modelling results indicated that more active sites from PILs surface were involved in the removal of 4-nitrophenol than those required for the 4-chlorophenol adsorption. The calculation of adsorption energies confirmed that the adsorption of 4-NP and 4-CP on PILs was exothermic and driven by physical forces involving hydrogen bonds and van der Waals forces. Three thermodynamic functions were analyzed to complete the macroscopic analysis of the adsorption mechanism for these relevant phenolic contaminants.

Decoding of the saltiness enhancement taste peptides from Jinhua ham and its molecular mechanism of interaction with ENaC/TMC4 receptors

This study focused on unlocking the potential of Jinhua ham-derived peptides (JHP) for enhancing saltiness. JHP (<3 kDa) was obtained through ultrafiltration and desalting, reducing the salt content by 96 %. Four peptide fractions (JHP-P1/P2/P3/P4) were isolated using Sephadex G-25 gel filtration and anion-exchange chromatography. Sensory evaluation and electronic tongue analysis revealed that JHP-P2 (0.5 mg/mL) exhibited the highest saltiness which could replace four-fold NaCl salinity. Three peptides (DL, FMSALF, and HVRRK) identified by UPLC-QTOF-MS/MS were simulated with salty taste receptors ENaC/TMC4. Results indicated that Ser84 and Phe89 of ENaC and Asn404 and Lys567 of TMC4 are crucial for peptide docking related to salty taste. Molecular dynamics simulations showed that the three peptides bind to the TMC4 and ENaC through van der Waals forces, electrostatic interactions, and hydrogen bonds. These findings establish a robust theoretical foundation for salt reduction strategies and provide novel insights into the potential applications of Jinhua ham.

Comparative studies on the interaction of casticin with five digestive enzymes using multi-spectroscopic methods, enzyme activities, and computational simulations

Casticin, which belongs to the flavonoid class, has been studied extensively due to its interesting biological activities. α-Amylase, trypsin, α-chymotrypsin, pepsin and lipase are common digestive enzymes with important physiological functions. In this study, the interactions of casticin with α-amylase, trypsin, α-chymotrypsin, pepsin and lipase were investigated by spectroscopy, enzymology and computational simulations. It has been shown that casticin binds to five digestive enzymes to form casticin-enzyme complexes with weak quenching ability, binding affinity and inhibitory activity. It is elucidated that casticin has different effects on the quenching constants, binding constants, number of binding sites, thermodynamic parameters, conformational microenvironment, secondary structure and binding stability of digestive enzymes. The interactions between casticin and α-amylase, trypsin, α-chymotrypsin, pepsin and lipase are a spontaneous exothermic process driven by enthalpy and entropy, and the binding forces are hydrogen bonds, van der Waals forces and hydrophobic interactions. Computational simulations, including molecular docking and molecular dynamics simulations, were employed to predict the binding model of casticin to these digestive enzymes. In summary, our research provides a theoretical guidance for exploring the role of casticin in pharmacology and biochemistry, which contributes to the understanding of the binding mechanism of casticin to digestive enzymes and its biological activity in vivo.

Adsorption and C-C bond cleavage of benzene on hematite α-Fe2O3 surfaces: a DFT mechanistic study.

Reforming tar molecules into smaller gaseous molecules has been a critical challenge for biomass energy utilization. Hematite (α-Fe2O3) has been demonstrated as an effective catalyst for the catalytic reforming of tar, nevertheless, the detailed mechanism of α-Fe2O3 catalyzed tar reforming remains unclear. In this work, we apply the density functional theory method to investigate this problem. Specifically, we study both (0001) and (01[Formula: see text]2) surface structures of α-Fe2O3 and then use the structures to investigate the adsorption and C-C bond cleavage of benzene on these surfaces. Our results show that the dominant interactions between benzene and a single Fe-terminated (0001) surface are van der Waals forces, yet benzene could be chemisorbed on the Fe and O co-exposed (01[Formula: see text]2) surface via strong C-O interactions. As a result, the (0001) surface is not active towards benzene cleavage, whereas the (01[Formula: see text]2) surface can promote the aromatic C-C bond breaking. Furthermore, our calculations indicate that chain-like alkene species and carbonyl species are the two types of potential products that form after the C-C bond cleavage of benzene on the α-Fe2O3 (01[Formula: see text]2) surface, with the activation energy of 1.78eV and 2.62eV, respectively. In summary, we reveal the importance of co-adsorption on both Fe and O centers and oxidative addition on C-C bond cleavage of aromatic compounds on the α-Fe2O3 surface, which provides novel insights into the mechanisms of tar cracking on oxide catalysts.

