Validating Metal-Organic Framework Nanoparticles for Their Nanosafety in Diverse Biomedical Applications

Autonomous humidity regulation by MOF/wood composites

Maintaining indoor air relative humidity (R.H.) within the 40-60% range recommended by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) significantly impacts human comfort and health. However, conventional solutions like dehumidifiers and humidifiers increase energy consumption, challenging the building sector's carbon neutrality goals. Here, we present an innovative composite material comprising wood and metal-organic frameworks (MOFs) that passively regulates indoor humidity by absorbing and releasing moisture. Our universal fabrication strategy enhances wood scaffold accessibility and increases MOF loading, resulting in a significant surface area increase, surpassing previous MOF/wood composites. This MOF/wood composite exhibits remarkable water sorption capacity, autonomously maintaining indoor humidity around 45% R.H. without external energy consumption. This aligns with ASHRAE recommendations, offering indirect energy savings and promoting a health-friendly indoor environment. Furthermore, the MOF/wood composite outperforms many existing materials in mechanical strength, dimensional stability, and scalability, making it highly suitable for building applications and contributing to carbon neutrality in the building sector.

Construction of a Multifunctional Upconversion Nanoplatform Based on Autophagy Inhibition and Photodynamic Therapy Combined with Chemotherapy for Antitumor Therapy

Inhibition of autophagy increases the sensitivity of tumor cells to radiotherapy and chemotherapy and improves the therapeutic effect on tumors. Recently, photodynamic therapy (PDT) combined with chemotherapy has been proven to further improve the efficiency of cancer treatment. As such, combining autophagy inhibition with PDT and chemotherapy may represent a potentially effective new strategy for cancer treatment. However, currently widely studied autophagy inhibitors inevitably produce various toxic side effects due to their inherent pharmacological activity. To overcome this constraint, in this study, we designed an ideal multifunctional upconversion nanoplatform, UCNP-Ce6-EPI@mPPA + NIR (MUCEN). Control, UCNP-EPI@mPPA (MUE), UCNP-EPI@mPPA + NIR (MUEN), Ce6-EPI@mPPA (MCE), Ce6-EPI@mPPA + NIR (MCEN), and UCNP-Ce6-EPI@mPPA (MUCE) groups were set up separately as controls. Based on a combination of autophagy inhibition and PDT, the average particle size of MUCEN was 197 nm, which can simultaneously achieve the double encapsulation of chlorine e6 (Ce6) and epirubicin (EPI). In vitro tests revealed that MUCE was efficiently endocytosed by 4T1 cells under near-infrared light irradiation. Further, in vivo tests revealed that MUCE dramatically inhibited tumor growth. Immunohistochemistry results indicated that MUCE efficiently increased the expression of autophagy inhibitors p62 and LC3 in tumor tissues. The synergistic effect of autophagy inhibition and PDT with MUCE exhibited superior tumor suppression, providing an innovative approach to cancer treatment.

In vivo safety evaluation method for nanomaterials for cancer therapy

Nanomaterials are extensively used in the diagnosis and treatment of cancer and other diseases because of their distinctive physicochemical properties, including the small size and ease of modification. The approval of numerous nanomaterials for clinical treatment has led to a significant increase in human exposure to these materials. When nanomaterials enter organisms, they interact with DNA, cells, tissues, and organs, potentially causing various adverse effects, such as genotoxicity, reproductive toxicity, immunotoxicity, and damage to tissues and organs. Therefore, it is crucial to elucidate the side effects and toxicity mechanisms of nanomaterials thoroughly before their clinical applications. Although methods for in vitro safety evaluation of nanomaterials are well established, systematic methods for in vivo safety evaluation are still lacking. This review focuses on the in vivo safety evaluation of nanomaterials and explores their potential effects. In addition, the experimental methods for assessing such effects in various disciplines, including toxicology, pharmacology, physiopathology, immunology, and bioinformatics are also discussed.

Advances in the Optimization of Fe Nanoparticles: Unlocking Antifungal Properties for Biomedical Applications

In recent years, nanotechnology has achieved a remarkable status in shaping the future of biological applications, especially in combating fungal diseases. Owing to excellence in nanotechnology, iron nanoparticles (Fe NPs) have gained enormous attention in recent years. In this review, we have provided a comprehensive overview of Fe NPs covering key synthesis approaches and underlying working principles, the factors that influence their properties, essential characterization techniques, and the optimization of their antifungal potential. In addition, the diverse kinds of Fe NP delivery platforms that command highly effective release, with fewer toxic effects on patients, are of great significance in the medical field. The issues of biocompatibility, toxicity profiles, and applications of optimized Fe NPs in the field of biomedicine have also been described because these are the most significant factors determining their inclusion in clinical use. Besides this, the difficulties and regulations that exist in the transition from laboratory to experimental clinical studies (toxicity, specific standards, and safety concerns) of Fe NPs-based antifungal agents have been also summarized.

Nanocomposites Based on Magnetic Nanoparticles and Metal-Organic Frameworks for Therapy, Diagnosis, and Theragnostics

In the last two decades, metal-organic frameworks (MOFs) with highly tunable structure and porosity, have emerged as drug nanocarriers in the biomedical field. In particular, nanoscaled MOFs (nanoMOFs) have been widely investigated because of their potential biocompatibility, high drug loadings, and progressive release. To enhance their properties, MOFs have been combined with magnetic nanoparticles (MNPs) to form magnetic nanocomposites (MNP@MOF) with additional functionalities. Due to the magnetic properties of the MNPs, their presence in the nanosystems enables potential combinatorial magnetic targeted therapy and diagnosis. In this Review, we analyze the four main synthetic strategies currently employed for the fabrication of MNP@MOF nanocomposites, namely, mixing, in situ formation of MNPs in presynthesized MOF, in situ formation of MOFs in the presence of MNPs, and layer-by-layer methods. Additionally, we discuss the current progress in bioapplications, focusing on drug delivery systems (DDSs), magnetic resonance imaging (MRI), magnetic hyperthermia (MHT), and theragnostic systems. Overall, we provide a comprehensive overview of the recent advances in the development and bioapplications of MNP@MOF nanocomposites, highlighting their potential for future biomedical applications with a critical analysis of the challenges and limitations of these nanocomposites in terms of their synthesis, characterization, biocompatibility, and applicability.

