Fe Metal-organic Frameworks Research Articles

A Novel Silver Nanoparticles‐Decorated Metal‐Organic Framework with Rapid and Sustained Antimicrobial Activity against Drug‐Resistant Candida albicans through Synergistic Chemodynamic and Sonodynamic Therapy

AbstractVaginal candidiasis caused by Candida albicans is a chronic, recurrent disease that is difficult to treat. Current available antifungal drugs have limited efficacy and cause adverse effects necessitating novel therapeutic options. In this study, a novel metal‐organic framework (MOF) containing the sonosensitizer rose bengal (RB) and decorated with silver nanoparticles (AgNPs), Fe–MOF(RB)@AgNPs (MRA), is developed which integrates chemodynamic therapy (CDT) and sonodynamic therapy (SDT) with the long‐term antifungal effects of AgNPs into a single nanoscale entity. MRA exhibited low cytotoxicity in mammalian cells and strong catalytic activity for the conversion of H2O2 to •OH under acidic conditions, similar to those found in vaginal candidiasis. When exposed to ultrasound, MRA generated 1O2 and offered rapid synergistic fungicidal effects through CDT and SDT, as well as long‐lasting antifungal benefits through AgNPs, leading to the complete eradication of drug‐resistant C. albicans. Moreover, MRA exhibited 99.999% efficacy against a clinical isolate of drug‐resistant C. albicans at 120 µg mL−1. Hence, MRA has considerable potential for clinical applications in the treatment of drug‐resistant C. albicans‐induced vaginal candidiasis.

Rapid and Ultrasensitive Fluorescence Sensing Platform Based on Nanometer-Sized Metal–Organic Frameworks for Transgenic CaMV 35S Promoter Detection

Rapid and sensitive identification of genetically modified organisms (GMOs) is urgent for food safety and people health. Herein, a rapid and ultrasensitive fluorescence sensing platform is developed based on the single-strand DNA-labeled FAM dye (FAM-ssDNA) and nanometer-sized Fe-metal–organic framework (Fe-MOF), Fe-MIL-88. Fe-MIL-88 possesses a large specific surface area, remarkable preferential combining capacity with ssDNA versus dsDNA, and great quenching ability. FAM-ssDNA probes are elaborately designed as facile fluorescent probes to be fully complementary with the target of cauliflower mosaic virus 35S promoter (CaMV 35S), which can be absorbed to the surface of Fe-MIL-88 through π–π stacking and electrostatic interaction. The results indicate that the quenching ability of Fe-MIL-88 is attributed to the combination of photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) processes. Benefiting from the distinguishable ability of Fe-MIL-88, the fluorescent biosensor exhibits a satisfactory linear range from 5 pM to 50 nM and a low limit of detection (LOD) down to 0.184 pM. Also, the operation time was less than 1 h. Furthermore, the sensor also performs well in the anti-interference test and real sample test. Importantly, the sensing platform is equipped with easier operation without any complicated and difficult immobilization steps. Therefore, the sensor owns cheering potential for the detection of GMOs.

Furfural conversion over calcined Ti and Fe metal-organic frameworks under continuous flow conditions

Furfural conversion over calcined Ti and Fe metal-organic frameworks under continuous flow conditions

MIL-88B(Fe) MOF modified screen-printed electrodes for non-enzymatic electrochemical sensing of malathion

ABSTRACT An enzyme-free electrochemical approach for ultra-trace quantification of the organophosphate insecticide malathion is proposed in this study. It is premised on screen-printed carbon electrodes modified by the MIL-88B(Fe) metal–organic framework (MOF). A one-pot solvothermal method was used to synthesise MIL-88B(Fe). The surface modification of electrodes allowed for increased electroactive surface area and accelerated electron transport on the electrode. Inhibition in the redox signal of MIL-88B(Fe) was observed due to the affinity between metal centres of the MOF and the functional groups of malathion, leading to an accurate determination of malathion. The proposed sensor effectively quantified malathion in the wide concentration range of 1 × 10−12 M to 1 × 10−6 M. The limit of detection for malathion was 0.79 pM. The proposed sensor also possessed excellent stability, repeatability, and anti-interference characteristics. Furthermore, the proposed sensor demonstrated satisfactory malathion recovery in spiked vegetable samples.

