A "green" strategy to construct non-covalent, stable and bioactive coatings on porous MOF nanoparticles

A comprehensive investigation of the interactions of human serum albumin with polymeric and hybrid nanoparticles

Nanoparticles (NPs) engineered as drug delivery systems continue to make breakthroughs as they offer numerous advantages over free therapeutics. However, the poor understanding of the interplay between the NPs and biomolecules, especially blood proteins, obstructs NP translation to clinics. Nano-bio interactions determine the NPs' in vivo fate, efficacy and immunotoxicity, potentially altering protein function. To fulfill the growing need to investigate nano-bio interactions, this study provides a systematic understanding of two key aspects: (i) protein corona (PC) formation and (ii) NP-induced modifications on protein's structure and stability. A methodology was developed by combining orthogonal techniques to analyze both quantitative and qualitative aspects of nano-bio interactions, using human serum albumin (HSA) as a model protein. Protein quantification via liquid chromatography-mass spectrometry, and capillary zone electrophoresis (CZE) clarified adsorbed protein quantity and stability. CZE further unveiled qualitative insights into HSA forms (native, glycated HSA and cysteinylated), while synchrotron radiation circular dichroism enabled analyzing HSA's secondary structure and thermal stability. Comparative investigations of NP cores (organic vs. hybrid), and shells (with or without polyethylene glycol (PEG)) revealed pivotal factors influencing nano-bio interactions. Polymeric NPs based on poly(lactic-co-glycolic acid) (PLGA) and hybrid NPs based on metal-organic frameworks (nanoMOFs) presented distinct HSA adsorption profiles. PLGA NPs had protein-repelling properties while inducing structural modifications on HSA. In contrast, HSA exhibited a high affinity for nanoMOFs forming a PC altering thereby the protein structure. A shielding effect was gained through PEGylation for both types of NPs, avoiding the PC formation as well as the alteration of unbound HSA structure.

β-CD@AgNPs with peroxisase-like activity for colorimetric determination of chiral tryptophan

Different enantiomer forms of amino acids play different roles in multifarious fields, and improper use will cause irreversible effects. Therefore, the identification of chiral amino acids is a vital issue in the field of pharmaceutical analysis. Herein, a chiral sensing system of β-cyclodextrin coated silver nanoparticle (β-CD@AgNPs) with peroxidase-like activity was designed for the fast and efficient colorimetric identification of tryptophan (Trp) enantiomers based on the difference in binding capacity between D/L-Trp and β-CD. The results showed the satisfactory linearity for detecting D/L-Trp over the concentration range from 0.2 to 4 mM with a LOD of 0.16 and 0.18 mM, respectively. Moreover, the absorbance increased linearly with the rise of D-Trp concentration percentage in the Trp enantiomer mixture. The proposed method avoided the use of natural enzymes and improved the stability due to the protective effect of cyclodextrin, which provided a new idea for selective colorimetric recognition and detection of D/L-Trp based on cyclodextrin.

Polyoxometalate-Polymer Directed Macromolecular Architectonics of Silver Nanoparticles as Effective Antimicrobials

A novel inorganic-organic-inorganic ternary bioactive material formulated on antimicrobial peptide-based polymer has been reported. Supramolecular approach has been employed to incorporate molecularly crowded tyrosine-based polymer stabilized silver nanoparticles into membrane bound vesicles exploiting polyoxometalate-triggered surface templating strategy. Utilizing the covalent reversible addition fragmentation chain transfer (RAFT) polymerization and exploiting templated supramolecular architectonics at biopolymer interface, the bioactive ternary polymeric nanohybrids have been designed against Shigellosis leveraging the antibacterial activities of silver nanoparticle, cationic amphiphilic tyrosine polymer and inorganic polyoxometalate. The detail investigation against Shigella flexneri 2a cell line demonstrates that the collaborative mechanism of the ternary hybrid composite enhances the bactericidal activity in comparison to only polyoxometalate and polymer stabilized silver nanoparticle with an altered mechanism of action which is established via detailed biological analysis.

Metal-Organic Framework as a New Type of Magnetothermally-Triggered On-Demand Release Carrier

The development of external stimuli-controlled payload systems has been sought after with increasing interest toward magnetothermally-triggered drug release (MTDR) carriers due to their non-invasive features. However, current MTDR carriers present several limitations, such as poor heating efficiency caused by the aggregation of iron oxide nanoparticles (IONPs) or the presence of antiferromagnetic phases which affect their efficiency. Herein, a novel MTDR carrier is developed using a controlled encapsulation method that fully fixes and confines IONPs of various sizes within the metal-organic frameworks (MOFs). This novel carrier preserves the MOF's morphology, porosity, and IONP segregation, while enhances heating efficiency through the oxidation of antiferromagnetic phases in IONPs during encapsulation. It also features a magnetothermally-responsive nanobrush that is stimulated by an alternating magnetic field to enable on-demand drug release. The novel carrier shows improved heating, which has potential applications as contrast agents and for combined chemo and magnetic hyperthermia therapy. It holds a great promise for magneto-thermally modulated drug dosing at tumor sites, making it an exciting avenue for cancer treatment.

