Zeolitic Imidazolate Framework Research Articles

Microwave synthesis of composite of AgInS2 quantum dots and zeolitic imidazolate framework-8 for application in white light emitting diodes

Preparation of AgInS2 quantum dots (AIS QDs) with high photoluminescence quantum yield (PLQY) and thermal stability remains an important challenge. In this paper, AIS QDs were successfully introduced into zeolitic imidazolate framework-8 (ZIF-8) by microwave-assisted hydrothermal method. Due to the effective isolation of the ZIF-8, the AIS QDs avoid the concentration quenching when they were assembled into white light emitting diodes (WLEDs) devices as color conversion materials. More importantly, the generation of ZnS layer between the interfaces of AIS QDs and ZIF-8 can efficiently improve the optical performance of AIS QDs, resulting in the fluorescence lifetime extended to 470.05 ns. Meanwhile, the PLQY of AIS/ZIF-8 composite reached up 34.30 % when microwave hydrothermal heating at 120 °C for 60 min with AgIn/Zn=1/3, which was higher than that of the pristine AIS QDs as 25.30 %. Finally, the WLED devices were fabricated by combining AIS/ZIF-8 composite fluorescent powder with (Ba, Sr)Si2O2N2:Eu2+ phosphors and blue LED. At 20 mA, the AIS/ZIF-8 based WLED shows the luminous efficiency (LE) of 44.54 lm/W, correlated color temperature (CCT) of 4242 K and color rendering index (CRI) of 89.1. Moreover, the Commission International de L'Eclairage (CIE) was (0.36, 0.35), indicating the WLED emited warm white light. The present strategy aims at enhancing the optical performance of AIS QDs, which also may trigger the development of QDs-based WLED.

Template Role of Long Alkyl-Chain Amides in the Synthesis of Zeolitic Imidazolate Frameworks.

Organic amides as solvents and structure directing agents (SDAs) are crucial for synthesizing zeolitic imidazolate frameworks (ZIFs). However, current research focuses only on the use of short alkyl-chain amides as solvents/SDAs. Here, we investigate the role of amides with varying alkyl-chain lengths on the structures and topologies of Zn(Im)2 polymorphs. Using short alkyl-chain amides as solvents, the Zn(Im)2 topological structures are affected by the synthesis conditions, leading to "one SDA/multiple topological structures". In contrast, when long alkyl-chain amides are used as solvents, the Zn(Im)2 topological structures are essentially unaffected by other synthesis conditions. Thus, long alkyl-chain amides are shown for the first time to exhibit a significant template role, leading to "one template/one topological structure". Specifically, the use of long alkyl-chain N,N-dimethyl-Cn amides (abbreviated as DM-Cn amides, n = 3, 4, 6, 8, and 10) can lead to only DTF-type Zn(Im)2 frameworks under broad crystallization conditions. Single-crystal X-ray diffraction confirmed that the exquisite structural compatibility between long alkyl-chain DM-Cn amides and the DFT-type Zn(Im)2 framework results in a highly regular head-to-tail arrangement of amides along the (kaa-lov) n chain of the DFT framework. The template role for long alkyl-chain amides was further identified to be multiple C-H···π interactions between DM-Cn amides and Zn(Im)2 frameworks thanks to molecular simulations.

Machine Learning Optimizing Enzyme/ZIF Biocomposites for Enhanced Encapsulation Efficiency and Bioactivity.

In this study, we present the first example of using a machine learning (ML)-assisted design strategy to optimize the synthesis formulation of enzyme/ZIFs (zeolitic imidazolate framework) for enhanced performance. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were chosen as model enzymes, while Zn(eIM)2 (eIM = 2-ethylimidazolate) was selected as the model ZIF to test our ML-assisted workflow paradigm. Through an iterative ML-driven training-design-synthesis-measurement workflow, we efficiently discovered GOx/ZIF (G151) and HRP/ZIF (H150) with their overall performance index (OPI) values (OPI represents the product of encapsulation efficiency (E in %), retained enzymatic activity (A in %), and thermal stability (T in %)) at least 1.3 times higher than those in systematic seed data studies. Furthermore, advanced statistical methods derived from the trained random forest model qualitatively and quantitatively reveal the relationship among synthesis, structure, and performance in the enzyme/ZIF system, offering valuable guidance for future studies on enzyme/ZIFs. Overall, our proposed ML-assisted design strategy holds promise for accelerating the development of enzyme/ZIFs and other enzyme immobilization systems for biocatalysis applications and beyond, including drug delivery and sensing, among others.

