Electrostatic Research Articles

Metal organic frameworks (MOFs)-based fluorescent CA125 analysis: A comparative study of the quenching effects of MIL-101, Cu-MOF, ZIF-8, UiO-66

Metal-organic frameworks (MOFs) are a class of materials with highly ordered pore structures. Due to their unique physical and chemical properties, they show great potential in the field of biosensors. Some MOFs can adsorb fluorescently labeled nucleic acid aptamers through various interaction mechanisms (such as electrostatic interactions, π-π stacking, hydrogen bonding, etc.). These interactions not only ensure the stable binding of the aptamers but also allow for their controlled release under specific conditions (such as changes in pH, temperature, or the presence of specific molecules). This mechanism provides multiple possibilities for the design of biosensors. Herein, we have systematically compared the quenching effects of widely used MOFs that can bind to aptamers, i.e., Fe-MOF (MIL-101), Cu-MOF, Zn-MOF (ZIF-8) and Zr-MOF (UiO-66). The study on the kinetics, quenching efficiency, and influencing factors such as ionic strength pH and temperature is performed. Interestingly, Cu-MOF exhibits superior quenching abilities to the other three materials in both the quenching efficiency and kinetics. Thus, a Cu-MOF based fluorescent sensor is reported to detect the ovarian cancer marker carbohydrate antigen 125 (CA125), which provides convenient detection performance (assay time about 10 min), and a detection range from 0.1 to 400 ng/mL. Moreover, it is designed in a simple mix-and-detect format and can be directly applied to clinical sample detection. This work may offer guidance for the choice of MOFs and elaborate design of biosensors.

Development of polyfunctionalized biochar modified with manganese oxide and sulfur for immobilizing Hg(II) and Pb(II) in water and soil and improving soil health

Mercury (Hg) and lead (Pb) pose significant risks to human health due to their high toxicity and bioaccumulative properties. This study aimed to develop a novel biochar composite (HMB-S), polyfunctionalized with manganese dioxide (α-MnO2) and sulfur functional groups, for the effective immobilization of Hg(II) and Pb(II) from contaminated environments. HMB-S demonstrated superior adsorption capacities of 190.1 mg/g for Hg(II) and 259.9 mg/g for Pb(II), which significantly surpasses the capacities of unmodified biochar (HB) and biochar functionalized solely with Mn (HMB). Mechanistic studies revealed that the immobilization of these metals by HMB-S involved ion exchange, mineral precipitation, surface complexation, and electrostatic interactions. In soil incubation experiments, HMB-S significantly decreased the levels of extractable Hg(II) and Pb(II) compared to the control, reducing the mobility of these metals and converting 17 % of Hg(II) and 26 % of Pb(II) into less bioavailable residual forms. Pot experiments confirmed that all tested biochar materials (HB, HMB, and HMB-S) promoted spinach growth in contaminated soils, with HMB-S being the most effective at lowering Hg(II) and Pb(II) uptake by plants. Additionally, analysis of soil microbial communities indicated that HMB-S altered community composition and increased the relative abundance of metal-resistant bacteria. These findings highlight the potential of polyfunctionalized biochar HMB-S as an effective remediation strategy for Hg and Pb contamination in soil and aqueous environments.

Green room-temperature fabrication of phosphotungstic acid functionalized MOF-808 for efficient removal of cationic antibiotics

