The structural appeal of metal–organic frameworks in antimicrobial applications

Antimicrobial zeolites and metal-organic frameworks

The current surge in antibiotic resistance and the emergence of pandemics have created an urgent need for novel antimicrobial strategies. The controlled release of antimicrobial active principles remains the most viable strategy to date, and transition metal ions currently represent the main alternative to antibiotics. In this review, we explore the potential of two types of materials, zeolites and metal-organic frameworks (MOFs), for the controlled release of antimicrobial active principles, notably transition metal ions. These materials have unique crystalline microporous structures that act as reservoirs, enabling sustained bactericidal effects in various applications such as coatings, packaging, and medical devices. However, there are currently no convenient and standardised methods for evaluating their metal ion release and antimicrobial efficacy. This work discusses analytical techniques and the proposed mechanisms of action while highlighting recent advances in film, membrane, and coating technologies. By addressing the current limitations, microporous materials can revolutionise antimicrobial approaches, offering enhanced effectiveness and long-term sustainability.

Nanoscale Multipatterning Zn,Co-ZIF@FeOOH for Eradication of Multidrug-Resistant Bacteria and Antibacterial Treatment of Wounds

The rising incidence of infections caused by multidrug-resistant bacteria highlights the urgent need for innovative bacterial eradication strategies. Metal ions, such as Zn2+ and Co2+, have bactericidal effects by disrupting bacterial cell membranes and interfering with essential cellular processes. This has led to increased attention toward metal-organic frameworks (MOFs) as potential nonantibiotic bactericidal agents. However, the uniform and enhanced localized release of bactericidal metal ions remains a challenge. Herein, we introduce a nanoscale multipatterned Zn,Co-ZIF@FeOOH, featuring a multipod-like morphology with spiky corners, and dual-bactericidal metal ions. Compared to pure Zn,Co-ZIF, the multipod-like morphology of Zn,Co-ZIF@FeOOH exhibits enhanced adhesion toward bacterial surfaces via topological and multiple interactions of electrostatic interaction, significantly increasing the local release of Zn2+ and Co2+. Additionally, the spiky corners of the spindle-shaped FeOOH nanorods physically penetrate bacterial membranes, causing damage and further enhancing adhesion to bacteria. Nine Gram-negative and one Gram-positive bacteria were selected for in vitro test. Notably, the nanoscale multipatterned Zn,Co-ZIF@FeOOH exhibited high bactericidal efficacy against various multidrug-resistant bacteria, including extended-spectrum β-lactamase-producing (ESBL+) bacteria and carbapenem-resistant bacteria, performing well in both acidic and neutral environments. The wound healing activity of Zn,Co-ZIF@FeOOH was further demonstrated using female Balb/c mouse models infected with bacteria, where the materials show robust antibacterial efficacy and commendable biocompatibility. This study showcases the assembly of metal oxide/MOF composites for nanoscale multipatterning, aims at synergistic bacterial eradication and offers insights into developing nanomaterial-based strategies against multidrug-resistant bacteria.

Improving the particulate matter filtration, antibacterial, and degradation properties of electrospinning poly(lactic acid) membranes with ZIF-8@chitosan

In order to improve the filtration efficiency of electrospinning poly(lactic acid) (PLA) membrane on particulate matter (PM), endow the membrane with good antibacterial properties, and accelerate the degradation effect of PLA materials in natural water and soil environments, ZIF-8@chitosan (ZIF-8@CS) was prepared by in situ growth method and was combined with PLA to manufacture the PLA/ZIF-8@CS electrospinning membranes. The PLA/ZIF-8@CS (3 wt%) membrane exhibited filtration efficiencies of 96.79 % for PM2.5 and 91.21 % for PM10, which were significantly higher than that of PP melt-blown cloth. Due to the inherently positive charge and the synergistic interaction between CS and ZIF-8, the antibacterial rates of PLA/ZIF-8@CS membranes were up to 100 % for E. coli and S. aureus after contact for 8 h. The addition of ZIF-8@CS in the membranes also influenced the degradation behavior of PLA/ZIF-8@CS membranes evidently.