Fe-metal organic framework converts mechanical energy with piezoelectric polarization to remove carbamazepine in water: Efficiency, pathway and mechanism

Piezocatalysis is a new technique that directly transforms mechanical energy into chemical energy. Although this approach can potentially be used to replace traditional water treatment methods, the structural tailorability and limited surface area of conventional inorganic piezoelectric materials restrict their catalytic efficiency. Herein, we employed a piezoelectric material made of an organic Fe-metal organic framework (MOFs) to purify water via piezocatalysis. We analyzed the physicochemical properties of MIL-100(Fe), including its piezoelectricity, bandgap structure, and charge separation efficiency. Carbamazepine (CBZ) was used as a representative aqueous drug pollutant, and MIL-100(Fe) removed 92 % of CBZ in 30 min via applying ultrasonication (US), which was 5.1 and 11.5 times higher than either the individual MIL-100(Fe) or US. The mechanical US stresses generated a built-in electric field in MIL-100(Fe) to promoted free charge migration, and also modulated the band structure of the sample. This promoted the production of reactive oxygen species. In this work, shows that porous piezoelectric nanostructures based on MOFs can convert mechanical energy into chemical energy to drive chemical oxidation processes.

Mechanistic Elucidations of Highly Dispersed Metalloporphyrin Metal‐Organic Framework Catalysts for CO2Electroreduction

AbstractImmobilization of porphyrin complexes into crystalline metal–organic frameworks (MOFs) enables high exposure of porphyrin active sites for CO2electroreduction. Herein, well‐dispersed iron‐porphyrin‐based MOF (PCN‐222(Fe)) on carbon‐based electrodes revealed optimal turnover frequencies for CO2electroreduction to CO at 1 wt.% catalyst loading, beyond which the intrinsic catalyst activity declined due to CO2mass transport limitations. In situ Raman suggested that PCN‐222(Fe) maintained its structure under electrochemical bias, permitting mechanistic investigations. These revealed a stepwise electron transfer‐proton transfer mechanism for CO2electroreduction on PCN‐222(Fe) electrodes, which followed a shift from a rate‐limiting electron transfer to CO2mass transfer as the potential increased from −0.6 V to −1.0 V vs. RHE. Our results demonstrate how intrinsic catalytic investigations and in situ spectroscopy are needed to elucidate CO2electroreduction mechanisms on PCN‐222(Fe) MOFs.

Mechanistic Elucidations of Highly Dispersed Metalloporphyrin Metal-Organic Framework Catalysts for CO2 Electroreduction.

Immobilization of porphyrin complexes into crystalline metal-organic frameworks (MOFs) enables high exposure of porphyrin active sites for CO2 electroreduction. Herein, well-dispersed iron-porphyrin-based MOF (PCN-222(Fe)) on carbon-based electrodes revealed optimal turnover frequencies for CO2 electroreduction to CO at 1 wt.% catalyst loading, beyond which the intrinsic catalyst activity declined due to CO2 mass transport limitations. In situ Raman suggested that PCN-222(Fe) maintained its structure under electrochemical bias, permitting mechanistic investigations. These revealed a stepwise electron transfer-proton transfer mechanism for CO2 electroreduction on PCN-222(Fe) electrodes, which followed a shift from a rate-limiting electron transfer to CO2 mass transfer as the potential increased from -0.6 V to -1.0 V vs. RHE. Our results demonstrate how intrinsic catalytic investigations and in situ spectroscopy are needed to elucidate CO2 electroreduction mechanisms on PCN-222(Fe) MOFs.

