Modified Metal Organic Framework Research Articles

Enhanced CO 2 Photoconversion at Elevated Pressures Using Conductive Polymer Modified Metal–Organic Framework

Enhanced CO ₂ Photoconversion at Elevated Pressures Using Conductive Polymer Modified Metal–Organic Framework

Direct construction of imidazoles via oxidative C(sp3)–H amination and annulation of aryethylamines by a Single-Atom cobalt catalyst

The development of reusable catalytic systems for achieving site-selective functionalization of C(sp3)-H bond remains a significant challenge. Herein, we designed a modified metal–organic framework (MOF)-derived N, P co-doped carbon supported single-atom cobalt catalyst, which was successfully applied in oxidative C(sp3)–H amination and cyclization of aryethylamines for construction of polysubstituted imidazoles. The advantages of the present method include: broad substrate scope, recyclable base metal catalyst, and naturally abundant O2 as green oxidant. The structural − activity relationship of the catalyst indicated that the atomically dispersed CoN3P1 is the active species responsible for the catalytic process. Furthermore, the synthesized imidazoles exhibited exceptional insecticidal activity against wheat pests, and may become lead molecules in the development of novel agricultural pesticide candidates, with significant application potential.

The detection of acetone in exhaled breath using gas Pre-Concentrator by modified Metal-Organic framework nanoparticles

Volatile organic compounds (VOCs) from exhaled breath are promising indicators for the diagnostics of human health conditions. However, the composition of breath is rather complex, including water vapors and various tiny amounts of gases and biomarkers. Pre-concentrator plays a significant role in capturing and concentrating target gas in the gas mixture. In this work, the MIL-101 (Cr) nanoparticles are coated with polydimethylsiloxane (PDMS) through physical vapor deposition process to concentrate acetone under high humidity and room temperature. Experimentally, the newly developed material exhibits significant improvement in signal intensity that is 76.3 times greater than a commercial reference material under relative humility of 80 %. The detection range is also proven to be desirable (from 100 ppb to 2500 ppb), capturing the spectrum of acetone concentrations typically found in human exhaled breath. Moreover, following a thermal desorption process, the device demonstrates a high degree of linearity with a coefficient of 0.9956. The modified metal–organic framework materials are made into a flexible thin-film-shape device, that could be embedded in a facemask. The proposed device could meet the critical requirements for sampling, concentrating and detecting of exhaled breath biomarkers, thereby opening a new opportunity as part of the flexible electronic systems on face masks to facilitate quantitative breath analyses.

Specific adsorption of antiviral drugs on ionic liquid-modified metal–organic framework: Adsorption behavior, mechanism, and DFT analysis

As emerging contaminants, antiviral drugs (ATVs) in water pose an increasing threat to human health and the ecosystem. Using specific and selective adsorption methods to remove ATVs remains challenging due to their trace concentration in real matrices. In this study, pyridine ionic liquid ([BPy][Sal])-modified metal–organic framework (MOF), a type of novel material, was synthesized as [BPy][Sal]@MOF to adsorb ATVs with different molecular structures, i.e., Arbidol (Arb) and Favipiravir (Fav). Arb adsorption followed the pseudo-second-order model, indicating that chemisorption is the dominant process. The Langmuir isothermal model showed that the maximum adsorption capacities toward Arb and Fav were 506.9 and 35.3 mg g−1, respectively, suggesting specific adsorption of Arb on [BPy][Sal]@MOF. Density functional theory (DFT) was used to investigate the specific adsorption mechanism. The molecular electrostatic potential and the intermolecular weak interaction analysis using the DFT method illustrated that the amino hydrogens in MOF could form hydrogen bonds (NHO) with the hydroxyl oxygens in Arb. Simultaneously, the indole ring in Arb could cause π–π interaction with the pyridine ring in [BPy][Sal] part from [BPy][Sal]@MOF. In contrast, the adsorption of Fav only involved π–π interaction between the benzene rings in Fav and the MOF part from [BPy][Sal]@MOF. The adsorption energy and energy gap calculation results verified that the adsorption strength of Arb was higher than that of Fav, and the key role of [BPy][Sal] in [BPy][Sal]@MOF helped achieve specific adsorption was confirmed. [BPy][Sal]@MOF exhibited exceptional recyclability after five adsorption–desorption cycles in environmental waters, demonstrating its excellent adsorption performance in practical applications.