Coordination Assemblies of Acetylenic Dithioether Ligands on Silver(I) Salts: Crystal Structure, Antibacterial and Cytotoxicity Activities

Coordination polymers (CPs) and metal-organic frameworks (MOFs) constitute a new class of antibacterial materials. Interest in them stems from their wide range of topology, dimensionality, and secondary building units that can be tuned by an appropriate choice of metal ions and ligands. In particular, silver-based species feature good antibacterial properties. In this study, we explored the coordination of three acetylenic dithioether RSCH2C≡CCH2SR [R = phenyl (LPh), cyclohexyl (LCy), or tert-butyl (LtBu)] ligands on several silver salts (silver tosylate, silver triflate, and silver trifluoroacetate). The crystallographic characterization evidenced the formation of a molecular macrocycle and six CPs with different dimensionalities, ranging from one to two dimensions. In most cases, they are composed of four-coordinated silver atoms in a tetrahedral environment. Their antibacterial activity was investigated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. All CPs present good antibacterial properties against the tested bacteria with minimal inhibitory concentrations ranging from 5 to 40 μg of Ag/mL. Interestingly, we found that these values could not be correlated to their architecture or morphology or to the amount of silver released. The cytotoxicity of these compounds was also evaluated on normal human dermal fibroblasts, and three of these CPs were found to be biocompatible.

Advancements in wound management: integrating nanotechnology and smart materials for enhanced therapeutic interventions

Wound management spans various techniques and materials tailored to address acute and chronic non-healing wounds, with the primary objective of achieving successful wound closure. Chronic wounds pose additional challenges, often necessitating dressings to prepare the wound bed for subsequent surgical procedures like skin grafting. Ideal dressing materials should not only expedite wound healing but also mitigate protein, electrolyte, and fluid loss while minimizing pain and infection risk. Nanotechnology has emerged as a transformative tool in wound care, revolutionizing the landscape of biomedical dressings. Its application offers remarkable efficacy in accelerating wound healing and combating bacterial infections, representing a significant advancement in wound care practices. Integration of nanotechnology into dressings has resulted in enhanced properties, including improved mechanical strength and controlled drug release, facilitating tailored therapeutic interventions. This review article comprehensively explores recent breakthroughs in wound healing therapies, with a focus on innovative medical dressings such as nano-enzymes. Additionally, the utilization of smart materials, like hydrogels and electroactive polymers, in wound dressings offers dynamic functionalities to promote tissue regeneration. Emerging concepts such as bio-fabrication, microfluidic systems, bio-responsive scaffolds, and personalized therapeutics show promise in expediting wound healing and minimizing scarring. Through an in-depth exploration of these advancements, this review aims to catalyze a paradigm shift in wound care strategies, promoting a patient-centric approach to therapeutic interventions.

Inhibition mechanism of Rhizoctonia solani by pectin-coated iron metal-organic framework nanoparticles and evidence of an induced defense response in rice

Nanocrop protectants have attracted much attention as sustainable platforms for controlling pests and diseases and improving crop nutrition. Here, we reported the fungicidal activity and disease inhibition potential of pectin-coated metal-iron organic framework nanoparticles (Fe-MOF-PT NPs) against rice stripe blight (RSB). An in vitro bacterial inhibition assay showed that Fe-MOF-PT NPs (80 mg/L) significantly inhibited mycelial growth and nucleus formation. The Fe-MOF-PT NPs adsorbed to the surface of mycelia and induced toxicity by disrupting cell membranes, mitochondria, and DNA. The results of a nontargeted metabolomics analysis showed that the metabolites of amino acids and their metabolites, heterocyclic compounds, fatty acids, and nucleotides and their metabolites were significantly downregulated after treatment with 80 mg/L NPs. The difference in metabolite abundance between the CK and Fe-MOF-PT NPs (80 mg/L) treatment groups was mainly related to nucleotide metabolism, pyrimidine metabolism, purine metabolism, fatty acid metabolism, and amino acid metabolism. The results of the greenhouse experiment showed that Fe-MOF-PT NPs improved rice resistance to R. solani by inhibiting mycelial invasion, enhancing antioxidant enzyme activities, activating the jasmonic acid signaling pathway, and enhancing photosynthesis. These findings indicate the great potential of Fe-MOF-PT NPs as a new RSB disease management strategy and provide new insights into plant fungal disease management.

Recent advances and potential applications for metal-organic framework (MOFs) and MOFs-derived materials: Characterizations and antimicrobial activities

Microbial infections, particularly those caused by antibiotic-resistant pathogens, pose a critical global health threat. Metal-Organic Frameworks (MOFs), porous crystalline structures built from metal ions and organic linkers, initially developed for gas adsorption, have emerged as promising alternatives to traditional antibiotics. This review, covering research up to 2023, explores the potential of MOFs and MOF-based materials as broad-spectrum antimicrobial agents against bacteria, viruses, fungi, and even parasites. It delves into the historical context of antimicrobial agents, recent advancements in MOF research, and the diverse synthesis techniques employed for their production. Furthermore, the review comprehensively analyzes the mechanisms of action by which MOFs combat various microbial threats. By highlighting the vast potential of MOFs, their diverse synthesis methods, and their effectiveness against various pathogens, this study underscores their potential as a novel solution to the growing challenge of antibiotic resistance.

