In Vitro Toxicity Study of a Porous Iron(III) Metal‒Organic Framework

Effect of sub-acute exposure of metal-organic framework-199 on cognitive function and oxidative stress level of brain tissue in rat

Metal-Organic Framework-199 (MOF-199) is a subgroup of MOFs that is utilized in different medical fields such as drug delivery. In the current study, the effect of sub-acute exposure to MOF-199 on spatial memory, working memory, inflammatory mediators' expression, and oxidative stress level of brain tissue has been investigated. Thirty-two male Wistar rats were randomly divided into four groups as vehicle, MOF-199 at doses 0.3, 3, or 6 mg/kg. After four injections of relevant interventions via tail vein during 14 days, behavioral parameters were investigated using Y-maze and Morris Water Maze (MWM) tests. Oxidative stress was measured by ferric reducing antioxidant power (FRAP) and thiobarbituric acid-reacting substance (TBARS) tests. The expression levels of TNF-α and IL-1β were assessed by quantitative real-time reverse-transcription PCR (qRT-PCR). No significant differences were observed in working memory, spatial learning and memory of MOF-199 receiving rats. Additionally, the level of oxidative stress and inflammatory genes expression were not remarkably changed in the brain tissues of MOF-199 treated rats. Despite the lack of remarkable toxic effects of sub-acute exposure to MOF-199, more studies with a longer duration of administration are necessary to use this substance for drug delivery systems in diseases related to the nervous system.

Enhanced binding interaction and antibacterial inhibition for nanometal oxide particles activated with Aloe Vulgarize through one-pot ultrasonication techniques

The interaction of green zinc oxide nanoparticles (ZnO NPs) with bacterial strains are still scarcely reported. This work was conducted to study the green-one-pot-synthesized ZnO NPs from the Aloe Vulgarize (AV) leaf peel extract assisted with different sonication techniques followed by the physicochemical, biological activities and molecular docking studies. The NPs structure was analyzed using FTIR, UV-vis and EDX. The morphology, particle size and crystallinity of ZnO NPs were identified using FESEM and XRD. It was found that the formed flower-like structure with sharp edge and fine size of particulates in ZnO NPs/AV could enhance the bacterial inhibition. The minimum inhibitory concentration (MIC) for all the tested bacterial strains is at 3.125 µg/ml and the bacterial growth curve are dependent on the ZnO NPs dosage. The results of disc diffusion revealed that the ZnO NPs/AV possess better antibacterial effect with bigger ZOI due to the presence of AV active ingredient. The molecular docking between active ingredients of AV in the NPs with the protein of IFCM and 1MWU revealed that low binding energy (Ebind = -6.56 kcal/mol and -8.99 kcal/mol, respectively) attributes to the excessive hydrogen bond from AV that highly influenced their interaction with the amino acid of the selected proteins. Finally, the cytotoxicity test on the biosynthesized ZnO NPs with concentration below 20 µg/ml are found nontoxic on the HDF cell. Overall, ZnO NPs/20 % AV (probe sonication) is considered as the best synthesis option due to its efficient one-pot method, short sonication time but own the best antibacterial effect.

Green and environmentally friendly architecture of starch-based ternary magnetic biocomposite (Starch/MIL100/CoFe2O4): Synthesis and photocatalytic degradation of tetracycline and dye

The presence of tetracycline and dye as organic contaminants has led to the poisoning of wastewater. The aim of this study is to synthesize a novel biocomposite material by decorating natural starch polymer granules with metal-organic framework (MIL100) and cobalt ferrite magnetic (CoFe2O4) nanoparticles. The synthesized ternary magnetic biocomposite (Starch/MIL100/CoFe2O4) was used for the photocatalytic degradation of methylene blue (MB) and tetracycline (TCN) using LED visible light. The synthesis of the biocomposite was confirmed through comprehensive analyses (XRD, SEM, FTIR, BET, EDX, MAP, DRS, pHzpc, TGA, and Raman). The evaluation examined the influence of initial pollutant concentration, catalyst dosage, pH, and the impact of anions on pollutant removal. The results show that the pollutant degradation ability of biocomposite has been significantly improved, so that the base biopolymer, starch, achieved 18% tetracycline degradation, but when decorated with MIL100 and cobalt ferrite, it increased to 91.2%. It was observed that the degradation for methylene blue improved from 12% for starch to 96.6% for the magnetic biocomposite. The tetracycline degradation decreased by more than 20% in the presence of NaCl, NaNO3, and Na2SO4. The finding shows that the biocomposite adheres to first-order kinetics for both pollutants. The scavengers test identified hydroxyl radicals as the most effective active species in the degradation process. High stability, even after passing 5 cycles of recycling was observed for the biocomposite. The results indicated that the facile and green synthesized Starch/MIL100/CoFe2O4 magnetic biocomposite could be used as an effective photocatalyst for the degradation of Tetracycline and dye at room temperature.