Sodium Alginate/UiO-66-NH2 Nanocomposite for Phosphate Removal.

Environmental pollution of phosphorus is becoming increasingly concerning, and phosphate removal from water has become an important issue for controlling eutrophication. Modified metal-organic framework (MOF) materials, such as UiO-66-NH2, are promising adsorbents for phosphate removal in aquatic environments due to their high specific surface area, high porosity, and open active metal sites. In this study, a millimeter-sized alginate/UiO-66-NH2 composite hydrogel modified by polyethyleneimine (UiO-66-NH2/SA@PEI) was prepared. The entrapping of UiO-66-NH2 in the alginate microspheres and its modification with PEI facilitate easy separation in addition to enhanced adsorption properties. The materials were characterized by SEM, FTIR, XRD, and BET. Static, dynamic, and cyclic adsorption experiments were conducted under different pH, temperature, adsorbent dosage, and initial concentration conditions to assess the phosphate adsorption ability of UiO-66-NH2/SA@PEI. Under optimal conditions of 65 °C and pH = 2, 0.05 g UiO-66-NH2/SA@PEI adsorbed 68.75 mg/g, and the adsorption rate remained at 99% after five cycles of UiO-66-NH2/SA@PEI. These results suggest that UiO-66-NH2/SA@PEI composite materials can be used as an effective adsorbent for phosphate removal from wastewater.

Sea urchin inspired ultrafast response low humidity sensor based on ionic liquid modified UiO-66 with advanced applications

Numerous applications require low humidity sensors that not only sensitive but also stable, small hysteresis, high resolution and fast response. However, most reported low humidity sensors cannot possess these properties at the same time. In this work, inspired by sea urchin, we developed an ionic liquid (IL) modified metal organic framework (UiO-66) based low humidity sensor. Owing to the synergistic effect of the hydrophilicity and ionic conductivity of IL and the steric hindrance effects of UiO-66, the optimized low humidity sensor simultaneously exhibits high response (47.5), small hysteresis (0.3 % RH), ultrafast response speed (0.2 s), high resolution (1 % RH), and excellent long-term stability (>120 days). In particular, the sensor has been proved to have potential applications in visual humidity detection and water source location. This work provides a preliminary design principle that will contribute to the preparation of high-performance low humidity sensing materials.

Modified Metal–Organic Framework (MOF-818) inspired by natural enzymes for intelligent detection of total antioxidants and bisphenol A in infant beverages

BackgroundAccurate and quick judgement of the food quality can protect the legitimate rights of consumers. Currently, nanozymes are widely employed in the rapid detection of food due to their stability and economy. The contents of bisphenol A and antioxidant can be used to measure the quality of beverages. However, due to the complexity of the actual samples, it is still challenging to achieve the sensitive detection of both at the same time. The development of nanozyme with high enzyme activity is essential for sensitive detection of targets in complex foods. ResultsIn this work, a novel nanomaterial (ZrTGA) was synthesized based on thioglycolic acid-modified Metal–Organic Framework (MOF-818). The interaction between Cu–S bonds and increase in the proportion of Cu1+ resulted in ZrTGA exhibiting higher peroxidase-like and polyphenol oxidase-like activities. These enzyme activities were 317 % and 200 % of the original values, respectively. With high enzyme activity can sensitively detect two important indicators of bisphenol A and antioxidants in beverages. The increased enzyme activity of ZrTGA enabled the content of both substances to be detected by smartphone extraction of RGB. Finally, through the output of the ''0″ and ''1″ signals of the logic gates, it is possible to quickly determine the level of the two substances and thus directly assess the quality of the beverages. SignificanceThe modification of nanozyme enables the detection of substances at low concentrations based on enhancing dual-enzyme activity. The combination of mobile phone photography and logic gate technology enables the continuous detection of two important indicators in beverages, overcoming the limitations of traditional large-scale instruments. It also provides an alternative strategy for food quality detection.