ZrⅣ-based metal–organic frameworks (MOFs)–featuring exceptional water stability, large surface area, and structural tunability–hold promise for efficient antibiotics adsorption from water. However, their inherent positive charge in neutral environments and the harsh conditions required for their synthesis hinder their effective removal of cationic antibiotics. To address this challenge, a green one-pot synthesis approach was proposed to fabricate phosphotungstic acid-functionalized MOF-808 (termed as PTA@MOF-808) at room temperature for elevated antibiotic adsorption. This approach not only leverages the strong electronegativity of PTA to improve electrostatic interactions and π-π stacking but also finely tailors the pore size of MOF-808, resulting in enhanced adsorption capacity of PTA@MOF-808. The influence of PTA loading, solution pH, and absorbent dosage on the performance of PTA@MOF-808 were studied in detail. Adsorption experiments demonstrated that PTA@MOF-808 outperformed unmodified MOF-808 in removing various positively charged antibiotics, with 5 % PTA@MOF-808 exhibiting maximum adsorption capacities of 548.1 mg g−1 and 482.9 mg g−1, for DOX and TCHC, respectively. The adsorption process followed the Langmuir isothermal model and the pseudo-second-order kinetic equation. Furthermore, the composite PTA@MOF-808 displayed excellent reusability after multiple adsorption–desorption cycles. These findings highlight the potential of PTA@MOF-808 as a promising absorbent for removing specific antibiotics from water, with significant implications for wastewater treatment.

New Hypothesis on Enhancing β-Sheet Formation during the Tau Fragment Dimer Transition from a Flexible Monomer: Insights into Primary Nucleation Processes by Histidine Behaviors.

Slight perturbations in pH can have significant effects on the primary nucleation processes of the tau protein. The behaviors of histidine due to its pivotal role in modulating H-bonding network interactions and electrostatic interactions have garnered considerable attention, as it can influence the structural characteristics and aggregation properties. However, the nucleation mechanisms and related intermediates are still unclear. In the current study, we performed nine independent replica exchange molecular dynamics simulations to investigate dimer formation involving R3(εδ) in conjunction with the R1, R2, and R4 monomers. Our findings substantiate that, in comparison to R1-R3(εδ) and R4-R3(εδ) systems, the R2-R3(εδ) systems consistently manifest the highest averaged β-sheet content, with the fundamental feature of R3(εδ) promoting R2 rearrangement. Our comprehensive analysis reveals that high-β-sheet-rich systems exhibit a conserved three/five β-strand structure. In these β-strand-rich systems, one chain [R1/R2/R4 or R3(εδ)] with robust intrachain H-bonding interactions coordinates with another chain through interchain H-bonding interactions, contributing to the overall stability. Furthermore, we discuss distinct histidine behaviors, including backbone/side chain interactions and donor/acceptor roles. This study provides a comprehensive understanding of the aggregation propensities of soluble tau oligomers and sheds light on the primary nucleation mechanism. It contributes to a new perspective for understanding protein folding and misfolding.

Ionically assembled hemostatic powders with rapid self-gelation, strong acid resistance, and on-demand removability for upper gastrointestinal bleeding.

Upper gastrointestinal bleeding (UGIB) is bleeding in the upper part of the gastrointestinal tract with an acidic and dynamic environment that limits the application of conventional hemostatic materials. This study focuses on the development of N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride/phytic acid (HTCC/PA, HP) powders with fast hemostatic capability and strong acid resistance, for potential applications in managing UGIB. Upon contact with liquids within 5 seconds, HP powders rapidly transform into hydrogels, forming ionic networks through electrostatic interactions. The ionic crosslinking process facilitates the HP powders with high blood absorption (3.4 times of self-weight), sufficient tissue adhesion (5.2 and 6.1 kPa on porcine skin and stomach, respectively), and hemostasis (within 15 seconds for in vitro clotting). Interestingly, the PA imparts the HP powders with strong acid resistance (69.8% mass remaining after 10 days of incubation at pH 1) and on-demand removable sealing while HTCC contributes to fast hemostasis and good wet adhesion. Moreover, the HP powders show good biocompatibility and promote wound healing. Therefore, these characteristics highlight the promising clinical potential of HP powders for effectively managing UGIB.

Form Equals Function: Influence of Coacervate Architecture on Drug Delivery Applications.