Iron-based metal-organic framework/graphene oxide composite electrodes for efficient flow-injection amperometric detection of dexamethasone

A highly stable flow-injection amperometric sensor for dexamethasone (DEX) was developed using a pencil graphite electrode (PGE) modified with Fe-based metal organic frameworks, MIL-100(Fe) and graphene oxide composite materials (MIL-100(Fe)/GO). Scanning electron microscopy and energy-dispersive X-ray spectroscopy, transmission electron microscopy, powder X-ray diffraction, and Fourier-transform infrared spectroscopy were used to characterize the MIL-100(Fe) composites. The MIL-100(Fe)/GO-modified PGE (denoted MIL-100(Fe)/GO/PGE) was further electrochemically characterized using cyclic voltammetry. As an electrode material, MIL-100(Fe) is a sensing element that undergoes oxidation from Fe(ii)-MOF to Fe(iii)-MOF, and GO possesses high conductivity and a large surface area, which exhibits high absorbability. In the presence of DEX, Fe(iii) is reduced, which accelerates electron transfer at the electrode interface. Therefore, DEX can be quantitatively detected by analyzing the anodic current of MIL-100(Fe). When coupled with amperometric flow injection analysis, excellent performance can be obtained even when a low detection potential is applied (+0.10 V vs. Ag/AgCl). The concentration was linear in the range 0.10-5.0 μM and 0.010-5.0 mM with LOD of 0.030 μM based on 3(sd/slope). The modified electrode also exhibited a remarkably stable response under optimized conditions, and up to 55 injections can be used per electrode. The sensor exhibits high repeatability, reproducibility, and anti-interference properties when used for DEX detection. The effective determination of dexamethasone in real pharmaceutical and cosmetic samples demonstrated the feasibility of the electrochemical sensor, and the results were in good agreement with those obtained from the HPLC-DAD analysis. Acceptable percentage recoveries from the spiked pharmaceutical and cosmetic samples were obtained, ranging from 93-111% for this new method compared with 84-107% for the HPLC-DAD standard method.

Chemistries and materials for atmospheric water harvesting

Atmospheric water harvesting (AWH) is recognized as a crucial strategy to address the global challenge of water scarcity by tapping into the vast reserves of atmospheric moisture for potable water supply. Within this domain, sorbents lie in the core of AWH technologies as they possess broad adaptability across a wide spectrum of humidity levels, underpinned by the cyclic sorption and desorption processes of sorbents, necessitating a multi-scale viewpoint regarding the rational material and chemical selection and design. This Invited Review delves into the essential sorption mechanisms observed across various classes of sorbent systems, emphasizing the water-sorbent interactions and the progression of water networks. A special focus is placed on the insights derived from isotherm profiles, which elucidate sorbent structures and sorption dynamics. From these foundational principles, we derive material and chemical design guidelines and identify key tuning factors from a structural-functional perspective across multiple material systems, addressing their fundamental chemistries and unique attributes. The review further navigates through system-level design considerations to optimize water production efficiency. This review aims to equip researchers in the field of AWH with a thorough understanding of the water-sorbent interactions, material design principles, and system-level considerations essential for advancing this technology.

Novel Application of Metal-Organic Frameworks as Efficient Sorbents for Solid-Phase Extraction of Chemical Warfare Agents and Related Compounds in Water Samples

In this work, we test metal-organic frameworks (MOFs) as sorbents in the solid-phase extraction (SPE) technique to determine chemical warfare agents (CWAs) and their related compounds in water samples. During this study, we used 13 target compounds to test the selectivity of MOFs thoroughly. Three MOFs were used: MIL-100(Fe), ZIF-8(Zn), and UiO-66(Zr). The obtained materials were characterized using FT-IR/ATR, SEM, and XRD. CWA's and related compounds were analyzed using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The effect of the type of elution solvent and the amount of sorbent (MOFs) in the column on the efficiency of the conducted extraction were verified. The LOD ranged from 0.04 to 7.54 ng mL-1, and the linearity range for the analytes tested extended from 0.11/22.62 (depending on the compound) to 1000 ng mL-1. It was found that MOFs showed the most excellent selectivity to compounds having aromatic rings in their structure or a "spread" spatial structure. The best recoveries were obtained for DPAA, CAP, and malathion. Environmental water samples collected from the Baltic Sea were analyzed using an optimized procedure to verify the developed method's usefulness.