Theranostic doxorubicin encapsulated FeAu alloy@metal-organic framework nanostructures enable magnetic hyperthermia and medical imaging in oral carcinoma

Metal-organic frameworks (MOFs) have emerged as attractive candidates in cancer theranostics due to their ability to envelop magnetic nanoparticles, resulting in reduced cytotoxicity and high porosity, enabling chemodrug encapsulation. Here, FeAu alloy nanoparticles (FeAu NPs) are synthesized and coated with MIL-100(Fe) MOFs to fabricate FeAu@MOF nanostructures. We encapsulated Doxorubicin within the nanostructures and evaluated the suitability of this platform for medical imaging and cancer theranostics. FeAu@MOF nanostructures (FeAu@MIL-100(Fe)) exhibited superparamagnetism, magnetic hyperthermia behavior and displayed DOX encapsulation and release efficiency of 69.95 % and 97.19 %, respectively, when stimulated with alternating magnetic field (AMF). In-vitro experiments showed that AMF-induced hyperthermia resulted in 90 % HSC-3 oral squamous carcinoma cell death, indicating application in cancer theranostics. Finally, in an in-vivo mouse model, FeAu@MOF nanostructures improved image contrast, reduced tumor volume by 30-fold and tumor weight by 10-fold, which translated to enhancement in cumulative survival, highlighting the prospect of this platform for oral cancer treatment.

Delivery of Immobilized IFN-γ With PCN-333 and Its Effect on Human Mesenchymal Stem Cells

Interferon-gamma (IFN-γ) plays a vital role in modulating the immunosuppressive properties of human mesenchymal stem/stromal cells (hMSCs) used in cell therapies. However, IFN-γ suffers from low bioavailability and degrades in media, creating a challenge when using IFN-γ during the manufacturing of hMSCs. Metal-organic frameworks (MOFs), with their porous interiors, biocompatibility, high loading capacity, and ability to be functionalized for targeting, have become an increasingly suitable platform for protein delivery. In this work, we synthesize the MOF PCN-333(Fe) and show that it can be utilized to immobilize and deliver IFN-γ to the local extracellular environment of hMSCs. In doing so, the cells proliferate and differentiate appropriately with no observed side effects. We demonstrate that PCN-333(Fe) MOFs containing IFN-γ are not cytotoxic to hMSCs, can promote the expression of proteins that play a role in immune response, and are capable of inducing indoleamine 2,3-dioxygenase (IDO) production similar to that of soluble IFN-γ at lower concentrations. Overall, using MOFs to deliver IFN-γ may be leveraged in the future in the manufacturing of therapeutically relevant hMSCs.

Exploring the potential of iron-based metal-organic frameworks as peroxidase nanozymes for glucose detection with various secondary building units.

Finding materials in biosensing that balance enzyme-like reactivity, stability, and affordability is essential for the future. Because of their unique peroxidase properties, including variable pore size, surface area, and Lewis acid active sites, iron-based metal-organic frameworks (MOFs) have evolved as viable possibilities. In this study, we constructed a Fe-MOF and tested its peroxidase-like activity and responsiveness toward H2O2 colorimetric techniques. Using encapsulation, we incorporated glucose oxidase into the ZIF-90 PVP MOF and conducted a sequential reaction with the Fe-MOF to detect glucose. The results showed better peroxidase catalytic activity of the MIL-88B(Fe) (1,4-NDC) MOF and similar secondary building unit (SBU) Fe-MOFs were studied in other peroxidase nanozyme studies. When combined with an enzyme-encapsulating ZIF-90 PVP MOF, they could be sequentially employed for glucose detection purposes. This study highlights the potential of nanozymes as an alternative to natural enzymes, with promising applications in biosensing and beyond.

Ternary transition metal organic frameworks (MOFs) CuZn-MIL101 (Fe) for peroxymonosulfate activation to degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA): A non-radical pathway dominated by singlet oxygen

