Organic Gel Research Articles

A smart low-molecular-mass naphthalene-pyrazoline gelator: Gelation behavior and selective fluorescent detection Cu2+

A smart low-molecular-mass organic gelator based on naphthalene-pyrazoline has been designed and synthesized. The gelator G can form a thermo reversible stable gel in tert-butanol, cyclohexane, cyclohexanol, and DMSO through self-assembly, it emits blue and yellow-green fluorescence under ultraviolet radiation. Notably, it has multiple stimulus responses of light, heat, shock and ion. In addition, it could act as an efficient fluorescent probe for the selective sensing of Cu2+ in the solution containing water. The detection limit of Cu2+ in THF deionized aqueous solution (V:V = 9:1) is 5.65 × 10−8 M. The complex ratio of G to Cu2+ is 1:1. In addition, the G has good biocompatibility in living cells.

Preparation and application of a novel imine-linked covalent organic framework@silica composite for reversed-phase and hydrophilic interaction chromatographic separations

The composites of covalent organic frameworks (COFs) and silica gel have been considered to be promising chromatographic separation materials due to the distinct advantages such as large specific surface area, good mechanical strength and high porosity. In the present study, a novel imine-linked COF@silica composite was prepared by in-situ growth of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and 2,5-dihydroxyterephthalaldehyde (DHTA) monomers on the surface of aminated silica gel (SiO2–NH2). The successful surface-modification of TAPT-DHTA-COF distinctly enhanced the separation selectivity and efficiency of SiO2–NH2. Multiple types of analyte-stationary phase interactions contributed to the selective retention of structurally similar analytes. The designed TAPT-DHTA-COF@SiO2 was observed to effectively separate hydrophobic phenyl ketones, phthalate esters and steroid hormones. Moreover, the polar amino and hydroxyl groups of TAPT-DHTA-COF facilitated the selective determination of hydrophilic nucleosides/bases. The kinetic performance and thermodynamic behavior of TAPT-DHTA-COF@SiO2 column were particularly explored. It was found that column efficiency was mainly affected by the mass transfer resistance, and the retention of nucleosides/bases on the TAPT-DHTA-COF@SiO2 column was temperature dependent. The developed versatile TAPT-DHTA-COF@SiO2 column was finally applied for detecting environmental hormones as well as water-soluble nicotinamide in real samples. In summary, the potential application of TAPT-DHTA-COF@SiO2 composite material for liquid chromatographic separations was first explored and verified. The TAPT-DHTA-COF@SiO2 was proved to be a promising chromatographic separation material.

Understanding physical and chemical interactions deriving polymer–metal–organic framework gel formation for drug delivery

Understanding physical and chemical interactions deriving polymer–metal–organic framework gel formation for drug delivery

Recent Advances in Various Inorganic Nanoparticle Embedded Chitosan-based Multifunctional Materials for Wound Healing

Abstract: Scarless wound management remains a clinical challenge worldwide because of its com-plicated and overlapping phases of inflammation, clearing, and regeneration. Among the currently available dressing materials, hydrogels have attracted emerging attention as potential wound dress-ing materials because of their specific properties, such as porosity, tissue-mimicking architecture, softness, and improved mechanical, biological as well as physicochemical properties. However, naturally driven hydrogels have shown several advantages over conventional hydrogels because of their biodegradability, biocompatibility, high mechanical strength, and functionality. Recently, na-noparticle (NPs) integrated polymeric hydrogels (metals, non-metals, metal oxides, and polymeric moieties) have been established as analogous to these naturally driven hydrogels because of the synergistic effects of the NPs and polymers in the three-dimensional composite material. Over the years, researchers have reported the synthesis and potential applications of diverse inorganic and organic nanocomposite gels with antioxidant or antibacterial properties where they have exploited the intelligent incorporation of biomolecules into the NP-polymeric network that are beneficial for wound healing. Among various natural polymers as hydrogel matrix, chitosan-mediated hydrogel dressings have received extensive interest resulting in improved mechanical, biological, and physi-cochemical properties due to the well-reported antibacterial, antitumor, antioxidant, and tissue re-generation efficacies of chitosan polymer. This review is intended to summarize the recent devel-opments of inorganic nanoparticle-incorporated chitosan-based hydrogels as wound dressing mate-rials where various synthetic methodologies of these nanocomposite gels are extensively discussed via incorporating nanoparticles, active biomolecules, and other substances into the intrinsic struc-ture of the gels. In addition, the future and prospects of chitosan-based nanocomposite hydrogels as a novel wound dressing as well as tissue engineering materials are also highlighted.