Complex coacervates, formed through electrostatic interactions between oppositely charged polymers, present a versatile platform for drug delivery, providing rapid assembly, selective encapsulation, and responsiveness to environmental stimuli. The architecture and properties of coacervates can be tuned by controlling structural and environmental design factors, which significantly impact the stability and delivery efficiency of the drugs. While environmental design factors such as salt, pH, and temperature play a crucial role in coacervate formation, structural design factors such as polymer concentration, polymer structure, mixing ratio, and chain length serve as the core framework that shapes coacervate architecture. These elements modulate the phase behavior and material properties of coacervates, allowing for a highly tunable system. In this review, we primarily analyze how these structural design factors contribute to the formation of diverse coacervate architecture, ranging from bulk coacervates to polyion complex micelles, vesicles, and cross-linked gels, though environmental design factors are considered. We then examine the effectiveness of these architectures in enhancing the delivery and efficacy of drugs across various administration routes, such as noninvasive (e.g., oral and transdermal) and invasive delivery. This review aims to provide foundational insights into the design of advanced drug delivery systems by examining how the origin and chemical structure of polymers influence coacervate architecture, which in turn defines their material properties. We then explore how the architecture can be tailored to optimize drug delivery for specific administration routes. This approach leverages the intrinsic properties derived from the coacervate architecture to enable targeted, controlled, and efficient drug release, ultimately enhancing therapeutic outcomes in precision medicine.

Harnessing the targeting potential of hyaluronic acid for augmented anticancer activity and safety of duvelisib-loaded nanoparticles in hematological malignancies

Duvelisib (DUV) is effective against numerous hematological malignancies; however, it suffers from numerous setbacks like poor aqueous solubility, low cellular uptake and adverse effects. Hyaluronic acid is an excellent ligand for CD44 receptors that are overexpressed on cancer cell surfaces. Thus, for the targeted delivery of DUV in hematological malignancies, we have fabricated hyaluronic acid-coated polylactide-co-glycolide nanoparticles (DUV-P/CH/HA-NPs) through electrostatic interactions. DUV-P/CH/HA-NPs exhibited optimum characteristics such as mean particle size of 183.63 ± 0.23 nm, polydispersity index of 0.261 ± 0.02 and drug loading capacity of 5.75 ± 0.05 %. An in-vitro release study demonstrated sustained release behavior of DUV-P/CH/HA-NPs (77.65 ± 2.89 % release in 48 h). The flow cytometry experiments revealed 1.62-fold and 1.50-fold enhanced uptake of DUV-P/CH/HA-NPs compared to non-coated nanoparticles in MOLT-4 and HH cells, respectively. The DUV-P/CH/HA-NPs showed higher cytotoxicity, arrested the cell cycle in G0/G1 phase and showed increased apoptosis compared to non-coated nanoparticles and free DUV. An in-vivo pharmacokinetic study revealed 2.9-fold and 3.6-fold enhancement in AUC0-t and MRT with the DUV-P/CH/HA-NPs compared to free DUV. Further, toxicity evaluation and hemolysis assessment of DUV-P/CH/HA-NPs indicated good safety for intravenous administration. Conclusively, DUV-P/CH/HA-NPs are an excellent option for selectively targeting hematological malignant cells.

Facile modification of TiO2 as S-Scheme multifunctional materials for environmental protection and energy-storage applications