Advanced Characterization Methodology to Unravel the Biodegradability of Metal-Organic Framework Nanoparticles in Extremely Diluted Conditions

Porous iron(III) carboxylate metal-organic frameworks (MIL-100; MIL stands for Material of Institute Lavoisier) of submicronic size (nanoMOFs) have attracted a growing interest in the field of drug delivery due to their high drug payloads, excellent entrapment efficiencies, biodegradable character, and poor toxicity. However, only a few studies have dealt with the nanoMOF degradation mechanism, which is key to their biological applications. Complementary methods have been used here to investigate the degradation mechanism of Fe-based nanoMOFs under neutral or acidic conditions and in the presence of albumin. High-resolution STEM-HAADF coupled with energy-dispersive X-ray spectroscopy enabled the monitoring of the crystalline organization and elemental distribution during degradation. NanoMOFs were also deposited onto silicon substrates by dip-coating, forming stable thin films of high optical quality. The mean film thickness and structural changes were further monitored by IR ellipsometry, approaching the "sink conditions" occurring in vivo. This approach is essential for the successful design of biocompatible nano-vectors under extreme diluted conditions. It was revealed that while the presence of a protein coating layer did not impede the degradation process, the pH of the medium in contact with the nanoMOFs played a major role. The degradation of nanoMOFs occurred to a larger extent under neutral conditions, rapidly and homogeneously within the crystalline matrices, and was associated with the departure of their constitutive organic ligand. Remarkably, the nanoMOFs' particles maintained their global morphology during degradation.

A Versatile Shaping Method of Very-High Loading Porous Solids Paper Adsorbent Composites

Owing to their high porosity and tunability, porous solids such as metal-organic frameworks (MOFs), zeolites, or activated carbons (ACs) are of great interest in the fields of air purification, gas separation, and catalysis, among others. Nonetheless, these materials are usually synthetized as powders and need to be shaped in a more practical way that does not modify their intrinsic property (i.e., porosity). Elaborating porous, freestanding and flexible sheets is a relevant shaping strategy. However, when high loadings (>70 wt.%) are achieved the mechanical properties are challenged. A new straightforward and green method involving the combination softwood bleached kraft pulp fibers (S) and nano-fibrillated cellulose (NFC) is reported, where S provides flexibility while NFC acts as a micro-structuring and mechanical reinforcement agent to form high loadings porous solids paper sheets (>70 wt.%). The composite has unobstructed porosity and good mechanical strength. The sheets prepared with various fillers (MOFs, ACs, and zeolites) can be rolled, handled, and adapted to different uses, such as air purification. As an example of potential application, a MOF paper composite has been considered for the capture of polar volatile organic compounds exhibiting better performance than beads and granules.

Glycyrrhetinic Acid Receptor-Mediated Zeolitic Imidazolate Framework-8 Loaded Doxorubicin as a Nanotherapeutic System for Liver Cancer Treatment

In this study, we designed and developed a DOX nanodrug delivery system (PEG-GA@ZIF-8@DOX) using ZIF-8 as the carrier and glycyrrhetinic acid (GA) as the targeting ligand. We confirmed that DOX was loaded and PEG-GA was successfully modified on the surface of the nanoparticles. The in vitro release profile of the system was investigated at pH 5.0 and 7.4. The cellular uptake, in vitro cytotoxicity, and lysosomal escape characteristics were examined using HepG2 cells. We established an H22 tumor-bearing mouse model and evaluated the in vivo antitumor activity. The results showed that the system had a uniform nanomorphology. The drug loading capacity was 11.22 ± 0.87%. In acidic conditions (pH 5.0), the final release rate of DOX was 57.73%, while at pH 7.4, it was 25.12%. GA-mediated targeting facilitated the uptake of DOX by the HepG2 cells. PEG-GA@ZIF-8@DOX could escape from the lysosomes and release the drug in the cytoplasm, thus exerting its antitumor effect. When the in vivo efficacy was analyzed, we found that the tumor inhibition rate of PEG-GA@ZIF-8@DOX was 67.64%; it also alleviated the loss of the body weight of the treated mice. This drug delivery system significantly enhanced the antitumor effect of doxorubicin in vitro and in vivo, while mitigating its toxic side effects.

Nanoparticles based on MIL-101 metal-organic frameworks as efficient carriers of therapeutic188Re radionuclide for nuclear medicine

Nuclear medicine presents one of the most promising modalities for efficient non-invasive treatment of a variety of cancers, but the application of radionuclides in cancer therapy and diagnostics is severely limited by their nonspecific tissue accumulation and poor biocompatibility. Here, we explore the use of nanosized metal-organic frameworks (MOFs) as carriers of radionuclides to order to improve their delivery to tumour. To demonstrate the concept, we prepared polymer-coated MIL-101(Cr)-NH2MOFs and conjugated them with clinically utilized radionuclide188Re. The nanoparticles demonstrated high loading efficacy of radionuclide reaching specific activity of 49 MBq mg-1. Pharmacokinetics of loaded MOFs was investigated in mice bearing colon adenocarcinoma. The biological half-life of the radionuclide in blood was (20.9 ± 1.3) h, and nanoparticles enabled it to passively accumulate and retain in the tumour. The radionuclide delivery with MOFs led to a significant decrease of radioactivity uptake by the thyroid gland and stomach as compared with perrhenate salt injection, which is beneficial for reducing the side toxicity of nuclear therapy. The reported data on the functionalization and pharmacokinetics of MIL-101(Cr)-NH2for radionuclide delivery unveils the promising potential of these MOFs for nuclear medicine.

