Recent Advances in Research on the Effect of Physicochemical Properties on the Cytotoxicity of Metal-Organic Frameworks

Multifunctional sorafenib-loaded MXene for enhanced cancer therapy: In vitro and in vivo study based on chemotherapy/photothermal therapy approach

Cancer, characterized by uncontrolled cell proliferation, remains one of the deadliest diseases. Multifunctional hybrid nanosystems that combine drugs with photothermal therapy (PTT) offer enhanced tumor treatment options through localized thermal increase and smart drug delivery (SDD). MXene, a 2D inorganic nanomaterial consisting of titanium carbide (Ti3C2), has garnered significant interest for cancer applications. MXene was combined with the metal-organic framework MOF-UiO-67 to create MX-Uio-67. The anticancer drug sorafenib (SN) was then load onto MX-UiO-67 and coated with chitosan (CS) to form SN-MX-UiO-67@CS aiming to improve chemo-PTT mediated by near-infrared (NIR) laser irradiation. The release of SN from SN-MX-UiO-67@CS was studied at pH 4.6 and pH 7.4 conditions, both with and without NIR, over a period of 96 h. The cumulative release of SN from MX-UiO-67@CS reached 80.16 % at pH 7.4 and 93.77 % at pH 4.6 under NIR irradiation. MTT assay results demonstrated significant cytotoxicity against HepG2 cells, with SN-MX-UiO-67@CS (chemo-PTT) displaying an IC50 value of 22.4 µg/mL and achieving a necrosis was 36.1 % and apoptosis rate of 50.94 %, highlighting its potential as an effective anticancer agent. Furthermore, in vivo PTT via xenograft model and biodistribution studies were performed in healthy BALB/c mice under NIR. A bio-analytical technique was established utilizing HepG2 cells for the quantitative examination of SN in mice plasma, spleen, liver, heart, kidneys, tumor and lungs. A highly significant difference was observed in the plasma concentration-time curves and pharmacokinetic parameters of SN, SN-MX, and SN-MX-UiO-67following the intravenous administration of SN-MX-UiO-67@CS. Notably, the formulation exhibited higher key pharmacokinetic parameters, involving Cmax and AUC(0-72).

Unleashing the antibacterial potential of ZIFs and their derivatives: mechanistic insights

Antibiotic resistance presents an alarming threat to global health, with bacterial infections now ranking among the leading causes of mortality. To address this escalating challenge, strategies such as antibiotic stewardship, development of antimicrobial therapies, and exploration of alternative treatment modalities are imperative. Metal-organic frameworks (MOFs), acclaimed for their outstanding biocompatibility and in vivo biodegradability, are promising avenues for the synthesis of novel antibiotic agents under mild conditions. Among these, zeolitic imidazolate frameworks (ZIFs), a remarkable subclass of MOFs, have emerged as potent antibacterial materials; the efficacy of which stems from their porous structure, metal ion content, and tunable functionalized groups. This could be further enhanced by incorporating or encapsulating metal ions, such as Cu, Fe, Ti, Ag, and others. This perspective aims to underscore the potential of ZIFs as antibacterial agents and their underlying mechanisms including the release of metal ions, generation of reactive oxygen species (ROS), disruption of bacterial cell walls, and synergistic interactions with other antibacterial agents. These attributes position ZIFs as promising candidates for advanced applications in combating bacterial infections. Furthermore, we propose a novel approach for synthesizing ZIFs and their derivatives, demonstrating exceptional antibacterial efficacy against Escherichia coli and Staphylococcus aureus. By highlighting the benefits of ZIFs and their derivatives as antibacterial agents, this perspective emphasizes their potential to address the critical challenge of antibiotic resistance.

Metal-organic framework (MOF)-bioactive glass (BG) systems for biomedical applications - A review

In recent years, metal-organic frameworks (MOFs) have emerged as promising materials for biomedical applications, owing to their superior chemical versatility, unique textural properties and enhanced mechanical properties. However, their fast and uncontrolled degradation, together with the reduced bioactivity have restricted their clinical potential. To overcome these limitations, MOFs can be synergistically combined with other materials, such as bioactive glasses (BGs), known for their bioactivity and therapeutic ion releasing capabilities. Besides comparing MOFs and BGs, this review aims to present the latest achievements of different MOFs/BGs materials, with a particular focus on their complementary and synergistic properties. Key findings show that combining MOFs and BGs enables the development of composite materials with superior physicochemical and biological properties. Moreover, by choosing appropriate processing techniques, BGs and MOFs can be fabricated as scaffolds or coatings with fast mineralization ability and high corrosion resistance. In addition, incorporation of MOFs/BGs in hydrogels improves mechanical stability, bioactivity and antibacterial properties, while maintaining biocompatibility. The mechanisms behind the antibacterial properties, likely coming from the release of metal ions and organic ligands, are also discussed. Overall, this review highlights the current research directions and emerging trends in the synergistic use of MOFs and BGs for biomedical applications, which represents a novel strategy for developing a new family of advanced therapeutic materials.

