Iron-based Metal-organic Frameworks Research Articles

Reassessing the Role of Thermal Convection in Simultaneous Water Production and Pollutant Degradation in Interfacial Photothermal-Photocatalytic Systems.

The interfacial photothermal-photocatalyticsystemscan generate clean water while purifying wastewater containing organic pollutants, but the impact of thermal convection on synergistic effects remains unexplored. This paper aims to regulate the thermal convection at the interface to significantly enhance the synergistic effect of interfacial photothermal-photocatalytic systems. A novel heterogeneous structure comprising iron-based metal-organic frameworks and multi-walled carbon nanotubes with a gelatin-polyvinyl alcohol (PVA) double network hydrogel (MWCNTs@NM88B/PVA/gelatin hydrogel, denoted as MMH) is developed and employed in the construction of the solar-driven interfacial evaporation (SIE) system. The system shows high activity for solar water evaporation and simultaneous photocatalytic degradation of organic pollutants. MMH demonstrates an evaporation rate of 2.84kg m-2h-1, achieving an efficiency of 95.3% under 1 sun. COMSOL simulations reveal that the implementation of a three-phase interface configuration with SIE technology significantly boosts thermal convection, effectively diminishing the barrier to gas release from the reaction system and consequently enhancing the efficiency of the interfacial photothermal-photocatalytic process. Furthermore, the potential mechanism of photocatalytic decomposition of organic pollutants in MMH/H2O2/visible light reaction system is proposed by combining the experiments of KPFM, in situ XPS, and ESR spectra. Therefore, this work offers a fresh perspective on evaluating the impact of thermal convection on water evaporation and pollutant degradation in interface photothermal-photocatalytic systems.

Iron-based MOF with Catalase-like activity improves the synergistic therapeutic effect of PDT/ferroptosis/starvation therapy by reversing the tumor hypoxic microenvironment

Reversing the hypoxic microenvironment of tumors is an important method to enhance the synergistic effect of tumor treatment. In this work, we developed the nanoparticles called Ce6@HGMOF, which consists of a photosensitizer (Ce6), glucose oxidase (GOX), chemotherapy drugs (HCPT) and an iron-based metal-organic framework (MOF). Ce6@HGMOF can consume glucose in tumor cells through “starvation therapy”, cut off their nutrition source, and produce gluconic acid and hydrogen peroxide (H2O2). Utilizing this feature, Ce6@HGMOF can produce oxygen through catalase-like catalytic activity, thereby reversing the hypoxic microenvironment of tumors. This strategy of changing the hypoxic environment can help to slow down the growth of tumor blood vessels and improve the drug-resistant microenvironment to some extent. Meanwhile, increasing the supply of oxygen can enhance the effect of photodynamic therapy (PDT) and enhance the oxidative stress damage caused by reactive oxygen species (ROS) in tumor cells. On the other hand, cancer cells usually produce higher levels of glutathione (GSH) to adapt to high oxidative stress and protect themselves. The Ce6@HGMOF we designed can also consume GSH and induce ferroptosis of tumor cells through Fenton reaction with H2O2, while enhancing the effect of PDT. This innovative synergistic strategy, the combination of PDT/ferroptosis /starvation therapy, can complement each other and enhance each other. It has great potential as a powerful new anti-tumor paradigm in the future.

Efficient degradation of DDBAC in water by a heterogeneous Vis/H2O2 catalytic system based on MIL-53(Fe)

In this study, the iron-based metal–organic framework MIL-53(Fe) was successfully prepared by a solvent method and used as a photocatalyst for the efficient degradation of DDBAC under visible light. The morphology, structure and photocatalytic properties of MIL-53(Fe) were investigated by SEM, XRD, XPS and UV–vis DRS characterization methods. The optimum conditions for the degradation of DD pathways of DDBAC were analyzed in combination with DFT calculations. Based on molecular orbital theory and free radical quenching experiments, it was demonstrated that hydroxyl radicals were the main contributors in the oxidative degradation of DDBAC. The toxicity of DDBAC and its intermediates was evaluated by culturing Chlorella vulgaris, and the results showed that the Vis/MIL-53(Fe)/H2O2 system was capable of solution detoxification.