In this study, ternary CuZn-MIL101(Fe) MOFs were prepared by introducing Cu and Zn ions into MIL-101(Fe) to obtain catalysts with excellent peroxymonosulfate (PMS) activation properties. The comprehensive characterization analysis revealed that although the adsorption performance of CuZn-MIL101(Fe) decreased, the PMS activation performance was significantly improved and complete degradation of MCPA was reached in 20 min. Calculation of the specific rate constants (kSA) yielded that the intrinsic activity of CuZn-MIL101(Fe) for PMS was 34 and 37 times higher than that of CuZn0.25-MIL101(Fe) and Cu0.25Zn-MIL101(Fe), respectively. The quenching experiments combined with electron paramagnetic resonance (EPR) spectroscopy verified the composition of the active substances in the system, whose contributions were in the order of O21 > ·OH > SO4⋅− > O2⋅. Using PMSO as a probe, an important role of high-valent iron was found in the system. The HOMO-LUMO gap of MCPA was calculated to be 0.205 eV by density functional theory (DFT), and the difference in adsorption energy of MCPA when adsorbing different radicals was investigated. The intermediate products were obtained by GC-MS and analyzed for toxicity, and the mechanism of singlet oxygen-dominated degradation of MCPA was proposed, which laid the foundation for the subsequent in-depth study of phenoxyacetic acid-based herbicides.

Enhanced photocatalytic hydrogen evolution with a Mixed-Valence iron Metal-Organic framework

Fe-oxo cluster-based metal–organic frameworks (MOFs) offer a tunable platform for visible-light-driven catalysis, yet the unmatched energy level and the ease of charge recombination strongly hinder their application in photocatalytic H2 generation. In this work, we report an Fe(II/III) mixed-valence catalyst derived from the transition of an Fe(II)2N2O10 cluster-based MOF in water through a solvent displacement pathway. Both electronic band structure and charge transfer dynamics are effectively optimized via heteroatom coordination and valence mixing in the iron clusters. 25 times the visible-light-induced H2 yield of pristine FeMOF was obtained by Fe(II/III) MOF with platinum as cocatalyst. The Fe MOF catalyst also shows significantly superior performance in comparison with the well-known oxide catalyst α-Fe2O3 and the commonly investigated MOF catalyst NH2-UiO-66. This work provides a direction for the structural engineering of Fe-MOFs for photocatalysts.

Comprehensive evaluation of antibiotic tetracycline and oxytetracycline removal by Fe-metal organic framework/biopolymer-clay hydrogel

Tetracycline (TC) and oxytetracycline (OTC) are antibiotic compounds increasingly detected in various water sources. In this study, Fe-metal organic framework incorporated biopolymer-clay hydrogels (CAMIL-MMT and CAMIL-SEP) were prepared to remove TC and OTC from water. The physicochemical properties of the as-prepared hydrogels were thoroughly characterized, and the effect of various operating parameters on the adsorption performance was systematically examined. The CAMIL-MMT hydrogel showed the maximum adsorption capacity for TC and OTC (24.59 and 26.14 mg/g, respectively) compared to the CAMIL-SEP and other forms of biopolymer hydrogel precursors. The effects of the contact time and initial concentration on TC and OTC adsorption by CAMIL-MMT and CAMIL-SEP hydrogels were well suited to the pseudo-second-order kinetics and Freundlich isotherm models. The adsorption performance of CAMIL-MMT and CAMIL-SEP hydrogels slightly decreased with an increase in solution pH, while it was not much influenced by the co-existing anions. The thermodynamic study indicated that the reactions for the uptake of TC and OTC were spontaneous and highly favorable. Moreover, the as-synthesized CAMIL-MMT and CAMIL-SEP hydrogels demonstrated strong potential for reuse in TC and OTC removal with high reusability and strong stability. The photocatalysis study revealed that residual TC and OTC after adsorption could be further degraded by CAMIL-MMT and CAMIL-SEP hydrogels under visible light irradiation. From the above-mentioned results, the as-synthesized CAMIL-MMT and CAMIL-SEP hydrogels are promising to be considered alternative materials for the adsorptive and photocatalytic removal of TC and OTC in practical application of water and wastewater treatment.

Glyco-conjugated metal-organic framework biosensor for fluorescent detection of bacteria.