Targeted Delivery of Letrozole Using a Modified Metal–Organic Framework as a Promising Candidate in Breast Cancer Therapy

Targeted Delivery of Letrozole Using a Modified Metal–Organic Framework as a Promising Candidate in Breast Cancer Therapy

Enhanced Gas Sensing Characteristics of a Polythiophene Gas Sensor Blended with UiO‐66 via Ligand Functionalization

AbstractConjugated polymers exhibit significant potential for use in gas sensors owing to their flexibility and straightforward preparation. However, the performance of organic gas sensors based on such materials is currently suboptimal owing to their poor charge‐transport properties and limited selectivity. To address this limitation, a novel strategy that involves blending a chemically modified metal–organic framework (MOF) material, UiO‐66, with a conjugated polymer is developed. The MOF porous material is chemically modified with polar nitrogen‐containing functional groups (amino and nitro groups) to create gas molecule adsorption sites. To evaluate the impact of these modifications on the sensing performance, experiments that combined the sensing performance with a density functional theory simulation are conducted. The findings reveal that gas sensors fabricated using an amine‐functionalized MOF blended with conjugated polymers exhibit significantly higher sensitivity than home polymer devices, the sensing performance of the UiO‐66‐NH2/P3HT blend film improved by a factor of two with a sensitivity of ≈2%/ppm and an LOD of 0.001 ppt. Additionally, these devices exhibit exclusive NO2‐sensing performance for other gases such as CO2 and SO2.

Baicalin nanodelivery system based on functionalized metal-organic framework for targeted therapy of osteoarthritis by modulating macrophage polarization

Intra-articular drugs used to treat osteoarthritis (OA) often suffer from poor pharmacokinetics and stability. Nano-platforms as drug delivery systems for drug delivery are promising for OA therapy. In this study, we reported an M1 macrophage-targeted delivery system Bai@FA-UIO-66-NH2 based on folic acid (FA) -modified metal-organic framework (MOF) loaded with baicalin (Bai) as antioxidant agent for OA therapy. With outstanding biocompatibility and high drug loading efficiency, Bai@FA-UIO-66-NH2 could be specifically uptaken by LPS-induced macrophages to serve as a potent ROS scavenger, gradually releasing Bai at the subcellular level to reduce ROS production, modulate macrophage polarization to M2, leading to alleviation of synovial inflammation in OA joints. The synergistic effect of Bai@FA-UIO-66-NH2 on macrophage polarization and ROS scavenging significantly improved the therapeutic efficacy of OA, which may provide a new insight into the design of OA precision therapy.

Synthesis of rare earth MOF/CZS materials derived from aromatic tetracarboxylic acids and photocatalytic hydrogen production

With the increasing urgency of clean energy, photocatalytic hydrogen production serves as a sustainable hydrogen manufacturing method to improve the increasing scarcity of fossil fuels and environmental pollution. Herein, Cd0.2Zn0.8S (CZS)-modified Metal-Organic Framework (MOF) composites Pr–NO2–TPTC/CZS were successfully prepared through the reaction of Pr3+, aromatic tetracarboxylic acid, and Cd0.2Zn0.8S nanoparticles. Pr–NO2–TPTC/CZS composite materials exhibited enhanced photolysis performance compared to pure Pr–NO2–TPTC and Cd0.2Zn0.8S materials. With the decrease of Cd0.2Zn0.8S in Pr–NO2–TPTC/CZS composites, the photocatalytic performance of the synthesized composites is constantly improved. Pr–NO2–TPTC/CZS (1:1) photocatalyst exhibited excellent hydrogen evolution performance, with a hydrogen production capacity of 6321 μmol g−1 h−1. Photoluminescence spectroscopy (PL), photocurrent-time test (I-t), and electrochemical impedance spectroscopy (EIS) confirmed that the heterojunction interface formed between Pr–NO2–TPTC and CZS promoted electron-hole separation and transfer. Electron paramagnetic resonance (EPR) indicated that CZS-modified Pr–NO2–TPTC can promote the production of ·OH and ·O2− in the system, thereby increasing the photocatalytic hydrogen production performance. This work provides an effective solution for photocatalytic hydrogen production and a potential method for solving the energy crisis and environmental pollution.