Metal-organic framework-based adsorbents for blood purification: progress, challenges, and prospects

Blood purification, such as hemodialysis (HD), plasma exchange (PE), and hemoperfusion (HP), is widely applied in patients with organ failure (such as kidney and liver failure). Among them, HP mainly relies on porous adsorbents to efficiently adsorb accumulated metabolic wastes and toxins, thus improving purification efficiency. Metal-organic frameworks (MOFs), with a high porosity, large surface area, high loading capacity, and tailorable topology, are emerging as some of the most promising materials for HP. Compared with non-metal framework counterparts, the self-built metal centers of MOFs feature the intrinsic advantages of coordination with toxin molecules. However, research on MOFs in blood purification is insufficient, particularly in contrast to materials applied in other biomedical applications. Thus, to broaden this area, this review first discusses the essential characteristics, potential mechanisms, and structure-function relationship between MOFs and toxin adsorption based on porosity, topology, ligand functionalization, metal centers, and toxin types. Moreover, the stability, utilization safety, and hemocompatibility of MOFs are illustrated for adsorbent selection. The current development and progress in MOF composites for HD, HP, and extracorporeal membrane oxygenation (ECMO) are also summarized to highlight their practicability. Finally, we propose future opportunities and challenges from materials design and manufacture to the computational prediction of MOFs in blood purification. It is anticipated that our review will expand the interest of researchers for more impact in this area.

Antibacterial, antibiofilm, and antioxidant activities of two novel metal-organic frameworks (MOFs) based on 4,6-diamino-2-pyrimidinethiol with Zn and Co metal ions as coordination polymers

In the present era, the increase in free radical species (FRs) and multidrug-resistant (MDR) bacteria represents a major worldwide concern for public health. Biofilm development and the overuse and misuse of antibiotics could lead to the adaptation of bacteria to antimicrobial agents. Consequently, finding novel multifunctional species with antibacterial, antioxidant, and antibiofilm properties has become crucial in the fight against challenging bacterial infections and chronic inflammatory conditions. Metal-organic frameworks (MOFs) with zinc and cobalt metal centers are widely utilized in biological and environmental remediation owing to their versatility. In this study, multifunctional Zn-MOFs and Co-MOFs were successfully synthesized with zinc and cobalt as metal centers and 4,6-diamino-2-pyrimidinethiol as an organic linker using a hydrothermal technique. Numerous characterization techniques were used to fully examine the MOF structure, functionality, chemical makeup, crystalline structure, surface appearance, thermal behavior, and magnetic characteristics; the techniques included XPS, PXRD, FTIR, FESEM, EDX, UV-visible, BET, BJH, TGA/DTG, DSC, and magnetic susceptibility measurement. The antioxidant, antibacterial, and antibiofilm activities of the MOFs were examined, and they demonstrated potent activity in each of these aspects. The proposed mechanisms of antibacterial activity suggest that bacterial cell death results from multiple toxic effects, including electrostatic interaction and lipid peroxidation, when MOFs are attached to bacteria, leading to the formation of reactive oxygen species (ROSs). Zn-MOFs exhibit high antibacterial and antibiofilm efficacy owing to their large surface-to-volume ratio and porous nature, while Co-MOFs exhibit high antioxidant capacity owing to their redox properties.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Role of Metal-Organic Frameworks (MOFs) in treating and diagnosing microbial infections

This review article highlights the innovative role of metal-organic frameworks (MOFs) in addressing global healthcare challenges related to microbial infections. MOFs, comprised of metal nodes and organic ligands, offer unique properties that can be applied in the treatment and diagnosis of these infections. Traditional methods, such as antibiotics and conventional diagnostics, face issues such as antibiotic resistance and diagnostic limitations. MOFs, with their highly porous and customizable structure, can encapsulate and deliver therapeutic or diagnostic molecules precisely. Their large surface area and customizable pore structures allow for sensitive detection and selective recognition of microbial pathogens. They also show potential in delivering therapeutic agents to infection sites, enabling controlled release and possible synergistic effects. However, challenges like optimizing synthesis techniques, enhancing stability, and developing targeted delivery systems remain. Regulatory and safety considerations for clinical translation also need to be addressed. This review not only explores the potential of MOFs in treating and diagnosing microbial infections but also emphasizes their unique approach and discusses existing challenges and future directions.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Loaded with P-Cymene against Rice Bacterial Blight

