Functionalization of mixed ligand metal-organic frameworks as the transport vehicles for drugs

Biomimetic functionalized metal organic frameworks as multifunctional agents: Paving the way for cancer vaccine advances

Biomimetic functionalized metal-organic frameworks (Fn-MOFs) represent a cutting-edge approach in the realm of cancer vaccines. These multifunctional agents, inspired by biological systems, offer unprecedented opportunities for the development of next-generation cancer vaccines. The vast surface area, tunable pore size, and diverse chemistry of MOFs provide a versatile scaffold for the encapsulation and protection of antigenic components, crucial for vaccine stability and delivery. This work delves into the innovative design and application of Fn-MOFs, highlighting their role as carriers for immune enhancement and their potential to revolutionize vaccine delivery. By mimicking natural processes, Fn-MOFs, with their ability to be functionalized with a myriad of chemical and biological entities, exhibit superior biocompatibility and stimuli-responsive behavior and facilitate targeted delivery to tumor sites. This review encapsulates the latest advancements in Fn-MOF technology, from their synthesis and surface modification to their integration into stimuli-responsive and combination therapies. It underscores the significance of biomimetic approaches in overcoming current challenges in cancer vaccine development, such as antigen stability and immune evasion. By leveraging the biomimetic nature of Fn-MOFs, this work paves the way for innovative strategies in cancer vaccines, aiming to induce potent and long-lasting immune responses against malignancies.

Eco-Friendly Sustainable and Responsive High-Performance Benzotriazole-Metal Organic Frameworks/Silica Composite Coating with Active/Passive Corrosion Protection on Copper

Coatings with only passive protection cannot offer long-term anticorrosion on metals. Eco-friendly sustainable and responsive coating for active/passive corrosion protection is desirable to extend the service life of metals. Here, benzotriazole (BTA)-metal organic frameworks (Cu-MOFs, UiO-66) were embedded in silica (SiO2) coating by one-step electrodeposition on copper. Combined with passive capability of MOFs and active protection of BTA inhibitor, the composite coating (BTA-MOF/SiO2) exhibited high and stable corrosion resistance, confirmed by microstructure characterizations and electrochemical tests. As a result, the as-prepared composite coating exhibited superhydrophobicity with a water contact angle of 154.2°. With loading of BTA-MOF in SiO2 coating, the impedance modulus at 0.01 Hz increased by ∼10-fold and the corrosion current density decreased to 3.472 × 10-9 A·cm-2. Immersion and salt spray tests confirmed the long-term protection of the composite coating. The responsive release of BTA inhibitor endows the coating with a responsively anticorrosive behavior. The active-passive ability makes the coating a good candidate for protection on metals used in highly salty environments.

Effects of Fluorinated Functionalization of Linker on Quercetin Encapsulation, Release and Hela Cell Cytotoxicity of Cu-Based MOFs as Smart pH-Stimuli Nanocarriers

Controlled delivery of target molecules is required in many medical and chemical applications. For such purposes, metal-organic frameworks (MOFs), which possess desirable features such as high porosity, large surface area, and adjustable functionalities, hold great potential as drug carriers. Herein, Quercetin (QU), as an anticancer drug, was loaded on Cu2 (BDC)2 (DABCO) and Cu2 (F4 BDC)2 )DABCO) MOFs (BDC=1,4-benzenedicarboxylate and DABCO=1,4-diazabicyclo[2.2.2]octane). As these Cu-MOFs have a high surface area, an appropriate pore size, and biocompatible ingredients, they can be utilized to deliver QU. The loading efficiency of QU in these MOFs was 49.5 % and 41.3 %, respectively. The drug-loaded compounds displayed sustained drug release over 15 days, remarkably high drug loading capacities and pH-controlled release behavior. The prepared nanostructures were characterized by different characterization technics including FT-IR, PXRD, ZP, TEM, FE-SEM, UV-vis, and BET. In addition, MTT assays were carried out on the HEK-293 and HeLa cell lines to investigate cytotoxicity. Cellular apoptosis analysis was performed to investigate the cell death mechanisms. Grand Canonical Monte Carlo simulations were conducted to analyze the interactions between MOFs and QU. Moreover, the stability of MOFs was also investigated during and after the drug release process. Ultimately, kinetic models of drug release were evaluated.