Poly-l-lysine modified MOF nanoparticles with pH/ROS sensitive CIP release and CUR triggered photodynamic therapy against drug-resistant bacterial infection

The challenge of drug resistance in bacteria caused by the over use of biotics is increasing during the therapy process, which has attracted great attentions of the clinicians and scientists around the world. Recently, photodynamic therapy (PDT) triggered by photosensitizer (PS) has become a promising treatment method because of its high efficacy, easy operation, and low side effect. Herein, the poly-l-lysine (PLL) modified metal-organic framework (MOF) nanoparticles, ZIF/PLL-CIP/CUR, were synthesized to allow both reactive oxygen species (ROS) responsive drug release and photodynamic effect for synergistic therapy against drug resistant bacterial infections. The PLL was modified on the shell of the zeolite imidazole framework (ZIF) by the ROS-responsive thioketal linker for controllable CIP release. CUR were encapsulated in ZIF as the photosensitizer for blue light mediated photodynamic effect to produce singlet oxygen (1O2) and superoxide anion radical (O2−) for efficient inhibition towards methicillin-resistant Staphylococcus aureus (MRSA). The charge conversion from negative charge (−4.6 mV) to positive charge (2.6 mV) was observed at pH 7.4 and pH 5.5, and 70.9 % CIP was found released at pH 5.5 in the presence of H2O2, which suggests the good biosafety at physiological pH and ROS-responsive drug release of the as-prepared nanoparticle in the bacterial microenvironment. The as-prepared nanoparticles could effectively kill MRSA and disrupt bacterial biofilm by combination of chemo- and photodynamic therapy. In mice model, the as-prepared nanoparticles exhibited excellent biosafety and synergistic effect with 98.81 % healing rate in treatment of MRSA infection, which is considered as a promising candidate in combating drug resistant bacterial infection.

A natural killer T cell nanoagonist-initiated immune cascade for hepatocellular carcinoma synergistic immunotherapy.

Natural killer T (NKT) cell-mediated immunotherapy shows great promise in hepatocellular carcinoma featuring an inherent immunosuppressive microenvironment. However, targeted delivery of NKT cell agonists remains challenging. Here, we developed a hyaluronic acid (HA) modified metal organic framework (zeolitic imidazolate framework-8, ZIF-8) to encapsulate α-galactosylceramide (α-Galcer), a classic NKT cell agonist, and doxorubicin (DOX) for eliminating liver cancer, denoted as α-Galcer/DOX@ZIF-8@HA. In the tumor microenvironment (TME), these pH-responsive nano-frameworks can gradually collapse to release α-Galcer for activating NKT cells and further boosting other immune cells in order to initiate an antitumor immune cascade. Along with DOX, the released α-Galcer enabled efficient NKT cell activation in TME for synergistic immunotherapy and tumor elimination, leading to evident tumor suppression and prolonged animal survival in both subcutaneous and orthotopic liver tumor models. Manipulating NKT cell agonists into functional nano-frameworks in TME may be matched with other advanced managements applied in a wider range of cancer therapies.

Post-therapy via integrated curcumin and doxorubicin modified cerium-based UiO-66 MOFs using an antioxidant and anticancer therapeutic strategy.

