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Air filtration has become an essential need for passive pollution control. However, most of the commercial air purifiers rely on dense fibrous filters, which have good particulate matter (PM) removal capability but poor biocidal effect. Here we present the photocatalytic bactericidal properties of a series of metal-organic frameworks (MOFs) and their potentials in air pollution control and personal protection. Specifically, a zinc-imidazolate MOF (ZIF-8) exhibits almost complete inactivation of Escherichia coli ( E. coli ) (>99.9999% inactivation efficiency) in saline within 2 h of simulated solar irradiation. Mechanistic studies indicate that photoelectrons trapped at Zn + centers within ZIF-8 via ligand to metal charge transfer (LMCT) are responsible for oxygen-reduction related reactive oxygen species (ROS) production, which is the dominant disinfection mechanism. Air filters fabricated from ZIF-8 show remarkable performance for integrated pollution control, with >99.99% photocatalytic killing efficiency against airborne bacteria in 30 min and 97% PM removal. This work may shed light on designing new porous solids with photocatalytic antibiotic capability for public health protection. Personal protective air filtration masks are becoming increasingly desirable, but most commercial air purifiers have poor biocidal capabilities. Here the authors fabricate metal–organic framework-based air filters with both high particulate matter removal efficiencies and photocatalytic bactericidal properties.

The utilization of polymer/metal organic framework (MOF) nanocomposites in various biomedical applications has been widely studied due to their unique properties that arise from MOFs or hybrid composite systems. This review focuses on the types of polymer/MOF nanocomposites used in drug delivery and imaging applications. Initially, a comprehensive introduction to the synthesis and structure of MOFs and bio-MOFs is presented. Subsequently, the properties and the performance of polymer/MOF nanocomposites used in these applications are examined, in relation to the approach applied for their synthesis: (i) non-covalent attachment, (ii) covalent attachment, (iii) polymer coordination to metal ions, (iv) MOF encapsulation in polymers, and (v) other strategies. A critical comparison and discussion of the effectiveness of polymer/MOF nanocomposites regarding their synthesis methods and their structural characteristics is presented.

Selective delivery of photosensitizers to mitochondria of cancer cells can enhance the efficacy of photodynamic therapy (PDT). Though cationic Ru-based photosensitizers accumulate in mitochondria, they require excitation with less penetrating short-wavelength photons, limiting their application in PDT. We recently discovered X-ray based cancer therapy by nanoscale metal–organic frameworks (nMOFs) via enhancing radiotherapy (RT) and enabling radiodynamic therapy (RDT). Herein we report Hf-DBB-Ru as a mitochondria-targeted nMOF for RT-RDT. Constructed from Ru-based photosensitizers, the cationic framework exhibits strong mitochondria-targeting property. Upon X-ray irradiation, Hf-DBB-Ru efficiently generates hydroxyl radicals from the Hf 6 SBUs and singlet oxygen from the DBB-Ru photosensitizers to lead to RT-RDT effects. Mitochondria-targeted RT-RDT depolarizes the mitochondrial membrane to initiate apoptosis of cancer cells, leading to significant regression of colorectal tumors in mouse models. Our work establishes an effective strategy to selectively target mitochondria with cationic nMOFs for enhanced cancer therapy via RT-RDT with low doses of deeply penetrating X-rays. Photosensitizers delivered to mitochondria of cancer cells can enhance photodynamic therapy. Here, the authors report mitochondria-targeted radiation therapy and radiodynamic therapy of colorectal cancer models with a cationic nanoscale metal-organic framework to overcome shallow light penetration of Ru-based photosensitizers.

