Molecules Of Different Sizes Research Articles

Size-tunable transmembrane nanopores assembled from decomposable molecular templates

Transmembrane nanopores, as key elements in molecular transport and single-molecule sensors, are assembled naturally from multiple monomers in the presence of lipid bilayers. The nanopore size, especially the precise diameter of the inner space, determines its sensing targets and further biological application. In this paper, we introduce a template molecule-aided assembly strategy for constructing size-tunable transmembrane nanopores. Inspired by the barrel-like structure, similar to many transmembrane proteins, cyclodextrin molecules of different sizes are utilized as templates and modulators to assemble the α-helical barreled peptide of polysaccharide transporters (Wza). The functional nanopores assembled by this strategy possess high biological and chemical activity and can be inserted into lipid bilayers, forming stable single channels for single-molecule sensing. After enzyme digestion, the cyclodextrins on protein nanopores can be degraded, and the remaining nontemplate transmembrane protein nanopores can also preserve the integrity of their structure and function. The template molecule-aided assembly strategy employed a simple and convenient method for fully artificially synthesizing transmembrane protein nanopores; the pore size is completely dependent on the size of the template molecule and controllable, ranging from 1.1 to 1.8 nm. Furthermore, by chemically synthesized peptides and modifications, the pore function is easily modulated and does not involve the cumbersome genetic mutations of other biological techniques.

Bio‐inspired hierarchical bamboo‐based air filters for efficient removal of particulate matter and toxic gases

AbstractAir pollution is caused by the perilous accumulation of particulate matter (PM) and harmful gas molecules of different sizes. There is an urgent need to develop highly efficient air filtration systems capable of removing particles with a wide size distribution. However, the efficiency of current air filters is compromised by controlling their hierarchical pore size. Inspired by the graded filtration mechanisms in the human respiratory system, microporous ZIF‐67 is in situ synthesized on a 3D interconnected network of bamboo cellulose fibers (BCFs) to fabricate a multiscale porous filter with a comprehensive pore size distribution. The macropores between the BCFs, mesopores formed by the BCF microfibers, and micropores within the ZIF‐67 synergistically facilitate the removal of particulates of different sizes. The filtration capabilities of PM2.5 and PM0.3 could reach 99.3% and 98.6%, respectively, whereas the adsorption of formaldehyde is 88.7% within 30 min. In addition, the filter exhibits excellent antibacterial properties (99.9%), biodegradability (80.1% degradation after 14 days), thermal stability, and skin‐friendly properties (0 irritation). This study may inspire the research of using natural features of renewable resources to design high‐performance air‐filtration materials for various applications.

Modulating the Microstructure and Surface Acidity of MnO2 by Doping-Induced Phase Transition for Simultaneous Removal of Toluene and NOx at Low Temperature.

It is a great challenge to remove VOCs and NOx simultaneously from flue gas in nonelectric industries. This study focuses on the construction of Fe-MnO2 catalysts that perform well in the simultaneous removal of toluene and NOx at low temperatures. Utilizing the Fe-induced phase transition of MnO2, Fe-MnO2-F&R catalysts with a composite morphology of nanoflowers and nanorods were successfully prepared that provided an abundant microporous structure to facilitate the diffusion of molecules of different sizes. Through in-depth investigation of the active sites and reaction mechanism, we discovered that Fe-induced phase transition could modulate the surface acidity of Fe-MnO2-F&R. The higher concentration of surface Mn4+ provided numerous Brønsted acid sites, which effectively promoted the activation of toluene to reactive intermediates, such as benzyl alcohol/benzoate/maleic acid. Simultaneously, Fe provided a large number of Lewis acid sites that anchor and activate NH3 species, thereby inhibiting NH3 nonselective oxidation. Furthermore, additional Brønsted acid sites were generated during the simultaneous reaction process, enhancing toluene activation. Consequently, the simultaneous removal of toluene and NOx was achieved through regulation of the physical structure and the concentration of acidic sites. The present work provides new insights into the rational design of bifunctional catalysts for the synergistic control of VOCs and NOx emissions.

Efficient Method for Numerical Calculations of Molecular Vibrational Frequencies by Exploiting Sparseness of Hessian Matrix.