The formation of high CO2 loading solid phase from 1,4-butanediamine/ethylene glycol biphasic solvent: Phase-changing behavior and mechanism

Liquid-solid phase change absorption has been considered a promising strategy for CO2 capture. To achieve efficient and economic CO2 capture in industrial-scale applications, it is essential to understand the phase-change behaviors and mechanisms of the biphasic system. In this study, a blend of 1, 4-Butanediamine (BDA) and ethylene glycol (EG) was developed as a biphasic solvent that can form a high CO2 loading solid phase product (BESP) after absorption. The total solvent loading reached 0.9039 mol·mol−1, with 90.74% of the loading enriched in the solid phase, which only accounts for 51.01% of the total solvent mass. Based on the 13C NMR analysis and quantum chemical calculations, the reaction and phase change mechanism of CO2 capture was proposed. The BDA/EG system absorbs CO2 to generate carbamate species, protonated amines and alkyl-carbonates, which combine each other through hydrogen bonding or electrostatic attraction. The self-aggregation of zwitterions and the high polarity of the absorption products are considered to be the main reasons for the phase change. Alkyl-carbonate species are believed to co-precipitate through organic gelation via van der Waals force with the carbamate or protonated amine. Moreover, the viscosity, turbidity, solid-phase mass, and particle size distribution changes also demonstrate the growth and aggregation of particles during absorption. BESP, identified as a coupling product of carbamate and alkyl-carbonate ([2BDAH+COO-]·[EG‐OCO2-]), decomposes at a peak temperature of 127.4 °C. The calorimetric method determined regeneration heat to be approximately 3.17 GJ·ton-1 CO2, indicating its potential for alternative uses rather than direct heat regeneration. Such a biphasic solvent may provide unique solutions for industries to reduce CO2 emissions.

Preparation and application of corona noise-suppressing anti-shedding materials for UHV transmission lines

Abstract With the continuous expansion of the construction scale of the State Grid and the gradual improvement of people’s awareness of environmental protection, the power contradictions and disputes caused by the North–South Power Transmission and Transformation Project have become increasingly prominent, which has attracted widespread attention from all walks of life. This study focuses on the development of conductive silicone gel for UHV transmission lines using carbon fiber (CF) powder, carbon black (CB), and carbon nanotubes as fillers, and organic silicone polymer as the matrix. The aim was to address the issues of corona noise and detachment. We prepared a series of conductive silicone gels with different proportions of CF and CB conductive fillers and conducted a comprehensive analysis of their electrical conductivity, tensile performance, hydrophobicity, and rheological properties. The research results demonstrated that the maximum electrical conductivity of the conductive silicone gel was achieved when the CF and CB contents reached a ratio of 2:1. In the case of a 70% organic silicone polymer gel, the electrical conductivity reached 0.73 S/cm, while it increased to 1.17 S/cm in an 80% organic silicone polymer gel. This indicates that optimizing the proportion of fillers can significantly enhance the electrical conductivity of the conductive silicone gel, meeting the requirements of UHV transmission lines. Additionally, the study evaluated the tensile performance, hydrophobicity, and rheological properties of the conductive silicone gel. The results showed that the 70% organic silicone polymer gel exhibited a tensile strength, Young’s modulus, and elongation at a break of 678.6 MPa, 1.3 MPa, and 15.22%, respectively. The corresponding values for the 80% organic silicone polymer gel were 129.9 MPa, 1.6 MPa, and 55.89%. This indicates that the conductive silicone gel possesses excellent mechanical properties and ductility, enabling it to withstand stress and deformation in UHV transmission lines while providing anti-detachment effects. In summary, this study successfully developed a conductive silicone gel that meets the requirements of UHV transmission lines. By optimizing the ratio of CF and CB contents, the electrical conductivity of the gel was maximized. Furthermore, the conductive silicone gel exhibited favorable tensile performance, electrical conductivity, and anti-detachment effects, effectively addressing corona noise and detachment issues in UHV transmission lines. These research findings are of great significance for the design and application of UHV transmission lines.