Recent advances in surface-mounted metal-organic framework thin film coatings for biomaterials and medical applications: a review

Coatings of metal-organic frameworks (MOFs) have potential applications in surface modification for medical implants, tissue engineering, and drug delivery systems. Therefore, developing an applicable method for surface-mounted MOF engineering to fabricate protective coating for implant tissue engineering is a crucial issue. Besides, the coating process was desgined for drug infusion and effect opposing chemical and mechanical resistance. In the present review, we discuss the techniques of MOF coatings for medical application in both in vitro and in vivo in various systems such as in situ growth of MOFs, dip coating of MOFs, spin coating of MOFs, Layer-by-layer methods, spray coating of MOFs, gas phase deposition of MOFs, electrochemical deposition of MOFs. The current study investigates the modification in the implant surface to change the properties of the alloy surface by MOF to improve properties such as reduction of the biofilm adhesion, prevention of infection, improvement of drugs and ions rate release, and corrosion resistance. MOF coatings on the surface of alloys can be considered as an opportunity or a restriction. The presence of MOF coatings in the outer layer of alloys would significantly demonstrate the biological, chemical and mechanical effects. Additionally, the impact of MOF properties and specific interactions with the surface of alloys on the anti-microbial resistance, anti-corrosion, and self-healing of MOF coatings are reported. Thus, the importance of multifunctional methods to improve the adhesion of alloy surfaces, microbial and corrosion resistance and prospects are summarized.

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.

Functional MOF-Based Materials for Environmental and Biomedical Applications: A Critical Review

Over the last ten years, there has been a growing interest in metal-organic frameworks (MOFs), which are a unique category of porous materials that combine organic and inorganic components. MOFs have garnered significant attention due to their highly favorable characteristics, such as environmentally friendly nature, enhanced surface area and pore volume, hierarchical arrangements, and adjustable properties, as well as their versatile applications in fields such as chemical engineering, materials science, and the environmental and biomedical sectors. This article centers on examining the advancements in using MOFs for environmental remediation purposes. Additionally, it discusses the latest developments in employing MOFs as potential tools for disease diagnosis and drug delivery across various ailments, including cancer, diabetes, neurological disorders, and ocular diseases. Firstly, a concise overview of MOF evolution and the synthetic techniques employed for creating MOFs are provided, presenting their advantages and limitations. Subsequently, the challenges, potential avenues, and perspectives for future advancements in the utilization of MOFs in the respective application domains are addressed. Lastly, a comprehensive comparison of the materials presently employed in these applications is conducted.

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.

Induction of cytotoxic effects and changes in DNA methylation-related gene expression in a human fibroblast cell line by the metal-organic framework [H2NMe2]3 [Tb(III)(2,6 pyridinedicarboxylate)3] (Tb-MOF)

Lanthanide metal-organic frameworks (lanthanide MOFs) may be utilized for a variety of environmental and human health applications due to their luminescent properties and high thermal and water stability. However, the cytotoxic and epigenetic effects produced in human cells are not known. Therefore, we evaluated the cytotoxic effects, internalization, and changes in the mRNA abundance of DNA methylation and demethylation enzymes by exposing human fibroblast cells to a metal-organic framework [H₂NMe₂]₃ [Tb(III)(2,6 pyridinedicarboxylate)₃] (Tb-MOF). For this purpose, the cells were exposed to six concentrations (0.05 to 1.6 mg/mL) of Tb-MOF for 48 h. Field emission electron microscopy coupled to linear energy dispersive spectroscopy (FESEM‒EDS) and confocal microscopy analysis were performed. The cytotoxicity was determined with crystal violet and MTT assays. The results demonstrated the internalization of Tb-MOF at concentrations as low as 0.05 mg/mL, as well as concentration-dependent toxicity. Additionally, we detected significant changes in the gene expression levels of DNA methyltransferases and demethylases due to the presence of Tb-MOF, suggesting that Tb-MOF could generate epigenetic changes even at low concentrations. The results of our study may establish a foundation for future research attempting to develop and apply secure nanomaterials (e.g., MOFs) to minimize damage to the environment and human health.

Nanoscale Iron-Based Metal-Organic Frameworks: Incorporation of Functionalized Drugs and Degradation in Biological Media

Metal-organic frameworks (MOFs) attract growing interest in biomedical applications. Among thousands of MOF structures, the mesoporous iron(III) carboxylate MIL-100(Fe) (MIL stands for the Materials of Lavoisier Institute) is among the most studied MOF nanocarrier, owing to its high porosity, biodegradability, and lack of toxicity. Nanosized MIL-100(Fe) particles (nanoMOFs) readily coordinate with drugs leading to unprecedented payloads and controlled release. Here, we show how the functional groups of the challenging anticancer drug prednisolone influence their interactions with the nanoMOFs and their release in various media. Molecular modeling enabled predicting the strength of interactions between prednisolone-bearing or not phosphate or sulfate moieties (PP and PS, respectively) and the oxo-trimer of MIL-100(Fe) as well as understanding the pore filling of MIL-100(Fe). Noticeably, PP showed the strongest interactions (drug loading up to 30 wt %, encapsulation efficiency > 98%) and slowed down the nanoMOFs' degradation in simulated body fluid. This drug was shown to bind to the iron Lewis acid sites and was not displaced by other ions in the suspension media. On the contrary, PS was entrapped with lower efficiencies and was easily displaced by phosphates in the release media. Noticeably, the nanoMOFs maintained their size and faceted structures after drug loading and even after degradation in blood or serum after losing almost the totality of the constitutive trimesate ligands. Scanning electron microscopy with high annular dark field (STEM-HAADF) in conjunction with X-Ray energy-dispersive spectrometry (XEDS) was a powerful tool enabling the unraveling of the main elements to gain insights on the MOF structural evolution after drug loading and/or upon degradation.