Molecular vibrational frequency analysis plays an important role in theoretical and computational chemistry. However, in many cases, the analytical frequencies are unavailable, whereas frequency calculations using conventional numerical methods are very expensive. In this work, we propose an efficient method to numerically calculate the frequencies. Our main strategies are to exploit the sparseness of the Hessian matrix and to construct the N-fold two-variable potential energy surfaces to fit the parabola parameters, which are later used for the construction of Hessian matrices. A set of benchmark calculations is performed for typical molecules of different sizes and complexities using the proposed method. The obtained frequencies are compared to those calculated with the analytical methods and conventional numerical methods. It is shown that the results yielded with the new method are in very good agreement with corresponding accurate values (with a maximum error of ∼20 cm-1), while the required computation resource is largely reduced compared to that required by conventional numerical methods. For medium-sized molecules, the calculational scaling is lowered to O(N1.6) (this work) from that of O(N2) (conventional numerical methods). For even larger molecules, more computational savings can be achieved, and the scaling is estimated to be quasilinear with respect to the molecular size.

Construction of covalent organic frameworks membranes in situ through nonsolvent-induce phase separation for fast and accurate nanofiltration

With the development of covalent organic frameworks (COFs), their superior separation performance in membrane separation has gradually becoming apparent. The method of combining COFs with membrane materials is crucial for their applications prospect. In this study, inspired by the traditional Chinese mortise and tenon structure, we selected 1,3,5-triacetaldehyde mesityl phenol (TFP) and 1,3,5-tris(4-aminophenyl)benzene (TAPB) as the reactive building monomers. P-Phenylenediamine (PDA) was introduced into the casting solution to construct Polyether-sulfone (PES) bottom membranes with amino ligand sites, utilizing the phase transition effect generated by the non-invasive solvent-induced method (NIPS). Subsequently, COFs composite nanofiltration membranes with two-dimensional layered structures were prepared through mild interfacial polymerization (IP) under optimized reaction conditions. The synthesis of COFs composite nanofiltration membranes was demonstrated through a series of characterizations, including scanning transmission electron microscopy and infrared spectroscopy. The COFs composite nanofiltration membranes synthesized by this method exhibited better alignment, greater chemical stability, and higher separation efficiency compared to traditional interracially polymerized COFs composite nanofiltration membranes. As the method involves the addition of additives, it can be more widely applied to a broad range of organic polymer membranes. Furthermore, we demonstrated the effectiveness of the COF composite nanofiltration membranes produced using this method in the separation of molecular dyes. They exhibited rejection exceeding 99% for 0.1 g L−1 methyl blue (MB), Congo red (CR) and chrome black-T (EBT). Additionally, they achieved separation fluxes of up to 300 L m−2 h−1 bar−1 for mixed solutions (dyes/salts) and proved to be effective under extreme conditions, such as 1 M HCl/NaOH. Moreover, COFs-NH2PES composite nanofiltration membranes exhibited the ability to efficiently separate dye molecules of different sizes. This work introduces new ideas for constructing stable and durable COF functional composite membrane materials for practical applications.

Diffusion Mediates Molecular Transport through the Perivascular Space in the Brain.

The perivascular space has been proposed as a clearance pathway for degradation products in the brain, including amyloid β, the accumulation of which may induce Alzheimer's disease. Live images were acquired using a two-photon microscope through a closed cranial window in mice. In topical application experiments, the dynamics of FITC-dextran were evaluated from 30 to 150 min after the application and closure of the window. In continuous injection experiments, image acquisition began before the continuous injection of FITC-dextran. The transport of dextran molecules of different sizes was evaluated. In topical application experiments, circumferential accumulation around the penetrating arteries, veins, and capillaries was observed, even at the beginning of the observation period. No further increases were detected. In continuous injection experiments, a time-dependent increase in the fluorescence intensity was observed around the penetrating arteries and veins. Lower-molecular-weight dextran was transported more rapidly than higher-molecular-weight dextran, especially around the arteries. The largest dextran molecules were not transported significantly during the observation period. The size-dependent transport of dextran observed in the present study strongly suggests that diffusion is the main mechanism mediating substance transport in the perivascular space.

The role of lipid oxidation pathway in reactive oxygen species-mediated cargo release from liposomes.

