Controlled syntheses of Mg-MOF-74 nanorods for drug delivery

MOFs for next-generation cancer therapeutics through a biophysical approach-a review

Metal-organic frameworks (MOFs) have emerged as promising nanocarriers for cancer treatment due to their unique properties. Featuring high porosity, extensive surface area, chemical stability, and good biocompatibility, MOFs are ideal for efficient drug delivery, targeted therapy, and controlled release. They can be designed to target specific cellular organelles to disrupt metabolic processes in cancer cells. Additionally, functionalization with enzymes mimics their catalytic activity, enhancing photodynamic therapy and overcoming apoptosis resistance in cancer cells. The controllable and regular structure of MOFs, along with their tumor microenvironment responsiveness, make them promising nanocarriers for anticancer drugs. These carriers can effectively deliver a wide range of drugs with improved bioavailability, controlled release rate, and targeted delivery efficiency compared to alternatives. In this article, we review both experimental and computational studies focusing on the interaction between MOFs and drug, explicating the release mechanisms and stability in physiological conditions. Notably, we explore the relationship between MOF structure and its ability to damage cancer cells, elucidating why MOFs are excellent candidates for bio-applicability. By understanding the problem and exploring potential solutions, this review provides insights into the future directions for harnessing the full potential of MOFs, ultimately leading to improved therapeutic outcomes in cancer treatment.

Long-Term Antioxidant Metal-Organic Frameworks

Free radicals produced during metabolism induce effects, such as cell damage and cancer, because of their high reactivity. Although antioxidants in food products can eliminate free radicals, they are expelled within a relatively short period of time after serving their function. In this study, we investigated the possibility of using metal-organic frameworks (MOFs) with antioxidants as their ligands. Metal-organic frameworks are crystalline polymers with repetitively coordinated ligands and metal centers. We assume that once antioxidant-based MOFs are ingested, ligands are released on a long-term basis during the process of chemical and physical disintegration. To evaluate their eligibility, we established criteria for biocompatibility, particle size, and long-term antioxidant effects. For biocompatibility, we treated cells with various concentrations of MOFs and their precursors followed by a water-soluble tetrazolium 8 (WST-8) assay. The particle size distribution was analyzed using TEM and ImageJ software, and the antioxidant release was quantified using UV-vis spectroscopy. We concluded that Fe-based FeTHQ with the antioxidant tetrahydroxy-1,4-benzoquinone (THQ) as its ligand is the most effective long-term antioxidant with its effect lasting up to 7 days. Furthermore, microwave synthesis of FeTHQ was conducted to produce more suitable particles for in vivo antioxidant applications.

A Cu-Based Metal-Organic Framework Cu-Cip with Cuproptosis for Cancer Therapy and Inhibition of Cancer Cell Migration

Microflora within cancer cells plays a pivotal role in promoting metastasis of cancer. However, contemporary anticancer research often overlooks the potential benefits of combining anticancer and antibacterial agents. Consequently, a metal-organic framework Cu-Cip with cuproptosis and antibacterial properties was synthesized for cancer therapy. To enhance the anticancer effect of the material, Mn2+ was loaded into Cu-Cip, yielding Mn@Cu-Cip. The fabricated material was characterized using single-crystal X-ray diffraction, PXRD, and FT-IR. By interacting with overexpressed H2O2 to produce ROS and accumulating Cu ions in cancer cells, MOFs exhibited excellent anticancer performance. Moreover, the material displayed the function of damaging Staphylococcus aureus and Escherichia coli, revealing the admirable antibacterial properties of the material. In addition, the antibacterial ability could inhibit tumor cell migration. The Cu-based MOF revealed promising applications in the field of tumor treatment.

Nanoscale Zinc-Based Metal-Organic Frameworks Induce Neurotoxicity by Disturbing the Metabolism of Catecholamine Neurotransmitters

As a group of new nanomaterials, nanoscale metal-organic frameworks (MOFs) are widely applied in the biomedical field, exerting unknown risks to the human body, especially the central nervous system. Herein, the impacts of MOF-74-Zn nanoparticles on neurological behaviors and neurotransmitter metabolism are explored in both in vivo and in vitro assays modeled by C57BL/6 mice and PC12 cells, respectively. The mice exhibit increased negative-like behaviors, as demonstrated by the observed decrease in exploring behaviors and increase in despair-like behaviors in the open field test and forced swimming test after exposure to low doses of MOF-74-Zn nanoparticles. Disorders in the catecholamine neurotransmitter metabolism may be responsible for the MOF-74-Zn-induced abnormal behaviors. Part of the reason for this is the inhibition of neurotransmitter synthesis caused by restrained neurite extension. In addition, MOF-74-Zn promotes the translocation of more calcium into the cytoplasm, accelerating the release and uptake and finally resulting in an imbalance between synthesis and catabolism. Taken together, the results from this study indicate the human toxicity risks of nanoscale low-toxicity metal-based MOFs and provide valuable insight into the rational and safe use of MOF nanomaterials.