Photoresponse enhanced CsPbBr3 quantum dots quantum-confined in mesoporous PCN-600 single crystal microwires

In this work, the CsPbBr3 quantum dots (QDs) are encapsulated into the mesoporous iron-based metal-organic framework (PCN-600) by using a two-step solvothermal method. The success formation of CsPbBr3@PCN-600 composite is confirmed via SEM, TEM, XRD, FTIR, EDS and other measurements. Besides, the characterization of fluorescence lifetime of CsPbBr3@PCN-600 composite reveals the presence of the electron transfer between PCN-600 and CsPbBr3 QDs. Especially, CsPbBr3@PCN-600 exhibits a prominent emission peak at 473 nm due to the quantum confinement effect, and the photoluminescence quantum yield of CsPbBr3 QDs protected by the mesoporous PCN-600 increases to 71% compared to 52% of the pristine CsPbBr3 QDs. Also, the protection of CsPbBr3 QDs by the PCN-600 channel enhances the luminescence stability, thermal stability and blue-light stability of CsPbBr3. In fact, under light illumination, the photogenerated carriers from the encapsulated CsPbBr3 QDs could be captured by catalytically active sites on the inner surface of the PCN-600 channel. This charge capture effect can increase the photocurrent and implies much effective separation of electron-hole pairs of the CsPbBr3@PCN-600 composite. These results make this composite a promising candidate for high-performance photoelectronic devices.

Competent CuS QDs@Fe MIL101 heterojunction for Sunlight-driven degradation of pharmaceutical contaminants from wastewater

In this study, we introduce an advanced photocatalyst developed by integrating copper sulfide quantum dots (CuS QDs) with an iron-based metal–organic framework (MOF), specifically Fe MIL101. The resulting CuS QDs@Fe MIL101 photocatalyst is engineered to efficiently degrade meloxicam (MLX) under simulated sunlight. The heterojunctions were generated by incorporating different concentrations of CuS QDs (5 %, 10 %, 15 %, 20 %, and 50 %) into the Fe MIL101 MOF matrix using the microwave-assisted hydrothermal method. The results of the XRD and the TEM studies confirmed the formation of the heterojunctions, which maintain the structural integrity of both CuS QDs and Fe MIL101. The BET measurements indicated a decrease in surface area upon CuS QDs incorporation, attributed to porés blockage and structural modifications. UV–Vis diffuse reflectance spectroscopy (DRS) revealed a redshift in absorption edges as CuS QDs content increased, enhancing visible light absorption. Photoluminescence (PL) investigations revealed that the 15 % CuS QDs@Fe MIL101 heterojunction had an effective charge separation and low recombination rates. The zeta potential analysis revealed a negative surface charge, indicating an overall electronegative characteristic. The photocatalytic performance, assessed through the degradation of MLX, demonstrated that the 15 % CuS QDs@Fe MIL101 heterojunction achieved the maximum degradation efficiency, reaching 96 % after 45 min of irradiation at a dosage of 0.1 g/L. This exceptional performance is attributed to potent charge separation, improving visible light absorption, high surface area and adsorption capacity. Various scavengers were used to investigate the roles of different reactive species, revealing holes as the predominant active species in the photocatalytic degradation process. These results highlight the potential of 15 % CuS QDs@Fe MIL101 heterojunctions as efficient photocatalyst for environmental remediation from pharmaceutical pollutants under simulated sunlight. These findings highlight the potential for application of CuS QDs@Fe MIL101 in real-world wastewater treatment systems, particularly in addressing pharmaceutical contaminants like meloxicam in industrial effluents.

Gadolinium doping-induced electronic structure optimization of MIL-101-NH2: Efficient adsorption of arsenic (V) and phosphorus and electrochemical regeneration