Modulation of defects in metal organic gels to enhance anhydrous proton conduction from subzero to moderate temperature

Exploitation of solid-state proton-conducting materials with high anhydrous proton conductivity from subzero temperature (<273 K) to moderate temperature (>353 K) is a great challenge. Here, Brönsted acid-dopped zirconium-organic xerogels (Zr/BTC-xerogels) are prepared for anhydrous proton conduction from subzero to moderate temperature. Abundant acid sites and strong H-bonding interactions make the CF3SO3H (TMSA)-introduced xerogel gain high proton conductivity from 9.0 × 10-4 S cm−1 (253 K) to 1.40 × 10-2 S cm−1 (363 K) under anhydrous conditions, which are in the leading level. This provides a new possibility to develop wide-operating-temperature conductors.

Performance of Self-healing microgel incorporating Nano-Silica as plugging material for drilling fluid

Lost circulation severely threatens the safety and efficiency of oil drilling operations, especially at high temperatures. Accordingly, many plugging materials have also been studied and applied, such as inert bridge materials, inorganic cement, and organic gel. However, these materials have certain limitations. For example, inert materials are difficult to form dense plugging slugs and have weak cementing strength with the formation; cement slurry is easily diluted and dispersed in the formation, and the waiting process required for cement greatly increases the non-productive time. Comparatively, polymer gel is widely used in lost circulation control because of its good deformability and water absorption capacity. However, conventional polymer gel usually has low mechanical strength and weak retention capacity in the leakage layer. In addition, there is a lack of sufficient interaction between plugging materials and the formation, which makes it difficult to form a highly dense plugging layer. Under high pressure conditions, a large amount of leakage still occurs, and even repeated leakage occurs under frequent pressure fluctuations, resulting in plugging failure. Herein, we synthesized zwitterionic polymer/nano-silica microgels (P(MPTC-co-NaSS)@SiO2) with dynamic crosslinking ability through a facile one-step reversed phase emulsion polymerization. They exhibited spherical particles of narrow size distribution around 40 μm in aqueous dispersion. The strong hydrogen bonds, electrostatic interaction and cation-π endowed microgels excellent self-healing ability, strong mechanical strength and sufficient high-temperature stability. Although high temperature and salinity decreased the particle size and rheological property as well as the particle quantity, P(MPTC-co-NaSS)@SiO2 microgels maintained fairly constant rheological properties and achieved significant plugging performance in the temperature range of 70–––150 °C and simultaneously with a salinity tolerance up to 7.5 wt% NaCl contamination. P(MPTC-co-NaSS)@SiO2 microgels were well dispersed in water-based drilling fluid (WBDF) and generated a bulk gel when concentrated in pores and cracks, which was applicable to plugging drilling fluids. A conventional WBDF with remarkable plugging property was formulated by facilely supplementing with P(MPTC-co-NaSS)@SiO2, which has a great prospect for applications in oil field. This study builds a bridge between fundamental research on microgels and the applications of soft particles as plugging materials in oil industry.