The quest for effective cancer treatment methodologies underpins numerous research endeavors. Despite the therapeutic efficacy of conventional chemotherapy against malignant tumors, tumor recurrence post-therapy remains a formidable challenge. Addressing this, we developed a dual drug delivery system, rooted in a modified metal-organic framework (MOF), specifically by substituting the metal nodes of Uio-66 with cerium to augment its anti-oxidative potential. This engineered system, pyrene-modified hyaluronic acid, functions as a linker, enabling the self-assembly and encapsulation of both the material and the therapeutic agents, and encompasses both doxorubicin and curcumin, aimed at targeting cancer cell eradication and tumorigenesis inhibition. This system demonstrated significant antioxidant capacity through free radical scavenging assays, positioning it as a potential agent in mitigating tumor recurrence. Enhanced anti-tumor activity was distinctly evidenced in human colon cancer cell lines. Additionally, in vitro drug release assessments revealed slow-release kinetics and acid-responsive traits, attributed to the incorporation of pyrenylated hyaluronic acid. Within the xenograft nude mouse model, this system contained a lower amount of doxorubicin, yet, exhibited tumor inhibition capability comparable to the free doxorubicin group. Moreover, it delivered anticancer efficiency under conditions of enhanced antioxidative capacity, underscoring its prospective utility in clinical cancer therapeutics. This dual drug delivery platform not only advances cancer treatment and prophylaxis but also extends novel insights into the therapeutic implications of simultaneous dual drug delivery systems.

Doxorubicin bioavailability to human hemoglobin and cancer cells via MOF-A520

Cancer is one of the most serious and challenging issues in the life sciences, with complicated and multifactorial mechanisms making it difficult to manage. With this complexity comes various strategies for attacking tumors, including using nanomaterials to target tumor cells, bioavailability and deliver anticancer drugs directly. Doxorubicin (DOX) is a well-known and powerful anticancer drug, but its high toxicity limits its application. Intending to reduce the cytotoxic effects of DOX on normal cell line and deliver it to cancerous cell line, the present study attempts to design and synthesize a modified metal–organic framework (MOF) named A520 and a composite containing DOX (A520@DOX). The synthesized MOFs were characterized using X-ray diffraction (XRD), electron microscopy (TEM and FESEM), and FTIR. Subsequently, the toxicity of DOX was assessed at the cellular and molecular levels using MTT assays (for the cell lines MCF −10A and MCF-7) and various biophysical assays targeting human hemoglobin (Hb). Following expectations, free DOX was highly cytotoxic and strongly affected Hb structure (converting it into methemoglobin species), while the toxicity was significantly reduced in the A520@DOX composite form. It is important to mention that DOX released from the A520@DOX was significantly pH-sensitive, so it was more pronounced in acidic pH 5 (resembling a cancerous pH environment). Furthermore, the effect of DOX released from A520@DOX resulted in more oxyHb and deoxyHb species as functional Hb species. The present study used an effective DOX delivery and bioavailability nanosystem to control cytotoxicity and ensure slow drug release.

A self-supporting multi-component collaborative structure for enhancing interface electron transfer in hybrid supercapacitor

Multi-component synergistic effect is a feasible strategy to boost the capacity of electrode materials. Herein, carbon nanotubes (CNTs) film supporting NiCo phosphide (NiCoP) modified metal-organic framework (MOF) is reasonably synthesised as a self-supporting electrode for high-performance supercapacitors. Benefiting from the synergistic effect of the high conductivity of the CNT film substrate, the specific surface area of Cu-MOF (HKUST-1), and the high activity of NiCoP, the charge transfer and ionic diffusion among the electrode greatly improved. The as-prepared electrode displays a remarkably enhanced specific capacitance of 1154 F g−1. In addition, the as-assembled NiCoP/HKUST-1@CNTs//activated carbon supercapacitor possesses a considerable energy density of 58.2 W h kg−1 and satisfactory cyclic performance (retaining 80.6 % capacitance over 10,000 cycles). The synthesis approach of this study provides some reference for the controllable preparation of new high-capacity MOF-based electrode materials.

A Sensitive Fluorescence Probe for the Trace Detection of Fe(III) Based on a Post‐Synthesis‐Modified Copper‐Based Metal‐Organic Framework

AbstractThis work presents the generation of a post‐synthetically modified Metal‐Organic Framework (MOF), denoted as Cu‐BDC‐NH2‐DHB, achieved through a Schiff‐base reaction by converting the pendant amino group in pristine Cu‐BDC‐NH2 MOF to an imine group using 3,4‐dihydroxybenzaldehyde (DHB). The resulting material exhibited exceptional luminescence and fluorescence stability in water, prompting investigation into its potential as a metal sensor. Fluorescence tests revealed that Cu‐BDC‐NH2‐DHB could be transformed into a highly selective and sensitive sensor for detecting Fe3+ ions amid co‐interfering metal ions, with a remarkable detection limit of 3.08 μM. Furthermore, the results demonstrated that Fe3+ induced a rapid and strong quenching effect, with a reaction time measured in seconds. This research provides a promising technique for the facile and immediate detection of Fe3+ ions in practical applications.