Application of metal-organic frameworks in infectious wound healing

Metal-organic frameworks (MOFs) are metal-organic skeleton compounds composed of self-assembled metal ions or clusters and organic ligands. MOF materials often have porous structures, high specific surface areas, uniform and adjustable pores, high surface activity and easy modification and have a wide range of prospects for application. MOFs have been widely used. In recent years, with the continuous expansion of MOF materials, they have also achieved remarkable results in the field of antimicrobial agents. In this review, the structural composition and synthetic modification of MOF materials are introduced in detail, and the antimicrobial mechanisms and applications of these materials in the healing of infected wounds are described. Moreover, the opportunities and challenges encountered in the development of MOF materials are presented, and we expect that additional MOF materials with high biosafety and efficient antimicrobial capacity will be developed in the future.

The green synthesis and applications of biological metal-organic frameworks for targeted drug delivery and tumor treatments

Biological metal-organic frameworks (bio-MOFs) constitute a growing subclass of MOFs composed of metals and bio-ligands derived from biology, such as nucleobases, peptides, saccharides, and amino acids. Bio-ligands are more abundant than other traditional organic ligands, providing multiple coordination sites for MOFs. However, bio-MOFs are typically prepared using hazardous or harmful solvents or reagents, as well as laborious processes that do not conform to environmentally friendly standards. To improve biocompatibility and biosafety, eco-friendly synthesis and functionalization techniques should be employed with mild conditions and safer materials, aiming to reduce or avoid the use of toxic and hazardous chemical agents. Recently, bio-MOF applications have gained importance in some research areas, including imaging, tumor therapy, and targeted drug delivery, owing to their flexibility, low steric hindrances, low toxicity, remarkable biocompatibility, surface property refining, and degradability. This has led to an exponential increase in research on these materials. This paper provides a comprehensive review of updated strategies for the synthesis of environmentally friendly bio-MOFs, as well as an examination of the current progress and accomplishments in green-synthesized bio-MOFs for drug delivery aims and tumor treatments. In conclusion, we consider the challenges of applying bio-MOFs for biomedical applications and clarify the possible research orientation that can lead to highly efficient therapeutic outcomes.

Application and Development Prospect of Nanoscale Iron Based Metal-Organic Frameworks in Biomedicine

Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe2+/Fe3+ exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.

Fe-Based Metal Organic Frameworks (Fe-MOFs) for Bio-Related Applications

Metal-organic frameworks (MOFs) are porous materials composed of metal ions and organic ligands. Due to their large surface area, easy modification, and good biocompatibility, MOFs are often used in bio-related fields. Fe-based metal-organic frameworks (Fe-MOFs), as important types of MOF, are favored by biomedical researchers for their advantages, such as low toxicity, good stability, high drug-loading capacity, and flexible structure. Fe-MOFs are diverse and widely used. Many new Fe-MOFs have appeared in recent years, with new modification methods and innovative design ideas, leading to the transformation of Fe-MOFs from single-mode therapy to multi-mode therapy. In this paper, the therapeutic principles, classification, characteristics, preparation methods, surface modification, and applications of Fe-MOFs in recent years are reviewed to understand the development trends and existing problems in Fe-MOFs, with the view to provide new ideas and directions for future research.

Virus Management Using Metal-Organic Framework-Based Technologies

The eradication and isolation of viruses are two concurrent approaches to protect ourselves from viral infections and diseases. The quite versatile porous materials called metal-organic frameworks (MOFs), have recently emerged as efficient nanosized tools to manage viruses, and several strategies to accomplish these tasks have been developed. This review describes these strategies employing nanoscale MOFs against SARS-CoV-2, HIV-1, tobacco mosaic virus, etc., which include the sequestration by host-guest penetration inside pores, mineralization, design of a physical barrier, controlled delivery of organic and inorganic antiviral drugs or bioinhibitors, photosensitization of singlet oxygen, and direct contact with inherently cytotoxic MOFs.