Degradation and Erosion of Metal-Organic Frameworks: Comparative Study of a NanoMIL-100 Drug Delivery System

To make a drug work better, the active substance can be incorporated into a vehicle for optimal protection and control of the drug delivery time and space. For making the drug carrier, the porous metal-organic framework (MOF) can offer high drug-loading capacity and various designs for effective drug delivery performance, biocompatibility, and biodegradability. Nevertheless, its degradation process is complex and not easily predictable, and the toxicity concern related to the MOF degradation products remains a challenge for their clinical translation. Here, we describe an in-depth molecular and nanoscale degradation mechanism of aluminum- and iron-based nanoMIL-100 materials exposed to phosphate-buffered saline. Using a combination of analytical tools, including X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, small-angle X-ray scattering, and electron microscopy, we demonstrate qualitatively and quantitatively the formation of a new coordination bond between metal(III) and phosphate, trimesate release, and correlation between these two processes. Moreover, the extent of material erosion, i.e., bulk or surface erosion, was examined from the transformation of nanoparticles' surface, morphology, and interaction with water. Similar analyses show the impact of drug loading and surface coating on nanoMIL-100 degradation and drug release as a function of the metal-ligand binding strength. Our results indicate how the chemistry of nanoMIL-100(Al) and nanoMIL-100(Fe) drug carriers affects their degradation behaviors in a simulated physiological medium. This difference in behavior between the two nanoMIL-100s enables us to better correlate the nanoscale and atomic-scale mechanisms of the observed phenomena, thus validating the presented multiscale approach.

An in-depth physicochemical investigation of drug-loaded core-shell UiO66 nanoMOFs

Nanosized UiO66 are among the most studied MOF materials. They have been extensively applied in various areas, such as catalysis, gas absorption, electrochemistry, chemical sensing, and biomedical applications. However, the preparation of stable nano-sized UiO66 for drug delivery applications is challenging because of the high tendency of UiO66 to aggregate during storage. To address this issue, we coated UiO66 with oligomers made of crosslinked cyclodextrins. The coated UiO66 exhibited a good stability upon storage for more than three weeks, even for low quantities of coating materials. The resulting core-shell UiO66 were characterized using a set of complementary methods including microscopies, spectroscopies, X-ray diffraction, and thermogravimetric investigations. Size distribution was assessed by orthogonal methods. Cisplatin was loaded in the core-shell nanoparticles, followed by an in-depth analysis by asymmetric flow field-flow fractionation (AF4) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS). This method combines the extremely high elemental selectivity and ultratrace detection limits of mass spectrometry with the capacity of AF4 to differentiate the diverse populations present in the sample. Free cisplatin and UiO66-associated cisplatin could be well separated by AF4. AF4-ICP-MS/MS analysis provided the exact drug loading, without the need of separating the nanoparticles from their suspension media. These data suggest the potential of AF4-ICP-MS/MS in the optimization of drug delivery systems.

Interfacing metal organic frameworks with polymers or carbon-based materials: from simple to hierarchical porous and nanostructured composites

In the past few years, metal organic frameworks (MOFs) have been assembled with (bio)polymers and a series of carbon-based materials (graphene, graphene oxide, carbon nanotubes, carbon quantum dots, etc.) leading to a wide range of composites differing in their chemical composition, pore structure and functionality. The objective was mainly to overcome the limitations of MOFs in terms of mechanical properties, chemical stability and processability while imparting novel functionality (electron conductivity, (photo)catalytic activity, etc.) and hierarchical porosity. These composites were considered for numerous applications including gas/liquid adsorption and separation, (photo)catalysis, biomedicine, energy storage, conversion and so on. The performance of such composites depends strongly on their microstructural and physico-chemical properties which are mainly driven by the chemical strategies used to design and process such composites. In this perspective article, we propose to cover this topic and provide a useful survey of recent progress in the synthesis and design of MOFs-carbon material composites. This article will describe the development of composites with increasing complexity in terms of porous architecture, spatial structuration and organisation, and functionality.

Developing Mixed Matrix Membranes with Good CO2 Separation Performance Based on PEG-Modified UiO-66 MOF and 6FDA-Durene Polyimide

The use of mixed matrix membranes (MMMs) comprising metal-organic frameworks (MOFs) for the separation of CO2 from flue gas has gained recognition as an effective strategy for enhancing gas separation efficiency. When incorporating porous materials like MOFs into a polymeric matrix to create MMMs, the combined characteristics of each constituent typically manifest. Nevertheless, the inadequate dispersion of an inorganic MOF filler within an organic polymer matrix can compromise the compatibility between the filler and matrix. In this context, the aspiration is to develop an MMM that not only exhibits optimal interfacial compatibility between the polymer and filler but also delivers superior gas separation performance, specifically in the efficient extraction of CO2 from flue gas. In this study, we introduce a modification technique involving the grafting of poly(ethylene glycol) diglycidyl ether (PEGDE) onto a UiO-66-NH2 MOF filler (referred to as PEG-MOF), aimed at enhancing its compatibility with the 6FDA-durene matrix. Moreover, the inherent CO2-philic nature of PEGDE is anticipated to enhance the selectivity of CO2 over N2 and CH4. The resultant MMM, incorporating 10 wt% of PEG-MOF loading, exhibits a CO2 permeability of 1671.00 Barrer and a CO2/CH4 selectivity of 22.40. Notably, these values surpass the upper bound reported by Robeson in 2008.