The high concentration of acids/bases used to regenerate MOF adsorbents can compromise their structural integrity and may generate additional environmental pollution. The regeneration challenges of MOF adsorbents limit their use in environmental applications. Here, the electronic structure of the iron-based metal–organic framework MIL-101-NH2 was optimized by gadolinium (Gd) doping to provide oxygen vacancies and enhance the electrochemical activity for the selective removal of arsenic(V) and phosphorus from water. 0.75GF-MILN, which was prepared using a gadolinium to iron molar ratio of 0.75, showed a maximum arsenic(V) adsorption capacity of 220.7 mg g−1 and maximum phosphorus adsorption capacity of 112.8 mg P g−1. Increasing the temperature was conducive to the adsorption of arsenic(V) and phosphorus by 0.75GF-MILN, which also maintained a high uptake capacity for arsenic(V) and phosphorus over the pH range of 4.0–9.0. The electro-assisted desorption of arsenic(V) and phosphorus from 0.75GF-MILN was achieved at −3 V. Moreover, 0.75GF-MILN still maintained 99 % arsenic(V) and phosphorus removal efficiencies from real water samples even after four cycles of electro-assisted adsorption–desorption. Density functional theory calculations and electrochemical tests showed that gadolinium doping optimizes the electron structure of MIL-101-NH2, leading to improved electron mobility. This is beneficial for electrochemical elution. Unlike other rare earth-doped MOF materials, arsenic can be desorbed from 0.75GF-MILN using a capacitive deionization process, avoiding the destruction of the MOF via exposure to a highly concentrated acid-base desorption solution. This study provides a design strategy for constructing adsorbents suitable for electrochemical elution to co-remove arsenic(V) and phosphorus, demonstrating the practicality of using rare earth-doped MOF materials in the field of water treatment.

Self-enhancement of bioenergy recovery from anaerobically digesting WAS with novel iron-based metal-organic framework assistance: Insights into electron transfer and metabolic pathways

Inadequate methane production and insufficient hydrolysis-acidification activity impede the practical application of anaerobic digestion (AD) of waste activated sludge (WAS). Recently, metal-organic framework (MOF) materials attains promising capability of controlling proton/electron transfer in AD processes. This study used a typical iron-based MOF and MIL-88A(Fe) to improve the methane production via digesting WAS. These materials were prepared via a one-step hydrothermal method. The findings indicated that the addition of 150 mg MIL-88A(Fe)/g WAS VS resulted in a 57.23% increase in accumulated methane production and a 43.84% increase in daily maximum methane production. The methane production rate (Rmax) also increased from 22.25 to 29.14 mL/g VS/d. The enhanced electron transfer capacity, improved hydrolysis of WAS, boosted acetate generation, and mitigated accumulation of volatile fatty acids (VFAs) collectively contributed to the better methane yield in the MIL-88A(Fe)-added system. The significant enrichment of Methanobacterium and Methanosaeta along with the up-regulation of key methanogenesis enzyme-encoding genes jointly suggested that the CO2 reduction and methanogenesis were strengthened. Moreover, MIL-88A(Fe) stimulated the production of c-type cytochrome and e-pili, facilitating direct interspecies electron transfer (DIET) between norank-f-SC-I-84 and Methanobacterium. This study provided new solutions for improving methane production and offered insights into the mechanism of enhanced methanogenesis of AD in the presence of MIL-88A(Fe).

Heterocyclic effect boosted peroxidase-like activity of MIL(Fe) metal-organic framework for colorimetric assay and dye removal

Metal-organic frameworks (MOFs) have emerged as promising candidates for enzyme mimics due to their abundant pore structures and adjustable active sites. The catalytic activity particularly depends on the electronic character of the organic ligand. In this study, we report an iron-based MOF nanozyme FeTDC, created by replacing the 1,4-dicarboxybenzene ligand with five-membered 2,5-thiophenedicarboxylic acid (H2TDC). In comparison with the phenyl analogue, the sulfur-based heterocyclic ligand demonstrates high electron delocalization, and a low pKa value, which are beneficial for enhancing the metal/ligand interactions. Accordingly, FeTDC can facilitate the oxidation of the benzidine substrate in the presence of H2O2, thereby exhibiting remarkable peroxidase-like activity. The generation of hydroxyl radical (•OH) at the Fe active sites contributes to the catalytic process. Furthermore, the smartphone-assisted colorimetric assay of pyrophosphate was developed with high sensitivity, based on its inhibitory effect. When FeTDC was utilized for the removal of benzidine dye under high-salt condition, a 90 % of removal rate was achieved due to the synergistic effect of enzyme catalysis and physical adsorption. This work presents a novel perspective of heterocyclic effect on the design of MOF nanozymes, thereby expanding their applicability in the control of pollutants.