This paper reports a simple one-step modification of commercial TiO2 with a conducting polytrimethoxyslilypropyl aniline (PTMSPA, a polyaniline derivative having silyl networks) to have multi-functional (photocatalytic, optical, pseudocapacitive, hydrophobic, porous, antibacterial, and electromagnetic interference shielding (EMI)) properties and demonstrates associated applications. We present the S-Scheme heterojunction (SHJ) formation between TiO2 and PTMSPA through band position alignments and designate the resultant TiO2 - TiO2- based SHJ multifunctional materials as MF-TSSM. The internal electric field that is generated at the interface facilitates the transportation of the photogenerated electron transfer . The XRD pattern of MF-TSSM exhibits mainly the peaks of anatase TiO2. The TEM image of MF-TSSM indicates that the TiO2 particles are spherical in shape with sizes showing variations in diameters ranging from 60 nm to 250 nm depending on the experimental conditions of preparation and TiO2 particles are homogeneously distributed within the PTMSPA matrix. The optical energy band gap of MF-TSSM is 1.60 eV, a much lower value than PTMSPA (3.02 eV), suggesting that the composite formation between TiO2 and PTMSPA. The contact angle of MF-TSSM is significantly increased to 47.1 ° from 8.0 of TiO2, informing the increase of hydrophobic characteristics. The rate constant (k) for methylene blue photodegradation was 0.030 min-1, and 0.010 min-1 for MF-TSSM and pristine TiO2, respectively, The MF-TSSM composite exhibits a higher specific capacitance value (28.7 F/g) than TMSPA (21.1 F/g). At a frequency of 0.42 THz, MF-TSSM and PTMSPA exhibit return loss features indicating good EMI shielding performance. The MF-TSSM has been tested against two different Gram-positive and Gram-negative bacterial strains. The nanoparticles were evaluated at doses of 10, 20, 40, and 80 µg/ml. The results indicated that Klebsiella pneumoniae demonstrated a greater zone of inhibition, ranging from 9 mm at 10 µg/ml to 23 mm at 80 µg/ml, indicating increased susceptibility. Pseudomonas aeruginosa exhibited reduced inhibition zones, ranging from 10 mm at 10 µg/ml to 14 mm at 80 µg/ml, indicating increased resistance. The excellent effectiveness of MF-TSSM against various Gram-positive and Gram-negative pathogenic bacteria is explained by the interaction between reactive oxygen species and the cellular components of the bacteria as well the electrostatic interaction arising between positive charges in TMSPA and negative charges in the cell components, resulting in notable cytotoxicity and damage to the bacterial cells. The research underscores the capability of these modified TiO₂ nanoparticles in addressing bacterial infections, with efficiency differing by bacterial strain.

Unveiling Fluorescence Spectroscopy, Molecular Docking and Dynamic Simulations: Interactions Between Protein and 2, 4-Dinitrophenylhydrazine Schiff Base.

In this study, we aimed to explore the interaction mechanism between bovine serum albumin (BSA) and a Schiff base compound derived from 2,4-dinotrophenyl hydrazine (L) using various spectroscopic techniques. The interaction between BSA and synthesizing molecule can provide insights into binding affinity, conformational changes and potential applications in drug delivery or biochemistry. The interaction between BSA and L was studied by using UV-Vis and fluorescence titration analysis. The fluorescence quenching emission was observed at 343nm, upon addition of L to the buffer solution of BSA. The binding between BSA and ligand is static in nature using fluorescence quenching emission. The thermodynamic parameters were calculated from the temperature-dependent binding constants (i.e., ∆H = -0.318kcal/mol, ∆G = -7.857kcal/mol and ∆S = 0.023kcal/mol), which indicated that the protein-ligand complex formation between L and BSA is mainly due to the electrostatic interactions. The experimental and theoretical results showed excellent agreement with respect to the mechanism of binding and binding constants. The molecular docking and molecular dynamic analysis experiments were performed to establish the interaction between protein and ligand.

Hierarchical assembly and environmental enhancement of bacterial ice nucleators

Bacterial ice nucleating proteins (INPs) are exceptionally effective in promoting the kinetically hindered transition of water to ice. Their efficiency relies on the assembly of INPs into large functional aggregates, with the size of ice nucleation sites determining activity. Experimental freezing spectra have revealed two distinct, defined aggregate sizes, typically classified as class A and C ice nucleators (INs). Despite the importance of INPs and years of extensive research, the precise number of INPs forming the two aggregate classes, and their assembly mechanism have remained enigmatic. Here, we report that bacterial ice nucleation activity emerges from more than two prevailing aggregate species and identify the specific number of INPs responsible for distinct crystallization temperatures. We find that INP dimers constitute class C INs, tetramers class B INs, and hexamers and larger multimers are responsible for the most efficient class A activity. We propose a hierarchical assembly mechanism based on tyrosine interactions for dimers, and electrostatic interactions between INP dimers to produce larger aggregates. This assembly is membrane-assisted: Increasing the bacterial outer membrane fluidity decreases the population of the larger aggregates, while preserving the dimers. Inversely, Dulbecco's Phosphate-Buffered Saline buffer increases the population of multimeric class A and B aggregates 200-fold and endows the bacteria with enhanced stability toward repeated freeze-thaw cycles. Our analysis suggests that the enhancement results from the better alignment of dimers in the negatively charged outer membrane, due to screening of their electrostatic repulsion. This demonstrates significant enhancement of the most potent bacterial INs.