MRI Contrasting Agent Based on Mn-MOF-74 Nanoparticles with Coordinatively Unsaturated Sites

PURPOSE

The development of magnetic resonance imaging (MRI) contrasting agents (CAs) that are safer and have a higher relaxivity than Gd(III)-based agents is a significant research topic. Herein, we propose the use of a Mn-based metal organic framework (MOF), Mn-MOF-74, characterized by a safe paramagnetic center, a coordinatively unsaturated site (CUS) for aquation, and a long rotational correlation time, endowing high relaxivity. Furthermore, biocompatibility and delivery to the tumor are generally expected for MOFs that are obtainable in the nanometer size range.

PROCEDURE

Drop-wise mixing of 2,5-dihydroxyterephthalic acid (DHTP) and Mn(II) acetate yielded Mn-MOF-74 with a diameter of < 150 nm, which was then modified with 1-fivefold higher amounts of poly(ethylene glycol) (M.W. = 5000) to afford MOFs stably dispersed in water for at least 24 h.

RESULTS

The longitudinal and transverse relaxivity of the PEG-modified MOF was in the range of r1 = 8.08-13.5 and r2 = 32.7-46.8 mM-1 s-1, respectively (1.0 T, 23.7-23.9 °C), being larger than those of typical Gd(III)- and Mn(II)-based CAs of single-nuclear metal complexes. The in vivo imaging of a tumor-bearing mouse clearly showed that the tumor could be readily recognized due to signal enhancement (117%) in T1-weighted images, whereas other tissues showed small signal changes.

CONCLUSIONS

These results suggest that PEG-Mn-MOF-74 can be passively delivered to tumors and can act as a high-relaxivity T1 agent.

Covalent connections between metal-organic frameworks and polymers including covalent organic frameworks

Hybrid composite materials combining metal-organic frameworks (MOFs) and polymers have emerged as a versatile platform for a broad range of applications. The crystalline, porous nature of MOFs and the flexibility and processability of polymers are synergistically integrated in MOF-polymer composite materials. Covalent bonds, which form between two distinct materials, have been extensively studied as a means of creating strong molecular connections to facilitate the dispersion of "hard" MOF particles in "soft" polymers. Numerous organic transformations have been applied to post-synthetically connect MOFs with polymeric species, resulting in a variety of covalently connected MOF-polymer systems with unique properties that are dependent on the characteristics of the MOFs, polymers, and connection modes. In this review, we provide a comprehensive overview of the development and strategies involved in preparing covalently connected MOFs and polymers, including recently developed MOF-covalent organic framework composites. The covalent bonds, grafting strategies, types of MOFs, and polymer backbones are summarized and categorized, along with their respective applications. We highlight how this knowledge can serve as a basis for preparing macromolecular composites with advanced functionality.

Biocompatible Drug Delivery System Based on a MOF Platform for a Sustained and Controlled Release of the Poorly Soluble Drug Norfloxacin

Norfloxacin (NFX), an important antibacterial fluoroquinolone, is a class IV drug according to the biopharmaceutics classification system (BCS) and has low solubility and permeability issues. Such poor physicochemical properties of drug molecules lead to poor delivery and are of serious concern to the pharmaceutical industry for clinical development. We present here a conceptually new approach to deliver NFX, by loading the drug molecule on the porous platform of a biocompatible metal-organic framework (MOF), MIL-100(Fe). The loading of the drug on the MOF leading to NFX@MIL-100(Fe) was characterized by Fourier transform infrared (FTIR), UV-visible spectroscopy, thermogravimetric analyses (TGA), and nitrogen adsorption studies. Controlled experiments resulted in the high loading of the drug molecule (∼20 wt %) along with the desired sustained release. We could further control the release of norfloxacin by coating drug-loaded MIL-100(Fe) with PEG, PEG{NFX@MIL-100(Fe)}. Both drug delivery systems (DDSs), NFX@MIL-100(Fe) and PEG{NFX@MIL-100(Fe)}, were tested for their biocompatibility through toxicity studies. The DDSs are biocompatible and show insignificant cytotoxicity, as revealed by cell viability studies through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Synergistic Photodynamic/Antibiotic Therapy with Photosensitive MOF-Based Nanoparticles to Eradicate Bacterial Biofilms

