Metal-organic frameworks for diagnosis and therapy of infectious diseases

Metal-Organic Frameworks in Surface Enhanced Raman Spectroscopy-Based Analysis of Volatile Organic Compounds

Volatile Organic Compounds (VOC) are a major class of environmental pollutants hazardous to human health, but also highly relevant in other fields including early disease diagnostics and organoleptic perception of aliments. Therefore, accurate analysis of VOC is essential, and a need for new analytical methods is witnessed for rapid on-site detection without complex sample preparation. Surface-Enhanced Raman Spectroscopy (SERS) offers a rapidly developing versatile analytical platform for the portable detection of chemical species. Nonetheless, the need for efficient docking of target analytes at the metallic surface significantly narrows the applicability of SERS. This limitation can be circumvented by interfacing the sensor surface with Metal-Organic Frameworks (MOF). These materials featuring chemical and structural versatility can efficiently pre-concentrate low molecular weight species such as VOC through their ordered porous structure. This review presents recent trends in the development of MOF-based SERS substrates with a focus on elucidating respective design rules for maximizing analytical performance. An overview of the status of the detection of harmful VOC is discussed in the context of industrial and environmental monitoring. In addition, a survey of the analysis of VOC biomarkers for medical diagnosis and emerging applications in aroma and flavor profiling is included.

Colorimetric sensing for translational applications: from colorants to mechanisms

Colorimetric sensing offers instant reporting via visible signals. Versus labor-intensive and instrument-dependent detection methods, colorimetric sensors present advantages including short acquisition time, high throughput screening, low cost, portability, and a user-friendly approach. These advantages have driven substantial growth in colorimetric sensors, particularly in point-of-care (POC) diagnostics. Rapid progress in nanotechnology, materials science, microfluidics technology, biomarker discovery, digital technology, and signal pattern analysis has led to a variety of colorimetric reagents and detection mechanisms, which are fundamental to advance colorimetric sensing applications. This review first summarizes the basic components (e.g., color reagents, recognition interactions, and sampling procedures) in the design of a colorimetric sensing system. It then presents the rationale design and typical examples of POC devices, e.g., lateral flow devices, microfluidic paper-based analytical devices, and wearable sensing devices. Two highlighted colorimetric formats are discussed: combinational and activatable systems based on the sensor-array and lock-and-key mechanisms, respectively. Case discussions in colorimetric assays are organized by the analyte identities. Finally, the review presents challenges and perspectives for the design and development of colorimetric detection schemes as well as applications. The goal of this review is to provide a foundational resource for developing colorimetric systems and underscoring the colorants and mechanisms that facilitate the continuing evolution of POC sensors.

Biocompatible metal-organic frameworks as promising platforms to eradicate HIV reservoirs ex vivo in people living with HIV

The HIV attacks the immune system provoking an infection that is considered a global health challenge. Despite antiretroviral treatments being effective in reducing the plasma viral load in the blood to undetectable levels in people living with HIV (PLWH), the disease is not cured and has become chronic. This happens because of the existence of anatomical and cellular viral reservoirs, mainly located in the lymph nodes and gastrointestinal tract, which are composed of infected CD4+ T cells with a resting memory phenotype and inaccessible to antiretroviral therapy. Herein, a new therapeutic strategy based on nanotechnology is presented. Different combinations of antiretroviral drugs (bictegravir/tenofovir/emtricitabine and nevirapine/tenofovir/emtricitabine) and toll-like receptor agonists were encapsulated into metal-organic frameworks (MOFs) PCN-224 and ZIF-8. The encapsulation efficiencies of all the drugs, as well as their release rate from the carriers, were measured. In vitro studies about the cell viability, the hemocompatibility, and the platelet aggregation of the MOFs were carried out. Epifluorescence microscopy assays confirmed the ability of ZIF-8 to target a carboxyfluorescein probe inside HeLa cell lines and PBMCs. These results pave the way for the use of these structures to eliminate latent HIV reservoirs from anatomical compartments through the activation of innate immune cells, and a higher efficacy of the triplet combinations of antiretroviral drugs.