Exploring the antimicrobial potential of isoniazid loaded Cu-based metal-organic frameworks as a novel strategy for effective killing of Mycobacterium tuberculosis

Tuberculosis (TB) remains one of the most infectious pathogens with the highest human mortality and morbidity. Biofilm formation during Mycobacterium tuberculosis (Mtb) infection is responsible for bacterial growth, communication, and, most essentially, increased resistance/tolerance to antibiotics leading to higher bacterial persistence. Thus, biofilm growth is presently considered a key virulence factor in the case of chronic disease. Metal-Organic Frameworks (MOFs) have recently emerged as a highly efficient system to improve existing antibiotics' therapeutic efficacy and reduce adverse effects. In this regard, we have synthesized Cu-MOF (IITI-3) using a solvothermal approach. IITI-3 was well characterized by various spectroscopic techniques. Herein, IITI-3 was first encapsulated with isoniazid (INH) to form INH@IITI-3 with 10 wt% loading within 1 hour. INH@IITI-3 was well characterized by PXRD, TGA, FTIR, and BET surface area analysis. Furthermore, the drug release kinetics studies of INH@IITI-3 have been performed at pH 5.8 and 7.4 to mimic the small intestine and blood pH, respectively. The results show that drug release follows first-order kinetics. Furthermore, the antimycobacterial activity of INH@IITI-3 demonstrated significant bacterial killing and altered the structural morphology of the bacteria. Moreover, INH@IITI-3 was able to inhibit the mycobacterial biofilm formation upon treatment and showed less cytotoxicity toward the murine RAW264.7 macrophages. Thus, this work significantly opens up new possibilities for the applications of INH@IITI-3 in biofilm infections in Mtb and further contributes to TB therapeutics.

Density Functional Theory Study of Synergistic Gas Sensing Using an Electrically Conductive Mixed Ligand Two-Dimensional Metal-Organic Framework

Two-dimensional conductive metal-organic frameworks (2D-cMOFs) have been adopted in electrochemical sensing applications owing to their superior electrical conductivity and large surface area. Here, we performed a density functional theory (DFT) analysis to study the synergistic impact of introducing a secondary organic ligand to the 2D-cMOF system. In this study, cobalt-hexaiminobenzene (Co-HIB) and cobalt-2,3,6,7,10,11-hexaiminotriphenylene (Co-HITP) were combined to form a mixed ligand MOF named, Co-HIB-HITP. A DFT-level comparative study was designed to access stability, synergistic gas adsorption capability, and gas adsorption mechanism, important factors in sensing material development. A potential energy surface calculation predicted the structural stability of Co-HIB-HITP at larger interlayer displacements around 3.6-4.2 Å regions along the ab-plane than its unmixed states, Co-HIB and Co-HITP, indicating the tunability of the stacking mode using the mixed ligand system. Furthermore, the adsorption capabilities toward toxic gases, NH3, H2S, NO, and NO2, were investigated, and Co-HIB-HITP revealed superiority over unmixed 2D-cMOFs in H2S and NH3 gas adsorption energies by showing 158 and 170% improvement, respectively. Finally, an electron charge density analysis revealed Co-HIB-HITP's unique stacking mode and Co-metal density as contributing factors to its gas-selective synergy effect. The AB stacked layers and an intermediate metal density (5.25%) significantly improved the electrostatic interactions with H2S and NH3 by inducing a change in the chemical environment of the gas binding sites. This work proposes the dual-ligand 2D-cMOF as the promising design strategy for the next-generation sensing material.

Functionalized nanozyme with drug loading for enhanced tumour combination treatment of catalytic therapy and chemotherapy

Nanozyme-based tumour catalytic therapy has attracted widespread attention in recent years, but the therapeutic efficacy is limited due to the trapping of hydroxyl radicals (˙OH) by endogenous glutathione (GSH) in the tumour microenvironment (TME). Zr/Ce-MOFs/DOX/MnO2 is constructed in this work to serve as a new kind of nanozyme for combination chemotherapy and catalytic treatment. Zr/Ce-MOFs can produce ˙OH in a mimic TME, and the MnO2 on the surface could deplete the GSH, further promoting the ˙OH generation. The pH/GSH dual stimulation accelerates the release of anticancer drug doxorubicin (DOX) in tumour tissue for enhanced tumour chemotherapy. Moreover, Mn2+ produced by the reaction of Zr/Ce-MOFs/DOX/MnO2 and GSH can be used as the contrast agent for T1-MRI. The potential antitumour effect of Zr/Ce-MOFs/DOX/MnO2 is demonstrated by in vitro and in vivo cancer treatment tests. This work thus provides a new nanozyme-based platform for enhanced combination chemotherapy and catalytic treatment for tumours.