Internalization of the Metal-Organic Framework MIL-101(Cr)-NH2 by a Freshwater Alga and Transfer to Zooplankton

The common metal-organic framework (MOF) MIL-101(Cr)-NH₂ has attracted considerable attention due to its great potential applications in the environmental field. Nevertheless, its behavior and fate in aquatic systems are unknown. This study quantified and visualized the interactions of MIL-101(Cr)-NH₂ with the freshwater phytoplanktonic alga Chlamydomonas reinhardtii and its potential trophic transfer to zooplankton. The unicellular alga absorbed and accumulated the MOF by surface attachment, forming agglomerates and eventually cosettling out from water. Bioimaging revealed that MIL-101(Cr)-NH₂ was internalized by the algal cells and mainly occurred in the pyrenoid. Without algae in a freshwater system, MIL-101(Cr)-NH₂ was ingested by Daphnia magna, showing steadily increasing concentrations approaching 1-9% of dry body weight. Addition of algae substantially suppressed D. magna uptake of MIL-101(Cr)-NH₂ by 63.8-97.9%. Such inhibition could be explained by the competitive uptake of MOF by the algae and the inductive effects of algal food on MOF elimination by D. magna. The MOF (≤1 mg/L) ingested by D. magna was centered in the gut regions, whereas large MOF or algae-MOF aggregates were adsorbed onto the carapace and appendages, including the antennae, at 10 mg/L. Overall, the algae were the major targets for MIL-101(Cr)-NH₂, with nearly all algal cells settling out at 10 mg/L within 24 h. The possibility of trophic transfer of MIL-101(Cr)-NH₂ to D. magna in aquatic systems with algae present was limited due to its low accumulation potential and short retention time in D. magna.

Exploring the Physicochemical, Electroactive, and Biodelivery Properties of Metal Nanoparticles on Peripheral Nerve Regeneration

Despite the advances in the regeneration/rehabilitation field of damaged tissues, the functional recovery of peripheral nerves (PNs), especially in a long gap injury, is considered a great medical challenge. Recent progress in nanomedicine has provided great hope for PN regeneration through the strategy of controlling cell behavior by metal nanoparticles individually or loaded on scaffolds/conduits. Despite the confirmed toxicity of metal nanoparticles due to long-term accumulation in nontarget tissues, they play a role in the damaged PN regeneration based on the topography modification of scaffolds/conduits, enhancing neurotrophic factor secretion, the ion flow improvement, and the regulation of electrical signals. Determining the fate of neural progenitor cells would be a major achievement in PN regeneration, which seems to be achievable by metal nanoparticles through altering cell vital approaches and controlling their functions. Therefore, in this literature, an attempt was made to provide an overview of the effective activities of metal nanoparticles on the PN regeneration, until the vital clues of the PN regeneration and how they are changed by metal nanoparticles are revealed to the researcher.

A review of synthesis, fabrication, and emerging biomedical applications of metal-organic frameworks

The overwhelming potential of porous coordination polymers (PCP), also known as Metal-Organic Frameworks (MOFs), especially their nanostructures for various biomedical applications, have made these materials worth investigating for more applications and uses. MOFs unique structure has enabled them for most applications, particularly in biomedical and healthcare. A number of very informative review papers are available on the biomedical applications of MOFs for the reader's convenience. However, many of those reviews focus mainly on drug delivery applications, and no significant work has been reported on other MOFs for biomedical applications. This review aims to present a compact and highly informative global assessment of the recent developments in biomedical applications (excluding drug-delivery) of MOFs along with critical analysis. Researchers have recently adopted both synthetic and post-synthetic routes for the fabrication and modification of MOFs that have been discussed and analyzed. A critical review of the latest reports on the significant and exotic area of bio-sensing capabilities and applications of MOFs has been given in this study. In addition, other essential applications of MOFs, including photothermal therapy, photodynamic therapy, and antimicrobial activities, are also included. These recently grown emergent techniques and cancer treatment options have gained attention and require further investigations to achieve fruitful outcomes. MOF's role in these applications has been thoroughly discussed, along with future challenges and valuable suggestions for the research community that will help meet future demands.

Metal organic framework-based antibacterial agents and their underlying mechanisms

Bacteria, as the most abundant living organisms, have always been a threat to human life until the development of antibiotics. However, with the wide use of antibiotics over a long time, bacteria have gradually gained tolerance to antibiotics, further aggravating threat to human beings and environmental safety significantly. In recent decades, new bacteria-killing methods based on metal ions, hyperthermia, free radicals, physical pricks, and the coordination of several multi-mechanisms have attracted increasing attention. Consequently, multiple types of new antibacterial agents have been developed. Among them, metal organic frameworks (MOFs) appear to play an increasingly important role. The unique characteristics of MOFs make them suitable multiple-functional platforms. By selecting the appropriate metastable coordination bonds, MOFs can act as reservoirs and release antibacterial metal ions or organic linkers; by constructing a porous structure, MOFs can act as carriers for multiple types of agents and achieve slow and sustained release; and by designing their composition and the pore structure precisely, MOFs can be endowed with properties to produce heat and free radicals under stimulation. Importantly, in combination with other materials, MOFs can act as a platform to kill bacteria effectively through the synergistic effect of multiple types of mechanisms. In this review, we focus on the recent development of MOF-based antibacterial agents, which are classified according to their antibacterial mechanisms.

Self-Supply Oxygen ROS Reactor via Fenton-like Reaction and Modulating Glutathione for Amplified Cancer Therapy Effect

Reactive oxygen species (ROS) are highly reactive oxidant molecules that can kill cancer cells through irreversible damage to biomacromolecules. ROS-mediated cancer therapies, such as chemodynamic (CDT) and photodynamic therapy (PDT), are often limited by the hypoxia tumor microenvironment (TME) with high glutathione (GSH) level. This paper reported the preparation, characterization, in vitro and in vivo antitumor bioactivity of a meso-tetra(4-carboxyphenyl)porphine (TCPP)-based therapeutic nanoplatform (CMMFTP) to overcome the limitations of TME. Using Cu²⁺ as the central ion and TCPP as the ligand, the 2D metal-organic framework Cu-TCPP was synthesized by the solvothermal method, then CMMFTP was prepared by modifying MnO₂, folic acid (FA), triphenylphosphine (TPP), and poly (allylamine hydrochloride) (PAH) on the surface of Cu-TCPP MOFs. CMMFTP was designed as a self-oxygenating ROS nanoreactor based on the PDT process of TCPP MOFs and the CDT process by Cu(II) and MnO₂ components (mainly through Fenton-like reaction). The in vitro assay suggested CMMFTP caused a 96% lethality rate against Hela cells (MTT analysis) in specific response to TME stimulation. Moreover, the Cu(II) and MnO₂ in CMMFTP efficiently depleted the glutathione (80%) in tumor cells and consequently amplified ROS levels to improve CDT/PDT effects. The FA-induced tumor targeting and TPP-induced mitochondria targeting further enhanced the antitumor activity. Therefore, the nanoreactor based on dual targeting and self-oxygenation-enhanced ROS mechanism provided a new strategy for cancer therapy.