Modulating N doping in cobalt-derived catalyst from zeolitic imidazolate frameworks for high performance zinc-air batteries

In this work, the N-content was varied using ammonium hydroxide (A), urea (U), and melamine (M) impregnated in a zeolitic imidazolate framework (ZIF-67) with a Co to Zn ratio of 7:93. The N-doped ZIF-derived carbon materials and the reference ZIF Co 7:93 underwent pyrolysis under identical conditions, yielding C-ZIF, CA-ZIF, CU-ZIF, and CM-ZIF. Different nitrogen sources mainly affected the surface area and graphitic-N content, yielding up to three times the N-content of the reference. All materials presented ORR onset potentials near 0.9 V and E10mA cm−2 near 1.6 V for the OER. However, CM-ZIF enabled rechargeability at different current densities, with a round-trip efficiency of 68.8 % at 5 mA cm−2, decreasing only to 54 % at 15 mA cm−2.

Illuminating the fight against breast cancer: Preparation and visualized photothermal therapy of hyaluronic acid coated ZIF-8 loading with indocyanine green and cryptotanshinone for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterized by higher recurrence rate and mortality. Thermally-mediated ablation via photothermal therapy (PTT) demonstrates considerable promise for the eradication of breast cancer. Nonetheless, the efficacy of PTT is impeded by the thermal tolerance of tumor cells, which is attributed to the augmented expression of heat shock proteins (HSPs). These proteins, which function as ATP-dependent molecular chaperones, confer protection to cancer cells against the cytotoxic heat generated during PTT. Glycolysis is an important way for breast cancer cells to produce ATP, which can promote the occurrence and development of lung metastasis of breast cancer. Therefore, inhibiting glycolysis may diminish the expression of HSPs, curtail the growth of breast cancer, and prevent its metastasis. Glycolytic metabolism plays a pivotal role in the ATP biosynthesis within breast cancer cells, facilitating the progression and dissemination of pulmonary metastases. Consequently, targeting glycolysis presents a strategic approach to HSP expression, the proliferation of breast cancer, and impede its metastatic spread. Herein, we designed an indocyanine green (ICG) and cryptotanshinone (CTS) loaded hyaluronic acid (HA) coated Zeolitic Imidazolate Framework-8 (ZIF-8) drug delivery system. The drug delivery system had excellent photothermal properties, which could reach temperature sufficient for photothermal ablation of tumor cells. (ICG + CTS)@HA-ZIF-8 also showed pH-responsive drug release, enhancing the sustained release of ICG and CTS to extend their systemic circulation duration. Moreover, the HA modification of ZIF-8 served to augment its targeting capabilities both in vitro and in vivo, leveraging the enhanced permeation and retention (EPR) effect, as well as active tumor targeting via the CD44 receptor pathway, resulting in a higher drug concentration and a better therapeutic effect in tumor. (ICG + CTS)@HA-ZIF-8 could downregulate the expression of glycolysis-related protein pyruvate kinase-M2 (PKM2), thereby inhibiting the glycolysis process, further suppressing tumor cell energy metabolism, downregulating the expression of HSPs, overcoming tumor cell heat resistance, and improving PTT effect. It exhibited a notable suppressive impact on both the proliferation and migration of breast cancer cells, potentially offering innovative insights for the visualized PTT in breast cancer treatment.

Efficient photocatalytic degradation of malachite green dye from wastewater using facilely synthesized ternary ZIF-8/Ag/Ag2S nanocomposite: Optimization by RSM (CCD)