Probing amikacin interaction with albumin: A combined multispectral and molecular docking investigation

The fate of a drug administered to a living organism depends on the pharmacological and pharmacokinetic behavior of drugs. Biological macromolecules like serum albumins have a crucial role in the design and biological safety assessments of drugs. Amikacin as an example of the most used semi-synthetic aminoglycosides antibiotics, is included in the crucial drug list of the World Health Organization. This in vitro study aimed to explore Amikacin's binding specification with bovine serum albumin (BSA) through a computational and experimental approach. According to fluorescence spectra, it was declared that the innate fluorescence emission of serum albumin was quenched by the Amikacin via a static quenching mechanism. Meantime, the binding constants and thermodynamic parameters of Amikacin with BSA were calculated at various temperatures. Based on this calculation, negative ΔG°, ΔH°, and ΔS° values showed that spontaneous binding process occurred via hydrogen bond and van der Waals interaction. Additionally, based on UV–vis absorption, Amikacin leads to conformational modifications of BSA with the construction of a ground state complex, which may affect the physiological functions of this serum albumin. The results of FTIR spectroscopy showed that the binding of amikacin led in the change of BSA secondary structure and confirmed the possibility of changing the physiological functions of BSA. It is anticipated that this research will supply significant insight into the pharmacological properties of Amikacin and its related effects on human health in vivo.

The effect of graphene properties on the extrusion of a shape memory epoxy vitrimer

Thermoset polymers exhibit very appealing mechanical and functional properties. Direct ink writing (DIW) could open new possibilities in the design and fabrication of intricate thermoset parts, but it often requires the use of additives such as fumed silica or nanoclays to modify the rheology of uncured epoxies. However, relatively large concentrations are usually needed what can be detrimental to properties. Graphene-derived additives are an appealing alternative, but we need to understand the key physicochemical characteristics that define an optimum graphene rheology modifier. Here we compare the effect of three different carbon fillers on the viscoelastic response of a reprocessable epoxy vitrimer with shape memory capabilities, graphene oxide (GO), reduced graphene oxide (rGO), and graphene powder (GP), and assess the effect of their chemistry and morphology. The analysis shows that large (∼20 μm in size) rGO flakes enable the formation of strong, printable gels, through Van der Waals interactions and physical entanglement. The vitrimer could be successfully printed by incorporating 5 wt% of rGO. The printed parts exhibit tensile strengths (30–60 MPa), moduli (2–3 GPa), strength recovery after reprocessing (∼80 %), shape-memory properties comparable to the pure epoxy, and improved water resistance due to the introduction of hydrophobic rGO.

Hierarchical Self-Organization and Disorganization of Helical Supramolecular Columns Mediated by H-Bonding and Shape Complementarity.

H-bonding, shape complementarity, and quasi-equivalence are widely accepted as some of the most influential molecular recognition events mediating biological and synthetic self-organizations. H-bonds are weaker than ionic but stronger than van der Waals forces. However, the directionality of H-bonds makes them the most powerful among all nonbonding interactions. Here, we selected two taper-shaped self-assembling dendrons, one flexible and one rigid, and equipped them with -CO2CH3, -CH2OH, and -COOH at their apex. They demonstrated the hierarchical way in which shape-complementarity in the presence of -CO2CH3 mediated highly ordered helical self-organization for the case of the rigid building block and less ordered helical arrays for the flexible one. Weak H-bonding by -CH2OH unwound the helix from the rigid dendron, yielding a porous column. Due to its quasi-equivalence, the flexible dendron tolerated better the H-bonding by -CH2OH self-organizing a different helical column. The rigid and the flexible dendrons yielded only disorganized nonhelical columns in the presence of -COOH at the apex. This balance between rigidity, flexibility, and tolerance or lack of it to diverse H-bonding architectures indicates that mechanistic elucidation of the self-organization process helps endow it with the same building block, both helical organizations approaching biological precision, and disorganized nonhelical arrangements.

Algae-based self-driven microrobot for efficient removal of nanoplastics from water environment

Nanoplastics (NPs) have the characteristics of various species, wide distribution, low concentration and difficult degradation. In recent years, the researches of NPs have mainly focused on its toxicity, origin and migration, and the quantitative detection and removal technology of NPs is an urgent technical problem to be solved. Here, an active biohybrid microrobots (DPA-algae robots, diphenolic acids-alage robots) was designed and developed for dynamic removal of NPs in water environment. Firstly, diphenolic acids were functionalized on algae to realize the specific adsorption of nanoplastics through hydrophobic force, electrostatic attraction and van der Waals force between diphenolic acids and nanoplastic particles. Secondly, to realize the rapid identification of NPs, the functionalized algae were assembled into microrobots through rapid click chemistry reaction, thus the self-propulsion ability of algae can be utilized to accelerate the identification and enrichment of target objects. The removal rate of nanoplastics by microalgae robots has increased to 83.1 % at the concentration of 0.125 mg/mL within 2 h compared with the unmodified algae, which is a very significant improvement. In addition, the removal rate was 84.1 % to 87.7 % in different media, so the dynamic removal of NPs is expected to be applied into the filtration process of waterworks by preparing a large number of algae-based microrobots. This multi-functional microrobot is cost-effective and biocompatible, providing a new solution to the global “plastic crisis”.