Reactive oxygen species (ROS)-mediated photooxidation is an efficient method for triggering a drug release from liposomes. In addition to the release of small molecules, it also allows the release of large macromolecules, making it a versatile tool for controlled drug delivery. However, the exact release mechanism of large macromolecules from ROS-sensitive liposomes is still unclear. There are no studies on the effect of lipid oxidation on the release of cargo molecules of different sizes. By using HPLC-HRMS method we analyzed the oxidation products of ROS-sensitive DOTAP lipid in phthalocyanine-loaded DOTAP:Cholesterol:DSPE-PEG liposomes after 630 nm light irradiation of different durations. Shorter illumination time (1-2 minutes) led to the formation of hydroperoxides and vic-alcohols predominantly. Longer 9-minute irradiation resulted already in aldehydes generation. Interestingly, the presence of epoxides/mono-hydroperoxides and vic-alcohols in a lipid bilayer ensured a high 90% release of small hydrophilic cargo molecules i.e. calcein, but not large (≥10 KDa) macromolecules. Oxidation till aldehydes was mandatory to deliver e.g. dextrans of 10-70 kDa with ca. 30% efficiency. Molecular dynamics simulations revealed that the formation of aldehydes is required to form pores or even fully disrupt the lipid membrane, while e.g. presence of hydroperoxides is enough to make the bilayer more permeable just for water and small molecules. This is an important finding that shed a light on the release mechanism of different cargo molecules from ROS-sensitive drug delivery systems.

In English

Features of interfacial adsorbate/adsorbent phenomena depend on several factors: particulate morphology, texture, and structure of adsorbents, molecular weight, shape, and polarity of adsorbates; as well as prehistory of adsorbents pretreated under different conditions. All these factors could affect the efficiency of practical applications of not only adsorbents but also polymer fillers, carriers, catalysts, etc. Interactions of nonpolar nitrogen, hexane, benzene, weakly polar acetonitrile, and polar diethylamine, triethylamine, and water with individual (silica, alumina), binary (silica/alumina (SA)) and ternary (alumina/silica/titania, AST) nanooxides were studied using experimental and theoretical methods to elucidate the influence of the morphological and textural characteristics and surface composition of the materials on the adsorption phenomena. The specific surface area SX / ratio (X is an adsorbate) changes from 0.7 for hexane adsorbed onto amorphous silica/alumina SA8 with 8 wt. % Al2O3 (degassed at 200 °C) to 1.9 for acetonitrile adsorbed onto pure fumed alumina (treated at 900 °C). These changes are relatively large because of variations in orientation, lateral interactions, and adsorption compressing of organic molecules interacting with surfaces characterized by certain set and amounts of various active sites, as well as due to changes in the accessibility of pore surface for probe molecules of different sizes. Larger SX / > 1 values are observed for complex fumed oxides with larger primary nanoparticles, greater surface roughness, hydrophilicity, and Brønsted and Lewis acidity of a surface. Both polar and nonpolar adsorbates can change the morphology and texture of aggregates of oxide nanoparticles, e.g., swelling of structures, compacted during various pretreatments, upon the adsorption of liquids. The studied effects should be considered upon practical applications of adsorbents, especially “soft” fumed oxides.

Effect of small-sized modifier on boron nitride for efficient heat transfer through thermal conductive epoxy composites

Surface modification of a crystalline filler is a powerful method for increasing the thermal conductivity (κ) of filler-impregnated composites. Herein, boron nitride (BN) filler was functionalized with cationic molecules of different sizes to directly recognize the effect of an amorphous area on the filler-polymer matrix interface. Measured thermal conductivity and temperature rise for a polymer composite was up to 67.1 % and 15.3 % greater, respectively, in the sample to which the smallest molecule-modified BN was added, compared to the comparable sample with free BN. The smaller the size of the modifier molecule, the better it bonds with the resin and the smaller the non-crystalline area. Such changes improve the heat transfer at the interface by reducing interfacial thermal resistance. These findings can serve as a reference to develop alternative and effective strategies for filler modification, an alternative approach instead of focusing on functional groups and modifiers.

Brain-Penetrating Peptide Shuttles across the Blood-Brain Barrier and Extracellular-like Space.