Integrated design and application of stimuli-responsive metal-organic frameworks in biomedicine: current status and future perspectives

In recent years, metal-organic frameworks (MOFs) have garnered widespread attention due to their distinctive attributes, such as high surface area, tunable properties, biodegradability, extremely low density, high loading capacity, diverse chemical functionalities, thermal stability, well-defined pore sizes, and molecular dimensions. Increasingly, biomedical researchers have turned their focus towards their multifaceted development. Among these, stimuli-responsive MOFs, with their unique advantages, have captured greater interest from researchers. This review will delve into the merits and drawbacks of both endogenous and exogenous stimuli-responsive MOFs, along with their application directions. Furthermore, it will outline the characteristics of different synthesis routes of MOFs, exploring various design schemes and modification strategies and their impacts on the properties of MOF products, as well as how to control them. Additionally, we will survey different types of stimuli-responsive MOFs, discussing the significance of various MOF products reported in biomedical applications. We will categorically summarize different strategies such as anticancer therapy, antibacterial treatment, tissue repair, and biomedical imaging, as well as insights into the development of novel MOFs nanomaterials in the future. Finally, this review will conclude by summarizing the challenges in the development of stimuli-responsive MOFs in the field of biomedicine and providing prospects for future research endeavors.

Drug carrier wonders: Synthetic strategies of zeolitic imidazolates frameworks (ZIFs) and their applications in drug delivery and anti-cancer activity

With the rapid advancement of nanotechnology, stimuli-responsive nanomaterials have emerged as a feasible choice for the designing of controlled drug delivery systems. Zeolitic imidazolates frameworks are a subclass of Metal-organic frameworks (MOFs) that are recognized by their excellent porosity, structural tunability and chemical modifications make them promising materials for loading targeted molecules and therapeutics agents. The biomedical industry uses these porous materials extensively as nano-carriers in drug delivery systems. These MOFs not only possess excellent targeted imaging ability but also cause the death of tumor cells drawing considerable attention in the current framework of anticancer drug delivery systems. In this review, the outline of stability, porosity, mechanism of encapsulation and release of anticancer drug have been reported extensively. In the end, we also discuss a brief outline of current challenges and future perspectives of ZIFs in the biomedical world.

Metal-Organic Framework-Based Nanomaterials for Regulation of the Osteogenic Microenvironment

As the global population ages, bone diseases have become increasingly prevalent in clinical settings. These conditions often involve detrimental factors such as infection, inflammation, and oxidative stress that disrupt bone homeostasis. Addressing these disorders requires exogenous strategies to regulate the osteogenic microenvironment (OME). The exogenous regulation of OME can be divided into four processes: induction, modulation, protection, and support, each serving a specific purpose. To this end, metal-organic frameworks (MOFs) are an emerging focus in nanomedicine, which show tremendous potential due to their superior delivery capability. MOFs play numerous roles in OME regulation such as metal ion donors, drug carriers, nanozymes, and photosensitizers, which have been extensively explored in recent studies. This review presents a comprehensive introduction to the exogenous regulation of OME by MOF-based nanomaterials. By discussing various functional MOF composites, this work aims to inspire and guide the creation of sophisticated and efficient nanomaterials for bone disease management.

The drug loading capacity prediction and cytotoxicity analysis of metal-organic frameworks using stacking algorithms of machine learning

Metal-organic frameworks (MOFs) have shown excellent performance in the field of drug delivery. Despite the synthesis of a vast array of MOFs exceeding 100,000 varieties, certain formulations have exhibited suboptimal performance characteristics. Therefore, there is a pressing need to enhance their efficacy by identifying MOFs with superior drug loading capacities and minimal cytotoxicity, which can be achieved through machine learning (ML). In this study, a stacking regression model was developed to predict drug loading capacity and cytotoxicity of MOFs using datasets compiled from various literature sources. The model exhibited exceptional predictive capabilities, achieving R2 values of 0.907 for drug loading capacity and 0.856 for cytotoxicity. Furthermore, various model interpretation methods including partial dependence plots, individual conditional expectation, Shapley additive explanation, decision tree, random forest, CatBoost Regressor, and light gradient-boosting machine were employed for feature importance analysis. The results revealed that specific metal atoms such as Zn, Cr, Fe, Zr, and Cu significantly influenced the drug loading capacity and cytotoxicity of MOFs. Through model validation encompassing experimental validation and computational verification, the reliability of the model was thoroughly established. In general, it is a good practice to use ML methods for predicting drug loading capacity and cytotoxicity analysis of MOFs, guiding the development of future property prediction methods for MOFs.