Recent advances in Metal-Organic Frameworks as nanocarriers for triggered release of anticancer drugs: Brief history, biomedical applications, challenges and future perspective

Metal-Organic Frameworks (MOFs) have emerged as a promising biomedical material due to its unique features such as high surface area, pore volume, variable pore size, flexible functional groups, and excellent efficiency for drug loading. In this review, we explored the use of novel and smart metal organic frameworks as drug delivery vehicles to discover a safer and more controlled mode of drug release aiming to minimize their side effects. Here, we systematically discussed the background of MOFs following a thorough review on structural and physical properties of MOFs, their synthesis techniques, and the important characteristics to establish a strong foundation for future research. Furthermore, the current status on the potential applications of MOF-based stimuli-responsive drug delivery systems, including pH-, ion-, temperature-, light-, and multiple responsive systems for the delivery of anticancer drugs has also been presented. Lastly, we discuss the prospects and challenges in implementation of MOF-based materials in the drug delivery. Therefore, this review will help researchers working in the relevant fields to enhance their understanding of MOFs for encapsulation of various drugs as well as their stimuli responsive mechanism.

Recent Advances in Metal-Organic-Framework-Based Nanocarriers for Controllable Drug Delivery and Release

Metal-organic frameworks (MOFs) have a good designability, a well-defined pore, stimulus responsiveness, a high surface area, and a controllable morphology. Up to now, various MOFs have been widely used as nanocarriers and have attracted lots of attention in the field of drug delivery and release because of their good biocompatibility and high-drug-loading capacity. Herein, we provide a comprehensive summary of MOF-based nanocarriers for drug delivery and release over the last five years. Meanwhile, some representative examples are highlighted in detail according to four categories, including the University of Oslo MOFs, Fe-MOFs, cyclodextrin MOFs, and other MOFs. Moreover, the opportunities and challenges of MOF-based smart delivery vehicles are discussed. We hope that this review will be helpful for researchers to understand the recent developments and challenges of MOF-based drug-delivery systems.

Metal-based nano-delivery platform for treating bone disease and regeneration

Owing to their excellent characteristics, such as large specific surface area, favorable biosafety, and versatile application, nanomaterials have attracted significant attention in biomedical applications. Among them, metal-based nanomaterials containing various metal elements exhibit significant bone tissue regeneration potential, unique antibacterial properties, and advanced drug delivery functions, thus becoming crucial development platforms for bone tissue engineering and drug therapy for orthopedic diseases. Herein, metal-based drug-loaded nanomaterial platforms are classified and introduced, and the achievable drug-loading methods are comprehensively generalized. Furthermore, their applications in bone tissue engineering, osteoarthritis, orthopedic implant infection, bone tumor, and joint lubrication are reviewed in detail. Finally, the merits and demerits of the current metal-based drug-loaded nanomaterial platforms are critically discussed, and the challenges faced to realize their future applications are summarized.

Vapor-Phase Adsorption of Xylene Isomers and Ethylbenzene in MOF-74 Thin Films

Thin films of Co-MOF-74 and Ni-MOF-74 were synthesized on Au-coated quartz crystal microbalance substrates by a vapor-assisted conversion (VAC) method that precludes the need for activation via postsynthetic solvent exchange. All thin films were structurally characterized by powder X-ray diffraction, reflection-absorption infrared spectroscopy, and Raman spectroscopy. Scanning electron microscopy (SEM) images reveal that the Ni-MOF-74 films exists as a dense base layer with hemispherical protrusions on the surface. In contrast, the scanning electron microscopy images of the Co-MOF-74 thin films show a rough surface with spherical deposits. The thin film morphologies were different than the powders resulting from the bulk synthesis. Gravimetric vapor-phase adsorption measurements for xylene isomers and ethylbenzene within Co-MOF-74 and Ni-MOF-74 thin films were conducted, and the results were compared with those reported for the corresponding bulk powders. Despite different morphologies, the saturation capacities of Ni-MOF-74 and Co-MOF-74 thin films were found to be nearly equivalent to those reported for the bulk powders. The results demonstrate that the VAC method can produce MOF-74 thin films that retain the intrinsic properties that are observed in bulk powders.