The current study compares the photocatalytic potential of zeolitic imidazolate framework-8 (ZIF-8) with ZIF-8 nanocomposites doped with two forms of silver (referred to as AgNPs/ZIF-8 and AgNPs/Ag2S/ZIF-8). Their physicochemical characteristics were evaluated using Fourier-transform infrared, X-ray diffraction, energy-dispersive X-ray, Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), photocurrent density, Mott-Schottky, and Brunauer Emmett Teller techniques. The photocatalytic activity of the composites was assessed for degradation of malachite green (MG) under visible light irradiation in a solar-based staircase photoreactor for the first time. The optimization of the photodegradation process was achieved by employing central composite design, 0.020 g of AgNPs/ZIF-8 and ZIF-8photocatalyst (in 20 ml of solution), MG Concentration of 7 mg/l, pH of 8, and the irradiation time of 50 min. The predicted model had R2 and R2adj correlation coefficients of 0.987 and 0.975 respectively, which showed experimental results were very close to the predicted values. The results indicated remarkable efficiency in both degradation and mineralization, achieving the degradation rate of up to 98.6 %, a high-rate constant value of 0.0701 min-¹, and an 80 % mineralization efficiency. AgNPs/Ag2S/ZIF-8 exhibited superior photocatalytic performance in comparison to both AgNPs/ZIF-8 and ZIF-8. Different scavengers were used in the experiment and demonstrated that O2− played a crucial role in the photodegradation of MG. Moreover, the nanocomposite AgNPs/Ag2S/ZIF-8 exhibited robust stability and could be repeatedly utilized up to five cycles without notable decline in efficacy, rendering it an environmentally sustainable photocatalyst with promising prospects for industrial utilization.

Copper-loaded ZIF-8-based immunosensor for early diagnosis of chronic kidney disease by detecting neutrophil gelatinase-associated lipocalin (NGAL) biomarker

Metal-organic frameworks (MOFs) is a promising contender among the nanomaterials for biosensors due to their special properties, including high surface area, tunable porosity, and adaptable functionalization competences. Zeolitic imidazolate frameworks (ZIFs), a subclass of MOFs, have drawn precise attention for their excellent chemical stability and ease of synthesis. This study, for the first time, concentrates on the preparation and characterization of a Cu-loaded ZIF-8-based immunosensor for the detection of neutrophil gelatinase-associated lipocalin (NGAL), a crucial biomarker for chronic kidney disease (CKD). Loading copper (Cu) into the ZIF-8 framework improves its electrochemical properties, conductivity, and surface area, leading it an ideal platform for antibody immobilization and NGAL detection. The immunosensor utilized Staphylococcal Protein A (SPA) IgG binding protein for antibody immobilization, providing an alternative to traditional crosslinking chemistry, enhancing biosensor functionality. Structural analysis, morphological assessment, elemental mapping, and stoichiometric analysis confirmed the successful synthesis of Cu-loaded ZIF-8 nanocomposite. Assessment of the electrochemical performance of the immunosensor demonstrated sufficiently low limit of detection (80 pg mL−1) over a wide range of 0.1 ng mL−1 to 1000 ng mL−1 of NGAL along with superior selectivity, reproducibility, stability, and clinical feasibility. This advancement contributes to the rising knowledge on MOF-based biosensors and holds promise for future applications in disease diagnosis and healthcare monitoring.

Portable smartphone-assisted amperometric immunosensor based on CoCe-layered double hydroxide for rapidly immunosensing erythromycin

Herein, we have manufactured a newly designed bifunctional impedimetric and amperometric immunosensor for rapidly detecting erythromycin (ERY) in complicated environments and food stuffs. For this, bimetallic cobalt/cerium-layered double hydroxide nanosheets (CoCe-LDH NSs), which was derived from Co-based zeolite imidazole framework via the structure conversion, was simultaneously utilized as the bioplatform for anchoring the ERY-targeted antibody and for modifying the gold and screen printed electrode. Basic characterizations revealed that CoCe-LDH NSs was composed of mixed metal valences, enrich redox, and abundant oxygen vacancies, facilitating the adhesion on the electrode, the antibody adsorption, and the electron transfers. The manufactured impedimetric and amperometric immunosensor based on CoCe-LDH has showed the comparable sensing performance, having a wide linear detection range from 1.0 fg mL−1 to 1.0 ng mL−1 with the ultralow detection limit toward ERY. Also, the portable, visualized, and efficient analysis of ERY was then attained at the smartphone-assisted CoCe-LDH-based SPE.