Metal-organic frameworks (MOFs) are hybrid materials constructed by the linkage between an inorganic secondary building unit and an organic linker. A number of MOFs are luminescent in nature and can be structurally tuned for desirable geometry, surface functionality, and porosity. Luminescent MOFs have been endorsed for various biosensing applications. Lectins and carbohydrates have been used for the development of simple and convenient biosensing and bioimaging tools. Lectins are mostly present on the surface of microorganisms where they aid in pathogenesis. Due to this, they can be potential targets for a microbial biosensor. The present study, for the first time, explores the usage of a carbohydrate-conjugated FeMOF (Glyco-MOF) bioprobe for the selective determination of Pseudomonas aeruginosa and Escherichia coli. NH2-MIL-53(Fe) MOF was synthesized via a room temperature protocol and separately conjugated with galactose and mannose sugars via glutaraldehyde chemistry. The synthesized bioprobe is validated for structural integrity, luminescent nature, stability, and analyte assay. Electron microscopy studies validated the unhindered MOF's morphology and structural integrity, after bioconjugation. The synthesized bioprobes were able to detect P. aeruginosa and E. coli up to respective detection limits of 202 and 8CFU/mL, respectively. The bioprobes are selective even in co-presence of possible interferants as well as being environmentally stable.

Enhancement from Anaerobic Digestion of Food Waste by Conductive Materials: Performance and Mechanism.

Conductive materials (CM) have recently attracted research interest in the anaerobic digestion of food waste to achieve reduction and resource utilization. Fe-metal organic frameworks (Fe-MOF) and Ketjen Black (KB), the conductive materials (CMs), were added for the enhancement of food waste digestion. This study therefore, is intended to fill in this knowledge gap and clarify the underlying mechanism of CM-promoted performance. Batch experiments revealed that the optimal additions of Fe-MOF and KB were 0.5 g·L-1 and 0.2 g·L-1, respectively. The biogas production increased by 27.50% and 29.45% compared with the blank group, and the removal efficiency of volatile solids (VS), total solids (TS), and chemical oxygen demand (COD) increased by 18.28%, 40.52%, and 15.31%. The lag period was shortened from 3.042 to 2.006 and 1.544 days, respectively. Mechanism studies revealed that Fe-MOF and KB were beneficial to food waste digestion, and the functional groups of Fe-MOF and KB increased the buffer capacity of the system to pH and ammonia nitrogen. The physicochemical properties of Fe-MOF and KB promote the activity of the electron transfer system (ETS); the ETS activity was about 2 times the 11.32 mg·(g·h)-1 of the blank group. Zeta potential and electrical conductivity were beneficial to the establishment of intermicrobial direct interspecies electron transfer (DIET).

Aptamer Trimode Biosensor for Trace Glyphosate Based on FeMOF Catalytic Oxidation of Tetramethylbenzidine.

The stable and highly catalytic Fe metal-organic framework (FeMOF) nanosol was prepared and characterized by electron microscopy, and energy and molecular spectral analysis. It was found that FeMOF strongly catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce TMBox, which had a fluorescence (FL) peak at 410 nm. When silver nanoparticles were added, it exhibited strong resonance Rayleigh scattering (RRS) activity and surface-enhanced Raman scattering (SERS) effect. This new FeMOF nanocatalytic trimode indicator reaction was combined with the glyphosate aptamer reaction to establish a new SERS/RRS/FL trimode biosensor for glyphosate. The sensor can be used for the analysis of environmental wastewater, and a new method for detecting glyphosate content in wastewater is proposed. The linear range of the sensor is 0.1-14 nmol/L, the detection limit is 0.05 nmol/L, the recovery is 92.1-97.5%, and the relative standard deviation is 3.6-8.7%.

Adsorptive removal of tetracycline and ciprofloxacin antibiotics from water using magnetic MIL101-Fe metal–organic framework/NiFe2O4 decorated with Preyssler-Pope-Jeannin [NaP5W30O110]14− polyanion