Tailoring the band-gap, optical and fluorescent properties of 3,5-diaminobenzoic acid via functionalization with chemical groups: A DFT study

3,5-diaminobenzoic acid (3,5-DABA) with chemical formula C₇H₈N₂O₂ was functionalized with CH₃-, OH-, NH₂- and NO₂- to obtain: CH₃-3,5 DABA, OH-3,5 DABA, NH₂-3,5DABA and NO₂-3,5DABA. These molecules were built with Gauss view 6.0 and their structural, spectroscopic, optoelectronic and molecular properties were investigated using density functional theory (DFT). B3LYP (Becke's 3-parameter exchange functional with Lee-Yang-Parr correlation energy) functional and 6-311+ G (d, p) basis set were used to understand their reactivity, stability and optical activity. Integral equation formalism polarizable continuum model (IEF - PCM) was used to calculate the absorption wavelength, energy required to excite the molecules and oscillator strength. Our results reveal that the functionalization of 3,5 DABA with the groups caused a decrease of the energy gap from 0.1563 eV, to 0.1461 eV, 0.13818 eV and 0.13811 eV in NO₂-3,5DABA, OH-3,5DABA and NH₂-3,5DABA respectively. The lowest energy gap of 0.13811 eV for NH₂-3,5DABA is in good agreement with its highest reactivity value (global softness of 7.240). The most observed significant donor - acceptor NBO interactions where found to occur between *ΠC16-O17 → *ΠC1-C2, *ΠC3-C4→ *ΠC1-C2, *ΠC1-C2 → *ΠC5-C6, *ΠC3-C4 → *ΠC5-C6, *ΠC2-C3 →*ΠC4-C5 natural bond orbitals having second- order stabilization energies of 101.95 kcal/mol, 368.41 kcal/mol, 174.51 kcal/mol, 255.63 kcal/mol and 235.92 kcal/mol in 3,5-DABA, CH₃-3,5-DABA, OH-3,5-DABA, NH₂-3,5-DABA and NO₂-3,5-DABA respectively. The highest perturbation energy was observed in CH₃-3,5DABA while the lowest perturbation energy was observed in 3,5DABA. The absorption band of the compounds were observed in the order: NH₂-3,5DABA (404 nm) > N0₂-3,5DABA (393 nm) > OH-3,5DABA (386 nm) > 3,5DABA (349 nm) > CH3-3,5DABA (347 nm).

Synthesis and characterization of novel denosumab/magnesium-based metal organic frameworks nanocomposite prepared by ultrasonic route as drug delivery system for the treatment of osteoporosis

Introduction: The metal-organic frameworks (MOF) have shown fascinating possibilities in biomedical applications, and designing a drug delivery system (DDS) based on the MOF is important. This work aimed at developing a suitable DDS based on Denosumab-loaded Metal Organic Framework/Magnesium (DSB@MOF (Mg)) for attenuating osteoarthritis. Materials and Methods: The MOF (Mg) (Mg3(BPT)2(H2O)4) was synthesized using a sonochemical protocol. The efficiency of MOF (Mg) as a DDS was evaluated by loading and releasing DSB as a drug. In addition, the performance of MOF (Mg) was evaluated by releasing Mg ions for bone formation. The MOF (Mg) and DSB@MOF (Mg) cytotoxicity towards the MG63 cells were explored by MTT assay. Results: MOF (Mg) characterized by using XRD, SEM, EDX, TGA, and BET. Drug loading, and releasing experiments proved that DSB was loaded on the MOF (Mg) and approximately 72% DSB was released from it after 8 h. The characterization techniques showed that MOF (Mg) was successfully synthesized with good crystal structure and thermal stability. The result of BET showed that MOF (Mg) had high surface areas and pore volume. This is the reason why its 25.73% DSB was loaded in the subsequent drug-loading experiment. Drug release and ion release experiments indicated DSB@MOF (Mg) had a good controlled release of DSB and Mg ions in solution. Cytotoxicity assay confirmed that the optimum dose of it had excellent biocompatibility and could stimulate the proliferation of MG63 cells as time went on. Conclusion: Due to the high loading amount of DSB and releasing time, DSB@MOF (Mg) can be promising as a suitable candidate for relieving bone pain caused by osteoporosis, with ossification-reinforcing functions.