Highly conductive alcohol‐processable n‐type conducting polymer enabled by finely tuned electrostatic interactions for green organic electronics

Solution‐processable conducting polymers open up a new era in organic electronics, fundamentally altering the processing methods of electronic devices. P‐type conducting polymers, exemplified by aqueous solution‐processed poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), have been successfully commercialized. However, the performance of electron‐transporting (n‐type) materials remains considerably poorer. One of the primary challenges lies in striking a balance between conductivity and solvent processability. At present, most n‐type conducting polymers necessitate toxic solvents for processing, which contradicts environmentally sustainable principles and impedes their potential for large‐scale industrial applications. Herein, we developed an alcohol‐processable high‐performance n‐type conducting polymer, poly(3,7‐dihydrobenzo[1,2‐b:4,5‐b’]difuran‐2,6‐dione): poly(2‐ethyl‐2‐oxazoline) (PBFDO:PEOx), which utilizes electrostatic interactions between PEOx and PBFDO to simultaneously achieve high conductivity and alcohol‐processability. The PBFDO:PEOx films exhibit remarkable electrical conductivity exceeding 1000 S cm−1 with outstanding stability even at temperatures up to 250 °C, establishing it as a prominent green solvent‐processed n‐type conducting polymer that rivals the most advanced p‐type counterparts. Various applications including organic thermoelectric, electrochemical transistor and electrochromic devices were showcased, highlighting the broad potential of PBFDO:PEOx in advancing green organic electronics.

Highly conductive alcohol-processable n-type conducting polymer enabled by finely tuned electrostatic interactions for green organic electronics.

Solution-processable conducting polymers open up a new era in organic electronics, fundamentally altering the processing methods of electronic devices. P-type conducting polymers, exemplified by aqueous solution-processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), have been successfully commercialized. However, the performance of electron-transporting (n-type) materials remains considerably poorer. One of the primary challenges lies in striking a balance between conductivity and solvent processability. At present, most n-type conducting polymers necessitate toxic solvents for processing, which contradicts environmentally sustainable principles and impedes their potential for large-scale industrial applications. Herein, we developed an alcohol-processable high-performance n-type conducting polymer, poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione): poly(2-ethyl-2-oxazoline) (PBFDO:PEOx), which utilizes electrostatic interactions between PEOx and PBFDO to simultaneously achieve high conductivity and alcohol-processability. The PBFDO:PEOx films exhibit remarkable electrical conductivity exceeding 1000 S cm-1 with outstanding stability even at temperatures up to 250 °C, establishing it as a prominent green solvent-processed n-type conducting polymer that rivals the most advanced p-type counterparts. Various applications including organic thermoelectric, electrochemical transistor and electrochromic devices were showcased, highlighting the broad potential of PBFDO:PEOx in advancing green organic electronics.

Balancing stretchability and conductivity: Carbon nanotube layer-enhanced non-ionic conductive hydrogels with a sandwich structure

In non-ionic conductive hydrogels, conductivity often conflicts with mechanical properties, posing a challenge in creating hydrogels that strike a balance between conductivity and mechanical properties. Here, we addressed this issue by integrating carboxylated carbon nanotube (CNT) layers in a sandwich structure onto the surface of the cationic hydrogel (P(AM-co-DMDAAC), PAD), followed by dehydration for densification. This approach simultaneously improved the conductivity of the hydrogel while maintaining its stretchability. The stability of the composite structure was ensured through electrostatic interactions, hydrogen bonding, and physical entanglement between the PAD hydrogel and the CNT layer. Additionally, adjusting the water–solid ratio of the hydrogel allows fine-tuning of its conductivity and stretchability. Remarkably, at a 500 % water–solid ratio, the hydrogel achieved a conductivity of 2.3 S/m. By further reducing the water content, the conductivity could be increased to 25 S/m, significantly higher than similar hydrogels. The PAD-CNT hydrogel found applications in swelling response, tunable resistance wires, and as strain sensors. Notably, the sandwich structure enables the PAD-CNT hydrogel to output capacitive signals, exhibiting a more sensitive response in monitoring human movement. Overall, this study introduces a novel composite structure for conductive hydrogels, holding tremendous potential in flexible conductivity and smart response fields.