Nanoparticle/metal–organic frameworks (MOF) based composites have recently attracted significant attention as a new class of catalysts. Such composites possess the unique features of MOFs (including clearly defined crystal structure, high surface area, single site catalyst, special confined nanopore, tunable, and uniform pore structure), but avoid some intrinsic weaknesses (like limited electrical conductivity and lack in the “conventional” catalytically active sites). This review summarizes the developed strategies for the fabrication of nanoparticle/MOF composites for catalyst uses, including the strategy using MOFs as host materials to hold and stabilize the guest nanoparticles, the strategy with subsequent MOF growth/assembly around pre-synthesized nanoparticles and the strategy mixing the precursors of NPs and MOFs together, followed by self-assembly process or post-treatment or post-modification. The applications of nanoparticle/MOF composites for CO oxidation, CO2 conversion, hydrogen production, organic transformations, and degradation of pollutants have been discussed. Superior catalytic performances in these reactions have been demonstrated. Challenges and future developments are finally addressed.

Cancer remains a severe threat to human health. To date, although various therapeutic methods, including radiotherapy (RT), chemotherapy, chemodynamic therapy (CDT), phototherapy, starvation therapy, and immunotherapy, have entered a new stage of rapid progress in cancer theranostics, their limited therapeutic effect and significant side effects need to be considered carefully. With the rapid development of nanotechnology, the marriage of nanomaterials and therapeutic methods provides the practical possibility to improve the deficiencies in cancer therapy. Notably, metal-organic frameworks (MOFs) composed of ions/clusters and bridging ligands through coordination bonds have been widely applied in cancer therapy to deal with the drawbacks of different therapeutic methods, such as severe side effects, low stability, and poor efficacy, owing to their controllable morphologies, tailorable diameters, diverse compositions, tunable porosities, high specific surface areas, facile functionalization, and good biocompatibility. This review summarizes the recent advanced developments and achievements of multifunctional MOF-based nanoplatforms for cancer therapy through single therapy methods, including RT, chemotherapy, CDT, phototherapy (photodynamic and photothermal therapy), starvation therapy and immunotherapy, and combination therapy methods. Moreover, the prospects and challenges of MOF-based nanoplatforms used in tumor therapy are also discussed.

The ever‐increasing concerns over indoor/outdoor air quality, industrial gas leakage, food freshness, and medical diagnosis require miniaturized gas sensors with excellent sensitivity, selectivity, stability, low power consumption, cost‐effectiveness, and long lifetime. Metal‐organic frameworks (MOFs), featuring structural diversity, large specific surface area, controllable pore size/geometry, and host‐guest interactions, hold great promises for fabricating various MOF‐based devices for diverse applications including gas sensing. Tremendous progress has been made in the past decade on the fabrication of MOF‐based sensors with elevated sensitivity and selectivity toward various analytes due to their preconcentrating and molecule‐sieving effects. Although several reviews have recently summarized different aspects of this field, a comprehensive review focusing on MOF‐based gas sensors is absent. In this review, the latest advance of MOF‐based gas sensors relying on different transduction mechanisms, for example, chemiresistive, capacitive/impedimetric, field‐effect transistor or Kelvin probe‐based, mass‐sensitive, and optical ones are comprehensively summarized. The latest progress for making large‐area MOF films essential to the mass‐production of relevant gas sensors is also included. The structural and compositional features of MOFs are intentionally correlated with the sensing performance. Challenges and opportunities for the further development and practical applications of MOF‐based gas sensors are also given. A comprehensive review on the latest progress of metal‐organic framework (MOF)‐based gas sensors relying on different transduction mechanisms is provided. The sensing performance in terms of sensitivity and selectivity is correlated with the structural and compositional features of MOFs and the transduction mechanisms. Critical future directions toward the further development of MOF‐based gas sensors are indicated.

A set of terms, definitions, and recommendations is provided for use in the classification of coordination polymers, networks, and metal–organic frameworks (MOFs). A hierarchical terminology is recommended in which the most general term is coordination polymer. Coordination networks are a subset of coordination polymers and MOFs a further subset of coordination networks. One of the criteria an MOF needs to fulfill is that it contains potential voids, but no physical measurements of porosity or other properties are demanded per se. The use of topology and topology descriptors to enhance the description of crystal structures of MOFs and 3D-coordination polymers is furthermore strongly recommended.