Molecular insights into the interaction between graphene oxide and β-galactosidase: From multispectral experiment, enzyme kinetics experiment to computational simulations

β-galactosidase has potential applications in various scientific disciplines, including the food industry, genetic engineering, and enzyme engineering. In this study, multi-spectral experiments combined with enzyme kinetics experiments and computational simulation were used to explore the interaction mechanism, structural and functional changes, and effects on the microenvironment of graphene oxide and β-galactosidase. Graphene oxide was synthesized using the improved Hummer method, and the characterization experiments demonstrated that the structure was flat and free of cracks, and the functional groups satisfied the required amount. Zeta potential experiments and molecular docking results jointly confirmed that graphene oxide and β-galactosidase were combined by van der Waals forces, electrostatic forces, and hydrophobic forces. Fluorescence quenching experiments showed that the quenching constant decreased from 2.90 × 1012 mLμg-1s−1 to 1.76 × 1012 mLμg−1 s−1 with the increase of temperature, indicating that the quenching mode was static quenching, accompanied by increased polarity and decreased hydrophilicity of β-galactosidase. Circular Dichroism Spectrum, Fourier Transform infrared spectroscopy, the ONPG experiment, and molecular dynamics simulation proved that the stability and activity of β-galactosidase were improved after binding with graphene oxide. These findings provide support for the potential applications of β-galactosidase in addressing lactose intolerance, optimizing gene expression efficiency, and developing innovative biosensors or bioprocessing systems.

Adsorption desulphurization performance of biochar that derived from eucalyptus waste

In this paper, microporous biochar materials with large specific surface area (2592.2 m2/g) and pore volume (1.15 cm3/g) was prepared by eucalyptus waste, and was successfully used for adsorption desulfurization (ADS) where it showed high dibenzothiophene (DBT) adsorption capacity (172.5 mg/g). The biochar materials were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption isotherms and various spectroscopies (Raman, XRD, FTIR) analyses. The adsorption process was well consistent with the pseudo-second-order kinetic model and Langmuir isothermal model. ADS behavior was explained by the intraparticle diffusion model. The adsorption energies of DBT in carbon nanotubes with different pore sizes were calculated by using the density functional theory. It is finally concluded that ADS mainly attributed to π-π interactions between DBT with biochar materials, also includes hydrogen bonding, acid-base interactions and van der Waals force. The present work provides a new idea of ADS, using waste biomass materials to prepare biochar materials.

Microextraction of steroidal hormones from urine samples using natural deep eutectic solvents: insights into chemical interactions using molecular dynamics simulations.

Natural deep eutectic solvents (NADES) are gaining significant attention in analytical chemistry due to attractive physico-chemical properties associated with sustainable aspects. They have been successfully evaluated in different fields, and applications in sample preparation have increased in the last years. However, there is a limited knowledge related to chemical interactions and mechanism of intermolecular action with specific analytes. In this regard, for the first time, this study exploited a computational investigation using molecular dynamics (MD) predictions combined with experimental data for the extraction/determination of steroidal hormones (estriol, β-estradiol, and estrone) in urine samples using NADES. The ultrasound-assisted liquid-liquid microextraction (UALLME) approach followed by high-performance liquid chromatography with diode array detection (HPLC-DAD) was employed using menthol:decanoic acid as extraction solvent. Experimental parameters were optimized through multivariate strategies, with the best conditions consisting of 3min of extraction, 150 μL of NADES, and 3mL of sample (tenfold diluted). According to molecular dynamics predictions confirmed by experimental data, a molar ratio that permitted the highest efficiency consisted of menthol:decanoic acid 2:1 v/v. Importantly, computational simulations revealed that van der Waals interactions were the most significant contributor to the interaction energy of analytes-NADES. Using the optimized conditions, limits of detection (LOD) ranged from 3 and 8μg L-1, and precision (n = 3) varied from 8 to 19%. Intraday precision was evaluated at 3 concentrations: low (LOQ according to each analyte), medium (100μg L-1), and high (750μg L-1). Accuracy was successfully assessed through recoveries that ranged from 82 to 98%. In this case, molecular dynamics simulations proved to be an important tool for in-depth investigations of interaction mechanisms of DES with different analytes.

Investigating the interaction mechanisms between arachin and resveratrol: Utilizing multi-spectroscopy and computational chemistry

Arachin (ARA) and resveratrol (RES) are the primary protein and bioactive compound in peanuts and their processed products. However, the mechanism of interaction between these two substances remained unclear. To investigate protein structural changes, conformational variations, and molecular mechanisms in the interaction between them, multispectral analysis and computational chemistry methods were employed. Experimental results confirmed that RES quenched ARA's intrinsic fluorescence through static quenching, indicating their interaction. Thermodynamic analysis revealed the interaction between them was endothermic, spontaneous, and primarily hydrophobic. Molecular dynamics (MD) simulations highlighted strong affinity between RES and ARA, with key amino acids (His425, Val426, Phe405, and Phe464) facilitating their interaction. RES binding increased stability without significant protein conformational changes. The independent gradient model based on Hirshfeld partition (IGMH) validated their interaction, emphasizing van der Waals (VDW) interactions and hydrogen bonds (H-bonds) as crucial for stable binding. This research lays a theoretical foundation for potential applications of ARA-RES complex products in the food industry.