Zwitterionic covalent organic nanosheets for selective analysis of domoic acid in marine environment

BackgroundDomoic acid (DA) is a neurotoxic compound causing amnesic shellfish poisoning, secreted by red algae and diatoms. As a glutamate analogue, DA accumulates in filter-feeding marine organisms, posing significant health risks to humans upon consumption. Detecting DA in marine environments remains challenging due to its low concentration and interference from complex matrices. Effective detection and removal require materials with high efficiency and selectivity, which traditional inorganic ionic materials lack due to their limited adsorption capacity and selectivity. Ionic covalent organic frameworks (iCOFs) expected to become highly efficient DA adsorbents due to tunable ionic sites. ResultsThus, a zwitterionic covalent organic nanosheet (TGDB-iCONs) was synthesized to selectively capture DA. TGDB-iCONs was prepared by one-step Schiff-base reaction of the charged monomer triaminoguanidine hydrochloride. It uniformly distributed positively charged guanidinium and negatively charged chloride ions on the surface, forming zwitterionic binding sites. The self-peeling of TGDB-iCONs facilitated the exposure of active sites and improved the adsorption efficiency. Several binding forces were generated between TGDB-iCONs and DA, including complementary electrostatic hydrophilic interactions, which were verified by density functional theory (DFT) calculation. TGDB-iCONs exhibited ultra-fast adsorption kinetics (7 min) and relatively high adsorption capacity (66.48 mg/g) for DA. Furthermore, TGDB-iCONs exhibit strong salt resistance, which is attributed to the charge “shielding” effect of the zwitterionic ions present in TGDB-iCONs. TGDB-iCONs could highly selectively enrich DA and detect trace DA from marine environment including seawater, algae and marine organisms and the limit of detection as low as 0.3 ng/kg. Significance and noveltyThis comprehensive study not only sheds light on the vast potential of ionic covalent organic frameworks nanosheets (iCONs) in supporting early warning, control, and traceability of DA, but also lays a solid foundation for future research endeavors aimed at designing and harnessing the unique properties of iCONs.

Removal of perfluoroalkyl acids and precursors with silylated clay: Efficient adsorption and enhanced reuse

Organically modified clays (organoclays) have been considered effective adsorbents for the treatment of per- and polyfluoroalkyl substances (PFAS). However, the stability of organoclays prepared through the conventional cation exchange approach has been a major concern for their practical application. In this study, we reported the development of a new organically functionalized clay by grafting pillared clay substrate with an organosilane through covalent bonding. The performance of the silylated clay (QAG-ZrMT) was systematically compared with an organoclay prepared from ion exchange (HDTMA-ZrMT) for the adsorption of two legacy perfluoroalkyl acids: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), and two precursor compounds 5:3 fluorotelomer carboxylic acid (5:3FTCA) and 6:2 fluorotelomer sulfonic acid (6:2FTS). Compared to HDTMA-ZrMT, QAG-ZrMT showed substantially improved performance for adsorption of less hydrophobic PFAS (e.g., 5:3FTCA), which could be related to the stronger electrostatic interactions between PFAS and QAG-ZrMT than HDTMA-ZrMT. More importantly, QAG-ZrMT could be conveniently regenerated and reused for multiple cycles with robust performance. In contrast, HDTMA-ZrMT almost completely lost its capacity for PFAS removal after regeneration, due to the loss of organic functional groups during solvent regeneration. Results can shed light on the design of efficient and regenerable organoclay adsorbents for remediation of PFAS-contaminated water matrices.