Bacterial biofilms pose a serious threat to human health, as they prevent the penetration of antimicrobial agents. Developing nanocarriers that can simultaneously permeate biofilms and deliver antibacterial agents is an attractive means of treating bacterial biofilm infections. Herein, photosensitive metal-organic framework (MOF) nanoparticles were developed to promote the penetration of antibiotics into biofilms, thereby achieving the goal of eradicating bacterial biofilms through synergistic photodynamic and antibiotic therapy. First, a ligand containing benzoselenadiazole was synthesized and incorporated into MOF skeletons to construct benzoselenadiazole-doped MOFs (Se-MOFs). The growth of the Se-MOFs could be regulated to obtain nanoparticles (Se-NPs) in the presence of benzoic acid. The singlet oxygen (¹O₂) generation efficiencies of the Se-MOFs and Se-NPs were evaluated. The results show that the Se-NPs exhibited a higher ¹O₂ generation efficacy than the Se-MOF under visible-light irradiation because the small size of the Se-NPs was conducive to the diffusion of ¹O₂. Afterward, an antibiotic drug, polymyxin B (PMB), was conjugated onto the surface of the Se-NPs via amidation to yield PMB-modified Se-NPs (PMB-Se-NPs). PMB-Se-NPs exhibit a synergistic antibacterial effect by specifically targeting the lipopolysaccharides present in the outer membranes of Gram-negative bacteria through surface-modified PMB. Benefiting from the synergistic therapeutic effects of antibiotic and photodynamic therapy, PMB-Se-NPs can efficiently eradicate bacterial biofilms at relatively low antibiotic doses and light intensities, providing a promising nanocomposite for combating biofilm infections.

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 Fe^2/3+, 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.

Green and facile synthesis of lignin/HKUST-1 as a novel hybrid biopolymer metal-organic-framework for a pH-controlled drug release system

This manuscript describes the synthesis and characterization of a hybrid polymer/HKUST-1 composite for oral drug delivery. A green, one-pot approach was employed to synthesize the modified metal-organic frameworks (MOFs) composite using alkali lignin as a novel pH-responsive biopolymer carrier for the simulated oral delivery system. Several analytical techniques, including Fourier transform infrared (FTIR), X-ray powder diffraction (XRPD), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to analyze the chemical and crystalline structure of HKUST-1 and L/HKUST-1 composite. The drug loading capacity and drug-controlled release behavior of HKUST-1 and L/HKUST-1 were examined using ibuprofen (IBU) as an oral drug model. L/HKUST-1 composite demonstrated a pH-controlled drug release behavior by advancing the drug stability at low pHs such as the gastric medium and controlling drug release in the pH range of 6.8-7.4, similar to intestinal pH. The results suggest that the L/HKUST-1 composite is a promising candidate for oral medication delivery.

Nanoscale Multimodal Analysis of Sensitive Nanomaterials by Monochromated STEM-EELS in Low-Dose and Cryogenic Conditions

Scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS) provides spatially resolved chemical information down to the atomic scale. However, studying radiation-sensitive specimens such as organic-inorganic composites remains extremely challenging. Here, we analyzed metal-organic framework nanoparticles (nanoMOFs) at low-dose (10 e^-/Ų) and liquid nitrogen temperatures, similar to cryo-TEM conditions usually employed for high-resolution imaging of biological specimens. Our results demonstrate that monochromated STEM-EELS enables damage-free analysis of nanoMOFs, providing in a single experiment, signatures of intact functional groups comparable with infrared, ultraviolet, and X-ray data, with an energy resolution down to 7 meV. The signals have been mapped at the nanoscale (<10 nm) for each of these energy spectral ranges, including the chemical features observed for high energy losses (X-ray range). By controlling beam irradiation and monitoring spectral changes, our work provides insights into the possible pathways of chemical reactions occurring under electron exposure. These results demonstrate the possibilities for characterizing at the nanoscale the chemistry of sensitive systems such as organic and biological materials.

Nanoscale metal-organic frameworks for the delivery of nucleic acids to cancer cells

Therapeutic nucleic acids (TNAs) are gaining increasing interest in the treatment of severe diseases including viral infections, inherited disorders, and cancers. However, the efficacy of intracellularly functioning TNAs is also reliant upon their delivery into the cellular environment, as unmodified nucleic acids are unable to cross the cell membrane mainly due to charge repulsion. Here we show that TNAs can be effectively delivered into the cellular environment using engineered nanoscale metal-organic frameworks (nanoMOFs), with the additional ability to tailor which cells receive the therapeutic cargo determined by the functional moieties grafted onto the nanoMOF's surface. This study paves the way to integrate the highly ordered programmable nucleic acids into larger-scale functionalized nanoassemblies.