Phosphate Coordination to Metal-Organic Layer Secondary Building Units Prolongs Drug Retention for Synergistic Chemoradiotherapy

Chemoradiotherapy combines radiotherapy with concurrent chemotherapy to potentiate antitumor activity but exacerbates toxicities and causes debilitating side effects in cancer patients. Herein, we report the use of a nanoscale metal-organic layer (MOL) as a 2D nanoradiosensitizer and a reservoir for the slow release of chemotherapeutics to amplify the antitumor effects of radiotherapy. Coordination of phosphate-containing drugs to MOL secondary building units prolongs their intratumoral retention, allowing for continuous release of gemcitabine monophosphate (GMP) for effective localized chemotherapy. In the meantime, the MOL sensitizes cancer cells to X-ray irradiation and provides potent radiotherapeutic effects. GMP-loaded MOL (GMP/MOL) enhances cytotoxicity by 2-fold and improves radiotherapeutic effects over free GMP in vitro. In a colon cancer model, GMP/MOL retains GMP in tumors for more than four days and, when combined with low-dose radiotherapy, inhibits tumor growth by 98 %. The synergistic chemoradiotherapy enabled by GMP/MOL shows a cure rate of 50 %, improves survival, and ameliorates cancer-proliferation histological biomarkers.

A metal-organic framework-integrated composite for piezocatalysis-assisted tumour therapy: design, related mechanisms, and recent advances

With the growing need for more effective tumour treatment, piezocatalytic therapy has emerged as a promising approach due to its distinctive capacities to generate ROS through stress induction and regulate the hypoxic state of the TME. MOF-based piezocatalysts not only possess the benefits of piezocatalysis but also exhibit several advantages associated with MOFs, such as tunable pore size, large specific surface area, and good biocompatibility. Therefore, they are expected to become a powerful promoter of piezocatalytic therapy. This review elaborates on the fundamental principles of piezocatalysis and summarises recent advances in the piezocatalytic therapy and combination therapies of tumours, generalising the strategies for constructing piezocatalytic systems based on MOFs. Finally, the challenges confronted and future opportunities for the design and application of piezocatalytic MOF anticancer systems have been discussed.

Highly Selective Extraction of U(VI) from Solutions by Metal Organic Framework-Based Nanomaterials through Sorption, Photochemistry, and Electrochemistry Strategies

With the rapid development of nuclear technology and peaceful utilization of nuclear energy, plentiful U(VI) not only is required to be extracted from solutions for a sustainable nuclear fuel supply but also is inevitably released into the surrounding environment to result in pollution and threaten human health. Thereby, realizing selective extraction of U(VI) from aqueous solutions is crucial for U(VI) pollution control and a sustainable nuclear industry. Metal organic frameworks (MOFs) have gained multidisciplinary attention due to their excellent properties including large specific surface areas, tunable pore structures, easy functionalization, etc. This Review comprehensively summarizes the research progress of MOFs and MOF-based materials on U(VI) removal from aqueous solutions by sorption, photocatalysis, electrocatalysis, membrane separation, etc. The efficient high extraction ability is dependent on the intrinsic properties of MOFs and the techniques used. The removal properties of MOF-based materials as adsorbents, photocatalysts, and electrocatalysts for U(VI) are discussed. Information about the interaction mechanisms between U(VI) and MOF-based materials are analyzed in-depth, including experiments, theoretical calculations, and advanced spectroscopy analysis. The removal properties for U(VI) of various MOF-based materials are assessed through different techniques. Finally, a summary and perspective on the direction and challenges of MOF-based materials and various pollutant removal technologies are proposed to provide some significant information on designing and fabricating MOF-based materials for environmental pollution management.