Recent advances in porous nanomaterials-based drug delivery systems for cancer immunotherapy

Cancer immunotherapy is a novel therapeutic regimen because of the specificity and durability of immune modulations to treat cancers. Current cancer immunotherapy is limited by some barriers such as poor response rate, low tumor specificity and systemic toxicities. Porous nanomaterials (PNMs) possess high loading capacity and tunable porosity, receiving intense attention in cancer immunotherapy. Recently, novel PNMs based drug delivery systems have been employed in antitumor immunotherapy to enhance tissue or organ targeting and reduce immune-related adverse events. Herein, we summarize the recent progress of PNMs including inorganic, organic, and organic–inorganic hybrid ones for cancer immunotherapy. The design of PNMs and their performance in cancer immunotherapy are discussed in detail, with a focus on how those designs can address the challenges in current conventional immunotherapy. Lastly, we present future directions of PNMs for cancer immunotherapy including the challenges and research gaps, providing new insights about the design of PNMs for efficient cancer immunotherapy with better performance as powerful weapons against tumors. Finally, we discussed the relevant challenges that urgently need to be addressed in clinical practice, coupled with corresponding solutions to these problems.

Explaining chemical clues of metal organic framework-nanozyme nano-/micro-motors in targeted treatment of cancers: benchmarks and challenges

Nowadays, nano-/micro-motors are considered as powerful tools in different areas ranging from cleaning all types of contaminants, to development of Targeted drug delivery systems and diagnostic activities. Therefore, the development and application of nano-/micro-motors based on metal-organic frameworks with nanozyme activity (abbreviated as: MOF-NZs) in biomedical activities have received much interest recently. Therefore, after investigating the catalytic properties and applications of MOF-NZs in the treatment of cancer, this study intends to point out their key role in the production of biocompatible nano-/micro-motors. Since reducing the toxicity of MOF-NZ nano-/micro-motors can pave the way for medical activities, this article examines the methods of making biocompatible nanomotors to address the benefits and drawbacks of the required propellants. In the following, an analysis of the amplified directional motion of MOF-NZ nano-/micro-motors under physiological conditions is presented, which can improve the motor behaviors in the propulsion function, conductivity, targeting, drug release, and possible elimination. Meanwhile, by explaining the use of MOF-NZ nano-/micro-motors in the treatment of cancer through the possible synergy of nanomotors with different therapies, it was revealed that MOF-NZ nano-/micro-motors can be effective in the treatment of cancer. Ultimately, by analyzing the potential challenges of MOF-NZ nano-/micro-motors in the treatment of cancers, we hope to encourage researchers to develop MOF-NZs-based nanomotors, in addition to opening up new ideas to address ongoing problems.

Toxicity of metal-organic framework nanoparticles: from essential analyses to potential applications

In the last two decades, the field of metal-organic frameworks (MOFs) has exploded, and MOF nanoparticles in particular are being investigated with increasing interest for various applications, including gas storage and separation, water harvesting, catalysis, energy conversion and storage, sensing, diagnosis, therapy, and theranostics. To further pave their way into real-world applications, and to push the synthesis of MOF nanoparticles that are 'safe-and-sustainable-by-design', this tutorial review aims to shed light on the importance of a systematic toxicity assessment. After clarifying and working out the most important terms and aspects from the field of nanotoxicity, the current state-of-the-art of in vitro and in vivo toxicity studies of MOF nanoparticles is evaluated. Moreover, the key aspects affecting the toxicity of MOF nanoparticles such as their chemical composition, their physico-chemical properties, including their colloidal and chemical stability, are discussed. We highlight the need of more targeted synthesis of MOF nanoparticles that are 'safe-and-sustainable-by-design', and their tailored hazard assessment in the context of their potential applications in order to tap the full potential of this versatile material class in the future.

Advances in antitumor nanomedicine based on functional metal-organic frameworks beyond drug carriers

Nanoscale metal-organic frameworks (MOFs) have attracted widespread interest due to their unique properties including a tunable porous structure, high drug loading capacity, structural diversity, and outstanding biocompatibility. MOFs have been extensively explored as drug nanocarriers in biotherapeutics. However, by harnessing the functionality of ligands and metal ions or clusters in MOFs, the applications of MOFs can be extended beyond drug delivery vehicles. Based on the intrinsic properties of the components of MOFs (e.g. magnetic moments of metal ions and fluorescence of ligands), different imaging modes can be achieved with varied MOFs. With careful design of the composition of MOFs (e.g. modification of organic linkers), they can respond to tumor microenvironments to realize on-demand treatment. By incorporating porphyrin-based ligands (photosensitizers for photodynamic therapy) or high-Z metal ions (radiosensitizers for radiotherapy) into the scaffold of MOFs, MOFs themselves can act as anticancer therapeutic agents. In this review, we highlight the application of MOFs from the above-mentioned aspects and discuss the prospects and challenges for using MOFs in stimuli-responsive imaging-guided antitumor therapy.