DBD plasma assisted synthesis of Ce-MIL-88B(Fe) with electron-rich CUSs and mixed-valent bimetallic sites for enhanced photo-Fenton performance

Iron-based metal-organic frameworks (Fe-MOFs) are regarded as a kind of prospective catalysts for photo-Fenton process. However, high cost, rate-limiting Fe(III)/Fe(II) circulation and limited metal sites greatly restricted the application of Fe-MOFs in photo-Fenton system. Ce-MIL-88B(Fe) was synthesized with mixed-valent bimetallic sites and tunable coordinated unsaturated metal sites (CUSs) using dielectric barrier discharge (DBD) plasma with waste PET. The incorporation of Ce altered the structure and the electron aggregation, as well as induced structural defects. Ce substitution in Fe-MOFs induced the regulation of the ratio of Fe ions and formation of electron-rich CUSs, which were beneficial for the rapid adsorption and activation of H2O2, thus enhancing the photo-Fenton performance. The effect of reaction conditions on TC degradation was investigated by response surface methodology (RSM) combined with Box-Behnken design (BBD). This study demonstrates a new perspective on the construction of bimetallic MOFs for the photo-Fenton system.

Iron-MOFs for Biomedical Applications.

Over the past two decades, iron-based metal-organic frameworks (Fe-MOFs) have attracted significant research interest in biomedicine due to their low toxicity, tunable degradability, substantial drug loading capacity, versatile structures, and multimodal functionalities. Despite their great potential, the transition of Fe-MOFs-based composites from laboratory research to clinical products remains challenging. This review evaluates the key properties that distinguish Fe-MOFs from other MOFs and highlights recent advances in synthesis routes, surface engineering, and shaping technologies. In particular, it focuses on their applications in biosensing, antimicrobial, and anticancer therapies. In addition, the review emphasizes the need to develop scalable, environmentally friendly, and cost-effective production methods for additional Fe-MOFs to meet the specific requirements of various biomedical applications. Despite the ability of Fe-MOFs-based composites to combine therapies, significant hurdles still remain, including the need for a deeper understanding of their therapeutic mechanisms and potential risks of resistance and overdose. Systematically addressing these challenges could significantly enhance the prospects of Fe-MOFs in biomedicine and potentially facilitate their integration into mainstream clinical practice.

Folic acid and ferritin functionalized reduced Iron-based metal-organic frameworks for anticancer therapy

Anticancer chemotherapies damage normal tissues and various drug carriers are under consideration to address this issue. Metal-organic frameworks (MOFs) are promising due to their drug-carrying capacity and tunable properties and target-inspired surface functionalization magnify their potential. In this study, we aim to investigate the anticancer activity of reduced iron-based MOFs (FeMOFs) functionalized with ferritin and folic acid and loaded with doxorubicin. Successful synthesis and functionalization are confirmed by Electron microscopes, Fourier transform infrared spectroscopy and X-ray diffraction. Anticancer activity is evaluated in different tumor cell lines at various doses. Results indicate that the folic acid functionalized MOF (FADMOF) showed maximum anticancer potential, leaving only 6 % of 4 T1 cells alive at the highest dose. While Ferritin and combo MOFs followed closely followed, and empty MOFs (RMOF) lagged. Further, in HeLa cells, the plain MOF (RMOF) shows best cytotoxicity reducing cell viability to a mere 30 % at the highest dose. Similarly, in MCF7 cells, the plain MOF (RMOF) shows best cytotoxicity reducing cell viability to a mere 25 % at the highest dose in a dose-dependent manner. Taken together, this study shows that functionalized MOFs have promising anticancer potential across various cancer cell lines. However, loading with Doxorubicin reduces their cytotoxicity.