Acetic Acid-Modulated Room Temperature Synthesis of MIL-100 (Fe) Nanoparticles for Drug Delivery Applications

Due to their flexible composition, large surface areas, versatile surface properties, and degradability, nanoscale metal organic frameworks (nano MOFs) are drawing significant attention in nanomedicine. In particular, iron trimesate MIL-100 (Fe) is studied extensively in the drug delivery field. Nanosized MIL-100 (Fe) are obtained mostly by microwave-assisted synthesis. Simpler, room-temperature (RT) synthesis methods attract growing interest and have scale-up potential. However, the preparation of RT MIL100 is still very challenging because of the high tendency of the nanoparticles to aggregate during their synthesis, purification and storage. To address this issue, we prepared RT MIL100 using acetic acid as a modulator and used non-toxic cyclodextrin-based coatings to ensure stability upon storage. Hydrodynamic diameters less than 100 nm were obtained after RT synthesis, however, ultrasonication was needed to disaggregate the nanoparticles after their purification by centrifugation. The model drug adenosine monophosphate (AMP) was successfully encapsulated in RT MIL100 obtained using acetic acid as a modulator. The coated RT MIL100 has CD-exhibited degradability, good colloidal stability, low cytotoxicity, as well as high drug payload efficiency. Further studies will focus on applications in the field of cancer therapy.

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.

Advances in Metal-Organic Framework (MOFs) based biosensors for diagnosis: An update

Metal-organic frameworks (MOFs) have significant advantages over other candidate classes of chemo-sensory materials owing to their extraordinary structural tunability and characteristics. MOF-based biosensing is a simple, and convenient method for identifying various species. Biomarkers are molecular or cellular processes that link environmental exposure to a health outcome. Biomarkers are important in understanding the links between environmental chemical exposure and the development of chronic diseases, as well as in identifying disease-prone subgroups. Until now, several species, including nanoparticles (NPs) and their nanocomposites, small molecules, and unique complex systems, have been used for the chemical sensing of biomarkers. Following the overview of the field, we discussed the various fabrication methods for MOFs development in this review. We provide a thorough overview of the previous five years of progress to broaden the scope of analytes for future research. Several enzymatic and non-enzymatic sensors are offered, together with a mandatory measuring method that includes detection range and dynamic range. In addition, we reviewed the comparison of enzymatic and non-enzymatic biosensors, inventive edges, and the difficulties that need to be solved. This work might open up new possibilities for material production, sensor development, medical diagnostics, and other sensing fields.

MXenes as Emerging Materials: Synthesis, Properties, and Applications

Due to their unique layered microstructure, the presence of various functional groups at the surface, earth abundance, and attractive electrical, optical, and thermal properties, MXenes are considered promising candidates for the solution of energy- and environmental-related problems. It is seen that the energy conversion and storage capacity of MXenes can be enhanced by changing the material dimensions, chemical composition, structure, and surface chemistry. Hence, it is also essential to understand how one can easily improve the structure–property relationship from an applied point of view. In the current review, we reviewed the fabrication, properties, and potential applications of MXenes. In addition, various properties of MXenes such as structural, optical, electrical, thermal, chemical, and mechanical have been discussed. Furthermore, the potential applications of MXenes in the areas of photocatalysis, electrocatalysis, nitrogen fixation, gas sensing, cancer therapy, and supercapacitors have also been outlooked. Based on the reported works, it could easily be observed that the properties and applications of MXenes can be further enhanced by applying various modification and functionalization approaches. This review also emphasizes the recent developments and future perspectives of MXenes-based composite materials, which will greatly help scientists working in the fields of academia and material science.

Hybrid liposome/metal-organic framework as a promising dual-responsive nanocarriers for anticancer drug delivery

In this work, liposome-coated iron (III) benzene-1,3,5-tricarboxylate (Fe-BTC) metal-organic framework is examined as a promising pH/Ultrasound dual-responsive nanocarriers for doxorubicin (DOX) delivery. The successful coating of the MOF particles (Lip-Fe-BTC) with the phospholipid bilayer (PBL) was established by direct fusion into the synthesized liposomes. The liposome coating was verified using several techniques, including dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS measurements showed an increase in the average particle diameter of liposomes from 150 nm to 163.1 nm for Lip-Fe-BTC particles. The Fe-BTC particles had the highest average particle diameter (287.3 nm). These results demonstrated that the PBL reduced the aggregation of the particles and improved their dispersity in the release medium. The TGA results demonstrated the MOF's excellent thermal stability. Furthermore, the nanocarrier's loading efficiency and capacity were determined to be ~90% and ~13.5 wt%, respectively. The in-vitro DOX release experiments demonstrated that the DOX-loaded Fe-BTC and liposome-coated Fe-BTC particles showed good pH and US dual-responsive capability, making them promising nanocarriers for drug delivery. The application of US enhanced DOX release from both Fe-BTC and liposome-coated Fe-BTC. In the case of Fe-BTC-DOX particles, the application of US enhanced the DOX release to around 38% and 67%, at pH levels of 7.4 and 5.3, respectively. Similarly, DOX release from the Lip-Fe-BTC-DOX particles reached ~35% and ~53%, at pH levels of 7.4 and 5.3, respectively. The MTT assay showed the biocompatibility and low cytotoxicity of these nanocarriers below 100 µg/ml.