Biomedical Applications of Metal-Organic Frameworks for Disease Diagnosis and Drug Delivery: A Review

Metal-organic frameworks (MOFs) are a novel class of porous hybrid organic-inorganic materials that have attracted increasing attention over the past decade. MOFs can be used in chemical engineering, materials science, and chemistry applications. Recently, these structures have been thoroughly studied as promising platforms for biomedical applications. Due to their unique physical and chemical properties, they are regarded as promising candidates for disease diagnosis and drug delivery. Their well-defined structure, high porosity, tunable frameworks, wide range of pore shapes, ultrahigh surface area, relatively low toxicity, and easy chemical functionalization have made them the focus of extensive research. This review highlights the up-to-date progress of MOFs as potential platforms for disease diagnosis and drug delivery for a wide range of diseases such as cancer, diabetes, neurological disorders, and ocular diseases. A brief description of the synthesis methods of MOFs is first presented. Various examples of MOF-based sensors and DDSs are introduced for the different diseases. Finally, the challenges and perspectives are discussed to provide context for the future development of MOFs as efficient platforms for disease diagnosis and drug delivery systems.

Prospects of Exploring the Metal-Organic Framework for Combating Antimicrobial Resistance

Infectious diseases are a major public health concern globally. Infections caused by pathogens with resistance against commonly used antimicrobial drugs or antibiotics (known as antimicrobial resistance, AMR) are becoming extremely difficult to control. AMR has thus been declared as one of the top 10 global public health threats, as it has very limited solutions. The drying pipeline of effective antibiotics has further worsened the situation. There is no absolute treatment, and the limitations of existing methods warrant further development in antimicrobials. Recent developments in the nanomaterial field present them as promising therapeutics and effective alternative to conventional antibiotics and synthetic drugs. The metal-organic framework (MOF) is a recent addition to the antimicrobial category with superior properties. The MOF exerts antimicrobial action on a wide range of species and is highly biocompatible. Additionally, their porous structures allow the incorporation of biomolecules and drugs for synergistic antimicrobial action. This review provides an inclusive summary of the molecular events responsible for resistance development and current trends in antimicrobials to combat antibiotic resistance and explores the potential role of the MOF in tackling the drug-resistant microbial species.

Heparin-Coated Photosensitive Metal-Organic Frameworks as Drug Delivery Nanoplatforms of Autophagy Inhibitors for Sensitized Photodynamic Therapy against Breast Cancer

Photosensitive nanosized metal-organic frameworks (nanoMOFs) with a tunable structure and high porosity have been developed recently as nanophotosensitizers (nanoPSs) for photodynamic therapy (PDT). However, the effect of photodynamic therapy is greatly limited by the fast blood clearance and poor tumor retention of the ordinary nanoPSs. Besides, autophagy, a prosurvival self-cannibalization pathway mediated by autolysosomes, was elevated by cytotoxic reactive oxygen species (ROS) produced during PDT. Herein, a chloroquine phosphate (CQ)-loaded photosensitive nanoMOF coated by heparin was fabricated for sensitized PDT by increasing the tumor accumulation of nanoPSs and abolishing the self-protective autophagy within cancer cells. After internalization by cancer cells, the encapsulated CQ alkalizes autolysosomes and blocks the postautophagy process, which disarm the vigilant cancer cells irritated by PDT and finally enhance the therapeutic effect. Furthermore, the accompanied antiangiogenesis ability of the heparin coat also helps improve the cancer therapy outcomes. This study would open up new horizons for building heparin-coated nanoMOFs and understanding the role of autophagy in cancer therapy.

Nanoscale covalent organic frameworks: from controlled synthesis to cancer therapy

Covalent organic frameworks (COFs), as a new type of crystalline porous materials, mainly consist of light-weight elements (H, B, C, N and O) linked by dynamic covalent bonds to form periodical structures of two or three dimensions. As an attribute of their low density, large surface area, and excellent adjustable pore size, COFs show great potential in many fields including energy storage and separation, catalysis, sensing, and biomedicine. However, compared with metal organic frameworks (MOFs), the relatively large size and irregular morphology of COFs affect their biocompatibility and bioavailability in vivo, thus impeding their further biomedical applications. This Review focuses on the controlled design strategies of nanoscale COFs (NCOFs), unique properties of NCOFs for biomedical applications, and recent progress in NCOFs for cancer therapy. In addition, current challenges for the biomedical use of NCOFs and perspectives for further improvements are presented.

Grafting of Gd-DTPA onto MOF-808 to enhance MRI performance for guiding photothermal therapy

Gd(III) chelates are important T₁-weighted contrast agents used in clinical magnetic resonance imaging (MRI), but their low longitudinal relaxivity (r₁) results in limited imaging efficiency. In this study, we utilize a geometric confinement strategy to restrict a Gd chelate (Gd-DTPA) within the channels of a porous metal-organic framework material (MOF-808) for increasing its r₁ relaxivity. Moreover, the Gd-DTPA-grafted MOF-808 nanoparticles were further surface modified with polyaniline (PANI) to construct an MRI-guided photothermal therapy platform. The resulting Gd-DTPA-MOF-808@PANI shows a high r₁ relaxivity of 30.1 mM^-1 s^-1 (0.5 T), which is 5.4 times higher than that of the commercial contrast agent Magnevist. In vivo experiments revealed that Gd-DTPA-MOF-808@PANI has good T₁-weighted contrast performance and can effectively guide photothermal ablation of tumors upon 808 nm laser irradiation. This work may shed some light on the design and preparation of high relaxation rate Gd-based contrast agents for theranostic application via utilization of versatile MOF materials.