BioMOF-Based Anti-Cancer Drug Delivery Systems

A variety of nanomaterials have been developed specifically for biomedical applications, such as drug delivery in cancer treatment. These materials involve both synthetic and natural nanoparticles and nanofibers of varying dimensions. The efficacy of a drug delivery system (DDS) depends on its biocompatibility, intrinsic high surface area, high interconnected porosity, and chemical functionality. Recent advances in metal-organic framework (MOF) nanostructures have led to the achievement of these desirable features. MOFs consist of metal ions and organic linkers that are assembled in different geometries and can be produced in 0, 1, 2, or 3 dimensions. The defining features of MOFs are their outstanding surface area, interconnected porosity, and variable chemical functionality, which enable an endless range of modalities for loading drugs into their hierarchical structures. MOFs, coupled with biocompatibility requisites, are now regarded as highly successful DDSs for the treatment of diverse diseases. This review aims to present the development and applications of DDSs based on chemically-functionalized MOF nanostructures in the context of cancer treatment. A concise overview of the structure, synthesis, and mode of action of MOF-DDS is provided.

Metal-organic frameworks: A promising option for the diagnosis and treatment of Alzheimer's disease

Beta-amyloid (Aβ) peptide is one of the main characteristic biomarkers of Alzheimer's disease (AD). Previous clinical investigations have proposed that unusual concentrations of this biomarker in cerebrospinal fluid, blood, and brain tissue are closely associated with the AD progression. Therefore, the critical point of early diagnosis, prevention, and treatment of AD is to monitor the levels of Aβ. In view of the potential of metal-organic frameworks (MOFs) for diagnosing and treating the AD, much attention has been focused in recent years. This review discusses the latest advances in the applications of MOFs for the early diagnosis of AD via fluorescence and electrochemiluminescence (ECL) detection of AD biomarkers, fluorescence detection of the main metal ions in the brain (Zn²⁺, Cu²⁺, Mn²⁺, Fe³⁺, and Al³⁺) in addition to magnetic resonance imaging (MRI) of the Aβ plaques. The current challenges and future strategies for translating the in vitro applications of MOFs into in vivo diagnosis of the AD are discussed.

A quest for cytocompatible metal organic frameworks in non-viral gene therapy: Relevance of zeolitic imidazolate framework-8

Metal-organic frameworks (MOFs) are an emerging group of nanomaterials for successful biomedical applications in gene therapy. The most commonly biocompatible MOFs are zinc-based ZIFs, zirconium-based UiOs, and iron-based MILs. However, despite increasing applications, a comparative study to underscore the critical factors for determining effective gene delivery by such MOFs is lacking. Herein, we evaluate the potential of UiO-66 and MIL-88B and ZIF-8 for gene therapeutics delivery; revealing the comparative importance of ZIF-8. Cytotoxicity assays proved insufficient for selecting the ideal gene delivery MOF vehicle. Synthesis conditions such as ability of the MOF scaffold to envelop the gene during in-situ synthesis, post-treatment such as washing, and gene loading efficiency proved to be the critical factors in determining the favourable MOF from the material selection perspective. Rapid in-situ synthesis under physiological conditions, successful gene loading, and low concentration requirements favour ZIF MOFs as gene delivery vehicles. Impact on cellular physiology, metabolism, and architecture revealed neutrality of the delivery system; and relative effects on pro-inflammatory and anti-inflammatory cytokines suggest immunomodulatory impact.

Low Toxicity of Metal-Organic Framework MOF-74(Co) Nano-Particles In Vitro and In Vivo

With the rapid development of metal-organic frameworks (MOF), the toxicity and environmental safety of MOF materials should be thoroughly investigated. The behaviors and bio-effects of MOF materials after oral exposure are largely unknown. In this study, we performed a pilot toxicity evaluation of MOF-74(Co) nanoparticles (NPs) both in vitro and in vivo. The cell viability and cell cycle were monitored after LO2 cells were incubated with MOF-74(Co). The Co contents, bodyweight, serum biochemistry, histopathological changes, and oxidative stress parameters were measured after oral exposure to MOF-74(Co) NPs in mice. LO2 cells showed viability loss at 100 mg/L. The cell cycle arrest was more sensitive, which was observed even at 12.5 mg/L. MOF-74(Co) NPs led to a significant accumulation of Co in the liver and kidneys. No bodyweight loss was observed and the serum biochemical index was mainly unchanged. Except for slight inflammation, the histopathological images of the liver and kidneys after oral exposure to MOF-74(Co) NPs were normal compared to the control. Meaningful oxidative stress was found in the liver and kidneys. The results collectively indicated the low toxicity of MOF-74(Co) NPs after oral exposure in mice.