Stable quasi-solid-state lithium-organic battery based on composite gel polymer electrolyte and compatible organic cathode material

High-performance organic small-molecule electrode materials are troubled with their high solubility in liquid electrolytes. The construction of quasi-solid-state lithium organic batteries (LOBs) using gel polymer electrolytes with high mechanical properties, compromised ionic conductivity, high safety, and eco-friendly is an effective way to inhibit the dissolution of active materials. Herein, two hexaazatriphenylene (HATN)-based organic cathode materials (HATNA-6OCH3 and HATNA-6OH) are synthesized and then matched with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)-based gel polymer electrolytes to construct quasi-solid-state LOBs. Thanks to the enhanced interfacial compatibility between organic cathode material and gel polymer electrolyte, HATNA-6OH with compatible hydroxyl group shows the enhanced electrochemical properties compared with HATNA-6OCH3. Further, the electrochemical performance is improved when HATNA-6OH is combined with a gel polymer electrolyte modified with a succinonitrile (SN) plasticizer (GPE-0.4SN), including a high specific capacity of 153.3 mAh g−1 at 50 mA g−1 and a good reversible capacity of 88 mAh g−1 after 100 cycles at 200 mA g−1. In addition, the good electrochemical properties and lithium-ion storage mechanism of HATNA-6OH have been elucidated using density functional theory (DFT) and spectral characterizations.

Effect of synthesis conditions on the structural properties of CNT-doped carbon aerogels

Resorcinol-formaldehyde (RF) sol-gels have attracted much attention in the last decade. Carbon aerogels with very light and porous structures can be produced by controlled drying and subsequent pyrolysis of these organic gels under a neutral atmosphere. In general, it is indispensable to tailor the aerogel pore structure according to the application. In this study, some parameters affecting the structure, like the carbon nanotubes doping, heating rate during carbonization process, and temperature of carbonization have been investigated by measuring N2 adsorption/desorption isotherms at 77 K. It was observed that by increasing the amount of carbon nanotubes (CNTs) from 0 mg to 100 mg, the Brunauer, Emmett and Teller (BET) surface area and the total pore volume showed a decreasing trend and then increased again at 180 mg. By increasing the heating rate from 5 °C/min to 15 °C/min, the surface of meso pores showed an increasing trend. With the increase of carbonization temperature from 600 °C to 1200 °C, the micro pore volume decreased. At low carbonization temperature (600 °C), meso pore surface was dominant, whereas at high carbonization temperature (1200 °C), micro pore surface prevailed. According to simultaneous thermal analysis (STA), the carbonization efficiency of the CNT-doped organic gel was about 45 %.

Hydrogen-bond acidic organic compound-sensitized ionic gel for dimethyl methylphosphonate detection

Due to the threat of chemical warfare agents (CWAs), there is a pressing need to develop miniaturized gas sensors with fast response, high sensitivity and good stability. Herein, hexafluoroisopropanol aniline (HFIPA), a hydrogen-bond acidic organic compound, is embedded into a cross-linked poly(ethylene glycol) diacrylate/ionic liquid (PEGDA/IL) matrix as a sensitive film for detecting sarin simulant dimethyl methylphosphonate (DMMP). We find that the IL in the film constructs efficient gas transport channels, improving the absorption-desorption kinetics of DMMP molecules. The introduction of HFIPA enhances selectivity and sensitivity to DMMP through hydrogen bonding interaction. As a result, the SAW gas sensor based on PEGDA/IL-HFIPA ionic gel exhibits a fast response/recovery time of 28/53 s to 20 ppm DMMP and a low detection limit of 0.2 ppm at room temperature. By comparing with PEGDA-HFIPA, PEGDA/IL-HFIPA shows excellent anti-humidity interference ability, which is also attributed to the stable gas transport channels constructed by IL. Overall, this work develops a novel strategy to improve the gas-sensing properties of organic polymer materials.

Sintering Metal–Organic Framework Gels for Application as Structural Adhesives (Small 25/2023)

Metal–Organic Frameworks The zeolitic imidazolate framework-67 (ZIF-67) gel sintering technique provides a microstructure of densely aggregated, large spherical ZIF-67 crystals, resulting in bonding of Cu substrates with shear strength exceeding 30 MPa, comparable to that of conventional structural adhesives. More details can be found in article number 2300298 by Izuru Miyazaki, Mitsutaro Umehara, and co-workers.