Enhanced removal of organic dyes by piezoelectric-Fenton-like treatment with Fe-MOF@MoS2 catalysts

The risks associated with dye wastewater to the ecological environment are becoming increasingly significant. The efficient utilization and effective protection of water resources have become a persistent challenge. Employing coupling technologies to enhance the wastewater treatment process is an effective strategy for achieving sustainable water resource utilization. Herein, composite catalysts with iron-based metal-organic frameworks loaded with molybdenum disulfide (Fe-MOF@MoS₂) were prepared by a hydrothermal approach. The Fe-MOF@MoS2 composite catalysts demonstrated superior degradation efficiencies towards various organic dyes like methylene blue, rhodamine B, and Congo red, especially in conditions of low hydrogen peroxide concentration and ultrasonic vibration. Results indicated that after 30 minutes of piezoelectric-Fenton-like treatment, the removal efficiency of the above organic dyes exceeded 90 %. The piezoelectric effect led to efficient cyclic conversion of Fe2+/Fe3+ ions, while the inclusion of MoS2 enhanced H2O2 activation efficiency. Moreover, the Fe-MOF@MoS2 catalyst displayed remarkable recycling capabilities, retaining 90 % of its initial catalytic activity even after six degradation cycles. Thus, the development of composite catalysts with combined piezoelectric and Fenton-like functions holds great promise for improving organic dye wastewater treatment and safeguarding environmental and water resources.

Gelatin-carboxymethyl cellulose/iron-based metal-organic framework nanocomposite hydrogel as a promising biodegradable fertilizer release system: Synthesis, characterization, and fertilizer release studies

Application of fertilizers is a routine method in agriculture to increase the fertility of plants However, conventional fertilizers have raised serious health and environmental problems in recent years. Therefore, the development of biodegradable superabsorbent hydrogels based on natural polymers with the capability for fertilizer controlled release has attracted much interest. In the current research, a novel nanocomposite hydrogel based on gelatin and carboxymethyl cellulose polymers enriched with an iron based metal- organic framework (MIL-53 (Iron)) was prepared. The prepared nanocomposite hydrogel was loaded with NPK fertilizer to obtain a slow release fertilizer system. The structural properties of the nanocomposite hydrogel were investigated using FTIR, XRD, and SEM techniques. The swelling and fertilizer release behavior of the nanocomposite hydrogel were evaluated in conditions. Results showed that by adding iron-based metal organic framework to the hydrogel matrix, the water absorption capacity of the hydrogel system was increased to 345.8 (g/g). Fertilizer release studies revealed that the release of fertilizer from the nanocomposite matrix has a slow and continuous release pattern. Therefore, the synthesized nanocomposite has an appropriate strength and high potential to be used as a slow-release fertilizer system.

MOF-Modified Microrollers for Bioimaging and Sustained Antibiotic Delivery.

Central nervous system (CNS) infections caused by neurosurgery or intrathecal injection of contaminated cerebrospinal fluid are a common and difficult complication. Drug-delivery microrobots are among the latest solutions proposed for antibacterial applications. However, there is a lack of research into developing microrobots with the ability to sustain antibody delivery while can move efficiently in the CNS. Here, biocompatible antibacterial metal-organic framework (MOF)-modified microrollers (MMRs) to combat CNS infections are proposed. The MMRs are iron-based metal-organic framework (NH2-MIL-101(Fe)) modified for enhanced adsorption and Fe/Al coated for magnetic actuation and biocompatibility. The MMRs have demonstrated a faster and unhindered magnetically actuated motion on the uneven biological tissue surface in an organ-on-a-chip that mimicked the CNS compared to it on smooth surface. CFD results consistently align with the experimental findings. The MMRs can be loaded with rhodamine 6G for bioimaging, allowing them to be imaged through sections of the main human tissues by fluorescence microscopy, or tetracycline hydrochloride for antibiotic delivery, allowing them to inhibit the growth of Staphylococcus aureus biofilms by sustained release of antibiotics for 9 days. This study provides a strategy to integrate high-capacity adsorption material with magnetically actuated locomotion for long-term targeted antibacterial applications in biological environments.

A Novel Nanocatalyst for Combined Chemodynamic and Starvation Therapy in Cancer Treatment

Cancer remains a significant challenge due to the limitations and side effects of tra- ditional treatments. Novel minimally invasive therapies are essential to enhance patient outcomes. This study introduces MIL-101(Fe)@MnO2 @Gox/HA, a nanocatalyst that com- bines glucose oxidase and manganese dioxide in an iron-based metal-organic framework (MOF) coated with hyaluronic acid. This nanoplatform demonstrates strong water affin- ity, tumor targeting, and durability. MIL-101(Fe)@MnO2 @Gox/HA presents a promis- ing anti-cancer strategy, warranting further investigation to enhance tumor targeting and treatment efficacy.