Mesoporous silica nanoparticles (MSNs) can be used as carrier materials for the controlled release of pesticides while reducing their negative environmental impact. In this study, we screened an active ingredient, p-cymene (PC), with an excellent inhibitory effect on rice bacterial blight. Subsequently, the PC was successfully loaded onto MSNs via physisorption (PC@MSNs). PC@MSNs, characterized by a regular spherical shape, smooth surface, and an MSN average size of 262.9 nm, achieved an 8.6% drug loading capacity. The release kinetics of the PC from the PC@MSNs demonstrated a sustained release (288 h) pattern influenced by drug diffusion. The efficacy of the PC@MSNs against Xanthomonas oryzae pv. Oryzae paralleled those of PC. Acute toxicity assays revealed that the PC@MSNs were less toxic to aquatic life (LC50 = 257.867 mg/L) and that the formulation showed no adverse effects on rice seedling growth. In summary, these results suggest that PC@MSNs can broaden PC's scope of application in managing rice diseases.

Redox Active Zn@MOFs as Spontaneous Reactive Oxygen Species Releasing Antimicrobials

The rapid development of antimicrobial resistance (AMR) among infectious pathogens has become a major threat and challenge in healthcare systems globally. A strategy distinct from minimizing the overuse of antimicrobials involves the development of novel antimicrobials with a mode of action that prevents the development of AMR microbial strains. Reactive oxygen species (ROS) are formed as a natural byproduct of the cellular aerobic metabolism. However, it becomes pathological when ROS is produced at excessive levels. Exploiting this phenomenon, research on redox-active bactericides has been demonstrated to be beneficial. Materials that release ROS via photodynamic, thermodynamic, and photocatalytic interventions have been developed as nanomedicines and are used in various applications. However, these materials require external stimuli for ROS release to be effective as biocides. In this paper, we report novel zinc-based metal organic framework (Zn@MOF) particles that promote the spontaneous release of active ROS species. The synthesized Zn@MOF spontaneously releases superoxide anions and hydrogen peroxide, exhibiting a potent antimicrobial efficacy against various microbes. Zn@MOF-incorporated plastic films and coatings show excellent, long-lasting antimicrobial potency even under continuous microbial challenge and an aging process. These disinfecting surfaces maintain their antimicrobial properties even after 500× surface wipes. Zn@MOF is also biocompatible and safe on the skin, illustrating its broad potential applications in medical technology and consumer care applications.

Integrating metal-organic framework ZIF-8 with green modifier empowered bacteria with improved bioremediation

Suspended microorganisms often experience diminished efficacy in the bioremediation of polycyclic aromatic hydrocarbons (PAHs). In this study, the potential of zeolite imidazolate framework-8 (ZIF-8) and the eco-friendly modifier citric acid (CA) was harnessed to generate a biomimetic mineralized protective shell on the surface of Bacillus subtilis ZL09-26, resulting in an enhanced capability for PAH degradation. This investigation encompassed the integrated responses of B. subtilis ZL09-26 to ZIF-8 and ZIF-8-CA at both cellular and proteomic levels. The amalgamation of ZIF-8 and CA not only stimulated the growth and bolstered the cell viability of B. subtilis ZL09-26, but also counteracted the toxic effects of phenanthrene (PHE) stress. Remarkably, the bioremediation prowess of B. subtilis ZL09-26@ZIF-8-CA surpassed that of ZL09-26@ZIF-8 and ZL09-26, achieving a PHE removal rate of 94.14 % within 6 days. After undergoing five cycles, ZL09-26@ZIF-8-CA demonstrated an enduring PHE removal rate exceeding 83.31 %. A complex interplay of various metabolic pathways orchestrated cellular responses, enhancing PHE transport and degradation. These pathways encompassed direct PHE biodegradation, central carbon metabolism, oxidative phosphorylation, purine metabolism, and aminoacyl-tRNA biosynthesis. This study not only extends the potential applications of biomineralized organisms but also offers alternative strategies for effective contaminant management.