Metal-organic frameworks for pharmaceutical and biomedical applications

Metal-organic framework (MOF) materials provide unprecedented opportunities for evaluating valuable compounds for various medical applications. MOFs merged with biomolecules, used as novel biomaterials, have become particularly useful in biological environments. Bio-MOFs can be promising materials in the global to avoid utilization above toxicological substances. Bio-MOFs with crystallin and porosity nature offer flexible structure via bio-linker and metal node variation, which improves their wide applicability in medical science.

Recent Progress of Metal-Organic Framework-Based Photodynamic Therapy for Cancer Treatment

Photodynamic therapy (PDT), combining photosensitizers (PSs) and excitation light at a specific wavelength to produce toxic reactive oxygen species, has been a novel and promising approach to cancer treatment with non-invasiveness, spatial specificity, and minimal systemic toxicity, compared with conventional cancer treatment. Recently, numerous basic research and clinical research have demonstrated the potential of PDT in the treatment of a variety of malignant tumors, such as esophageal cancer, bladder cancer, and so on. Metal-organic framework (MOF) has been developed as a new type of nanomaterial with the advantages of high porosity, large specific surface area, adjustable pore size, and easy functionalization, which could serve as carriers to load PSs or increase the accumulation of PSs in target cells during PDT. Moreover, active MOFs have the potential to construct multifunctional systems, which are conducive to refining the tumor microenvironment (TME) and implementing combination therapy to improve PDT efficacy. Hence, a comprehensive and in-depth depiction of the whole scene of the recent development of MOFs-based PDT in cancer treatment is desirable. This review summarized the recent research strategies of MOFs-based PDT in antitumor therapy from the perspective of MOFs functions, including active MOFs, inactive MOFs, and their further combination therapies in clinical antitumor treatment. In addition, the bottlenecks and obstacles in the application of MOFs in PDT are also described.

Loading and Sustained Release of Pralidoxime Chloride from Swellable MIL-88B(Fe) and Its Therapeutic Performance on Mice Poisoned by Neurotoxic Agents

Maintaining a long-term continuous and stable reactivator blood concentration to treat organophosphorus nerve agent poisoning using acetylcholinesterase (AChE) reactivator pralidoxime chloride (2-PAM) is very important yet difficult. Because the flexible framework of MIL-88B(Fe) nanoparticles (NPs) can swell in polar solvents, pralidoxime chloride (2-PAM) was loaded in MIL-88B(Fe) NPs (size: ca. 500 nm) by stirring and incubation in deionized water to obtain 2-PAM@MIL-88B(Fe), which had a maximum drug loading capacity of 12.6 wt %. The as-prepared composite was characterized by IR, powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM), ζ-potential, Brunauer-Emmett-Teller (BET), and thermogravimetry/differential thermal analysis (TG/DTA). The results showed that under constant conditions, the maximum drug release rates of 2-PAM@MIL-88B(Fe) in absolute ethanol, phosphate-buffered saline (PBS) solution (pH = 7.4), and PBS solution (pH = 4) at 150 h were 51.7, 80.6, and 67.1%, respectively. This was because the composite showed different swelling behaviors in different solvents. In PBS solution with pH = 2, the 2-PAM@MIL-88B(Fe) framework collapsed after 53 h and released 100% of 2-PAM. For mice after intragastric poisoning with sarin (a neurotoxic agent), an atropine-assisted 2-PAM@MIL-88B(Fe) treatment experiment revealed that 2-PAM@MIL-88B(Fe) continuously released 2-PAM for more than 72 h so that poisoned AChE was continuously and steadily reactivated. The reactivation rate of AChE was 56.7% after 72 h. This composite is expected to provide a prolonged, stable therapeutic drug for the mid- and late-stage treatment of neurotoxic agent poisoning.