In the current study, Preyssler-Pope-Jeannin K12.5Na1.5[NaP5W30O110]⋅15H2O heteropolyanions (abbreviated as {NaP5W30}) were successfully decorated on MIL101- Fe metal-organic framework containing nickel ferrite (NiFe2O4; NFO) as a magnetic component via a hydrothermal method. The characterization of the composition, structure, and morphology of the magnetic{NaP5W30}/MIL101-Fe/NFO nanocomposite was achieved using various analyses. The results showed that the {NaP5W30} heteropolyanion was encapsulated into the MIL101-Fe framework. The magnetic nanocomposite played the role of a great adsorbent for separating tetracycline (TC) and ciprofloxacin (CIP) antibiotic drugs from aqueous solutions. The factors like initial drug concentration, pH, temperature, and adsorbent dosage were investigated. The adsorption kinetics could be accurately described based on the Langmuir isotherm and the pseudo-second-order models. The outcomes suggested that the nanocomposite adsorbed 100% of drugs in 9 ​min for TC and 20 ​min for CIP from water with a maximum adsorption capacity of 263.15 ​mg ​g−1 and 796.23 ​mg ​g−1 respectively. The nanocomposite was highly stable and recyclable without any change in its structure thus making it a great choice for removing drugs from polluted water.

Electrochemical Dopamine Detection using a Fe/Fe3O4@C Composite derived from a Metal‐Organic Framework

AbstractIn this paper, a novel composite of Fe/Fe3O4@C is synthesized by taking a Fe‐metal‐organic framework (Fe‐MOF) as precursor template. Different treating temperature (450, 550, 650 and 750 °C) were carried out to investigate the composite of calcined products. The Fe/Fe3O4@C‐650 modified glassy carbon electrode (Fe/Fe3O4@C‐650GCE) shows good electrocatalytic activity towards dopamine (DA) oxidation. Three electrochemical measuring methods of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry i‐t are adopted to investigate the sensing behaviors of Fe/Fe3O4@C‐650/GCE. The results show that: the sensors based on CV and DPV technology exhibit excellent advantages in the aspect of sensitivity and linear range thanthose of the sensor based on amperometry i‐t technology. Meanwhile, the sensor based on CV method shows good selectivity for dopamine, and can resist the influence of various sugars, uric acid, ascorbic acid, as well as Na+ and K+. The sensor also shows good stability and repeatability in the sensing process. In addition, the Fe/Fe3O4@C‐650/GCE could be successfully applied in the DA detection in the human serum.

A facile synthesis of Fe/C composite derived from Fe-metal organic frameworks: Electromagnetic wave absorption with thin thickness

With the increasing utilization of microwaves in the gigahertz range, the preparation of high-performance microwave absorbing materials is technologically essential. In this research, porous carbon and iron composites derived from iron metal-organic frameworks (Fe-MOFs) were easily synthesized via solvothermal reactions and in situ pyrolysis processes. The porous carbon matrix and iron create a synergistic effect of dielectric loss and magnetic loss, which optimizes the impedance matching and improves the microwave absorbing performance. When the matching thickness is only 1.5 mm, the reflection loss and the effective absorbing bandwidth reach − 37.63 dB and 4.4 GHz, respectively. Meanwhile, It’s worthwhile to explore MOFs-derived carbon-based composite absorbers with high room for improvement. This research provides a new method for the preparation of high-performance microwave absorbing materials with thin thickness.

Synthesis, Structure, and Thermal Stability of a Mesoporous Titanium(III) Amine-Containing MOF.

The first mesoporous bimetallic TiIII/Al metal-organic framework (MOF) containing amine functionalities on its linkers has been selectively obtained by converting the cheap commercially available (TiCl3)3AlCl3 into Ti3-xAlxCl3(THF)3 and reacting this complex with 2-aminoterephthalic acid in dimethylformamide (DMF) under soft solvothermal conditions. This compound is structurally related to the previously described NH2-MIL-101(M) (M = Cr, Al, and Fe) MOFs. Thermal gravimetric analyses and in situ powder X-ray diffraction (PXRD) measurements demonstrated that this highly air-sensitive TiIII-containing MOF is structurally stable up to 200 °C. Nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and inductively coupled plasma (ICP) revealed that NH2-MIL-101(TiIII) contains trinuclear Ti3(μ3-O)Cl(DMF)2(RCOO)6 clusters with strongly bound DMF molecules and a small amount of aluminum. Sorption experiments revealed a higher affinity of this MOF for hydrogen compared to the previously described monometallic unfunctionalized MIL-101(TiIII) MOF.