(Nanocarbons Division Poster Award, 3rd Place) Investigating the Impact of Reaction and Carbonization Variables on ZIF-67 and Its Energy Storage Properties

Metal-organic frameworks (MOFs), with their exceptional properties such as high surface area, well-defined pores, and diverse chemical functionalities, have garnered widespread attention in scientific and industrial domains [1-2]. Among these, zeolitic imidazolate frameworks (ZIFs), known for their chemical and thermal stability, are extensively explored for applications ranging from catalysis and gas adsorption to electronic devices and sensors.By employing a novel hydrothermal method in aqueous solutions at room temperature, ZIF-67 nanocrystals were successfully synthesized, eliminating the need for toxic organic solvents and reducing overall costs. The resulting materials demonstrated notable efficiency in energy storage. To address the increasing demand for scalable synthesis methods, the study investigated the impact of reaction scale, reaction time, and reaction mixture dilution on the yield, morphology, and molecular structure of ZIF-67. The optimized conditions increased the production yield to 83%, surpassing the reported 75%. The subsequent carbonization process under three different regimes (800 °C, 800 °C with 3h ramp, 900 °C) resulted in materials exhibiting promising energy storage capabilities, with capacitance values reaching 81 F g−1 at a low sweep rate of 5 mV s−1. The carbonization yield showed a decrease with increasing carbonization time and temperature, and capacitance values were influenced by the presence of cobalt in the material.A slightly higher specific surface area of sample C-800 is reflected in the slightly higher capacitance values over all sweep rates indicating that specific surface area plays a role in the behavior of here synthesized materials. Capacitance is invariant at higher sweep rates (above 20mV s-1) which can be an indication that a part of the material surface, at macro- and mesopores, is highly responsive and highly conductive. At lower sweep rates micropores become available, due to prolonged time for ion insertion, which increases the capacitance that is unavailable at higher sweep rates. The highest percentage rise in capacitance is also seen in sample C-800 as its micropore volume, 40% of its total volume, is the highest among the samples investigated.Specifically, considering only the carbon part, the specific capacitance reached 176 F g−1, comparable to literature values for MOF-derived carbons [3]. The study suggests that dissolution of cobalt could enhance the material's capacitance behavior, opening avenues for further improvement in energy storage applications. This transformative approach addresses challenges associated with escalating energy demands and showcases the potential of ZIF-67-derived materials in electrochemical applications.AcknowledgementThis research was supported by the Science Fund of the Republic of Serbia, grant number 7750219, Advanced Conducting Polymer-Based Materials for Electrochemical Energy Conversion and Storage, Sensors and Environmental Protection-AdConPolyMat (IDEAS programme)

Synergistic Electrocatalysts Impact Efficient and Durable Oxygen Evolution Catalysis for Proton Exchange Membrane Water Splitting

Low-temperature water electrolysis can rapidly produce environmentally sustainable or green hydrogen, and is a prospective means of storing energy from renewable but intermittent power sources, such as wind and solar, in future clean energy infrastructure (1-4). Commercial water electrolysis either use liquid alkaline electrolyte or proton exchange membrane electrolyte (1). The proton exchange membrane water electrolysis (PEMWE) offers more advantages than the alkaline counterpart, such as higher purity of H2, lower resistance losses, more compact design, and what the most important is the compatible with the intermittent of the renewable energy (1-2). The grant challenge remaining in PEMWE is the development of the highly active, cost effective and stable catalysts for oxygen evolution reaction (OER), which is very sluggish requiring large amounts of precious metal as the catalysts, such as Ir, Ru and their oxides (1).In PEM water electrolysis cells, the catalysts should have high surface areas and high porosities that exposit sufficient active sites available to the reactants and electrolyte, as well as transferring the bubble out of the catalyst surface to ensure a fast mass transfer (5). Also, the OER is dependent on the inherent conductivity of the catalysts or the supports (1). For example, poor electronic conductivity within the catalyst layer will result in poor lateral conductivity across the catalyst layer, thus catalyst not in the vicinity of the porous transport layer will not participate in the reaction. To enable the widespread penetration of the PEMWE technologies, it is urgently to reduce the Ir loading to the sustainable level (~ 0.3 mg/cm2) compared with the current commercial usage (2-6 mg/cm2). Alternatively, to develop precious metal free catalyst with high efficiency and sustained durability (5).In this presentation, we will describe a method of preparing highly active yet stable synergistic electrocatalysts for oxygen evolution reaction for PEMWE. The new catalysts contain IrCoOx/ RuCoOx cluster and La&Li co-doped Co3O4 fiber which was derived from cobalt zeolitic imidazolate framework as precursor. The OER activities of the catalysts were first tested in O2 saturated acidic electrolyte by ring disk electrode (RDE), which displayed high mass activity 26-50 times that of commercial Ir and RuO2. The catalysts were fabricated into membrane electrode assemble and measured under real PEM water electrolysis condition. The cells demonstrated 2 A/cm2@1.76 V @0.25 ± 0.05 mgIr/cm2 loading, and negligible degradation after ~250 h chronoamperometric measurements at 2 A/cm2 (6), which meets the target set by US DOE for OER catalysts for PEMWE.The characterizations of the fresh and post-electrochemical samples were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), transmission electron microscopy (TEM), Raman spectroscopy and BET surface analysis. We also performed DFT simulation on the OER reaction pathways over Ir and Co sites of different facets parallelly on basis of the TEM results. The result reveals the synergy between Ir/Ru and Co resulting in the enhanced catalytic activities of both IrCoOx /RuCoOx and LaLi@Co3O4 toward OER.Acknowledgments:This work was supported by Overseas Outstanding Youth Fund project, shanghai Jiao Tong university, Shanghai, China; Shanghai Pujiang talent Plan, Shanghai, China; Argonne National Laboratory through Maria Goeppert Mayer Fellowship, US; State Key Laboratory of Metal Matrix Composites, shanghai Jiao Tong university, Shanghai, China. The works performed at Hydrogen research center, shanghai Jiao Tong university, and Argonne National Laboratory’s Center for Nanoscale Materials and Advanced Photo Source.Reference: K. Ayers et al., Annu. Rev. Chem. Biomol. Eng. 10, 219–239 (2019).M. Carmo, D. L. Fritz, J. Mergel, D. Stolten, Int. J. Hydrogen Energy 38, 4901–4934 (2013).M. T. M. Koper, J. Electroanal. Chem. 660, 254–260 (2011).R. D. L. Smith et al., Science 340, 60–63 (2013).Chong et al., Science 380, 609–616 (2023).Chong et al., Adv. Energy Mater. 2023, 2302306.