Systemic delivery of therapeutics into the brain is greatly impaired by multiple biological barriers─the blood-brain barrier (BBB) and the extracellular matrix (ECM) of the extracellular space. To address this problem, we developed a combinatorial approach to identify peptides that can shuttle and transport across both barriers. A cysteine-constrained heptapeptide M13 phage display library was iteratively panned against an established BBB model for three rounds to select for peptides that can transport across the barrier. Using next-generation DNA sequencing and in silico analysis, we identified peptides that were selectively enriched from successive rounds of panning for functional validation in vitro and in vivo. Select peptide-presenting phages exhibited efficient shuttling across the in vitro BBB model. Two clones, Pep-3 and Pep-9, exhibited higher specificity and efficiency of transcytosis than controls. We confirmed that peptides Pep-3 and Pep-9 demonstrated better diffusive transport through the extracellular matrix than gold standard nona-arginine and clinically trialed angiopep-2 peptides. In in vivo studies, we demonstrated that systemically administered Pep-3 and Pep-9 peptide-presenting phages penetrate the BBB and distribute into the brain parenchyma. In addition, free peptides Pep-3 and Pep-9 achieved higher accumulation in the brain than free angiopep-2 and may exhibit brain targeting. In summary, these in vitro and in vivo studies highlight that combinatorial phage display with a designed selection strategy can identify peptides as promising carriers, which are able to overcome the multiple biological barriers of the brain and shuttle different-sized molecules from small fluorophores to large macromolecules for improved delivery into the brain.

On adsorption azeotropy and a classification based on the dual site Langmuir isotherm

Adsorption azeotropy is a phenomenon that has been known for nearly a century, yet few properties have been formally proven. Here four general properties of adsorption azeotropy in porous materials are discussed and shown to apply irrespective of the isotherm, including the fact that there is always a lower bound on the pressure at which an azeotrope may be present. As molecules of different size will favour the occurrence of an azeotrope, this study considers in detail the thermodynamically consistent dual site Langmuir model, where azeotropy is solely the result of the adsorbent heterogeneity. Six categories of adsorption azeotropes, which can be grouped into three pairs of mirror cases, are formally identified for this model. Dimensionless ratios allow to determine formally each category and the analysis also includes a discussion of the crossing of the pure component isotherms. The heterogeneity of the adsorbent is shown to lead to azeotropes that can include an upper bound on pressure; that can occur even if the pure component isotherms do not cross; and can be present below the pressure at which the pure component isotherms cross. Finally, the analysis allows to identify also the ranges of parameters for which the pure component isotherms cross but an azeotrope is not present.

The Hyaluronan/CD44 Axis: A Double-Edged Sword in Cancer.

Hyaluronic acid (HA) receptor CD44 is widely used for identifying cancer stem cells and its activation promotes stemness. Recent evidence shows that overexpression of CD44 is associated with poor prognosis in most human cancers and mediates therapy resistance. For these reasons, in recent years, CD44 has become a treatment target in precision oncology, often via HA-conjugated antineoplastic drugs. Importantly, HA molecules of different sizes have a dual effect and, therefore, may enhance or attenuate the CD44-mediated signaling pathways, as they compete with endogenous HA for binding to the receptors. The magnitude of these effects could be crucial for cancer progression, as well as for driving the inflammatory response in the tumor microenvironment. The increasingly common use of HA-conjugated drugs in oncology, as well as HA-based compounds as adjuvants in cancer treatment, adds further complexity to the understanding of the net effect of hyaluronan-CD44 activation in cancers. In this review, I focus on the significance of CD44 in malignancy and discuss the dichotomous function of the hyaluronan/CD44 axis in cancer progression.

Effect of binding pockets on the kinetics and thermodynamics of Diels-alder reaction in cucurbit-Uril family

Cucurbit-uril (CB-uril) family has witnessed a considerable increase in popularity over the last two decades due to its amazing binding ability which impart broad range of applications. Cucurbit-uril family members exhibit diversity in their binding pocket to accommodate guest molecules of different sizes which in turn impact the remarkable properties of these molecules. Herein, we have studied the influence of encapsulation on the kinetics and thermodynamics of the Diels-Alder reaction. Effects of binding pockets on the Diels-Alder reaction are explored by selecting CBn(n = 5–8)-uril. Bond evolution theory (BET) and non-covalent interaction (NCI) analyses have also been performed to gain insight into electronic distribution along the reaction route as well as bond formation/breakage to understand the mechanism of action and the role of weak/strong interactions between CBn-uril and reaction during the process. Activation energies for Diels-Alder reaction in CBn=6–8-uril (22.63 kcal mol−1, 21.37 kcal mol−1, and 19.45 kcal mol−1, respectively) are significantly lower than that of the bare reaction (25.45 kcal mol−1). While for P-DA reactions, activation energies within CBn=7,8-uril are observed as 19.29 kcalmol−1 and 14.45 kcalmol−1 (cis-1,2-dicyanoethylene), 18.46 kcalmol−1 and 14.65 kcalmol−1 (trans-1,2-dicyanoethylene), and 16.01 kcalmol−1 and 20.86 kcalmol−1 (tetracyanoethylene). CB7-uril has predicted the lowest activation energies for DA reaction with cis-1,2-dicyanoethylene and trans-1,2-dicyanoethylene compared to bare Ea ≈ 20.15 kcalmol−1 and 19.57 kcalmol−1, respectively. By making the reaction more exothermic with ER ≈ -40 kcal mol−1, CB6-uril has the lowest activation energy of ≈ 19.45 kcal mol−1, predicting CBn-uril as an effective cavity for researching the Diels-Alder process.