Follow up of the prostate cancer treatment based on a novel sensing method for anti-prostate cancer drug (flutamide)

In this work, novel modified electrode (MXene/MIL-101(Cr)/GCE) are manufactured through simple layer-by-layer immobilization procedure. The fabricated electrochemical sensor was utilized for electrochemical sensing of flutamide in biological fluids. The immobilization of both MXene and metal-organic framework (MOF) materials on the electrode surface could improve the electrochemical performance of the modified glassy carbon electrode (GCE) towards flutamide due to the synergic effects. The established sensor illustrated the significant sensing ability for the determination of flutamide. The influence of solution pH and volume ratio of MXene/MIL-101(Cr) on electrochemical performance of the modified GCE was researched and optimized. The sensor demonstrated a favorable detection limit of 0.009 μM and a linear range of 0.025-100 μM using differential pulse voltammetry (DPV) technique. The suggested assay illustrated an excellent sensing efficiency towards flutamide in body fluids with recoveries ranging from 97.7% to 102.5%, which indicates its potential in real matrices. In addition, the MXene/MIL-101(Cr)/GCE was illustrated some advantages including simple preparation, good selectivity and reproducibility, and rapid flutamide detection.

Recent advances in metal-organic frameworks: Synthesis, application and toxicity

Metal-organic frameworks (MOFs) are a new class of crystalline porous hybrid materials with high porosity, large specific surface area and adjustable channel structure and biocompatibility, which are being investigated with increasing interest for energy storage and conversion, gas adsorption/separation, catalysis, sensing and biomedicine. However, the practical applications of MOFs make them release into the environment inevitable, posing a threat to humans and organisms. In this article, we cover advances in the currently available MOFs synthesis methods and the emerging applications of MOFs, especially in the biomedical field (therapeutic agents and bioimaging). Additionally, after evaluating the current status of main exposure routes and affecting factors in the field of MOFs-toxicity, the molecular mechanism is also clarified and identified. Knowledge gaps are identified from such a summarization and frontier development are explored for MOFs. Afterwards, we also present the limitations, challenges, and future perspectives in the study of the entire life cycle of MOFs. This review emphasizes the need for a more targeted discussion of the latest, widely used and effective versatile material class in order to exploit the full potential of high-performance and non-toxicity MOFs in the future.

Environmental implications of metal-organic frameworks and MXenes in biomedical applications: a perspective

Metal-organic frameworks (MOFs) and MXenes have demonstrated immense potential for biomedical applications, offering a plethora of advantages. MXenes, in particular, exhibit robust mechanical strength, hydrophilicity, large surface areas, significant light absorption potential, and tunable surface terminations, among other remarkable characteristics. Meanwhile, MOFs possess high porosity and large surface area, making them ideal for protecting active biomolecules and serving as carriers for drug delivery, hence their extensive study in the field of biomedicine. However, akin to other (nano)materials, concerns regarding their environmental implications persist. The number of studies investigating the toxicity and biocompatibility of MXenes and MOFs is growing, albeit further systematic research is needed to thoroughly understand their biosafety issues and biological effects prior to clinical trials. The synthesis of MXenes often involves the use of strong acids and high temperatures, which, if not properly managed, can have adverse effects on the environment. Efforts should be made to minimize the release of harmful byproducts and ensure proper waste management during the production process. In addition, it is crucial to assess the potential release of MXenes into the environment during their use in biomedical applications. For the biomedical applications of MOFs, several challenges exist. These include high fabrication costs, poor selectivity, low capacity, the quest for stable and water-resistant MOFs, as well as difficulties in recycling/regeneration and maintaining chemical/thermal/mechanical stability. Thus, careful consideration of the biosafety issues associated with their fabrication and utilization is vital. In addition to the synthesis and manufacturing processes, the ultimate utilization and fate of MOFs and MXenes in biomedical applications must be taken into account. While numerous reviews have been published regarding the biomedical applications of MOFs and MXenes, this perspective aims to shed light on the key environmental implications and biosafety issues, urging researchers to conduct further research in this field. Thus, the crucial aspects of the environmental implications and biosafety of MOFs and MXenes in biomedicine are thoroughly discussed, focusing on the main challenges and outlining future directions.