A chiral metal-organic framework {(HQA)(ZnCl2)(2.5H2O)}n for the enantioseparation of chiral amino acids and drugs

Chiral metal-organic frameworks (CMOFs) with enantiomeric subunits have been employed in chiral chemistry. In this study, a CMOF formed from 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid (HQA) and ZnCl₂, {(HQA)(ZnCl₂)(2.5H₂O)}_n, was constructed as a chiral stationary phase (CSP) via an in situ fabrication approach and used for chiral amino acid and drug analyses for the first time. The {(HQA)(ZnCl₂)(2.5H₂O)}_n nanocrystal and the corresponding chiral stationary phase were systematically characterised using a series of analytical techniques including scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, circular dichroism, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller surface area measurements. In open-tubular capillary electrochromatography (CEC), the novel chiral column exhibited strong and broad enantioselectivity toward a variety of chiral analytes, including 19 racemic dansyl amino acids and several model chiral drugs (both acidic and basic). The chiral CEC conditions were optimised, and the enantioseparation mechanisms are discussed. This study not only introduces a new high-efficiency member of the MOF-type CSP family but also demonstrates the potential of improving the enantioselectivities of traditional chiral recognition reagents by fully using the inherent characteristics of porous organic frameworks.

Metal-Organic Frameworks and Their Biodegradable Composites for Controlled Delivery of Antimicrobial Drugs

Antimicrobial resistance (AMR) is a growing global crisis with an increasing number of untreatable or exceedingly difficult-to-treat bacterial infections, due to their growing resistance to existing drugs. It is predicted that AMR will be the leading cause of death by 2050. In addition to ongoing efforts on preventive strategies and infection control, there is ongoing research towards the development of novel vaccines, antimicrobial agents, and optimised diagnostic practices to address AMR. However, developing new therapeutic agents and medicines can be a lengthy process. Therefore, there is a parallel ongoing worldwide effort to develop materials for optimised drug delivery to improve efficacy and minimise AMR. Examples of such materials include functionalisation of surfaces so that they can become self-disinfecting or non-fouling, and the development of nanoparticles with promising antimicrobial properties attributed to their ability to damage numerous essential components of pathogens. A relatively new class of materials, metal-organic frameworks (MOFs), is also being investigated for their ability to act as carriers of antimicrobial agents, because of their ultrahigh porosity and modular structures, which can be engineered to control the delivery mechanism of loaded drugs. Biodegradable polymers have also been found to show promising applications as antimicrobial carriers; and, recently, several studies have been reported on delivery of antimicrobial drugs using composites of MOF and biodegradable polymers. This review article reflects on MOFs and polymer-MOF composites, as carriers and delivery agents of antimicrobial drugs, that have been studied recently, and provides an overview of the state of the art in this highly topical area of research.

Magnetic Zr-Based Metal-Organic Frameworks: A Highly Efficient Au (III) Trapper for Gold Recycling

In this work, the magnetic Zr-based MOF composites with excellent retrievability were prepared using Fe₃O₄@SiO₂ as the core and UiO-66-NH₂ as the shell. Fe₃O₄@SiO₂ core could introduce mesopores and result in capillary condensation in MOF composites, which aggravated with the dosage of Fe₃O₄@SiO₂. The as-synthesized MOF composites could be rapidly retrieved from aqueous solution via magnetic separation in 10 seconds. pH imposed an important effect on Au (III) adsorption by governing the ion exchange and electrostatic interaction between Au (III) anions and adsorbents, and the optimal adsorption happened at pH 7. The adsorption process fitted well with the pseudo-second order kinetics model and Langmuir adsorption model. The maximum adsorption capacity of Au (III) by FSUN-10 and FSUN-50 at 298 K were determined to be 611.18 mg∙g^-1 and 463.85 mg∙g^-1, respectively. Additionally, Au (III) uptakes increased with temperature. Beyond experiments, the adsorption mechanisms were thoroughly studied through systematic characterization, molecular dynamics simulation (MDS) and density functional theory (DFT) study. It was verified that Au (III) was adsorbed via coordination to hydroxyl and amino groups and was reduced to Au (I) and Au (0) by amino groups. The diffusion coefficient of Au (III) along UiO-66-NH₂ was calculated to be 5.8 × 10^-5 cm²∙s^-1. Moreover, the magnetic Zr-based MOF composites exhibit great industrial value in gold recycling with high adsorption selectivity and good recyclability.

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.

Copper-based metal-organic frameworks for biomedical applications

Metal-organic frameworks (MOFs) are a class of important porous, crystalline materials composed of metal ions (clusters) and organic ligands. Owing to the unique redox chemistry, photochemical and electrical property, and catalytic activity of Cu^2+/+, copper-based MOFs (Cu-MOFs) have been recently and extensively explored in various biomedical fields. In this review, we first make a brief introduction to the synthesis of Cu-MOFs and their composites, and highlight the recent synthetic strategies of two most studied representatives, three-dimensional HKUST-1 and two-dimensional Cu-TCPP. The recent advances of Cu-MOFs in the applications of cancer treatment, bacterial inhibition, biosensing, biocatalysis, and wound healing are summarized and discussed. Furthermore, we propose a prospect of the future development of Cu-MOFs in biomedical fields and beyond.