Imine‐Linked Porous Organic Polymer Gel and Immobilization of Copper(II): Easy Synthesis and Excellent Catalyst for Huisgen [3+2] Cycloaddition Reactions

AbstractPorous organic polymeric gels (POP gels) were made by condensation of a newly synthesized C3‐symmetrical azobenzene‐based tri‐salicylaldehyde building block, 1,3,5‐tris(4‐((3‐formyl‐4‐hydroxyphenyl)diazenyl)phenyl)benzene (TAzo) with suitable aromatic tri‐ and di‐amines in N,N‐dimethylformamide (DMF) at ambient conditions. Here, we have furnished the pathway of an efficient, gentle, and simple one‐pot synthesis of imine‐linked porous organic polymers at room temperature without any acid catalysts. Detail rheological properties of the POP‐gels were studied and were also found to be stable for at least a year at room temperature. Nitrogen isotherm revealed the mesoporous nature of the gel‐powders with moderate surface area. Iminophenol moieties are known to provide binding sites to metallic species via the strong coordination interaction with hydroxy (−OH) and imine (−HC=N−) groups. We have successfully synthesized a copper‐metallated POP by immobilizing copper ions in one of the POP‐gels. The mesoporous POP material having 3 wt % copper loading was utilized for the solvent‐free Huisgen [3+2] cycloaddition reactions of various aryl, benzyl, and alkyl azides with terminal alkynes containing aromatic, heteroaromatic, and alkyl groups with excellent yield. The heterogeneous catalyst with low catalyst loading (1 mol %) was highly regioselective towards 1,4‐disubstituted 1,2,3‐triazoles, recyclable, and did not require the addition of a reducing agent.

MICRONEEDLES ASSISTED ENHANCEMENT OF TRANSDERMAL DELIVERY OF CURCUMIN THROUGH ORGANOGEL FORMULATION

Curcumin is a natural compound found in turmeric and has been shown to have anti-inflammatory and antioxidant properties. Topical delivery of curcumin through an organic emulsion-based gel can effectively target inflammation at specific sites on the body. The current study aims to formulate Pluronic based organogel of curcumin, whose absorption is further assisted by microneedles technology. Nine organogel formulations were prepared and optimized by 32 full factorization model to fix the ratio of lecithin[A] and Pluronic[B] concentration in order to get optimum drug release after 2 hours (Q2) and maximum release of drug after 8 hours (Q8). The in-vitro study through the Franz diffusion cell indicated a significant impact of Pluronic F-127 concentration on the release of drug. As increased concentration of Pluronic increased the viscosity of formulations which ultimately retarded the release of drug. Based on Design of Experiment (DoE) study, optimized batch containing 6.5% lecithin and 20.6% Pluronic was further studied for microneedle assisted ex-vivo skin permeation through rat skin. Permeation without microneedle poration was around 70.26% after 8 hours, which was significantly increased (around 25%) after microneedle treatment of the skin. The results indicated promising application microneedle assisted skin permeation as a non-invasive and controlled delivery of curcumin through the transdermal route. Further, in-vivo studies are recommended to further establish this promising concept, targeting a variety of inflammatory conditions, including arthritis, psoriasis, and eczema, etc., through non-invasive transdermal drug delivery systems.

Aluminum copper bimetallic metal organic gels/sodium alginate beads for efficient adsorption of ciprofloxacin and methylene blue: Adsorption isotherm, kinetic and mechanism studies