Electrostatically Dominated Pre-Organization inCyclodextrin Metal-Organic Frameworks.

Electrostatic interactions between oppositely charged entities play a key role in pre-organizing substrates and stabilizing transition states of reactions in enzymes. The use of electrostatic interactions to pre-organize ions in nanoconfined pores, however, has not been investigated to its full potential. Herein, we describe how carboxylate anions can be pre-organized at the behest of their electrostatic interactions with K+ cations in nanoconfined tunnels present in γ-cyclodextrin metal-organic frameworks, i.e., CD-MOFs. Several carboxylate anions, which are all much smaller than the cavities of the tunnels, were visualized by X-ray crystallography when nanoconfined in CD-MOFs, despite the large voids present in the tunnels. These anions were found to be aligned within a planar array defined by four K+ cations, positioned around the periphery of the tunnels. The strong electrostatic interactions between the carboxylate anions and the K+ cations dictate the orientation of the anions and override the influence of other possible noncovalent bonding interactions between them and the tunnels. Consequently, the aligned pairs of γ-cyclodextrin rings constituting the tunnels become distorted, resulting in their lower symmetry and fewer disordered carboxylate anions in the solid-state. Our findings offer a transformative strategy for controlling the packing and orientation of ions in nanoconfined environments.

Dissolved organic matter-mediated adsorption behavior of benzophenones on functionalized covalent triazine frameworks

Adsorption is a highly efficacious technique for the remediation of organic micropollutants (OMPs). However, the presence of dissolved organic matter (DOM) frequently impedes adsorbent process, with insufficient attention given to this influence. This study systematically evaluates the adsorption performance of covalent triazine frameworks (CTFs) functionalized with electron-donating or electron-withdrawing groups for benzophenones (BPs). The adsorption capacities of SO3H-CTF, OH-CTF, and NH2-CTF for BPs were 512.11 μmol/g, 1356.27 μmol/g, and 1421.85 μmol/g, respectively. The adsorption mechanism is predominantly governed by π-π electron donor–acceptor (EDA) interactions, supplemented by hydrogen bonding, particularly in hydroxyl-containing BPs, with electrostatic interactions being relatively negligible. Functionalization with − OH and − NH2 groups increased the electron density in π-conjugated regions, enhancing BPs adsorption capacity, whereas − SO3H modification, due to its electron-withdrawing nature, acted as a π electron acceptor. Importantly, the mediating role of humic acid (HA) in the adsorption process was investigated. The CTF-BPs-HA ternary system can either inhibit/enhance π-π EDA interactions between π-electron donor/acceptor and BPs by adsorbing onto the CTF materials. The HA-mediated system primarily affects the film diffusion stage, with minimal impact on pore diffusion and inner surface adsorption. The oxygenated functional groups in HA slightly enhanced hydrogen bonding within the adsorption system, with negligible influence on electrostatic interactions. In the presence of HA, the overall adsorption capacity of SO3H-CTF decreased by 67.0 %, while that of OH-CTF and NH2-CTF increased by 120.9 % and 55.3 %, respectively. This study elucidates the electronic behavior modifications of functionalized CTFs during BPs adsorption and underscores the significant role of HA in interaction mechanisms, providing theoretical guidance for the design of advanced adsorbents to enhance pollutant removal efficiency.

Assay for Characterizing Adsorption-Properties of Surfaces (APS).

Analytes, from sample preparation, until entering an analytical instrument, are prone to adsorb to surfaces, driven by the chemical properties of the surface and the liquids they are dissolved in. This problem can be addressed with internal standards when a single or few known analytes are quantified that are usually not available in omics. However, minimal to no loss of analytes is the aim. Here, we present a novel assay for qualifying and quantifying interactions responsible for adsorption of molecules to surfaces (APS) by using LC-MS/MS-based differential quantitative analysis. To reflect a broad range of chemical interactions with surfaces, a reference mixture of thousands of tryptic peptides, with known compositions was selected, representing a variety of different chemical characteristics. The assay was tested by investigating the adsorption properties of several different vials with different surface chemistries. A significant number of hydrophobic peptides adsorbed to conventional polypropylene vials. In contrast, only few peptides adsorbed to polypropylene vials, assigned as low-protein-binding. The highest number of peptides adsorbed to glass vials driven by electrostatic interactions. In summary, the new assay is suitable to characterize adsorption properties of different surfaces and to approximate the loss of analytes during sample preparation.