A sustainable avenue for the synthesis of propargylamines and benzofurans using a Cu-functionalized MIL-101(Cr) as a reusable heterogeneous catalyst

A heterogeneous copper-catalyzed A3 coupling reaction of aldehydes, amines, and alkynes for the synthesis of propargylamines and benzofurans has been developed. Here, the modified metal–organic framework MIL-101(Cr)-SB-Cu complex was chosen as the heterogeneous copper catalyst and prepared via post-synthetic modification of amino-functionalized MIL-101(Cr). The structure, morphology, thermal stability, and copper content of the catalyst were determined by FT-IR, PXRD, SEM, TEM, EDX, TGA, XPS, and ICP-OES. The catalyst shows high catalytic activity for the aforementioned reactions under solvent-free reaction conditions. High yields, low catalyst loading, easy catalyst recovery and reusability with not much shrink in catalytic activity, and a good yield of 82% in gram-scale synthesis are some of the benefits of this protocol that drove it towards sustainability.

Synthesis of novel benzoic acid modified metal organic framework for adsorptive removal of arsenate

Researchers worldwide have extensively studied metal organic framework (MOF) for its adsorption capabilities. Despite its potential, challenges such as particle agglomeration, low porosity and low surface area persist. This study aims to enhance the performance of MIL-100(Fe) for As(V) adsorption using a feasible and straightforward technique. To achieve this, benzoic acid was introduced as a modulator for ligand exchange, creating vacancy defects within the MIL-100(Fe) structure, resulting in defective MIL-100(Fe)-BA1. Through TEM imaging, visible deformations were observed on the surface of the adsorbent, with an average particle size of approximately 200 nm. XRD spectrum analysis revealed a reduction in peak intensity at 2–5°, indicating reduced crystallinity in the MIL-100(Fe) due to the presence of defects. Meanwhile, BET analysis demonstrated a significantly larger surface area for defective MIL-100(Fe) at 1081.09 m2/g, compared to the pristine MIL-100(Fe) with a surface area of 844.00 m2/g. Regarding adsorptive performance, the defective MIL-100(Fe) exhibited higher As(V) adsorption capacity (173.82 mg/g at pH8) than the pristine form (70 mg/g). This improvement can be attributed to the larger pore size of the particles and the exceptional affinity of As(V) anions towards the bulk Lewis Acid sites present on the surface of defective MIL-100(Fe). However, it is important to note that for effective As(V) adsorption by defective MIL-100(Fe)-BA1, it is crucial to eliminate competing compounds such as carbonate and phosphate anions from the water sources. Addressing these challenges will further enhance the efficacy of the adsorption process

A novel N-heterocyclic carbene-palladium modified metal–organic framework (Sm-MOF-Pd) for Suzuki-Miyaura cross-coupling reaction

A novel 3D Sm-MOF, namely {n[Sm(L)2·2(H2O)]·(Cl)n, H2L+Cl- = 1,3-bis(4-carboxybenzyl)-imidazolium chloride)}, was prepared under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. Then the N-heterocyclic carbene-Pd(II) functionalized metal–organic framework (Sm-MOF-Pd) was yielded by introducing Pd active sites into the Sm-MOF by the post-synthesis modification (PSM) method. This new material was characterized by powder X-ray diffraction (PXRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron (TEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) measurements, showing that Pd(II) ions were uniformly dispersed in the Sm-MOF after PSM. The Sm-MOF-Pd reached a catalytic yield of 99 % in Suzuki-Miyaura cross-coupling reactions under optimal reaction conditions. After four cycles, it still maintained high catalytic activity.