Leveraging Isothermal Titration Calorimetry to Obtain Thermodynamic Insights into the Binding Behavior and Formation of Metal-Organic Frameworks

Isothermal titration calorimetry (ITC) is a technique which directly measures the thermodynamic parameters of binding events. Although historically it has been used to investigate interactions in biological macromolecules and the kinetics of enzyme-catalyzed reactions, ITC has also been demonstrated to provide relevant thermodynamic information about interactions in synthetic systems, such as those in metal-organic frameworks (MOFs). MOFs are a family of crystalline porous materials that have been widely studied as supports for molecules ranging from gases to biomolecules through physisorption and chemisorption. Herein, we offer a perspective on the current applications of ITC in MOFs, including the mechanism of small molecule adsorption and the formation of MOF-based composite materials through noncovalent interactions. Experimental considerations specific to running ITC experiments in MOF systems are reviewed on the basis of existing reports. We conclude by discussing underexplored, but promising, MOF-related research directions which could be elucidated by ITC.

Pushing the Limits on the Intestinal Crossing of Metal-Organic Frameworks: An Ex Vivo and In Vivo Detailed Study

Biocompatible nanoscaled metal-organic frameworks (nanoMOFs) have been widely studied as drug delivery systems (DDSs), through different administration routes, with rare examples in the convenient and commonly used oral administration. So far, the main objective of nanoMOFs as oral DDSs was to increase the bioavailability of the cargo, without considering the MOF intestinal crossing with potential advantages (e.g., increasing drug availability, direct transport to systemic circulation). Thus, we propose to address the direct quantification and visualization of MOFs' intestinal bypass. For that purpose, we select the microporous Fe-based nanoMOF, MIL-127, exhibiting interesting properties as a nanocarrier (great biocompatibility, large porosity accessible to different drugs, green and multigram scale synthesis, outstanding stability along the gastrointestinal tract). Additionally, the outer surface of MIL-127 was engineered with the biopolymer chitosan (CS@MIL-127) to improve the nanoMOF intestinal permeation. The biocompatibility and intestinal crossing of nanoMOFs is confirmed using a simple and relevant in vivo model, Caenorhabditis elegans; these worms are able to ingest enormous amounts of nanoMOFs (up to 35 g per kg of body weight). Finally, an ex vivo intestinal model (rat) is used to further support the nanoMOFs' bypass across the intestinal barrier, demonstrating a fast crossing (only 2 h). To the best of our knowledge, this report on the intestinal crossing of intact nanoMOFs sheds light on the safe and efficient application of MOFs as oral DDSs.

Green synthesis of PEG-coated MIL-100(Fe) for controlled release of dacarbazine and its anticancer potential against human melanoma cells

In this study, the potential of using MIL-100(Fe) metal-organic framework (MOF) for loading and controlling the release of dacarbazine (DTIC) was evaluated for in vitro treatment of melanoma. The drug loading was performed during the green synthesis of MIL-100(Fe) in an aqueous media without using any harmful solvents, to obtain MIL-DTIC. The surface of this structure was then coated with polyethylene glycol (PEG) in the same aqueous solution to synthesize MIL-DTIC-PEG. The synthesized samples were characterized using various methods. Their release profile was studied in phosphate-buffered saline (PBS) and simulated cutaneous medium (SCM). The cytotoxicity of DTIC and its nano-MOF formulation were investigated against melanoma A375 cell lines. The results revealed that the PEG coating (PEGylation) changed the surface charge of MOF from -2.8 ± 0.9 mV to -42.8 ± 1.2 mV, which can contribute to the colloidal stability of MOF. The PEGylation showed a significant effect on controlled drug release, especially in SCM, which increases the complete release time from 60 h to 12 days. Moreover, both of the drug-containing MOFs showed more toxicity than DTIC and unloaded MOFs, confirming that the cumulative release of drug and better cellular uptake of NPs lead to increased toxicity.

The Emerging Role of Cyclodextrin Metal–Organic Frameworks in Ostheotherapeutics

Metal–Organic Frameworks (MOFs) are a class of coordination compounds with high versatility of design and a high loading ability. These properties have made them increasingly attractive for drug delivery, with research focusing mostly on the preparation of biocompatible MOFs. A suitable strategy is the use of cyclodextrins, cyclic oligosaccharides with excellent biosafety profiles. This review summarises the early steps taken in the application of cyclodextrin-coated and cyclodextrin-based MOFs in the treatment of bone-related diseases divided into three categories: cyclodextrin-coated MOFs, cyclodextrin-based MOFs and cross-linked derivatives of CD-MOFs. Applications in the delivery of bisphosphonates, osteoporotic regulating drugs and non-steroidal anti-inflammatory drugs, for osteoarthritis management, are highlighted. Lastly, the use of these materials in dentistry is exemplified with a recent report.

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

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

The Impact of MOF in pH-dependent Drug Delivery System: Progress in Last Decade

Metal-organic frameworks (MOFs) are porous crystalline materials of one-, two-, or three-dimensional networks manufactured from metal ions/clusters and multidentate organic linkers through coordination bonding. MOFs are one of the most...