Bio-mitigation of organic pollutants using horseradish peroxidase as a promising biocatalytic platform for environmental sustainability

A wide array of environmental pollutants is often generated and released into the ecosystem from industrial and human activities. Antibiotics, phenolic compounds, hydroquinone, industrial dyes, and Endocrine-Disrupting Chemicals (EDCs) are prevalent pollutants in water matrices. To promote environmental sustainability and minimize the impact of these pollutants, it is essential to eliminate such contaminants. Although there are multiple methods for pollutants removal, many of them are inefficient and environmentally unfriendly. Horseradish peroxidase (HRP) has been widely explored for its ability to oxidize the aforementioned pollutants, both alone and in combination with other peroxidases, and in an immobilized way. Numerous positive attributes make HRP an excellent biocatalyst in the biodegradation of diverse environmentally hazardous pollutants. In the present review, we underlined the major advancements in the HRP for environmental research. Numerous immobilization and combinational studies have been reviewed and summarized to comprehend the degradability, fate, and biotransformation of pollutants. In addition, a possible deployment of emerging computational methodologies for improved catalysis has been highlighted, along with future outlook and concluding remarks.

Current status and prospects of MIL-based MOF materials for biomedicine applications

This article mainly reviews the biomedicine applications of two metal-organic frameworks (MOFs), MIL-100(Fe) and MIL-101(Fe). These MOFs have advantages such as high specific surface area, adjustable pore size, and chemical stability, which make them widely used in drug delivery systems. The article first introduces the properties of these two materials and then discusses their applications in drug transport, antibacterial therapy, and cancer treatment. In cancer treatment, drug delivery systems based on MIL-100(Fe) and MIL-101(Fe) have made significant progress in chemotherapy (CT), chemodynamic therapy (CDT), photothermal therapy (PTT), photodynamic therapy (PDT), immunotherapy (IT), nano-enzyme therapy, and related combined therapy. Overall, these MIL-100(Fe) and MIL-101(Fe) materials have tremendous potential and diverse applications in the field of biomedicine.

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

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

Copper and Zinc Metal-Organic Frameworks with Bipyrazole Linkers Display Strong Antibacterial Activity against Both Gram+ and Gram- Bacterial Strains

Here, we report a new synthetic protocol based on microwave-assisted synthesis (MAS) for the preparation of higher yields of zinc and copper in MOFs based on different bis(pyrazolyl)-tagged ligands ([M(BPZ)]n where M = Zn(II), Cu(II), H2BPZ = 4,4'-bipyrazole, [M(BPZ-NH2)]n where M = Zn(II), Cu(II); H2BPZ-NH2 = 3-amino-4,4'-bipyrazole, and [Mx(Me4BPZPh)] where M = Zn(II), x = 1; Cu(II), x = 2; H2Me4BPZPh = bis-4'-(3',5'-dimethyl)-pyrazolylbenzene) and, for the first time, a detailed study of their antibacterial activity, tested against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as representative agents of infections. The results show that all MOFs exert a broad-spectrum activity and strong efficiency in bacterial growth inhibition, with a mechanism of action based on the surface contact of MOF particles with bacterial cells through the so-called "chelation effect" and reactive oxygen species (ROS) generation, without a significant release of Zn(II) and Cu(II) ions. In addition, morphological changes were elucidated by using a scanning electron microscope (SEM) and bacterial cell damage was further confirmed by a confocal laser scanning microscopy (CLSM) test.

Constructing Physiological Defense Systems against Infectious Disease with Metal-Organic Frameworks: A Review

The swift and deadly spread of infectious diseases, alongside the rapid advancement of scientific technology in the past several centuries, has led to the invention of various methods for protecting people from infection. In recent years, a class of crystalline porous materials, metal-organic frameworks (MOFs), has shown great potential in constructing defense systems against infectious diseases. This review addresses current approaches to combating infectious diseases through the utilization of MOFs in vaccine development, antiviral and antibacterial treatment, and personal protective equipment (PPE). Along with an updated account of MOFs used for designing defense systems against infectious diseases, directions are also suggested for expanding avenues of current MOF research to develop more effective approaches and tools to prevent the widespread nature of infectious diseases.

Innovative Metal-Organic Frameworks for Targeted Oral Cancer Therapy: A Review

Metal-organic frameworks (MOFs) have proven to be very effective carriers for drug delivery in various biological applications. In recent years, the development of hybrid nanostructures has made significant progress, including developing an innovative MOF-loaded nanocomposite with a highly porous structure and low toxicity that can be used to fabricate core-shell nanocomposites by combining complementary materials. This review study discusses using MOF materials in cancer treatment, imaging, and antibacterial effects, focusing on oral cancer cells. For patients with oral cancer, we offer a regular program for accurately designing and producing various anticancer and antibacterial agents to achieve maximum effectiveness and the lowest side effects. Also, we want to ensure that the anticancer agent works optimally and has as few side effects as possible before it is tested in vitro and in vivo. It is also essential that new anticancer drugs for cancer treatment are tested for efficacy and safety before they go into further research.