Coembedding Fe Single Atom-Coupled MoC Nanoparticles in N-Doped Hierarchically Porous Carbon Cubes for Oxygen Electroreduction.

Promotion of oxygen reduction reaction (ORR) kinetics, to a large extent, depends on the rational modulation of the electronic structure and mass diffusion of electrocatalysts. Herein, a ferrocene (Fc)-assisted strategy is developed to prepare Fc-trapped ZnMo-hybrid zeolitic imidazolate framework (Fc@ZnMo-HZIF-50) and the derived Fe single atom coupling with MoC nanoparticles, coembedded in hierarchically porous N-doped carbon cubes (MoC@FeNC-50). The introduced Fc is utilized not only as an iron source for single atoms but also as a morphology regulator for generating a hierarchically porous structure. The redistribution of electrons between Fe single atoms and MoC nanoparticles effectively promotes the adsorption of O2 and the formation of *OOH intermediates during the ORR process. Along with a 3D hierarchically porous architecture for enhanced mass transport, the as-fabricated MoC@FeNC-50 presents excellent activity (E1/2 = 0.83 V) and durability (only 9.5% decay in current after 40000 s). This work could inspire valuable insights into the construction of efficient electrocatalysts through electron configuration and kinetics engineering.

Reactive Extrusion Printing of Zeolitic Imidazolate Framework Films.

An outstanding challenge for the field of metal-organic frameworks (MOFs) is structuring to form forms with greater useability. Reactive extrusion printing (REP) is a technique for the direct formation of films from their molecular components on-demand and on-location. Here we apply REP for the first time to zeolitic imidazolate frameworks (ZIFs) and study the interplay of solvent and molarity ratio on the phase distribution between ZIF-8 and ZIF-L in reactive printed films. Our results show that REP controllably directs phase formation between ZIF-L and ZIF-8 and that REP also gives control over crystal size and that high-quality ZIF-8 films, in particular, are produced in low-dispersity interconnected nanoparticulate form. Importantly, we show that REP is responsive to established surface-functionalization techniques to control important printing parameters of line width and thickness. This work expands the repertoire of REP to the important class of ZIFs.

Nanoengineering Multilength-Scale Porous Hierarchy in Mesoporous Metal-Organic Framework Single Crystals.