Environment Responsive Metal-Organic Frameworks as Drug Delivery System for Tumor Therapy

Nanoparticles as drug delivery systems can alter the drugs' hydrophilicity to affect drug uptake and efflux in tissues. They prevent drugs from non-specifically binding with bio-macromolecules and enhance drug accumulation at the lesion sites, improving therapy effects and reducing unnecessary side effects. Metal-organic frameworks (MOFs), the typical nanoparticles, a class of crystalline porous materials via self-assembled organic linkers and metal ions, exhibit excellent biodegradability, pore shape and sizes, and finely tunable chemical composition. MOFs have a rigid molecular structure, and tunable pore size can improve the encapsulation drug's stability under harsh conditions. Besides, the surface of MOFs can be modified with small-molecule ligands and biomolecule, and binding with the biomarkers which is overexpressed on the surface of cancer cells. MOFs formulations for therapeutic have been developed to effectively respond to the unique tumor microenvironment (TEM), such as high H2O2 levels, hypoxia, and high concentration glutathione (GSH). Thus, MOFs as a drug delivery system should avoid drugs leaking during blood circulation and releasing at the lesion sites via a controlling manner. In this article, we will summary environment responsive MOFs as drug delivery systems for tumor therapy under different stimuli.

Metal-organic frameworks for advanced drug delivery

Metal-organic frameworks (MOFs), comprised of organic ligands and metal ions/metal clusters via coordinative bonds are highly porous, crystalline materials. Their tunable porosity, chemical composition, size and shape, and easy surface functionalization make this large family more and more popular for drug delivery. There is a growing interest over the last decades in the design of engineered MOFs with controlled sizes for a variety of biomedical applications. This article presents an overall review and perspectives of MOFs-based drug delivery systems (DDSs), starting with the MOFs classification adapted for DDSs based on the types of constituting metals and ligands. Then, the synthesis and characterization of MOFs for DDSs are developed, followed by the drug loading strategies, applications, biopharmaceutics and quality control. Importantly, a variety of representative applications of MOFs are detailed from a point of view of applications in pharmaceutics, diseases therapy and advanced DDSs. In particular, the biopharmaceutics and quality control of MOFs-based DDSs are summarized with critical issues to be addressed. Finally, challenges in MOFs development for DDSs are discussed, such as biostability, biosafety, biopharmaceutics and nomenclature.

Enhancing the Antitumor Effect of Doxorubicin with Photosensitive Metal-Organic Framework Nanoparticles against Breast Cancer

Breast cancer is one of the most common malignant tumors in women. The existence of multiple breast cancer subtypes often leads to chemotherapy failure or the development of drug resistance. In recent years, photodynamic therapy has been proven to enhance the sensitivity of tumors to chemotherapeutic drugs. Porphyrin-based metal-organic framework (MOF) materials could simultaneously be used as carriers for chemotherapy and photosensitizers in photodynamic therapy. In this paper, doxorubicin hydrochloride (DOX) was loaded in porphyrin MOFs, and the mechanism of the synergistic effect of the DOX carriers and photodynamic therapy on breast cancer was investigated. In vitro and in vivo experiments have shown that MOFs could prolong the residence time of DOX in tumor tissues and promote the endocytosis of DOX by tumor cells. In addition, adjuvant treatment with photodynamic therapy can promote breast cancer tumors to resensitize to DOX and synergistically enhance the chemotherapy effect of DOX. Therefore, this study can provide effective development ideas for reversing drug resistance during breast cancer chemotherapy and improving the therapeutic effect of chemotherapy on breast cancer.

Tumor Microenvironment-"AND" Near-Infrared Light-Activated Coordination Polymer Nanoprodrug for On-Demand CO-Sensitized Synergistic Cancer Therapy

Carbon monoxide (CO) as an emerging treatment holds great promise for inducing the apoptosis of cancer cells. Here coordination assembled strategy is first reported for synthesis of Cu(II)-flavone coordination polymer (NCu-FleCP) CO nanoprodrug that is stable in normal physiological conditions, and yet readily reduces to small size prodrug complex and releases CO on demand under glutathione (GSH) and near infrared (NIR) light. Specifically, after uptaking by cancer cells, local GSH attacked coordination bond within NCu-FleCP, resulting in the release of Cu(I) and free Fle. The CC bond of Fle is cleavage under NIR light to release CO for gas therapy, and Cu(I) reacts with local H₂ O₂ through Fenton like reaction to generate hydroxyl radicals (^• OH) for chemodynamic therapy. Detailed in vitro and in vivo experiments demonstrate that the CO prodrug system in generating a sufficient quantity of CO and ^• OH offers remarkable destructive effects against cancer cells without causing toxicity to surrounding normal tissues. The study provides a solid foundation to develop smart coordination polymer CO prodrugs with on-demand CO release, enhanced permeability and retention effect, and biodegradability for multimodal synergistic therapy.

Artificial Bioaugmentation of Biomacromolecules and Living Organisms for Biomedical Applications

The synergistic union of nanomaterials with biomaterials has revolutionized synthetic chemistry, enabling the creation of nanomaterial-based biohybrids with distinct properties for biomedical applications. This class of materials has drawn significant scientific interest from the perspective of functional extension via controllable coupling of synthetic and biomaterial components, resulting in enhancement of the chemical, physical, and biological properties of the obtained biohybrids. In this review, we highlight the forefront materials for the combination with biomacromolecules and living organisms and their advantageous properties as well as recent advances in the rational design and synthesis of artificial biohybrids. We further illustrate the incredible diversity of biomedical applications stemming from artificially bioaugmented characteristics of the nanomaterial-based biohybrids. Eventually, we aim to inspire scientists with the application horizons of the exciting field of synthetic augmented biohybrids.

Colloidal nano-MOFs nucleate and stabilize ultra-small quantum dots of lead bromide perovskites

The development of synthetic routes to access stable, ultra-small (i.e. <5 nm) lead halide perovskite (LHP) quantum dots (QDs) is of fundamental and technological interest. The considerable challenges include the high solubility of the ionic LHPs in polar solvents and aggregation to form larger particles. Here, we demonstrate a simple and effective host-guest strategy for preparing ultra-small lead bromide perovskite QDs through the use of nano-sized MOFs that function as nucleating and host sites. Cr3O(OH)(H2O)2(terephthalate)3 (Cr-MIL-101), made of large mesopore-sized pseudo-spherical cages, allows fast and efficient diffusion of perovskite precursors within its pores, and promotes the formation of stable, ∼3 nm-wide lead bromide perovskite QDs. CsPbBr3, MAPbBr3 (MA+ = methylammonium), and (FA)PbBr3 (FA+ = formamidinium) QDs exhibit significantly blue-shifted emission maxima at 440 nm, 446 nm, and 450 nm, respectively, as expected for strongly confined perovskite QDs. Optical characterization and composite modelling confirm that the APbBr3 (A = Cs, MA, FA) QDs owe their stability within the MIL-101 nanocrystals to both short- and long-range interfacial interactions with the MOF pore walls.