Raman Diffusion-Ordered Spectroscopy.

The Stokes-Einstein relation, which relates the diffusion coefficient of a molecule to its hydrodynamic radius, is commonly used to determine molecular sizes in chemical analysis methods. Here, we combine the size sensitivity of such diffusion-based methods with the structure sensitivity of Raman spectroscopy by performing Raman diffusion-ordered spectroscopy (Raman-DOSY). The core of the Raman-DOSY setup is a flow cell with a Y-shaped channel containing two inlets: one for the sample solution and one for the pure solvent. The two liquids are injected at the same flow rate, giving rise to two parallel laminar flows in the channel. After the flow stops, the solute molecules diffuse from the solution-filled half of the channel into the solvent-filled half at a rate determined by their hydrodynamic radius. The arrival of the solute molecules in the solvent-filled half of the channel is recorded in a spectrally resolved manner by Raman microspectroscopy. From the time series of Raman spectra, a two-dimensional Raman-DOSY spectrum is obtained, which has the Raman frequency on one axis and the diffusion coefficient (or equivalently, hydrodynamic radius) on the other. In this way, Raman-DOSY spectrally resolves overlapping Raman peaks arising from molecules of different sizes. We demonstrate Raman-DOSY on samples containing up to three compounds and derive the diffusion coefficients of small molecules, proteins, and supramolecules (micelles), illustrating the versatility of Raman-DOSY. Raman-DOSY is label-free and does not require deuterated solvents and can thus be applied to samples and matrices that might be difficult to investigate with other diffusion-based spectroscopy methods.

A novel 3D hexagonal honeycomb Zn-MOF for effective detection of Fe3+, CrO42-, and Cr2O72- and selective dye adsorption in aqueous media

Heavy metal ions and organic dye pollutants in water cause serious environmental problems and endanger human health. A 3D honeycomb Zn-MOF, Zn(C22N4O4H12)·16H2O (1), was synthesized by solvothermal reaction with ligand H2L (H2L = 2,5-bis-(1H-1,3-benzimidazol-1-yl)-terephthalic acid) as the skeleton and zinc cations as connecting points. The structure of Zn-MOF features one-dimensional channels with a window size of 4.6 Å. The 3D structure is simplified into a (4,4)-binode grid {426282}{4264}. Because of the structural characteristics of Zn-MOF, it exhibits superior luminescent properties and rapid separation of dye molecules of different sizes. The maximum adsorption capacity of Zn-MOF for cationic organic dyes CV, RHB, and JB was as high as 233 mg/g, 218 mg/g, and 168 mg/g, respectively. Luminescent sensing experiments show that Zn-MOF can simultaneously and selectively detect three heavy metal ions Fe3+, CrO42-, and Cr2O72- in aqueous media, and the detection limits are 1.68 μM, 0.15 μM, and 0.46 μM, respectively.

Two‐Dimensional LDH Film Templating for Controlled Preparation and Performance Enhancement of Polyamide Nanofiltration Membranes

AbstractTailored design of high‐performance nanofiltration membranes that can be used in a variety of applications such as water desalination, resource recovery, and sewage treatment is desirable. Herein, we describe the use of layered double hydroxides (LDH) intermediate layer to control the interfacial polymerization between trimesoyl chloride (TMC) and piperazine (PIP) for the preparation of polyamide (PA) membrane. The dense surface of LDH layer and its unique mass transfer behavior influence the diffusion of PIP, and the supporting role of the LDH layer allows the formation of ultrathin PA membranes. By only changing the concentration of PIP, a series of membranes with controllable thickness from 10 to 50 nm and tunable crosslinking‐degree can be prepared. The membrane prepared with a higher concentration of PIP shows excellent performance for divalent salt retention with water permeance of 28 Lm−2 h−1 bar−1, high rejection of 95.1 % for MgCl2 and 97.1 % for Na2SO4. While the membrane obtained with a lower concentration of PIP can sieve dye molecules of different sizes with a flux of up to 70 Lm−2 h−1 bar−1. This work demonstrates a novel strategy for the controllable preparation of high‐performance nanofiltration membranes and provides new insights into how the intermediate layer affects the IP reaction and the final separation performance.