Metal Organic Frameworks as Biosensing Materials for COVID-19

The novel coronavirus disease (COVID-19) pandemic outbreak is the most startling public health crises with attendant global socio-economic burden ever experienced in the twenty-first century. The level of devastation by this outbreak is such that highly impacted countries will take years to recover. Studies have shown that timely detection based on accelerated sample testing and accurate diagnosis are crucial steps to reducing or preventing the spread of any pandemic outbreak. In this opinionated review, the impacts of metal organic frameworks (MOFs) as a biosensor in a pandemic outbreak is investigated with reference to COVID-19. Biosensing technologies have been proven to be very effective in clinical analyses, especially in assessment of severe infectious diseases. Polymerase chain reactions (PCR, RT-PCR, CRISPR) - based test methods predominantly used for SARS-COV-2 diagnoses have serious limitations and the health scientists and researchers are urged to come up with a more robust and versatile system for solving diagnostic problem associated with the current and future pandemic outbreaks. MOFs, an emerging crystalline material with unique characteristics will serve as promising biosensing materials in a pandemic outbreak such as the one we are in. We hereby highlight the characteristics of MOFs and their sensing applications, potentials as biosensors in a pandemic outbreak and draw the attention of researchers to a new vista of research that needs immediate action.

Metal/metal oxide nanoparticles: Toxicity concerns associated with their physical state and remediation for biomedical applications

Metal/metal oxide nanoparticles show promise for various applications, including diagnosis, treatment, theranostics, sensors, cosmetics, etc. Their altered chemical, optical, magnetic, and structural properties have differential toxicity profiles. Depending upon their physical state, these NPs can also change their properties due to alteration in pH, interaction with proteins, lipids, blood cells, and genetic material. Metallic nanomaterials (comprised of a single metal element) tend to be relatively stable and do not readily undergo dissolution. Contrarily, metal oxide and metal alloy-based nanomaterials tend to exhibit a lower degree of stability and are more susceptible to dissolution and ion release when introduced to a biological milieu, leading to reactive oxygen species production and oxidative stress to cells. Since NPs have considerable mobility in various biological tissues, the investigation related to their adverse effects is a critical issue and required to be appropriately addressed before their biomedical applications. Short and long-term toxicity assessment of metal/metal oxide nanoparticles or their nano-formulations is of paramount importance to ensure the global biome's safety; otherwise, to face a fiasco. This article provides a comprehensive introspection regarding the effects of metal/metal oxides' physical state, their surface properties, the possible mechanism of actions along with the potential future strategy for remediation of their toxic effects.

Precision release systems of food bioactive compounds based on metal-organic frameworks: synthesis, mechanisms and recent applications

Controlled release (CR) systems have become a powerful platform for accurate and effective delivery of bioactive compounds (BCs). Metal-organic frameworks (MOFs) are one of the best BCs-loaded carriers for CR systems. In the review, the principles and methods of the design and synthesis of MOFs-CR systems are summarized in detail, the encapsulation of BCs by MOFs and CR mechanisms are explored, and their biological toxicity and biocompatibility are highlighted and applications in the food industry are discussed. In addition, current challenges in this field and possible future development directions are also presented. MOFs have been proven to encapsulate BCs effectively, including gaseous and solid molecules, and control the release of BCs through spontaneous diffusion or stimulus-response. The solubility, stability and biocompatibility of BCs encapsulated by MOFs are greatly improved, which expands their applications in foods. The effective CR of BCs by MOFs-CR systems is beneficial to assist in maintaining or even improving the quality and safety of food, reduce the BCs usage while increasing the bioavailability. Low- or non-biotoxic MOFs, especially bio-MOFs, show greater application prospects in the food industry.

Acute Toxicity of Cu-MOF Nanoparticles (nanoHKUST-1) towards Embryos and Adult Zebrafish