The Feasibility of Using Electrostatic Interactions for Immobilizing Ru-bda Catalysts in Covalent Organic Framework: A Proof-of-concept.

Heterogenetization of molecular catalysts effectively resolves the separation issues of homogeneous catalysts and expands their application scenarios. In recent years, more and more studies have been using non-covalent interactions to achieve the heterogenization of molecular catalysts. Herein, electrostatic attraction was used to immobilize molecular catalysts, Ru-bda small molecular catalysts in COF materials, where the charged Ru-bda catalysts were immobilized in the oppositely charged COF with a high [Ru] loading content of ~0.2 mmol [Ru] g-1 COF. The leakage experiment verified that the immobilization of Ru-bda catalysts in COF by electrostatic interactions is stable in 0.1 M HClO4 and less than 5% of molecular Ru-bda catalysts were leached into the solution in 2 hours. The chemical water oxidation experiment was conducted as a model catalysis reaction to verify the feasibility of using electrostatic interactions for immobilizing Ru-bda catalysts in COFs. The prepared Ru(bda)@COFs demonstrate a high catalytic activity of 268 μmol L-1 s-1 O2 for chemical water oxidation, illustrating the electrostatic attractions between COF and small molecules that can be used to immobilize homogeneous catalysts in heterogeneous materials. However, the robustness of COF material itself under catalytic conditions should be considered in practical applications.

Effects of Chitosan and N-Succinyl Chitosan on Metabolic Disorders Caused by Oral Administration of Olanzapine in Mice.

The issue of human mental health is gaining more and more attention nowadays. However, most mental disorders are treated with antipsychotic drugs that cause weight gain and metabolic disorders, which include olanzapine (OLZ). The search for and development of natural compounds for the prevention of obesity when taking antipsychotic drugs is an urgent task. The biopolymer chitosan (Chi) and its derivatives have lipid-lowering and anti-diabetic properties, which makes them potential therapeutic substances for use in the treatment of metabolic disorders. The purpose of this work was to analyze the effect of the natural biopolymer Chi, its derivative N-succinyl chitosan (SuChi), and Orlistat (ORL) as a control on the effects caused by the intake of OLZ in a mouse model. Mice were fed with pearl barley porridge mixed with OLZ or combinations OLZ + Chi, OLZ + SuChi, or OLZ + ORL for 2 months. The weight, lipid profile, blood chemokines, expression of genes associated with appetite regulation, and behavior of the mice were analyzed in dynamics. For the first time, data were obtained on the effects of Chi and SuChi on metabolic changes during the co-administration of antipsychotics. Oral OLZ increased body weight, food and water intake, and glucose, triglyceride, and cholesterol levels in blood. ORL and SuChi better normalized lipid metabolism than Chi, decreasing triglyceride and cholesterol levels. OLZ decreased the production of all chemokines tested at the 4th week of treatment and increased CXCL1, CXCL13, and CCL22 chemokine levels at the 7th week. All of the supplements corrected the level of CXCL1, CXCL13, and CCL22 chemokines but did not recover suppressed chemokines. SuChi and ORL stimulated the expression of satiety associated proopiomelanocortin (POMC) and suppressed the appetite-stimulating Agouti-related protein (AgRP) genes. All supplements improved the locomotion of mice. Taken collectively, we found that SuChi more than Chi possessed an activity close to that of ORL, preventing metabolic disorders in mice fed with OLZ. As OLZ carries positive charge and SuChi is negatively charged, we hypothesized that SuChi's protective effect can be explained by electrostatic interaction between OLZ byproducts and SuChi in the gastrointestinal tract.