An Fe-organic framework/arginine-glycine-aspartate peptide-modified sensor for electrochemically detecting nitric oxide released from living cells

Nitric oxide (NO) is a crucial cell-signaling molecule utilized in numerous physiological and pathological processes. Monitoring cellular levels of NO requires a sensor with sufficient sensitivity, transient recording capability, and biocompatibility. Owing to the large surface area and high catalytic activity of the metal-organic framework, Fe-BTC was used for the modification of screen-printed electrodes (SPEs). This study investigates the electrochemical sensing of NO on modified SPEs. Additionally, the introduction of a cell-adhesive molecule, arginine-glycine-aspartate peptide (RGD), considerably improved the cytocompatibility, resulting in superior cell attachment and growth on the SPE. The Fe-BTC/RGD-modified SPE (Fe-BTC/RGD/SPE) exhibited electrocatalytic NO oxidation at 0.8 V, demonstrating a linear response with a detection limit of 11.88 nM over a wide concentration range (0.17-47.37 μM) and a response time of approximately 0.9 s. Subsequently, the as-obtained Fe-BTC/RGD/SPE was successfully utilized for the real-time detection of NO released from human endothelial cells cultured on the electrode. Therefore, the study undertaken shows remarkable potential of Fe-BTC/RGD/SPE for practical applications in biological processes and clinical diagnostics.

Mitigating Metal-Organic Framework (MOF) Toxicity for Biomedical Applications

Metal-organic frameworks (MOFs) are a novel class of crystalline porous materials, consisting of metal ions and organic linkers. These hybrid materials possess exceptional porosity and specific surface area, which have recently garnered significant interest due to their potential applications in gas separation and storage, energy storage, biomedical imaging, and drug delivery. As MOFs are being explored for biomedical applications, it is essential to comprehensively assess their toxicity. Although nearly ninety thousand MOFs have been investigated, evaluating and optimizing their physico-chemical properties in relevant biological systems remain critical for their clinical translation. In this review article, we first provide a brief classification of MOFs based on their chemical structures. We then conduct a comprehensive evaluation of in vitro and in vivo studies that assess the biocompatibility of MOFs. Additionally, we discuss various approaches to mitigate the critical factors associated with MOF toxicity. To this end, the effects of chemistry, particle size, morphology, and particle aggregation are examined. To better understand MOFs' potential toxicity to living organisms, we also delve into the toxicity mechanisms of nanoparticles (NPs). Furthermore, we introduce and evaluate strategies such as surface modification to reduce the inherent toxicity of MOFs. Finally, we discuss current challenges, the path to clinical trials, and new research directions.

Metal-organic frameworks functionalized biomaterials for promoting bone repair

Bone defects induced by bone trauma, tumors and osteoarthritis greatly affect the life quality and health of patients. The biomaterials with numerous advantages are becoming the most preferred options for repairing bone defects and treating orthopedic diseases. However, their repairing effects remains unsatisfactory, especially in bone defects suffering from tumor, inflammation, and/or bacterial infection. There are several strategies to functionalize biomaterials, but a more general and efficient method is essential for accomplishing the functionalization of biomaterials. Possessing high specific surface, high porosity, controlled degradability and variable composition, metal-organic frameworks (MOFs) materials are inherently advantageous for functionalizing biomaterials, with tremendous improvements having been achieved. This review summarizes recent progresses in MOFs functionalized biomaterials for promoting bone repair and therapeutic effects. In specific, by utilizing various properties of diverse MOFs materials, integrated MOFs functionalized biomaterials achieve enhanced bone regeneration, antibacterial, anti-inflammatory and anti-tumor functions. Finally, the summary and prospects of on the development of MOFs-functionalized biomaterials for promoting bone repair were discussed.

Nanodrug constructed using dietary antioxidants for immunotherapy of metastatic tumors

Immunogenic cell death (ICD) induced by reactive oxygen species (ROS) represents a particular form of tumor cell death for approaching the problem of low immunogenicity of tumors in immunotherapy, while the oxidative damage to normal cells of current ICD inducers hinders their clinical application. Herein, a new ICD inducer VC@cLAV constructed solely by dietary antioxidants, lipoic acid (LA) and vitamin C (VC), is developed, which could promote heavy intracellular ROS production in cancer cells for ICD induction while acting as an anti-oxidant in non-cancer cells for cytoprotection, and thus hold high biosafety. In vitro studies show that VC@cLAV induced a release of antigens and a maturation rate of DCs up to 56.5%, approaching the positive control (58.4%). In vivo combined with αPD-1, VC@cLAV showed excellent antitumor activity against both primary and distant metastatic tumors with an inhibition rate of 84.8% and 79.0% compared to 14.2% and 10.0% in the αPD-1 alone group. Notably, VC@cLAV established a long-term antitumor immune memory effect against tumor rechallenging. This study not only presents a new kind of ICD inducer but also provides an impetus for the development of dietary antioxidant-based cancer drugs.