Syntheses, Characterization, and Antibacterial Evaluation of P. grandiflora Extracts Conjugated with Gold Nanoparticles

Background. With the recent increase in antibiotic resistance to conventional antibiotics, gold nanoparticles, and medicinal plants, extracts present an interesting alternative. Objectives. This study aimed to synthesize, characterize, and evaluate Pyrenacantha grandiflora Baill extracts and gold nanoparticle conjugates against pathogenic bacteria. Methods. We synthesized gold nanoparticles by chemical and biological methods. The nanoparticles were characterized by the use of UV-visible spectrophotometry, followed by transmission electron microscopy (TEM) and energy-dispersive X-ray analysis (EDX). Gold nanoparticles were conjugated to plant extracts and analyzed with a Fourier-transform infrared spectroscope (FTIR). We determined the antimicrobial activity of the conjugates using well diffusion and the microdilution assays. Results. The UV–visible spectra of gold nanoparticles showed a synthesis peak at 530 nm. FTIR analysis indicated functional biomolecules that were associated with plant extract conjugated gold nanoparticles; the formation of C–H group and carbonyl (C=O) groups, –OH carbonyl, and C≡C groups were also observed. Biologically synthesized nanoparticles were star-shaped when observed by TEM with an average size of 11 nm. Gold nanoparticles synthesized with P. grandiflora water extracts showed the largest zone of inhibition (22 mm). When the gold nanoparticles synthesized by the biological method were conjugated with acetone extracts of P. grandiflora, MIC as low as 0.0063 mg/mL was observed against beta-lactamase producing K. pneumonia. The activity of acetone extracts was improved with chemically synthesized gold nanoparticles particularly when beta-lactamase producing E. coli and MRSA were used as test organisms. A synergistic effect was observed against all tested bacteria, except for MRSA when gold nanoparticles were conjugated with acetone extract. Conclusion. Overall, P. grandiflora tuber extracts conjugated with gold nanoparticles showed a very good antibacterial activity that improved both plant extract and gold nanoparticle’s individual activity.

Cyclodextrin-Modified Nanomaterials for Drug Delivery: Classification and Advances in Controlled Release and Bioavailability

In drug delivery, one widely used way of overcoming the biopharmaceutical problems present in several active pharmaceutical ingredients, such as poor aqueous solubility, early instability, and low bioavailability, is the formation of inclusion compounds with cyclodextrins (CD). In recent years, the use of CD derivatives in combination with nanomaterials has shown to be a promising strategy for formulating new, optimized systems. The goals of this review are to give in-depth knowledge and critical appraisal of the main CD-modified or CD-based nanomaterials for drug delivery, such as lipid-based nanocarriers, natural and synthetic polymeric nanocarriers, nanosponges, graphene derivatives, mesoporous silica nanoparticles, plasmonic and magnetic nanoparticles, quantum dots and other miscellaneous systems such as nanovalves, metal-organic frameworks, Janus nanoparticles, and nanofibers. Special attention is given to nanosystems that achieve controlled drug release and increase their bioavailability during in vivo studies.

Advanced strategies in Metal-Organic Frameworks for CO2 Capture and Separation

The continuous carbon dioxide (CO₂ ) gas emissions associated with fossil fuel production, valorization, and utilization are serious challenges to the global environment. Therefore, several developments of CO₂ capture, separation, transportation, storage, and valorization have been explored. Consequently, we documented a comprehensive review of the most advanced strategies adopted in metal-organic frameworks (MOFs) for CO₂ capture and separation. The enhancements in CO₂ capture and separation are generally achieved due to the chemistry of MOFs by controlling pore window, pore size, open-metal sites, acidity, chemical doping, post or pre-synthetic modifications. The chemistry of defects engineering, breathing in MOFs, functionalization in MOFs, hydrophobicity, and topology are the salient advanced strategies, recently reported in MOFs for CO₂ capture and separation. Therefore, this review summarizes MOF materials' advancement explaining different strategies and their role in the CO₂ mitigations. The study also provided useful insights into key areas for further investigations.

Porous nanoparticles with engineered shells release their drug cargo in cancer cells

Highly porous nanoscale metal-organic frameworks (nanoMOFs) attract growing interest as drug nanocarriers. However, engineering "stealth" nanoMOFs with poly(ethylene glycol) (PEG) coatings remains a main challenge. Here we address the goal of coating nanoMOFs with biodegradable shells using novel cyclodextrin (CD)-based oligomers with a bulky structure to avoid their penetration inside the open nanoMOF porosity. The PEG chains were grafted by click chemistry onto the CDs which were further crosslinked by citric acid. Advantageously, the oligomers' free citrate units allowed their spontaneous anchoring onto the nanoMOFs by complexation with the iron sites in the top layers. Up to 31 wt% oligomers could be firmly attached by simple incubation with the nanoMOFs in an aqueous medium. Moreover, the anticancer drug doxorubicin (DOX) was successfully entrapped in the core-shell nanoMOFs with loadings up to 41 wt%. High resolution STEM (HR-STEM) showed that the organized crystalline structures were preserved. Remarkably, at the highest loadings, DOX was poorly released out of the nanoMOFs at pH 7.4 (<2% in 2 days). In contrast, around 80% of DOX was released out at pH 4.5 of artificial lysosomal fluid in 24 h. Confocal microscopy investigations showed that the DOX-loaded nanoMOFs penetrated inside Hela cancer cell together with their PEG shells. There, they released the DOX cargo which further diffused inside the nucleus to eradicate the cancer cells.