Metal-organic frameworks (MOFs) demonstrate unique properties, which are prospective for drug delivery, catalysis, and gas separation, but their biomedical applications might be limited due to their obscure interactions with the environment and humans. It is important to understand their toxic effect on nature before their wide practical application. In this study, HKUST-1 nanoparticles (Cu-nanoMOF, Cu₃(btc)₂, btc = benzene-1,3,5-tricarboxylate) were synthesized by the microwave (MW)-assisted ionothermal method and characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) techniques. The embryotoxicity and acute toxicity of HKUST-1 towards embryos and adult zebrafish were investigated. To gain a better understanding of the effects of Cu-MOF particles towards Danio rerio (D. rerio) embryos were exposed to HKUST-1 nanoparticles (NPs) and Cu²⁺ ions (CuSO₄). Cu²⁺ ions showed a higher toxic effect towards fish compared with Cu-MOF NPs for D. rerio. Both forms of fish were sensitive to the presence of HKUST-1 NPs. Estimated LC₅₀ values were 2.132 mg/L and 1.500 mg/L for zebrafish embryos and adults, respectively. During 96 h of exposure, the release of copper ions in a stock solution and accumulation of copper after 96 h were measured in the internal organs of adult fishes. Uptake examination of the major internal organs did not show any concentration dependency. An increase in the number of copper ions in the test medium was found on the first day of exposure. Toxicity was largely restricted to copper release from HKUST-1 nanomaterials structure into solution.

Thin Films of Metal-Organic Framework Interfaces Obtained by Laser Evaporation

Properties such as large surface area, high pore volume, high chemical and thermal stability, and structural flexibility render zeolitic imidazolate frameworks (ZIFs) well-suited materials for gas separation, chemical sensors, and optical and electrical devices. For such applications, film processing is a prerequisite. Herein, matrix-assisted pulsed laser evaporation (MAPLE) was successfully used as a single-step deposition process to fabricate ZIF-8 films. By correlating laser fluency and controlling the specific transfer of lab-synthesized ZIF-8, films with user-controlled physical and chemical properties were obtained. Films' characteristics were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The analysis showed that frameworks of ZIF-8 can be deposited successfully and controllably to yield polycrystalline films. The deposited films maintained the integrity of the individual ZIF-8 framework, while undergoing minor crystalline and surface chemistry changes. No significant changes in particle size were observed. Our study demonstrated control over both the MAPLE deposition conditions and the outcome, as well as the suitability of the listed deposition method to create composite architectures that could potentially be used in applications ranging from selective membranes to gas sensors.

Metal-organic frameworks for virus detection

Virus severely endangers human life and health, and the detection of viruses is essential for the prevention and treatment of associated diseases. Metal-organic framework (MOF), a novel hybrid porous material which is bridged by the metal clusters and organic linkers, has become a promising biosensor platform for virus detection due to its outstanding properties including high surface area, adjustable pore size, easy modification, etc. However, the MOF-based sensing platforms for virus detection are rarely summarized. This review systematically divided the detection platforms into nucleic acid and immunological (antigen and antibody) detection, and the underlying sensing mechanisms were interpreted. The nucleic acid sensing was discussed based on the properties of MOF (such as metal ion, functional group, geometry structure, size, porosity, stability, etc.), revealing the relationship between the sensing performance and properties of MOF. Moreover, antibodies sensing based on the fluorescence detection and antigens sensing based on molecular imprinting or electrochemical immunoassay were highlighted. Furthermore, the remaining challenges and future development of MOF for virus detection were further discussed and proposed. This review will provide valuable references for the construction of sophisticated sensing platform for the detection of viruses, especially the 2019 coronavirus.

Antibacterial application and toxicity of metal-organic frameworks

Metal-organic frameworks (MOFs), which are also referred to as coordination polymers, have been widely used in adsorption separation and catalysis, especially in the field of physical chemistry in the past few years, because of their unique physical structure and potential chemical properties. In recent years, particularly with the continuous expansion of the research field, deepening of research levels, and sustained advancements in science and technology, powerful and diverse MOFs that have demonstrated great biomedical application potential have been successively developed. Consequently, this study summarizes the origin, development, and common synthesis methods of MOFs, with major emphasis on their antibacterial application and safety evaluation in biomedicine.

Fabrication and biocompatibility assessment of polypyrrole/cobalt(II) metal-organic frameworks nanocomposites