The prophylactic and therapeutic impact of Trichinella spiralis larvae excretory secretory antigens- loaded Ca-BTC metal organic frameworks on induced murine colitis

Background: Inflammatory bowel disease is an autoimmune disease that affects the gut. T. spiralis larvae (E/S Ags) loaded on calcium-benzene-1,3,5-tricarboxylate metal-organic frameworks (Ca-BTC MOFs) were tested to determine whether they might prevent or cure acetic acid-induced murine colitis. Methods: T. spiralis larvae E/S Ags/Ca-BTC MOFs were used in prophylactic and therapeutic groups to either precede or follow the development of murine colitis. On the seventh day after colitis, mice were slaughtered. The effect of our target antigens on the progress of the colitis was evaluated using a variety of measures, including survival rate, disease activity index, colon weight/bodyweight, colon weight/length) ratios, and ratings for macroscopic and microscopic colon damage. The levels of inflammatory cytokines (interferon-γ and interleukin-4), oxidative stress marker malondialdehyde, and glutathione peroxidase in serum samples were evaluated. Foxp3 T-reg expression was carried out in colonic and splenic tissues. Results: T. spiralis larvae E/S Ags/Ca-BTC MOFs were the most effective in alleviating severe inflammation in murine colitis. The survival rate, disease activity index score, colon weight/length and colon weight/bodyweight ratios, and gross and microscopic colon damage scores have all considerably improved. A large decrease in proinflammatory cytokine (interferon-γ) and oxidative stress marker (malondialdehyde) expression and a significant increase in interleukin-4 and glutathione peroxidase expression were obtained. The expression of Foxp3+ Treg cells was elevated in colonic and splenic tissues. Conclusion: T. spiralis larvae E/S Ags/Ca-BTC MOFs had the highest anti-inflammatory, antioxidant, and cytoprotective capabilities against murine colitis and might be used to develop new preventative and treatment strategies.

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.

Recent advances in metal-organic frameworks for stimuli-responsive drug delivery

After entering the human body, drugs for treating diseases, which are prone to delivery and release in an uncontrolled manner, are affected by various factors. Based on this, many researchers utilize various microenvironmental changes encountered during drug delivery to trigger drug release and have proposed stimuli-responsive drug delivery systems. In recent years, metal-organic frameworks (MOFs) have become promising stimuli-responsive agents to release the loaded therapeutic agents at the target site to achieve more precise drug delivery due to their high drug loading, excellent biocompatibility, and high stimuli-responsiveness. The MOF-based stimuli-responsive systems can respond to various stimuli under pathological conditions at the site of the lesion, releasing the loaded therapeutic agent in a controlled manner, and improving the accuracy and safety of drug delivery. Due to the changes in different physical and chemical factors in the pathological process of diseases, the construction of stimuli-responsive systems based on MOFs has become a new direction in drug delivery and controlled release. Based on the background of the rapidly increasing attention to MOFs applied in drug delivery, we aim to review various MOF-based stimuli-responsive drug delivery systems and their response mechanisms to various stimuli. In addition, the current challenges and future perspectives of MOF-based stimuli-responsive drug delivery systems are also discussed in this review.

Research progress of metal-organic framework nanozymes in bacterial sensing, detection, and treatment

The high efficiency and specificity of enzymes make them play an important role in life activities, but the high cost, low stability and high sensitivity of natural enzymes severely restrict their application. In recent years, nanozymes have become convincing alternatives to natural enzymes, finding utility across diverse domains, including biosensing, antibacterial interventions, cancer treatment, and environmental preservation. Nanozymes are characterized by their remarkable attributes, encompassing high stability, cost-effectiveness and robust catalytic activity. Within the contemporary scientific landscape, metal-organic frameworks (MOFs) have garnered considerable attention, primarily due to their versatile applications, spanning catalysis. Notably, MOFs serve as scaffolds for the development of nanozymes, particularly in the context of bacterial detection and treatment. This paper presents a comprehensive review of recent literature pertaining to MOFs and their pivotal role in bacterial detection and treatment. We explored the limitations and prospects for the development of MOF-based nanozymes as a platform for bacterial detection and therapy, and anticipate their great potential and broader clinical applications in addressing medical challenges.

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.

Advancing Nanoscale Science: Synthesis and Bioprinting of Zeolitic Imidazole Framework-8 for Enhanced Anti-Infectious Therapeutic Efficacies