Degradation Mechanism of Porous Metal-Organic Frameworks by In Situ Atomic Force Microscopy

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs' stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

Metal-Organic Framework (MOF)-Based Biomaterials for Tissue Engineering and Regenerative Medicine

The synthesis of Metal-organic Frameworks (MOFs) and their evaluation for various applications is one of the largest research areas within materials sciences and chemistry. Here, the use of MOFs in biomaterials and implants is summarized as narrative review addressing primarely the Tissue Engineering and Regenerative Medicine (TERM) community. Focus is given on MOFs as bioactive component to aid tissue engineering and to augment clinically established or future therapies in regenerative medicine. A summary of synthesis methods suitable for TERM laboratories and key properties of MOFs relevant to biomaterials is provided. The use of MOFs is categorized according to their targeted organ (bone, cardio-vascular, skin and nervous tissue) and whether the MOFs are used as intrinsically bioactive material or as drug delivery vehicle. Further distinction between in vitro and in vivo studies provides a clear assessment of literature on the current progress of MOF based biomaterials. Although the present review is narrative in nature, systematic literature analysis has been performed, allowing a concise overview of this emerging research direction till the point of writing. While a number of excellent studies have been published, future studies will need to clearly highlight the safety and added value of MOFs compared to established materials for clinical TERM applications. The scope of the present review is clearly delimited from the general 'biomedical application' of MOFs that focuses mainly on drug delivery or diagnostic applications not involving aspects of tissue healing or better implant integration.

Porphyrin-Based Metal-Organic Frameworks for Biomedical Applications

Porphyrins and porphyrin derivatives have been widely explored for various applications owing to their excellent photophysical and electrochemical properties. However, inherent shortcomings, such as instability and self-quenching under physiological conditions, limit their biomedical applications. In recent years, metal-organic frameworks (MOFs) have received increasing attention. The construction of porphyrin-based MOFs by introducing porphyrin molecules into MOFs or using porphyrins as organic linkers to form MOFs can combine the unique features of porphyrins and MOFs as well as overcome the limitations of porphyrins. This Review summarizes important synthesis strategies for porphyrin-based MOFs including porphyrin@MOFs, porphyrinic MOFs, and composite porphyrinic MOFs, and highlights recent achievements and progress in the development of porphyrin-based MOFs for biomedical applications in tumor therapy and biosensing. Finally, the challenges and prospects presented by this class of emerging materials for biomedical applications are discussed.

Metal-Organic Frameworks for Drug Delivery: A Design Perspective

The use of metal-organic frameworks (MOFs) in biomedical applications has greatly expanded over the past decade due to the precision tunability, high surface areas, and high loading capacities of MOFs. Specifically, MOFs are being explored for a wide variety of drug delivery applications. Initially, MOFs were used for delivery of small-molecule pharmaceuticals; however, more recent work has focused on macromolecular cargos, such as proteins and nucleic acids. Here, we review the historical application of MOFs for drug delivery, with a specific focus on the available options for designing MOFs for specific drug delivery applications. These options include choices of MOF structure, synthetic method, and drug loading. Further considerations include tuning, modifications, biocompatibility, cellular targeting, and uptake. Altogether, this Review aims to guide MOF design for novel biomedical applications.

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.

Recent advances in cell membrane coated metal-organic frameworks (MOFs) for tumor therapy

In improving the tumor-targeting ability of metal-organic frameworks (MOFs) for tumor therapy and avoiding the clearance as well as capture by the immune system, there are still several challenges, which limit the development and bio-applications of MOFs. To overcome these challenges, various targeted modification strategies have been proposed. Amongst all the strategies, a promising cell membrane coating method has been explored and utilized for the syntheses of new cell membrane biomimetic MOFs (CMMs). Through such coating, various source cell membranes (e.g., red blood cell, immune cell, cancer cell, platelet, and fusion cell membranes) can be endowed with excellent properties such as long blood circulation, immune escape, and targeting ability. In the presented perspective, the synthetic method, characterization, and research progress in tumor therapy based on CMMs have been summarized. This is because, like many other technologies, the cell membrane coating technology also has several challenges to overcome. Hence, addressing and overcoming such challenges will promote and extend the bio-applications of MOFs which in the future may become a prospective carrier for cancer nano-medicine. Finally, the prospects and challenges of utilizing CMMs for tumor therapy have been discussed.

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.

Identifying Differing Intracellular Cargo Release Mechanisms by Monitoring In Vitro Drug Delivery from MOFs in Real Time

Metal-organic frameworks (MOFs) have been proposed as biocompatible candidates for the targeted intracellular delivery of chemotherapeutic payloads, but the site of drug loading and subsequent effect on intracellular release is often overlooked. Here, we analyze doxorubicin delivery to cancer cells by MIL-101(Cr) and UiO-66 in real time. Having experimentally and computationally verified that doxorubicin is pore loaded in MIL-101(Cr) and surface loaded on UiO-66, different time-dependent cytotoxicity profiles are observed by real-time cell analysis and confocal microscopy. The attenuated release of aggregated doxorubicin from the surface of Dox@UiO-66 results in a 12 to 16 h induction of cytotoxicity, while rapid release of pore-dispersed doxorubicin from Dox@MIL-101(Cr) leads to significantly higher intranuclear localization and rapid cell death. In verifying real-time cell analysis as a versatile tool to assess biocompatibility and drug delivery, we show that the localization of drugs in (or on) MOF nanoparticles controls delivery profiles and is key to understanding in vitro modes of action.