Nowadays, metal-organic frameworks (MOFs) have emerged as promising tools for different biological applications and therefore, efforts are ongoing to develop more biocompatible MOFs-based nanocomposites. We aimed to fabricate some new conductive nanocomposites of polypyrrole and cobalt-MOF with different weight percentages (PPy/x%Co-MOF) using the solution mixing method and characterize them through FT-IR (Fourier-transform infrared), PXRD (powder X-ray diffraction), SEM (scanning electron microscope), and TEM (transmission electron microscope) techniques. The biocompatibility of nanocomposites was assessed by haemolytic, cytotoxic, and quantitative reverse transcription PCR (qRT-PCR) assays. FT-IR and PXRD results revealed that nanocomposites consisted of pure MOFs and PPy. Moreover, SEM results indicated their spherical morphology along with an average diameter of 190 nm. (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed a concentration, and percentagedependent cytotoxic effect of the nanocomposites on some cell lines including 3T3 fibroblasts, MCF-7, and J774.A1 macrophages. Haematological toxicity of PPy/x%Co-MOF composites was less than 7% in most concentrations. Furthermore, PPy/x%Co-MOF composites did not show any significant effect on the expression of cyclooxygenase-2( COX-2) and inducible nitric oxide synthase( iNOS) genes. In sum, regarding the haemolytic, proinflammatory, and cytotoxic tests, prepared nanocomposite demonstrated the reasonable in vitro biocompatibility which may be considered as a hopeful platform for further investigations including clinical applications.

MIL-100(Fe) and its derivatives: from synthesis to application for wastewater decontamination

MIL-100(Fe), an environmental-friendly and water-stable metal-organic framework (MOF), has caught increasing research and application attention in the recent decade. Thanks to its mesoporous structure and eximious surface area, MIL-100(Fe) has been utilized as precursors for synthesizing various porous materials under high thermolysis temperature, which makes the derivatives of MIL-100(Fe) pretty promising candidates for the decontamination of wastewater. Herein, this review systematically summarizes the versatile synthetic methods and conditions for optimizing the properties of MIL-100(Fe) and its derivatives. Then, diverse environmental applications (i.e., adsorption, photocatalysis, and Fenton-like reaction) of MIL-100(Fe) and its derivatives and the corresponding removal mechanisms are detailed in the discussion. Finally, existing knowledge gaps related to fabrications and applications are discussed to close and promote the future development of MIL-100(Fe) and its derivatives toward environmental applications. Graphical abstract.

Metal–organic frameworks: a future toolbox for biomedicine?

The present review focuses on the use of Metal–Organic Frameworks, (MOFs) highlighting the most recent developments in the biological field and as bio-sensors.

Investigation of Metal-Organic Framework-5 (MOF-5) as an Antitumor Drug Oridonin Sustained Release Carrier

Oridonin (ORI) is a natural active ingredient with strong anticancer activity. But its clinical use is restricted due to its poor water solubility, short half-life, and low bioavailability. The aim of this study is to utilize the metal organic framework material MOF-5 to load ORI in order to improve its release characteristics and bioavailability. Herein, MOF-5 was synthesized by the solvothermal method and direct addition method, and characterized by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Thermogravimetric Analysis (TG), Brunauer-Emmett-Teller (BET), and Dynamic Light Scattering (DLS), respectively. MOF-5 prepared by the optimal synthesis method was selected for drug-loading and in vitro release experiments. HepG2 cells were model cells. MTT assay, 4',6-diamidino-2-phenylindole (DAPI) staining and Annexin V/PI assay were used to detect the biological safety of blank carriers and the anticancer activity of drug-loaded materials. The results showed that nano-MOF-5 prepared by the direct addition method had complete structure, uniform size and good biocompatibility, and was suitable as an ORI carrier. The drug loading of ORI@MOF-5 was 52.86% ± 0.59%. The sustained release effect was reliable, and the cumulative release rate was about 87% in 60 h. ORI@MOF-5 had significant cytotoxicity (IC50:22.99 μg/mL) and apoptosis effect on HepG2 cells. ORI@MOF-5 is hopeful to become a new anticancer sustained release preparation. MOF-5 has significant potential as a drug carrier material.

Metal-Organic Frameworks in Green Analytical Chemistry

Metal-organic frameworks (MOFs) are porous hybrid materials composed of metal ions and organic linkers, characterized by their crystallinity and by the highest known surface areas. MOFs structures present accessible cages, tunnels and modifiable pores, together with adequate mechanical and thermal stability. Their outstanding properties have led to their recognition as revolutionary materials in recent years. Analytical chemistry has also benefited from the potential of MOF applications. MOFs succeed as sorbent materials in extraction and microextraction procedures, as sensors, and as stationary or pseudo-stationary phases in chromatographic systems. To date, around 100 different MOFs form part of those analytical applications. This review intends to give an overview on the use of MOFs in analytical chemistry in recent years (2017–2019) within the framework of green analytical chemistry requirements, with a particular emphasis on possible toxicity issues of neat MOFs and trends to ensure green approaches in their preparation.