Bacterial infectious disorders are becoming a major health problem for public health. The zeolitic imidazole framework-8 with a novel Cordia myxa extract-based (CME@ZIF-8) nanocomposite showed variable functionality, high porosity, and bacteria-killing activity against Staphylococcus aureus, and Escherichia coli strains have been created by using a straightforward approach. The sizes of synthesized zeolitic imidazole framework-8 (ZIF-8) and CME@ZIF-8 were 11.38 nm and 12.44 nm, respectively. Prepared metal organic frameworks have been characterized by gas chromatography-mass spectroscopy, Fourier transform spectroscopy, UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An antibacterial potential comparison between CME@ZIF-8 and zeolitic imidazole framework-8 has shown that CME@ZIF-8 was 31.3%, 28.57%, 46%, and 47% more efficient than ZIF-8 against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, while it was 31.25%, 33.3%, 46%, and 46% more efficient than the commercially available ciprofloxacin drug against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, respectively, for 750, 500, 250, and 125 μg mL-1. Minimum inhibitory concentration values of CME@ZIF-8 for Escherichia coli and Staphylococcus aureus were 15.6 and 31.25 μg/mL respectively, while the value of zeolitic imidazole framework-8 alone was 62.5 μg/mL for both Escherichia coli and Staphylococcus aureus. The reactive oxygen species generated by CME@ZIF-8 destroys the bacterial cell and its organelles. Consequently, the CME@ZIF-8 nanocomposites have endless potential applications for treating infectious diseases.

Recent Advances in Multifunctional Reticular Framework Nanoparticles: A Paradigm Shift in Materials Science Road to a Structured Future

Porous organic frameworks (POFs) have become a highly sought-after research domain that offers a promising avenue for developing cutting-edge nanostructured materials, both in their pristine state and when subjected to various chemical and structural modifications. Metal-organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks are examples of these emerging materials that have gained significant attention due to their unique properties, such as high crystallinity, intrinsic porosity, unique structural regularity, diverse functionality, design flexibility, and outstanding stability. This review provides an overview of the state-of-the-art research on base-stable POFs, emphasizing the distinct pros and cons of reticular framework nanoparticles compared to other types of nanocluster materials. Thereafter, the review highlights the unique opportunity to produce multifunctional tailoring nanoparticles to meet specific application requirements. It is recommended that this potential for creating customized nanoparticles should be the driving force behind future synthesis efforts to tap the full potential of this multifaceted material category.

Application of honeybee venom loaded nanoparticles for the treatment of chronic toxoplasmosis: parasitological, histopathological, and immunohistochemical studies

Toxoplasma gondii is an opportunistic intracellular protozoon which may cause severe disease in the immunocompromised patients. Unfortunately, the majority of treatments on the market work against tachyzoites in the acute infection but can't affect tissue cysts in the chronic phase. So, this study aimed to evaluate the effect of bee venom (BV) loaded metal organic frameworks (MOFs) nanoparticles (NPs) for the treatment of chronic murine toxoplasmosis. Ninety laboratory Swiss Albino mice were divided into 9 groups (10 mice each); GI (negative control), GII (infected control), GIII-GXI (infected with Me49 strain of Toxoplasma and treated); GIII (MOFs-NPs), GIV and GV (BV alone and loaded on MOFs-NPs), GVI and GVII (spiramycin alone and loaded on MOFs-NPs), GVIII and GIX (ciprofloxacin alone and loaded on MOFs-NPs). Parasitological examination of brain cyst count, histopathological study of brain, retina, liver, and kidney tissue sections and immunohistochemical (IHC) evaluation of liver was performed. Counting of Toxoplasma brain cysts showed high statistically significant difference between the infected treated groups and GII. GV showed the least count of brain cysts; mean ± SD (281 ± 29.5). Histopathological examination revealed a marked ameliorative effect of BV administration when used alone or loaded MOFs-NPs. It significantly reduced tissue inflammation, degeneration, and fibrosis. IHC examination of liver sections revealed high density CD8+ infiltration in GII, low density CD8+ infiltration in GIII, GVI, GVII, GVIII, and GIX while GIV and GV showed intermediate density CD8+ infiltration. BV is a promising Apitherapy against chronic toxoplasmosis. This effect is markedly enhanced by MOFs-NPs.

Graphical abstract

Vein-Like Ni-BTC@Ni3S4 with Sulfur Vacancy and Ni3+ Fabricated In Situ Etching Vulcanization Strategy for an Electrochemical Sensor of Dopamine

In this study, a novel Ni-BTC@Ni₃S₄ composite was fabricated by solvothermal reaction using an in situ etching vulcanization strategy and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and Brunauer-Emmett-Teller (BET) analyses. The existence of a sulfur vacancy and Ni³⁺ in the as-prepared vein-like Ni-BTC@Ni₃S₄ greatly promoted the electrochemical sensing activity of the materials. Herein, a simple electrochemical sensor (Ni-BTC@Ni₃S₄/CPE) has been fabricated and used for the detection of dopamine (DA). The current signal of the Ni-BTC@Ni₃S₄/CPE-modified electrode was linear with the concentration of DA in the range of 0.05-750 μM (R² = 0.9995) with a sensitivity of 560.27 μA·mM^-1·cm^-2 and a detection limit of 0.016 μM. At the same time, the sensor has good stability and anti-interference ability. This study could provide a new idea and strategy for the structural regulation of composite electrode-modified materials and sensitive sensing detection of small biological molecules.