Two-dimensional LDH films templating for controlled preparation and performance enhancement of polyamide nanofiltration membranes.

Tailored design of high-performance nanofiltration membranes that can be used in a variety of applications such as water desalination, resource recovery, and sewage treatment is desirable. Herein, we describe the use of layered double hydroxides (LDH) intermediate layer to control the interfacial polymerization between trimesoyl chloride (TMC) and piperazine (PIP) for the preparation of polyamide (PA) membrane. The dense surface of LDH layer and its unique mass transfer behavior influence the diffusion of PIP, and the supporting role of the LDH layer allows the formation of ultrathin PA membranes. By only changing the concentration of PIP, a series of membranes with controllable thickness from 10 to 50 nm and tunable crosslinking-degree can be prepared. The membrane prepared with a higher concentration of PIP shows excellent performance for divalent salt retention with water permeance of 28 Lm-2h-1bar-1, high rejection of 95.1% for MgCl2 and 97.1% for Na2SO4. While the membrane obtained with a lower concentration of PIP can sieve dye molecules of different sizes with a flux of 70 Lm-2h-1bar-1. This work demonstrates a novel strategy for the controllable preparation of high-performancemembranes and provides new insights into how the intermediate layer affects the IP reaction and the final separation performance.

Characterization of (bio)molecular diffusion in porous hydrogels using fluorescence correlation spectroscopy superresolution optical fluctuation imaging (fcsSOFI).

The nanoscale physicochemical structure of porous microenvironments affects the diffusion dynamics of molecules within them. Chemical interactions between the diffusing molecules and porous media can further significantly change diffusion. Fluorescence correlation spectroscopy super-resolution optical fluctuation imaging (fcsSOFI) has been successfully applied to measure biomolecular diffusion in simulated hydrogels of varying matrix densities. In this work, we extended fcsSOFI to systematically characterize the diffusion dynamics of different molecules with varying size and chemical properties in the water, as well as in complex matrices such as patterned nano surfaces and porous agarose hydrogel. Our data shows that fcsSOFI can quantitively measure diffusion rates in these heterogeneous media as well as resolve their pore structures with high resolution. Using neutral dextran molecules of different sizes, we show that the diffusion coefficient in agarose hydrogel decreases with increasing size. However, using proteins such as BSA and lysozyme, we show that diffusion is slower compared to the similar-sized dextran due to the interaction of the agarose hydrogel matrix with the charged surfaces of proteins. Currently, we are working on characterizing protein diffusion in a more complex extracellular matrix (ECM) using fcsSOFI.

Biomimetic MXene membranes with negatively thermo-responsive switchable 2D nanochannels for graded molecular sieving

Negatively thermo-responsive 2D membranes, which mimic the stomatal opening/closing of plants, have drawn substantial interest for tunable molecular separation processes. However, these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation. Here, we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly (N-isopropylacrylamide) (PNIPAm) onto MXene nanosheets. The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes. As expected, the constructed membrane exhibits ultrahigh water permeance of 95.6 L m−2 h−1 bar−1 at 25 °C, which is eight-fold higher than the state-of-the-art negatively thermo-responsive 2D membranes. Moreover, the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye- and antibiotic-based ternary mixtures. This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes, showing promising applications in micro/nanofluidics and molecular separation.

Recent applications of organic cages in sensing and separation processes in solution.

Organic cages are three-dimensional polycyclic compounds of great interest in the scientific community due to their unique features, which generally include simple synthesis based on the dynamic covalent chemistry strategies, structural tunability and high selectivity. In this feature article, we present the advances over the last ten years in the application of organic cages as chemosensors or components in chemosensing devices for the determination of analytes (pollutants, analytes of biological interest) in complex aqueous media including wine, fruit juice, urine. Details on the recent applications of organic cages as selective (back-)extractants or masking agents for potential applications in relevant separation processes, such as the plutonium and uranium recovery by extraction, are also provided. Over the last ten years, organic cages with permanent porosity in the liquid and solid states have been highly appreciated as porous materials able to discriminate molecules of different sizes. These features, combined with good solvent processability and film-forming tendency, have proved useful in the fabrication of membranes for gas separation, solvent nanofiltration and water remediation processes. An overview of the recent applications of organic cages in membrane separation technologies is given.