Developing a reliable method for constructing mesoporous metal-organic frameworks (MOFs) with single-crystalline forms remains a challenging task despite numerous efforts. This study presents a solvent-mediated assembly method for fabricating zeolitic imidazolate framework (ZIF) single-crystal nanoparticles with a well-defined micro-mesoporous structure using polystyrene-block-poly(ethylene oxide) diblock copolymer micelles as a soft-template. The precise control of particle sizes, ranging from 85 to 1200 nm, is achieved by regulating nucleation and crystal growth rates while maintaining consistent pore diameters in mesoporous nanoparticles and a rhombohedral dodecahedron morphology. Furthermore, this study presents a robust platform for nanoarchitecturing to prepare hierarchically porous materials (e.g., core-shell and hollow structures), including microporous ZIF@mesoporous ZIF, hollow mesoporous ZIF, and mesoporous ZIF@mesoporous ZIF. Such a multimodal pore design, ranging from microporous to microporous/mesoporous and further micro-/meso-/macroporous, provides significant evidence for the future possibility of the structural design of MOFs.

New Insights into ZIF-90 Synthesis.

Zeolitic imidazolate frameworks (ZIFs) are traditionally synthesized using N, N-dimethylformamide (DMF). However, DMF is toxic and hazardous to human health and the environment, hence other alternative solvents need to be considered. Herein, three different solvents like methanol, water and acetone were used to replace DMF and to explore the syntheses of ZIF-90 using a conventional and a microwave-assisted solvothermal method to obtain hydrothermally stable products, which also exhibit an increased water uptake. Pure ZIF-90 was synthesized under ambient pressure at 60 °C for 90 min using the conventional solvothermal method in an acetone-water solution, while under microwave irradiation it was formed in only 5 min at 80 °C. Altering methanol, water and acetone in the reaction mixture significantly affected the structural and water adsorption properties of ZIF-90s, which were monitored via PXRD, TGA, nitrogen and water sorption, and SEM. The highly efficient, less toxic, low-cost and activation-free microwave synthesis resulted in the formation of ZIF-90 nanoparticles that exhibited the highest maximum water adsorption capacity (0.37 g/g) and the best hydrothermal stability between water adsorption at 30 °C and desorption at 100 °C at 12.5 mbar among all the products obtained.

Extent of Radiolytic Damage from Liquid Cell TEM Experiments on Metal-Organic Frameworks via Post-Mortem 4D-STEM.

We report a systematic analysis of electron beam damage of the zeolitic imidazolate framework (ZIF-8) during liquid cell transmission electron microscopy (LCTEM). Our analysis reveals ZIF-8 morphology is strongly affected by solvent used (water vs dimethylformamide), electron flux applied, and imaging mode (i.e., TEM vs STEM), while ZIF-8 crystallinity is primarily affected by accumulated electron fluence. Our observations indicate that the stability of ZIF-8 morphology is higher in dimethylformamide (DMF) than in water. However, in situ electron diffraction indicates that ZIF-8 nanocrystals lose crystallinity at critical fluence of ∼80 e-Å-2 independent of the presence of solvent. Furthermore, 4D-STEM analysis as a post-mortem method reveals the extent of electron beam damage beyond the imaging area and indicates that radiolytic reactions are more pronounced in TEM mode than in STEM mode. These results illustrate the significance of radiolysis occurring while imaging ZIF-8 and present a workflow for assessing damage in LCTEM experiments.

Monocyte/Macrophage-Mediated Transport of Dual-Drug ZIF Nanoplatforms Synergized with Programmed Cell Death Protein-1 Inhibitor Against Microsatellite-Stable Colorectal Cancer.

Microsatellite-stable colorectal cancer (MSS-CRC) exhibits resistance to programmed cell death protein-1 (PD-1) therapy. Improving the infiltration and tumor recognition of cytotoxic T-lymphocytes (CTLs) is a promising strategy, but it encounters huge challenges from drug delivery and mechanisms aspects. Here, a zeolitic imidazolate framework (ZIF) coated with apoptotic body membranes derived from MSS-CRC cells is engineered for the co-delivery of ginsenoside Rg1 (Rg1) and atractylenolide-I (Att) to MSS-CRC, named as Ab@Rg1/Att-ZIF. This system is selectively engulfed by Ly-6C+ monocytes during blood circulation and utilizes a "hitchhiking" mechanism to migrate toward the core of MSS-CRC. Ab@Rg1/Att-ZIF undergoes rapid disassembly in the tumor, released Rg1 promotes the processing and transportation of tumor antigens in dendritic cells (DCs), enhancing their maturation. Meanwhile, Att enhances the activity of the 26S proteasome complex in tumor cells, leading to increased expression of major histocompatibility complex class-I (MHC-I). These coordinated actions enhance the infiltration and recognition of CTLs in the center of MSS-CRC, significantly improving the tumor inhibition of PD-1 treatment from ≈5% to ≈69%. This innovative design, involving inflammation-guided precise drug co-delivery and a rational combination, achieves synergistic engineering of the tumor microenvironment, providing a novel strategy for successful PD-1 treatment of MSS-CRC.