Targeting subcellular organelle with multilevel damage has shown great promise for antitumor therapy. Here, we report a core-shell type of nanoagent with iron (III) carboxylate metal-organic frameworks (MOFs) as shell while upconversion nanoparticles (UCNPs) as core, which enables near-infrared (NIR) light-triggered synergistically reinforced oxidative stress and calcium overload to mitochondria. The folate decoration on MOFs shells enables efficient cellular uptake of nanoagents. Based on the upconversion ability of UCNPs, NIR light mediates Fe 3+ -to-Fe 2+ reduction and simultaneously activates the photoacid generator (pHP) encapsulated in MOFs cavities, which enables release of free Fe 2+ and acidification of intracellular microenvironment, respectively. The overexpressed H 2 O 2 in mitochondria, highly reactive Fe 2+ and acidic milieu synergistically reinforce Fenton reactions for producing lethal hydroxyl radicals (•OH) while plasma photoacidification inducing calcium influx, leading to mitochondria calcium overload. The dual-mitochondria-damage-based therapeutic potency of the nanoagent has been unequivocally confirmed in cell- and patient-derived tumor xenograft models in vivo. Targeting damage to mitochondria has become an effective strategy antitumor therapies. Here, the authors report on nanoagents with upconversion nanoparticles as cores and photoacid-loaded MOFs as shells for NIR triggered Fenton reaction, acidification and calcium overload to provide synergistic mitochondrial damage.

The flexibility and tunability of metal organic frameworks (MOFs), crystalline porous materials composed of a network of metal ions coordinated by organic ligands, confer their variety of applications as drug delivery systems or as sensing and imaging agents. However, such properties also add to the difficulty in ensuring their safe implementation when interaction with biological systems is considered. In the current study, we used real-time sensorial strategies and cellular-based approaches to allow for fast and effective screening of two MOFs of prevalent use, namely, MIL-160 representative of a hydrophilic and ZIF-8 representative of a hydrophobic framework. The two MOFs were synthesized \"in house\" and exposed to human bronchial epithelial (BEAS-2B) cells, a pertinent toxicological screening model. Analysis allowed evaluation and differentiation of particle-induced cellular effects as well identification of different degrees and routes of toxicity, all in a high-throughput manner. Our results show the importance of performing screening toxicity assessments before introducing MOFs to biomedical applications. Our proposed screening assays could be extended to a wider variety of cell lines to allow for identification of any deleterious effects of MOFs, with the range of toxic mechanisms to be differentiated based on cell viability, morphology and cell-substrate interactions, respectively. Our analysis highlights the importance of considering the physicochemical properties of MOFs when recommending a MOF-based therapeutic option or MOFs implementation in biomedical applications.

Metal-organic frameworks (MOFs) are a very promising platform for applications in various industries. In recent years, a variety of methods have been developed for the preparation and modification of MOFs, providing a wide range of materials for different applications in life science. Despite the wide range of different MOFs in terms of properties/sizes/chemical nature, they have not found wide application in biomedical practices at present. In this review, we look at the main methods for the preparation of MOFs that can ensure biomedical applications. In addition, we also review the available options for tuning the key parameters, such as size, morphology, and porosity, which are crucial for the use of MOFs in biomedical systems. This review also analyses possible applications for MOFs of different natures. Their high porosity allows the use of MOFs as universal carriers for different therapeutic molecules in the human body. The wide range of chemical species involved in the synthesis of MOFs makes it possible to enhance targeting and prolongation, as well as to create delivery systems that are sensitive to various factors. In addition, we also highlight how injectable, oral, and even ocular delivery systems based on MOFs can be used. The possibility of using MOFs as therapeutic agents and sensitizers in photodynamic, photothermal, and sonodynamic therapy was also reviewed. MOFs have demonstrated high selectivity in various diagnostic systems, making them promising for future applications. The present review aims to systematize the main ways of modifying MOFs, as well as the biomedical applications of various systems based on MOFs.