One-Pot Method Synthesis of Bimetallic MgCu-MOF-74 and Its CO2 Adsorption under Visible Light

A magnesium-based metal-organic framework (Mg-MOF-74) exhibits excellent CO₂ adsorption under ambient conditions. However, the photostability of Mg-MOF-74 for CO₂ adsorption is poor. In this study, Mg _x Cu_1-x -MOF-74 was synthesized by using a facile "one-pot" method. Furthermore, the effects of synthesis conditions on the CO₂ adsorption capacity were investigated comprehensively. X-ray diffraction, Fourier transform infrared, scanning electron microscopy, thermo gravimetric analysis, inductively coupled plasma atomic emission spectroscopy, ultraviolet-visible spectroscopy and photoluminescence spectroscopy, and CO₂ static adsorption-desorption techniques were used to characterize the structures, morphology, and physicochemical properties of Mg _x Cu_1-x -MOF-74. CO₂ uptake of Mg _x Cu_1-x -MOF-74 under visible light illumination was measured by the CO₂ static adsorption test combined with the Xe lamp. The results revealed that Mg _x Cu_1-x -MOF-74 exhibited excellent photocatalytic activity. Furthermore, the CO₂ adsorption capacity of Mg _x Cu_1-x -MOF-74 was excellent at a synthesis temperature and time of 398 K and 24 h in dimethylformamide (DMF)-EtOH-MeOH mixing solvents, respectively. Mg _x Cu_1-x -MOF-74 retained a crystal structure similar to that of the corresponding monometallic MOF-74, and its CO₂ uptake under visible light was superior to that of the corresponding monometallic MOF-74. Particularly, the CO₂ uptake of Mg_0.4Cu_0.6-MOF-74 under Xe lamp illumination for 24 h was the highest, up to 3.52 mmol·g^-1, which was 1.18 and 2.09 times higher than that of Mg- and Cu-MOF-74, respectively. The yield of the photocatalytic reduction of CO₂ to CO was 49.44 μmol·g_cat ^-1 over Mg_0.4Cu_0.6-MOF-74 under visible light for 8 h. Mg²⁺ and Cu²⁺ functioned as open alkali metal that could adsorb and activate CO₂. The synergistic effect between Mg and Cu metal strengthened Mg _x Cu_1-x -MOF-74 photostability for CO₂ adsorption and broadened the scope of its photocatalytic application. The "bimetallic" strategy exhibits considerable potential for use in MOF-based semiconductor composites and provides a feasible method for catalyst design with remarkable CO₂ adsorption capacity and photocatalytic activity.

Preparation of nanoscale cationic metal–organic framework Nano Mn(iii)-TP for theranostics based on valence changes

Schematic illustrations of the synthesis and working principle of a platform MTXNa@Nano Mn(iii)-TP for tumor theranostics.

An Mg-MOFs based multifunctional medicine for the treatment of osteoporotic pain

Bone pain is the primary problem for patients with osteoporosis. Ketoprofen is clinically used to treat osteoporotic pain, while long-term oral administration of ketoprofen can cause some side effects. In addition, osteoporosis is also accompanied by bone mass loss and inflammation. In this study, we designed a multifunctional drug (Ket@Mg-MOF-74) adopted Mg-MOF-74 to load ketoprofen to treat osteoporotic pain, bone loss and inflammation comprehensively. Mg-MOF-74 was prepared, and the physicochemical characterization proved that it had excellent physical and chemical stability. Ket@Mg-MOF-74 was synthesized by post-synthetic modification method and a high loading rate of ketoprofen was confirmed. Drug release and ion release experiments indicated Ket@Mg-MOF-74 had a good controlled release of ketoprofen and Mg in solution. Cell experiments in vitro proved the compound drug could significantly reduce the expression of pain-related genes of cyclooxygenase 2 (COX2), obviously up-regulated the expression of osteogenic cytokines and remarkably down-regulated the secretion of pro-inflammatory factors. Therefore, Ket@Mg-MOF-74 is believed a promising painkiller for osteoporotic bone pain, with the function of anti-inflammatory and promoting bone formation.

Biocompatibility and biodegradability of metal organic frameworks for biomedical applications

Metal organic frameworks (MOFs) are a unique class of smart hybrid materials that have recently attracted significant interest for catalysis, separation and biomedical applications. Different strategies have been developed to overcome the limitations of MOFs for bio-applications in order to produce a system with high biocompatibility and biodegradability. In this review, we outline the chemical and physical factors that dictate the biocompatibility and biodegradability characteristics of MOFs including the nature of the metal ions and organic ligands, size, surface properties and colloidal stability. This review includes the in vitro biodegradation and in vivo biodistribution studies of MOFs to better understand their pharmacokinetics, organ toxicity and immune response. Such studies can guide the design of future bio-friendly systems that bring us closer to safely translating these platforms into the pharmaceutical consumer market.