Click-response-driven high-speed and ultrasensitive electrochemical sensing interface: Addressing its accuracy challenge

For electrochemical sensors, maintaining accuracy while achieving sensitive detection is of paramount importance. The fixation of the signal substance as one of the main steps in the construction process of a sensor has a significant impact on the accuracy. Currently, physical and chemical methods are the primary approaches for the fixation of the signal substance, which have the following issues. The accuracy of a sensor may be affected by the instability resulting from the physical immobilization of the signal substance and the chemical immobilization process is typically time-consuming. To overcome these obstacles, the ultra-sensitive electrochemical sensing interface is constructed by click reaction to achieve accurate and rapid detection of tumor biomarkers. After the formation of immune-sandwich structure in a test tube, a large amount of ethynylferrocene (EFc) molecules in the Zeolitic imidazolate frameworks (ZIF-8) immunoprobe are released under acidic conditions, followed by covalently linking to the substrate within 6 minutes through a click reaction. Under optimal conditions, the electrochemical sensor had an ultralow detection limit of 32.90 fg mL−1 for the model analyte (CEA) with a wide detection range from 100 fg mL−1 to 100 ng mL−1. This work provides a new perspective for designing electrochemical sensors with excellent performance.

Investigating solvent effects on synthesizing novel cobalt hydroxide and fluoride complex from Co(BF4)2 as active materials of the battery supercapacitor hybrid

Metal-organic framework (MOF) derivatives with tunable pore structure and improved conductivity are intensively designed as electroactive materials. Incorporating structure directing agents (SDA) is beneficial for designing MOF derivatives with excellent electrochemical performances. Ammonium fluoroborate has been reported as an effective SDA, coupled with cobalt salt and 2-methylimidazole, to synthesize zeolitic imidazolate framework-67 (ZIF-67) derivatives for charge storage. However, the synthetic environment for growing cobalt-based active materials is relatively complex. In this study, cobalt tetrafluoroborate (Co(BF4)2) is proposed as a novel cobalt precursor, supplementing cobalt ions and acting as the SDA in a single chemical, to synthesize the cobalt-based electroactive material of energy storage electrodes. Interactions between solvent molecules and solutes play significant roles on the morphology, composition, and electrochemical performance of active materials. Deionized water, methanol and ethanol are used as precursor solvents to understand their effects on material and electrochemical properties. The optimal electrode presents a specific capacitance of 608.3 F/g at 20 mV/s, attributed to the highest electrochemical surface area and evident compositions of cobalt fluoride and hydroxide. A battery supercapacitor hybrid achieves the maximum energy density of 45 Wh/kg at 429 W/kg. The CF retention of 100% and Coulombic efficiency of 99% are achieved after 10,000 cycles.

Rational construction of a hollow bimetallic porous composite derived zeolite imidazole framework based reduced graphene oxide nanosheets for supercapacitor applications

Rational construction of a hollow bimetallic porous composite derived zeolite imidazole framework based reduced graphene oxide nanosheets for supercapacitor applications

Fabrication of cobalt phosphide/nitride/carbon nanotube composite: An efficient bifunctional catalyst for hydrogen and oxygen evolution

Designing composites with rational structure and composition is a promising approach to obtain efficient electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this study, zeolitic imidazolate frameworks-67 (ZIF-67) is employed as a self-sacrificing template to synthesize Co/carbon nanotubes (CNTs) precursor, which is subsequently in-situ nitrided and phosphorized to form cobalt phosphide/nitride/carbon nanotubes (Co2P/Co4N/CNTs) composite. The realized Co2P/Co4N composite exhibits heterogeneous nanoparticle microstucture with an average diameter of approximately 10 nm, encapsulated by carbon nanotubes with a porous dodecahedral array. Moreover, there is a well-defined interface between cobalt phosphide, cobalt nitride phases, and carbon nanotubes species. Benefiting from the synergistic effect of Co4N and Co2P, rich active sites, and high conductivity of CNTs, the composite catalyst demonstrates remarkable HER and OER activities, requiring overpotentials of 228 and 389 mV to support 100 mA cm−2 current density, respectively. This work presents a novel strategy for designing efficient bifunctional catalysts towards HER and OER.