Switchable Ion Current Saturation Regimes Enabled via Heterostructured Nanofluidic Devices Based on Metal-Organic Frameworks

The use of track-etched membranes allows further fine-tuning of transport regimes and thus enables their use in (bio)sensing and energy-harvesting applications, among others. Recently, metal-organic frameworks (MOFs) have been combined with such membranes to further increase their potential. Herein, the creation of a single track-etched nanochannel modified with the UiO-66 MOF is proposed. By the interfacial growth method, UiO-66-confined synthesis fills the nanochannel completely and smoothly, yet its constructional porosity renders a heterostructure along the axial coordinate of the channel. The MOF heterostructure confers notorious changes in the transport regime of the nanofluidic device. In particular, the tortuosity provided by the micro- and mesostructure of UiO-66 added to its charged state leads to iontronic outputs characterized by an asymmetric ion current saturation for transmembrane voltages exceeding 0.3 V. Remarkably, this behavior can be easily and reversibly modulated by changing the pH of the media and it can also be maintained for a wide range of KCl concentrations. In addition, it is found that the modified-nanochannel functionality cannot be explained by considering just the intrinsic microporosity of UiO-66, but rather the constructional porosity that arises during the MOF growth process plays a central and dominant role.

Nanoscale MOFs: From synthesis to drug delivery and theranostics applications

Since the first report in 1989, Metal-Organic Frameworks (MOFs) self-assembled from metal ions or clusters, as well as organic linkers, have attracted extensive attention. Due to their flexible composition, large surface areas, modifiable surface properties, and their degradability, there has been an exponential increase in the study of MOFs materials, specifically in drug delivery system areas such as infection, diabetes, pulmonary disease, ocular disease, imaging, tumor therapy, and especially cancer theranostics. In this review, we discuss the trends in MOFs biosafety, from "green" synthesis to applications in drug delivery systems. Firstly, we present the different "green" synthesis approaches used to prepare MOFs materials. Secondly, we detail the methods for the functional coating, either through grafting targeting units, poly(ethylene glycol) (PEG) chains or by using cell membranes. Then, we discuss drug encapsulation strategies, host-guest interactions, as well as drug release mechanisms. Lastly, we report on the drug delivery applications of nanoscale MOFs. In particular, we discuss MOFs-based imaging techniques, including magnetic resonance imaging (MRI), photoacoustic imaging (PAI), positron emission tomography (PET), and fluorescence imaging. MOFs-based cancer therapy methods are also presented, such as photothermal therapy (PTT), photodynamic therapy (PDT), radiotherapy (RT), chemotherapy, and immunotherapy.

Metal-organic frameworks for pharmaceutical and biomedical applications

Metal-organic framework (MOF) materials provide unprecedented opportunities for evaluating valuable compounds for various medical applications. MOFs merged with biomolecules, used as novel biomaterials, have become particularly useful in biological environments. Bio-MOFs can be promising materials in the global to avoid utilization above toxicological substances. Bio-MOFs with crystallin and porosity nature offer flexible structure via bio-linker and metal node variation, which improves their wide applicability in medical science.

Prospective Role of Bioactive Molecules and Exosomes in the Therapeutic Potential of Camel Milk against Human Diseases: An Updated Perspective

Camel milk (CM) constitutes an important dietary source in the hot and arid regions of the world. CM is a colloidal mixture of nutritional components (proteins, carbohydrates, lipids, vitamins, and minerals) and non-nutritional components (hormones, growth factors, cytokines, immunoglobulins, and exosomes). Although the majority of previous research has been focused on the nutritional components of CM; there has been immense interest in the non-nutritional components in the recent past. Reckoning with these, in this review, we have provided a glimpse of the recent trends in CM research endeavors and attempted to provide our perspective on the therapeutic efficacy of the nutritional and non-nutritional components of CM. Interestingly, with concerted efforts from the research fraternities, convincing evidence for the better understanding of the claimed traditional health benefits of CM can be foreseen with great enthusiasm and is indeed eagerly anticipated.