Designing of robust and sensitive assay via encapsulation of highly emissive and stable blue copper nanocluster into zeolitic imidazole framework (ZIF-8) with quantitative detection of tetracycline

Metal–organic frameworks (MOFs) with high stability and porosity have gained great attention in bioanalysis due to their potential in improving sensitivity and robustness of assays. Herein, to improve both the stability and the emission intensity of Cu nanoclusters (CuNCs), in situ entrapment strategy of CuNCs into zeolitic imidazolate framework-8 (ZIF-8) is described. Blue emissive and stable CuNCs was prepared, for the first time, using thiamine hydrochloride as capping agents, and showed strong and stable emission at 440 nm when excited at 375 nm with fluorescence quantum yields 12%. Encapsulation of CuNC into ZIF-8 showed dramatic enhancement of the fluorescence intensity up to 53% fluorescence quantum yield. Furthermore, the CuNCs@ZIF-8 possesses better stability (more than three months) due to protective and confinement effect of MOFs. Upon the addition of tetracycline to CuNCs@ZIF-8 solution, the blue emission intensity was significantly decreased. The fluorescence ratio (Fo/F) against the concentration of tetracycline exhibited a satisfactory linear relationship from 1.0 to 10.0 µM with a detection limit (LOD) of 0.30 µM. The current probe was applied for quantification of tetracycline in drug sample with satisfactory accuracy and precision.

Graphical abstract

Strategic Modulation of Target-Specific Isolated Fe,Co Single-Atom Active Sites for Oxygen Electrocatalysis Impacting High Power Zn-Air Battery

An effective modulation of the active sites in a bifunctional electrocatalyst is essentially desired, and it is a challenge to outperform the state-of-the-art catalysts toward oxygen electrocatalysis. Herein, we report the development of a bifunctional electrocatalyst having target-specific Fe-N₄/C and Co-N₄/C isolated active sites, exhibiting a symbiotic effect on overall oxygen electrocatalysis performances. The dualism of N-dopants and binary metals lower the d-band centers of both Fe and Co in the Fe,Co,N-C catalyst, improving the overpotential of the overall electrocatalytic processes (ΔE_ORR-OER = 0.74 ± 0.02 V vs RHE). Finally, the Fe,Co,N-C showed a high areal power density of 198.4 mW cm^-2 and 158 mW cm^-2 in the respective liquid and solid-state Zn-air batteries (ZABs), demonstrating suitable candidature of the active material as air cathode material in ZABs.

Journey to the Market: The Evolution of Biodegradable Drug Delivery Systems

Biodegradable polymers have been used as carriers in drug delivery systems for more than four decades. Early work used crude natural materials for particle fabrication, whereas more recent work has utilized synthetic polymers. Applications include the macroscale, the microscale, and the nanoscale. Since pioneering work in the 1960’s, an array of products that use biodegradable polymers to encapsulate the desired drug payload have been approved for human use by international regulatory agencies. The commercial success of these products has led to further research in the field aimed at bringing forward new formulation types for improved delivery of various small molecule and biologic drugs. Here, we review recent advances in the development of these materials and we provide insight on their drug delivery application. We also address payload encapsulation and drug release mechanisms from biodegradable formulations and their application in approved therapeutic products.

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.

Facile synthesis of Zn-based metal-organic framework in the presence of carboxymethyl cellulose: A safe carrier for ibuprofen

Fabrication of porous materials with a high surface area affords a great interest to achieve a system with a prolonged drug release manner. In this context, the subject of this work is to describe a novel green one-pot synthesis route for the growth of metal-organic framework (MOF) from zinc metal (Zn) and 1, 4-benzene dicarboxylic acid (BDC) in the vicinity of the carboxymethyl cellulose (CMC), which homogeneously confined in the biopolymeric chains. The synthesized Zn (BDC)@CMC was characterized and confirmed using different analyses. N₂ adsorption/desorption isotherms determined the mean diameter of pore size of about 2.3993 nm. Ibuprofen (IBU) as a model drug was highly loaded to the Zn(BDC)@CMC by immersing in the drug solution; 50.95%. The in vitro IBU release study indicated that the Zn(BDC)@CMC has more attractive performances than pristine Zn(BDC). The IBU release occurred via the Fickian mechanism. Isotherm studies showed that the IBU adsorption on obeys from Langmuir isotherm; R² 0.9623. The MTT results revealed the HEK 293A cell viability of higher than 90% for Zn(BDC)@CMC that confirms its cytocompatibility. Overall, obtained results confirm the functionality of CMC biopolymer for in situ growth of MOF in the presence of it due to having the reactive nature.