Metal-Organic Framework-Based Nanomedicines for the Treatment of Intracellular Bacterial Infections

Metal-organic frameworks (MOFs) are a highly versatile class of ordered porous materials, which hold great promise for different biomedical applications, including antibacterial therapy. In light of the antibacterial effects, these nanomaterials can be attractive for several reasons. First, MOFs exhibit a high loading capacity for numerous antibacterial drugs, including antibiotics, photosensitizers, and/or photothermal molecules. The inherent micro- or meso-porosity of MOF structures enables their use as nanocarriers for simultaneous encapsulation of multiple drugs resulting in a combined therapeutic effect. In addition to being encapsulated into an MOF's pores, antibacterial agents can sometimes be directly incorporated into an MOF skeleton as organic linkers. Next, MOFs contain coordinated metal ions in their structure. Incorporation of Fe2/3+, Cu2+, Zn2+, Co2+, and Ag+ can significantly increase the innate cytotoxicity of these materials for bacteria and cause a synergistic effect. Finally, abundance of functional groups enables modifying the external surface of MOF particles with stealth coating and ligand moieties for improved drug delivery. To date, there are a number of MOF-based nanomedicines available for the treatment of bacterial infections. This review is focused on biomedical consideration of MOF nano-formulations designed for the therapy of intracellular infections such as Staphylococcus aureus, Mycobacterium tuberculosis, and Chlamydia trachomatis. Increasing knowledge about the ability of MOF nanoparticles to accumulate in a pathogen intracellular niche in the host cells provides an excellent opportunity to use MOF-based nanomedicines for the eradication of persistent infections. Here, we discuss advantages and current limitations of MOFs, their clinical significance, and their prospects for the treatment of the mentioned infections.

Multi-emitter metal-organic frameworks as ratiometric luminescent sensors for food contamination and spoilage detection

Food contamination and spoilage is a worldwide concern considering its adverse effect on public health and food security. Real time monitoring food quality can reduce the risk of foodborne disease to consumers. Particularly, the emergence of multi-emitter luminescent metal-organic frameworks (LMOFs) as ratiometric sensory materials has provided the possibility for food quality and safety detection with high sensitivity and selectivity taking advantage of specific host-guest interactions, pre-concentrating and molecule-sieving effects of MOFs. Furthermore, the excellent sensing performance of multi-emitter MOF-based ratiometric sensors including self-calibration, multi-dimensional recognition and visual signal readout is able to meet the increasing rigor requirement of food safety evaluation. Multi-emitter MOF-based ratiometric sensors have become the focus of food safety detection. This review focuses on design strategies for different multiple emission sources assembly to construct multi-emitter MOFs materials based on at least two emitting centers. The design strategies for creating multi-emitter MOFs can be mainly classified into three categories: (1) multiple emission building blocks assembly in a single MOF phase; (2) single non-luminescent MOF or LMOF phase as a matrix for chromophore guest(s); (3) heterostructured hybrids of LMOF with other luminescent materials. In addition, the sensing signal output modes of multi-emitter MOF-based ratiometric sensors have critically discussed. Next, we highlight the recent progress for the development of multi-emitter MOF as ratiometric sensors in food contamination and spoilage detection. Their future improvement and advancing direction potential for their practical application is finally discussed.