Microplastics and dye removal from textile wastewater using MIL-53 (Fe) metal-organic framework-based ultrafiltration membranes

Microplastics (MPs) and other organic matters in textile wastewater have posed a formidable challenge for treatment processes, particularly in the primary stages such as ultrafiltration (UF). UF plays a crucial role in preventing the entry of pollutants into subsequent treatment steps. However, the performance efficiency of UF membranes is compromised by the potential fouling of membrane pores by MPs, dyes and other organic pollutants such as bovine serum albumin (BSA). This study focuses on enhancing UF membrane performance, specifically its antifouling properties, through the development of high-performance membranes using MIL-53(Fe) metal-organic framework (MOF) particles (noted as MIL-53 here). Various concentrations of the MIL-53 (0.05, 0.1, 0.2, and 0.5 wt%) were integrated into the membrane structure through phase inversion process. Streaming zeta potential results confirmed the negatively charged surface of the membranes and their high hydrophilicity was validated through contact angle analysis. FTIR, SEM, EDS, and XRD confirmed the presence of MIL-53 particles on the surface of membranes. The developed membranes were tested for 24 h to assess their antifouling properties, with a subsequent 30-min hydraulic flush to measure their flux recovery ratios. Methylene Blue (MB) dye was used as a cationic dye present in textile wastewater to evaluate the efficiency of the developed membranes in dye removal and the synergistic effects of dye rejection in the presence of organic matters (i.e., MPs and BSA). Since previous studies have not fully addressed the combination of dyes and organic matter, this study thoroughly investigated the effect of particle-type foulants (MPs) and their interactions with dye (MB), as well as water soluble protein-type foulants (BSA) and their interaction with MB. The results indicated that the developed membranes exhibited higher MB rejection when the dye was present with either MP or BSA, along with improved antifouling properties. The optimised UF membrane integrated with 0.1 wt% MIL-53 demonstrated nearly 96% BSA rejection and around 86% MB rejection in the mixed foulant case (BSA-MB). The modified membrane exhibited a substantial increase in water flux from 176 L m−2.h−1 to 327 L m−2.h−1. The findings of this research show the potential of iron-based MOFs in improving the performance of UF membranes and provide a platform for future studies on significant areas such as long-term stability studies and testing with other pollutants found in textile wastewater.

Photo-Fenton-Active MIL-88A/CNT-Based PVA Hydrogel for Solar-Driven Water Evaporation and Simultaneous Volatile Organic Compound Removal.

Solar-driven interfacial water evaporation (SIWE) has emerged as a promising avenue for cost-effective freshwater production from seawater or wastewater. However, the simultaneous evaporation of volatile organic compounds (VOCs) presents a limitation for the widespread implementation of this technique. Thus, developing dual-functional evaporators capable of both desalining seawater and degrading VOCs is challenging. Herein, we fabricated an iron-based metal-organic framework MIL-88A/carbon nanotubes (CNTs) poly(vinyl alcohol) hydrogel (MCH) evaporator via the conventional freezing method for solar-driven seawater desalination and simultaneous photo-Fenton VOC degradation. Because of the superior photothermal conversion capability of CNTs, reduced thermal conductivity and water evaporation enthalpy within the hydrogel, and the photo-Fenton activity of rod-shaped MIL-88A, the MCH evaporator exhibits a higher evaporation rate of 2.26 kg m-2 h-1 under 1 sun illumination with simultaneous VOC degradation. The higher hydrophilicity and vertical channels in the MCH evaporator enable its self-salt cleaning ability, facilitating consistent seawater desalination, even in high salt concentrations up to 10 wt %. The synergistic effects of localized heating from CNTs and hydrogen peroxide activation through reactive sites of MIL-88A allow the MCH evaporator to degrade more than 93% of the added phenol during evaporation. This work presents a sustainable and efficient approach for solar-driven seawater desalination, offering simultaneous VOC degradation.