In this research, a new aluminum-copper bimetallic organic gel was prepared by solvothermal method. It is hoped that the special structure and properties of this new material can be used to remove ciprofloxacin (CIP) and methylene blue (MB) from water to deal with environmental pollution problems. Their morphology and structure were characterized by XRD, FT-IR, XPS, SEM, BET, TGA and zeta potential. It is proved that they have sufficient active sites, large specific surface area (270.5 m2/g), hierarchical porous structure, and strong thermal stability. These properties contribute to their efficient removal of pollutants. Compared with other adsorbents, MOG-4 in this study showed good pollutant removal rate, wide pH adaptability, good anti-interference ability and excellent reuse rate. The maximum adsorption capacity of MOG-4 for CIP and MB was 458.72 mg/ g and 381.68 mg/ g respectively. The adsorption process followed the second-order kinetic model and Freundlich isotherm. More importantly, we constructed MOG-4 @SA beads by immobilizing MOG-4 in sodium alginate (SA) matrix, which not only overcame the shortcomings of difficult recovery and easy agglomeration of powder MOG-4, but also enhanced its adsorption capacity. Seven cycles show that the reuse rate of MOG-4 @SA is more than 84%. The adsorption mechanism involves hydrogen bonding, electrostatic interaction, π-π interaction, hydrophilic/hydrophobic interaction and pore filling. MOG-4 @SA beads adsorbent overcomes the shortcomings of traditional powder adsorbent, which is easy to lose, easy to aggregate and difficult to recover, and broadens the range of use of powder adsorbent and sodium alginate. Therefore, MOG-4 @SA has the advantages of good adsorption performance, high reuse rate, wide range of adaptation, strong anti-interference ability, and is expected to become a promising adsorbent.

A novel luminol-coordinated silver(I) organic gel with self-enhanced chemiluminescence applied for uric acid detection

A novel silver(I)-based metal–organic gel (AgMOG) consisting of luminol as the ligand was synthesized by a facile strategy, which was found to exhibit self-enhancing chemiluminescence (CL) property. Based on this, a new AgMOG-K2S2O8 CL system without additional catalyst was established. According to the results of CL spectra, electron spin resonance (ESR) spectra as well as the influence of radical scavengers to AgMOG-K2S2O8 system, the possible CL mechanism of this system was discussed. In this CL system, AgMOG exhibited the dual properties of catalysis and luminescence. On the one hand, AgMOG can catalyze K2S2O8 to produce SO4•−. The generated SO4•− can be converted to hydroxyl radical (OH•) under alkaline condition, and further converted to other radical oxygen species (ROS, such as 1O2 and O2•−). Furthermore, the reaction between the K2S2O8 and H2O can form H2O2, which also can be catalyzed by AgMOG to produce ROS. On the other hand, the AgMOG can be oxidized by ROS to emit strong CL signal. Then, based on the quenching effect of uric acid (UA) to this CL system, a method for UA detection was established with a good linearity over the range from 0.08 to 10 µmol·L−1. In this work, a new CL luminant with catalytic property was synthesized by a simple method, and a self-enhancing AgMOG-K2S2O8 CL system was developed for the first time, providing a novel direction for the application of MOG in the CL field.

Electrochemical Reconstruction Engineering: Metal–Organic Gels as Pre‐Catalysts for NiOOH/FeOOH Heterostructure to Boost Oxygen Evolution Reaction

Metal–organic gels (MOG) as new types of soft materials have shown promising applications in various fields such as chemosensors, environmental remediation, and gas adsorption/separation, owing to their high porosity, low density, and high surface area. However, the application of MOG materials in energy electrocatalysis and the active components made from them are rarely perceived. Herein, a new electrochemistry‐driven reconstruction strategy to synthesize the NiOOH/FeOOH heterostructure from MOG materials is reported. The reconstructed NiOOH/FeOOH exhibits superior oxygen evolution reaction activity and excellent stability, owing to the synergistic effect of bimetallic centers, the abundant interface between NiOOH and FeOOH, and the plentiful defects. Impressively, the activated Re–FeNi–MOG‐4 electrocatalyst displays remarkable catalytic activity with a low overpotential of 220 mV at a current density of 10 mA cm−2 and a small Tafel slope of 48 mV dec−1 in alkaline electrolyte, outperforming most recently reported electrocatalysts. Herein, a facile and effective electrochemical reconstruction engineering of pre‐catalysts is provided and the evolution of self‐reconstruction of MOG materials for accelerating the kinetics of the electrocatalytic process is highlighted.