Electrodeposition of Ag/ZIF-8-Modified Membrane for Water Remediation

Metal-organic framework (MOF)-based membranes have been widely used in gas and liquid separation due to their porous structures and tunable compositions. Depending on the guest components, heterostructured MOFs can exhibit multiple functions. In the present work, we report a facile and rapid preparation of zeolitic imidazolate framework-8 (ZIF-8) and silver nanoparticle incorporated ZIF-8 (Ag/ZIF-8)-based membranes on stainless-steel mesh (SSM) through a "green" electrodeposition method. The SSM was first coated with a Zn-plated layer which contains mainly zinc hydroxide nitrate (Zn₅(OH)₈(NO₃)₂·2H₂O) with a "leaf-like" morphology, providing anchoring points for the deposition of ZIF-8 and Ag/ZIF-8. It takes only 10 min to prepare a uniform coating of Zn₅(OH)₈(NO₃)₂·2H₂O in aqueous conditions without the use of a strong base; this is by far the most efficient way of making zinc hydroxide nitrate nanocrystals. Following a similar electrodeposition approach, ZIF-8 and Ag/ZIF-8-coated SSM can be prepared within 20 min by applying a small current. The encapsulation of Ag does not alter the chemical composition nor the crystal structure of ZIF-8. The resulting ZIF-8 and Ag/ZIF-8-coated SSM have been tested for their effectiveness for rhodamine B dye removal in a fast vacuum filtration setting. Additionally, growth of E. coli was significantly inhibited after overnight incubation with Ag/ZIF-8-coated SSM. Overall, we demonstrate a fast synthesis procedure to make ZIF-8 and Ag/ZIF-8-coated SSM membranes for organic dye removal with excellent antimicrobial activity.

Prostate-Specific Antigen Monitoring Using Nano Zinc(II) Metal-Organic Framework-Based Optical Biosensor

BACKGROUND

The prostate-specific antigen (PSA) is an important cancer biomarker that is commonly utilized in the diagnosis of prostate cancer. The development of a PSA determination technique that is rapid, simple, and inexpensive, in addition to highly accurate, sensitive, and selective, remains a formidable obstacle.

METHODS

In this study, we developed a practical biosensor based on Zn(II) metal-organic framework nanoparticles (Zn-MOFs-NPs). Many spectroscopic and microanalytical tools are used to determine the structure, morphology, and physicochemical properties of the prepared MOF.

RESULTS

According to the results, Zn-MOFs-NPs are sensitive to PSA, selective to an extremely greater extent, and stable in terms of chemical composition. Furthermore, the Zn-MOFs-NPs did not exhibit any interferences from other common analytes that might cause interference. The detection limit for PSA was calculated and was 0.145 fg/mL throughout a wide linear concentration range (0.1 fg/mL-20 pg/mL).

CONCLUSIONS

Zn-MOFs-NPs were successfully used as a growing biosensor for the monitoring and measurement of PSA in biological real samples.

Growth of Cu2O Nanoparticles on Two-Dimensional Zr-Ferrocene-Metal-Organic Framework Nanosheets for Photothermally Enhanced Chemodynamic Antibacterial Therapy

Two-dimensional (2D) metal-organic framework (MOF) nanosheets have been demonstrated to be promising templates for the growth of various kinds of nanomaterials on their surfaces to construct novel 2D composites, thus realizing enhanced performance in various applications. Herein, we report the growth of Cu₂O nanoparticles on 2D Zr-ferrocene (Zr-Fc)-MOF (Zr-Fc-MOF) nanosheets to prepare 2D composites for near-infrared (NIR) photothermally enhanced chemodynamic antibacterial therapy. The uniform Zr-Fc-MOF nanosheets are synthesized using the solvothermal method, followed by ultrasound sonication, and Cu₂O nanoparticles are then deposited on its surface to obtain the Cu₂O-decorated Zr-Fc-MOF (denoted as Cu₂O/Zr-Fc-MOF) 2D composite. Promisingly, the Cu₂O/Zr-Fc-MOF composite shows higher chemodynamic activity for producing ·OH via Fenton-like reaction than that of the pristine Zr-Fc-MOF nanosheets. More importantly, the chemodynamic activity of the Cu₂O/Zr-Fc-MOF composite can be further enhanced by the photothermal effect though NIR laser (808 nm) irradiation. Thus, the Cu₂O/Zr-Fc-MOF composite can be used as an efficient nanoagent for photothermally enhanced chemodynamic antibacterial therapy.

Application of Nanomaterials for Coping with Mycotoxin Contamination in Food Safety: From Detection to Control

Mycotoxins, which are toxic secondary metabolites produced by fungi, are harmful to humans. Mycotoxin-induced contamination has drawn attention worldwide. Consequently, the development of reliable and sensitive detection methods and high-efficiency control strategies for mycotoxins is important to safeguard food industry safety and public health. With the rapid development of nanotechnology, many novel nanomaterials that provide tremendous opportunities for greatly improving the detection and control performance of mycotoxins because of their unique properties have emerged. This review comprehensively summarizes recent trends in the application of nanomaterials for detecting mycotoxins (fluorescence, colorimetric, surface-enhanced Raman scattering, electrochemical, and point-of-care testing) and controlling mycotoxins (inhibition of fungal growth, mycotoxin absorption, and degradation). These detection methods possess the advantages of high sensitivity and selectivity, operational simplicity, and rapidity. With research attention on the control of mycotoxins and the gradual excavation of the properties of nanomaterials, nanomaterials are also employed for the inhibition of fungal growth, mycotoxin absorption, and mycotoxin degradation, and impressive controlling effects are obtained. This review is expected to provide the readers insight into this state-of-the-art area and a reference to design nanomaterials-based schemes for the detection and control of mycotoxins.