Ultrasensitive and Selective Detection of Uranium by a Luminescent Terbium-Organic Framework

Detection and remediation of radioactive components have become the focus of worldwide research interest due to the ever-increasing generation of nuclear waste and the concerns on nuclear accidents. Among the numerous radionuclides, uranium and its isotopes receive the most attention because of their high proportion in nuclear waste and long half-life. Herein, a highly luminescent terbium-organic framework, formulated as [Tb₄(C₂₉O₈H₁₇)₂(NO₃)₄(DMF)₄(H₂O)₄]·4H₂O·8.5DMF (YTU-100), with exceptional sensitivity and selectivity toward uranium was successfully prepared. The material exhibits fast adsorption kinetics and moderate sorption capacity. Interestingly, the luminescence intensity variation highly correlates to the amount of adsorbed uranium, which results in a quantitative, accurate, and selective uranium detection manner. The detection limits in deionized water and tap water were determined to be 1.07 and 0.75 ppb, respectively, which are lower than the US Environmental Protection Agency standard of the maximum contamination of uranium in drinking water. YTU-100 offers an alternative approach for building multifunctional MOFs used for simultaneous detection and removal of uranium from aqueous solutions.

Synthesis of a novel ternary ZIF-8/GO/MgFe2O4 nanocomposite and its application in drug delivery

In recent year, metal-organic frameworks (MOFs) have been displayed to be a category of promising drug delivery systems because of their crystalline structure, the potential of further functionality, and high porosity. In this research, graphene oxide was synthesized from pure graphite via hummer method and then MgFe2O4 nanoparticles was incorporated into the synthesized ZIF-8 metal-organic frameworks which followed with loading on the surfaces of graphene oxide. In continue, tetracycline as an antibiotic drug was loaded on the surfaces and the cavities of the prepared nanocomposite. The outcomes of this research revealed that 90% of the tetracycline was loaded on the synthesized ZIF-8/GO/MgFe2O4 nanostructure. Next, drug release was done at pH: 5 and pH: 7.4 within 3 days, resulting about 88% and 92% release of the tetracycline, respectively. With using different spectroscopic methods like X-ray crystallography (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermalgravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET), the structure of synthesized materials was confirmed. Furthermore, the antibiotic activity of tetracycline trapped into the ZIF-8/GO/MgFe2O4 was evaluated by agar-well diffusion method on both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, which showed good antibacterial results.

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.

Recent advances in MOF-based nanoplatforms generating reactive species for chemodynamic therapy

Still today, cancer remains a threat to human health. Possible common treatments to cure this disease include chemotherapy (CT), radiotherapy (RT), photothermal therapy (PTT), and surgical resection, which give unreasonable results because of their limited efficiency and also lead to side-effects. Hence, different strategies are now being exploited to not only enhance the efficiency of these traditional therapeutic methods or treat the tumor cells but also curtail the side effects. A latest method with authentic proof of chemodynamic therapy (CDT) utilizing the Fenton reaction is now gaining importance. This approach, which is developed based on the high level of hydrogen peroxide (H2O2) in a tumor microenvironment (TME), can be used to catalyze the Fenton reaction to generate cancer cell-killing reactive oxygen species (ROS). The selection of materials is extremely important and nanomaterials offer the most likely method to facilitate CDT. Among various materials, metal-organic frameworks (MOFs) which have been extensively applied in medical areas are regarded as a promising material and possess potential for the next generation of nanotechnology. This review focuses on summarizing the use of MOFs in CDT and their synergetic therapeutics as well as the challenges, obstacles, and development.

Modification of Metal-Organic Framework Nanoparticles Using Dental Pulp Mesenchymal Stem Cell Membranes to Target Oral Squamous Cell Carcinoma

Engineering a targetable nanoparticle to tumor cell is a challenge issue for clinical application. Our results demonstrated that the chemokine CXCL8 secreted by oral squamous cell carcinoma (OSCC) could act as a chemoattractant to attract dental pulp mesenchymal stem cell (DPSC), which expressed the CXCL8 binding receptor, CXCR2, to the OSCC. Therefore, to create OSCC targetable nanoparticles, we used DPSC membranes to modify nanoparticles of metal-organic framework nanoparticles (MOFs) resulting in a novel MOF@DPSCM nanoparticle. Interestingly, results from in vitro and in vivo experiments illustrated that MOF@DPSCM possessed specificity for the OSCC, and the MOF@DPSCM carried DOX (doxorubicin), MOF-DOX@DPSCM could induce CAL27 cell death in vitro and block CAL27 tumor growth in vivo. Our data suggest that this novel MOF-DOX@DPSCM nanoparticle is a potential targetable drug delivery system for the OSCC in the future clinical application.