Numerical simulations of the flow of a kerosene gel: Effects of thixotropy and shear-thinning

The ability of a gel to act like a solid-like material at rest and flow like a liquid when sheared can be very useful in propulsion system. Numerical simulation of the flow of gel fuels can be used as a reference to assist experimental studies and applications of these materials. Non-linear rheological effects such as shear thinning, yield stress, thixotropy and viscoelasticity can create difficulties in the formulation and in the numerical investigations. This paper uses a thixotropic shear-thinning constitutive relationship while using a second-order kinetic equation for the structural parameter, where the Carreau–Yasuda model is used for a 5% organic kerosene gel. We study the simple shear flow to verify the accuracy of the numerical method, and the impact of the constitutive parameters on the apparent viscosity as a function of shear rate. To look at the thixotropic flow in more complex flows, we initially study the pipe flow of an organic kerosene gel for different pumping conditions. After performing a parametric study, we find that the thixotropy of the gel strongly affects the shear history, that is, the nonuniform aging distribution. The destruction of the microstructure can be accelerated by adjusting the flow intensity and the model parameters, but it seems that it is difficult to arrive at the equilibrium state within the time scale of the propulsion system; this poses a challenge to the design of the system.

Facile synthesis of 2D Europium-metal organic frameworks nanosheets for highly efficient electrochemiluminescence in DNA detection

Lanthanide metal organic frameworks (Ln-MOFs) with self-luminous behavior are considered promising emitters of electrochemiluminescence (ECL) due to their unique antenna effects. In this study, the novel 2D Europium-metal organic frameworks (Eu-MOFs) nanosheets were synthesized by simply blending 1, 10-phenanthroline-2, 9-dicarboxylic acid (PDA) and Eu salts at room temperature. When N, N-diethylethylenediamine (DEAEA) was used as the efficient co-reactant, the 2D Eu-MOFs exhibited stronger and steadier ECL performance compared with 2D Europium-metal organic gels (Eu-MOGs) synthesized using similar steps, due to their rigid skeletons and higher crystalline degree, which facilitated electron transfer. In addition, we designed a switching mode ECL biosensor, which was combined with an exonuclease-assisted DNA walker cycling signal amplification strategy, enabled the ultra-sensitive detection of the I27L gene, which was significantly associated with an increased risk of maturity-onset diabetes of the young (MODY). When the target DNA was present, DNA walker recycle amplification occurred driven by exonuclease III (Exo III). Subsequently, the ECL intensity of the system was reduced by introducing the ferrocene-labeled probe (H2-Fc) as a signal quencher. Under the optimal experimental conditions, a wide detection linear range of the target DNA was observed from 1 fM to 10 nM with a low detection limit of 447 aM. This research provided new possibilities for a gentle and simple method to obtain 2D MOFs with stable ECL signals for the sensitive detection of specific DNA sequences.

A Hybrid Strategy‐Based Ultra‐Narrow Stretchable Microelectrodes with Cell‐Level Resolution

AbstractStretchable ultra‐narrow (e.g., 10 µm in width) microelectrodes are crucial for the electrophysiological monitoring of single cells providing the fundamental understanding to the working mechanism of neuro network or other electrically functional cells. Current fabrication strategies either focus on the preparation of normal stretchable electrodes with hundreds of micrometers or millimeters in width by using inorganic conductive materials or develop conductive organic polymer gel for ultra‐narrow electrodes which suffer from low stretchability and instability for long‐term implantation, therefore, it is still highly desirable to explore bio‐interfacial ultra‐narrow stretchable inorganic electrodes. Herein, a hybrid strategy is reported to prepare ultra‐narrow multi‐channel stretchable microelectrodes without using photolithography or laser‐assisting etching. A 10 µm × 10 µm monitoring window is fabricated with enhanced interfacial impedance by the special rough surface. The stretchability achieves to 120% for this 10 µm‐width stretchable electrode. Supported by these superior properties, it is demonstrated that the stretchable microelectrodes can detect electrophysiological signals of single cells in vitro and collect electrophysiological signals more precisely in vivo. The reported strategy will open up the accessible preparation of the fine‐size stretchable microelectrode. It will significantly improve the resolution of monitoring and stimulation of inorganic stretchable electrodes.