Recent Advances in Nanozymes for Bacteria-Infected Wound Therapy

Bacterial-infected wounds are a serious threat to public health. Bacterial invasion can easily delay the wound healing process and even cause more serious damage. Therefore, effective new methods or drugs are needed to treat wounds. Nanozyme is an artificial enzyme that mimics the activity of a natural enzyme, and a substitute for natural enzymes by mimicking the coordination environment of the catalytic site. Due to the numerous excellent properties of nanozymes, the generation of drug-resistant bacteria can be avoided while treating bacterial infection wounds by catalyzing the sterilization mechanism of generating reactive oxygen species (ROS). Notably, there are still some defects in the nanozyme antibacterial agents, and the design direction is to realize the multifunctionalization and intelligence of a single system. In this review, we first discuss the pathophysiology of bacteria infected wound healing, the formation of bacterial infection wounds, and the strategies for treating bacterially infected wounds. In addition, the antibacterial advantages and mechanism of nanozymes for bacteria-infected wounds are also described. Importantly, a series of nanomaterials based on nanozyme synthesis for the treatment of infected wounds are emphasized. Finally, the challenges and prospects of nanozymes for treating bacterial infection wounds are proposed for future research in this field.

Recent advances in metal-organic framework-based materials for anti-staphylococcus aureus infection

The rapid spread of staphylococcus aureus (S. aureus) causes an increased morbidity and mortality, as well as great economic losses in the world. Anti-S. aureus infection becomes a major challenge for clinicians and nursing professionals to address drug resistance. Hence, it is urgent to explore high efficiency, low toxicity, and environmental-friendly methods against S. aureus. Metal-organic frameworks (MOFs) represent great potential in treating S. aureus infection due to the unique features of MOFs including tunable chemical constitute, open crystalline structure, and high specific surface area. Especially, these properties endow MOF-based materials outstanding antibacterial effect, which can be mainly attributed to the continuously released active components and the exerted catalytic activity to fight bacterial infection. Herein, the structural characteristics of MOFs and evaluation method of antimicrobial activity are briefly summarized. Then we systematically give an overview on their recent progress on antibacterial mechanisms, metal ion sustained-release system, controlled delivery system, catalytic system, and energy conversion system based on MOF materials. Finally, suggestions and direction for future research to develop and mechanism understand MOF-based materials are discussed in antibacterial application.

Metal-organic frameworks for active food packaging. A review

Food wastage is a major concern for sustainable health and agriculture. To reduce food waste, classical preservation techniques such as drying, pasteurization, freeze-drying, fermentation, and microwave are available. Nonetheless, these techniques display shortcomings such as alteration of food and taste. Such shortcomings may be solved by active food packaging, which involves the incorporation of active agents into the packaging material. Recently, metal-organic frameworks, a class of porous hybrid supramolecular materials, have been developed as an active agent to extend food shelf life and maintain safety. Here, we review metal-organic frameworks in active packaging as oxygen scavengers, antimicrobials, moisture absorbers, and ethylene scavengers. We present methods of incorporation of metal-organic frameworks into packaging materials and their applications.

Metal-organic frameworks for diagnosis and therapy of infectious diseases

Infectious diseases are one of the leading cause of mortality and morbidity worldwide. Metal-Organic Frameworks (MOFs), which are porous coordination materials composed of bridging organic ligands and metallic ions or clusters, exhibits great potential to be used against several pathogens, such as bacteria, viruses, fungi and protozoa. MOFs can show sustained release capability, high surface area, adjustable pore size and structural flexibility, which makes them good candidates for new therapeutic systems. This review provides a detailed summary of the biological application of MOFs, focussing on diagnosis and treatment of infectious diseases. MOFs have been reported for usage as antimicrobial agents, drug delivery systems, therapeutic composites, nanozymes and phototherapies. Furthermore, different MOF-based biosensors have also been developed to detect specific pathogens by electrochemical, fluorometric and colorimetric assays. Finally, we present limitations and perspectives in this field.