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.

Development of a pH-sensitive functionalized metal organic framework: in vitro study for simultaneous delivery of doxorubicin and cyclophosphamide in breast cancer

Exploration of an efficient dual-drug based nanocarrier with high drug loading capacity, specific targeting properties, and long-term stability is highly desirable in cancer therapy. Metal–organic frameworks (MOFs) have proven to be a promising class of drug carriers due to their high porosity, crystalline properties with defined structure information, and their potential for further functionalization. To enhance the drug efficacy as well as to overcome the burst effect of drugs, here we synthesized a pH responsive folic acid (FA) and graphene oxide (GO) decorated zeolitical imidazolate frameworks-8 (GO–FA/ZIF-8), for targeted delivery of doxorubicin (DOX) and cyclophosphamide (CP), simultaneously. In this system, DOX molecules were encapsulated in the pores of ZIF-8 during in situ synthesis of ZIF-8 and CP molecules have been captured by the GO surface via hydrogen bonding and π–π interactions as well. Furthermore, the resulting pH-responsive nanocarrier (DOX@ZIF-8/GO–FA/CP) showed in vitro sustained release characteristics (76% of DOX and 80% of CP) by cleavage of chemical bonding and disruption of the MOFs structure under acidic condition (at pH 5.6). Moreover, DOX@ZIF-8/GO–FA/CP has synergistic cytotoxic effects as compared to the combination of both the drugs without ZIF-8/GO–FA when treating MCF-7 and MDA-MB-231 breast cancer cell lines (with a combination index of 0.29 and 0.75 for MCF-7 and MDA-MB-231 cell-lines, respectively). Hence this system can be applied as an effective platform for smart dual drug delivery in breast cancer treatment through its remarkable manageable multidrug release.

Exploration of an efficient dual-drug based nanocarrier with high drug loading capacity, specific targeting properties, and long-term stability is highly desirable in cancer therapy.

Luminescent probes for hypochlorous acid in vitro and in vivo

HClO/ClO^- is the most effective antibacterial active oxygen in neutrophils. However, its excessive existence often leads to the destruction of human physiological mechanisms. In recent years, the developed luminescent probes for the detection of HClO/ClO^- are not only conducive to improve the sensitivity and selectivity of HClO/ClO^- detection, but also play a crucial role in understanding the biological functions of HClO/ClO^-. In addition, luminescent probe-based biological imaging for HClO/ClO^- at sub-cellular resolution has become a powerful tool for biopathology and medical diagnostic research. This article reviews a variety of luminescent probes for the detection of HClO/ClO^-in vitro and in vivo with different design principles and mechanisms, including fluorescence, phosphorescence, and chemiluminescence. The photophysical/chemical properties and biological applications of these luminescent probes were outlined. Finally, we summarized the merits and demerits of the developed luminescent probes and discussed their challenges and future development trends. It is hoped that this review can provide some inspiration for the development of luminescent probe-based strategies and to promote the further research of biomedical luminescent probes for HClO/ClO^-.

Facile preparation of pH-sensitive chitosan microspheres for delivery of curcumin; characterization, drug release kinetics and evaluation of anticancer activity

Curcumin (CUR) is a lowly water-soluble natural polyphenol with chemopreventive and chemotherapeutic activities. Hence, to achieve the system with good CUR loading ability, porous MIL-88 (Fe) was prepared in the presence of the presynthesized graphene quantum dots (GQDs) (GQDs@MIL-88 (Fe)). In the following, CUR loaded in the fabricated GQDs@MIL-88 (Fe) nanohybrid. The characterization techniques; Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), and Brunauer-Emmett-Teller (BET) analysis showed success in the synthesis of GQDs@MIL-88 (Fe). Moreover, the FT-IR analysis displayed the loading of CUR and the formation of CUR@GQDs@MIL-88(Fe). Chitosan (CS) was used as a green coating to enhance the biocompatibility of the prepared system (CS/CUR@GQDs@MIL-88(Fe). The fabricated microspheres showed pH-sensitive swelling behavior and released 38.3% of CUR in pH 5.0 which is better fitted with the First-order kinetic model (R² = 0.9726). In comparison with CUR@GQDs@MIL-88(Fe), the MTT and DAPI assay exhibited less toxic effect for CS/CUR@GQDs@MIL-88(Fe) against MDA-MB 231 cells. Moreover, the safety of the CS/CUR@GQDs@MIL-88(Fe) confirmed after incubation against MCF 10A as a model of the normal cell line. The results conveyed a new concept that the CS/CUR@GQDs@MIL-88(Fe) is a potential candidate for using as a biocompatible carrier with controlled drug delivery ability.