Development of an electrochemical sensor based on platinum nanoparticles/iron-based metal–organic framework composite for efficient determination of butylated hydroxyanisole

Butylated hydroxyanisole (BHA), a synthetic antioxidant, is widely used in the food industry to prevent the oxidative deterioration of food products. Developing rapid, simple and sensitive methods for BHA determination is of great importance to ensure the safety and quality of food. In this study, we developed an amperometric sensor based on iron-based metal–organic framework and platinum nanoparticle modified glassy carbon electrode (PtNP/Fe-MOF/GCE) for efficient determination of BHA. The Fe-MOF was synthesized by the solvothermal method and characterized using various techniques such as powder X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. The synthesized Fe-MOF was modified onto GCE, and platinum nanoparticles were electrodeposited onto the Fe-MOF/GCE. Scanning electron microscopy and energy dispersive X-ray spectroscopy were utilized to enlighten the surface morphologies of the electrodes during the modification steps. Electrochemical characterization of the modified electrodes was performed by cyclic voltammetry and electrochemical impedance spectroscopy. Under the optimum conditions, the PtNP/Fe-MOF/GCE showed excellent electrocatalytic activity towards BHA oxidation due to its large surface area, porosity, and metal sites. The PtNP/Fe-MOF/GCE sensor exhibited a wide linear range from 6.0 × 10-8 to 5.4 × 10-5 M and a low detection limit of 9.4 × 10-9 M. The analytical applicability of the PtNP/Fe-MOF/GCE was tested by the analysis of BHA in potato chips samples.

Efficient CO2 Conversion through a Novel Dual-Fiber Reactor System.

Carbon dioxide (CO2) can be converted to valuable organic chemicals using light irradiation and photocatalysis. Today, light-energy loss, poor conversion efficiency, and low quantum efficiency (QE) hamper the application of photocatalytic CO2 reduction. To overcome these drawbacks, we developed an efficient photocatalytic reactor platform for producing formic acid (HCOOH) by coating an iron-based metal-organic framework (Fe-MOF) onto side-emitting polymeric optical fibers (POFs) and using hollow-fiber membranes (HFMs) to deliver bubble-free CO2. The photocatalyst, Fe-MOF with amine-group (-NH2) decoration, provided exceptional dissolved inorganic carbon (DIC) absorption. The dual-fiber system gave a CO2-to-HCOOH conversion rate of 116 ± 1.2 mM h-1 g-1, which is ≥18-fold higher than the rates in photocatalytic slurry systems. The 12% QE obtained using the POF was 18-fold greater than the QE obtained by a photocatalytic slurry. The conversion efficiency and product selectivity of CO2-to-HCOOH were up to 22 and 99%, respectively. Due to the dual efficiencies of bubble-free CO2 delivery and the high QE achieved using the POF platform, the dual-fiber system had energy consumption of only 0.60 ± 0.05 kWh mol-1, 3000-fold better than photocatalysis using slurry-based systems. This innovative dual-fiber design enables efficient CO2 valorization without the use of platinum group metals or rare earth elements.

Photothermal Iron-Based Riboflavin Microneedles for the Treatment of Bacterial Keratitis via Ion Therapy and Immunomodulation.

Bacterial biofilm formation protects bacteria from antibiotics and the immune system, excessive inflammation further complicates treatment. Here, iron-based metal-organic framework (MIL-101)-loaded riboflavin nanoparticles are designed for the therapeutic challenge of biofilm infection and hyperinflammation in bacterial keratitis. Specifically, MIL-101 produces a thermal effect under exogenous near-infrared light irradiation, which synergizes with ferroptosis-like bacterial death induced by iron ions to exert an effective biofilm infection eradication effect. On the other hand, the disintegration of MIL-101 sustains the release of riboflavin, which inhibits the pro-inflammatory response of macrophage over-activation by modulating their phenotypic switch. In addition, to solve the problems of short residence time, poor permeability, and low bioavailability of corneal medication, the MR@MN microneedle patch is further prepared by loading nanoparticles into SilMA hydrogel, which ultimately achieves painless, transepithelial, and highly efficient drug delivery. In vivo and ex vivo experiments demonstrate the effectiveness of this approach in eliminating bacterial infection and promoting corneal healing. Therefore, the MRMN patch, acting as an ocular drug delivery system with the ability of rapid corneal healing, promises a cost-effective solution for the treatment of bacterial keratitis, which may also lead to a new approach for treating bacterial keratitis in clinics.