PPI-Dendrimer-Functionalized Magnetic Metal-Organic Framework (Fe3O4@MOF@PPI) with High Adsorption Capacity for Sustainable Wastewater Treatment

Herein, a magnetic zirconium-based metal-organic framework nanocomposite was synthesized by a simple solvothermal method and used as an adsorbent for the removal of direct and acid dyes from aqueous solution. To enhance its adsorption performance, poly(propyleneimine) dendrimer was used to functionalize the as-synthesized magnetic porous nanocomposite. The dendrimer-functionalized magnetic nanocomposite was characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibration sample magnetometer. The obtained results revealed the successful synthesis and functionalization of the magnetic nanocomposite. The adsorbents exhibited good magnetic properties with high saturation magnetization and high specific surface area. The adsorption isotherms and kinetics of anionic dyes were described by the Freundlich and pseudo-second-order models, respectively. It was found that the kinetics of adsorption of both the investigated dyes by the dendrimer-functionalized magnetic composite is considerably faster than the magnetic composite under the same condition. The adsorption capacity of the dendrimer-functionalized magnetic composite for investigated direct and acid dyes was 173.7 and 122.5 mg/g, respectively, which was higher than those of the existing magnetic adsorbents. This work provides new insights into the synthesis and application of hybrid magnetic adsorbents with synergistic properties of nanoporous metal-organic frameworks and dendrimer with a large number of functional groups for the removal of organic dyes.

Chemical fixation of CO2 into cyclic carbonates catalyzed by bimetal mixed MOFs: the role of the interaction between Co and Zn

Catalytic conversion of carbon dioxide into cyclic carbonates in the presence of bimetal mixed MOFs.

Development of Nickel-BTC-MOF-Derived Nanocomposites with rGO Towards Electrocatalytic Oxidation of Methanol and Its Product Analysis

In this study, electrochemical oxidation of methanol to formic acid using the economical and highly active catalytic Nickel Benzene tricarboxylic acid metal organic framework (Ni-BTC-MOF) and reduced graphene oxide (rGO) nanocomposites modified glassy carbon electrode GCE in alkaline media, which was examined via cyclic voltammetry technique. Nickel based MOF and rGO nanocomposites were prepared by solvothermal approach, followed by morphological and structural characterization of prepared samples through X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and energy dispersive X-ray (EDX) analysis. The electrochemical testing of synthesized materials represents the effect of the sequential increase in rGO concentration on electrocatalytic activity. The Ni-BTC/4 wt % rGO composite with a pronounced current density of 200.22 mA/cm2 at 0.69 V versus Hg/HgO electrode at 50 mV/s was found to be a potential candidate for methanol oxidation in Direct Methanol Fuel Cell (DMFC) applications. Product analysis was carried out through Gas Chromatography (GC) and Nuclear Magnetic Resonance (NMR) spectroscopy, which confirmed the formation of formic acid during the oxidation process, with approximately 62% yield.

Photo-oxidative degradation of doxorubicin with siloxane MOFs by exposure to daylight

Doxorubicin (DOX) is a chemotherapeutic agent from anthracycline class, which acts unselectively on all cells; thus, it may have genotoxic and/or mutagenic effects and cause serious environmental problems. Herein, the decomposition of a diluted solution of DOX hydrochloride for injection has been investigated under photo-oxidative conditions, in ambient light and without pH modification, using hydrogen peroxide as oxidizing agent and hydrophobic siloxane-based metal-organic frameworks (MOFs) as heterogeneous catalysts. The kinetics of the photodegradation process was followed by UV-Vis spectroscopy and by ESI-MS. According to UV-Vis data, two pseudo-first-order kinetic steps describe the process, with rate constants in the order of 10^-3-10^-2 min^-1 for the rate-determining one. ESI-MS provided more accurate information, with a rate constant of 2.6 · 10^-2 min^-1 calculated from the variation of DOX ion abundance. Complete decomposition of DOX was achieved after 120 min in the shade and after only 20 min by exposure to sunlight. The analysis of the residual waters by mass spectrometry and 1D and 2D NMR spectroscopy showed complete disappearance of DOX in all cases, excluded any anthracycline species, which are destroyed in the tested conditions, and proved formation of an un-harmful compound-glycerol, while no trace of metal was detected by XRF. Preliminary data also showed decomposition of oxytetracycline in similar conditions. By this study, we bring into attention a less-addressed pollution issue and we propose a mild and effective method for the removal of drug emerging pollutants.