Solid-state NMR spectroscopy as a powerful tool to investigate the location of fluorinated lipids in highly porous hybrid organic-inorganic nanoparticles

Nanosized metal-organic frameworks (nanoMOFs) have emerged as a new class of biodegradable and nontoxic nanomaterials of high interest for biomedical applications thanks to the possibility to load large amounts of a wide variety of therapeutic molecules in their porous structure. The surface of the highly porous nanoMOFs is usually engineered to increase their colloidal stability, to tune their interactions with the biological environment, and to allow targeting specific cells or organs. However, the atomic-scale analysis of these complex core-shell materials is highly challenging. In this study, we report the investigation of aluminum-based nanoMOFs containing two fluorinated lipids by solid-state NMR spectroscopy, including ²⁷ Al, ¹ H and ¹⁹ F MAS NMR. The ensemble of NMR data provides a better understanding of the localization and conformation of the fluorinated lipids inside the pores or on the nanoMOF surface.

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.

When drug nanocarriers miss their target: extracellular diffusion and cell uptake are not enough to be effective

Biocompatible nanoscale iron carboxylate metal-organic frameworks (nanoMOFs) have already demonstrated their ability to efficiently deliver various therapeutic molecules. The versatility of the synthesis methods and functionalization strategies could further improve their drug carrier potential. However, in oncology, preclinical evaluation still suffers from the lack of relevant models able to mimic the heterogeneity and the microenvironment of human tumors. This may impact the significance of the preclinical data, hindering the clinical translation and drug development process. Motivated by this hurdle, a 3D lung tumor model is herein developed to investigate nanoMOFs, as bare nanoparticles or coated with polyethylene glycol. Loading with doxorubicin, as a model drug, enables the investigation of their penetration capacity and efficacy in the 3D tumor nodule. NanoMOFs carry a large cargo, can diffuse efficiently within the tumor and are capable of significant intracellular penetration. Nevertheless, they prove to be therapeutically ineffective because the loaded drug is sequestrated in the lysosomal compartment and does not reach the nucleus, the doxorubicin sub-cellular target. These results question the in vivo evaluation of these nanoMOFs and call for further optimization to achieve successful drug delivery.

An Overview on Recent Progress of Metal Oxide/Graphene/CNTs-Based Nanobiosensors

Nanobiosensors are convenient, practical, and sensitive analyzers that detect chemical and biological agents and convert the results into meaningful data between a biologically active molecule and a recognition element immobilized on the surface of the signal transducer by a physicochemical detector. Due to their fast, accurate and reliable operating characteristics, nanobiosensors are widely used in clinical and nonclinical applications, bedside testing, medical textile industry, environmental monitoring, food safety, etc. They play an important role in such critical applications. Therefore, the design of the biosensing interface is essential in determining the performance of the nanobiosensor. The unique chemical and physical properties of nanomaterials have paved the way for new and improved sensing devices in biosensors. The growing demand for devices with improved sensing and selectivity capability, short response time, lower limit of detection, and low cost causes novel investigations on nanobiomaterials to be used as biosensor scaffolds. Among all other nanomaterials, studies on developing nanobiosensors based on metal oxide nanostructures, graphene and its derivatives, carbon nanotubes, and the widespread use of these nanomaterials as a hybrid structure have recently attracted attention. Nanohybrid structures created by combining these nanostructures will directly meet the future biosensors' needs with their high electrocatalytic activities. This review addressed the recent developments on these nanomaterials and their derivatives, and their use as biosensor scaffolds. We reviewed these popular nanomaterials by evaluating them with comparative studies, tables, and charts.

Doxorubicin-Loaded Metal-Organic Frameworks Nanoparticles with Engineered Cyclodextrin Coatings: Insights on Drug Location by Solid State NMR Spectroscopy

Recently developed, nanoscale metal-organic frameworks (nanoMOFs) functionalized with versatile coatings are drawing special attention in the nanomedicine field. Here we show the preparation of core-shell MIL-100(Al) nanoMOFs for the delivery of the anticancer drug doxorubicin (DOX). DOX was efficiently incorporated in the MOFs and was released in a progressive manner, depending on the initial loading. Besides, the coatings were made of biodegradable γ-cyclodextrin-citrate oligomers (CD-CO) with affinity for both DOX and the MOF cores. DOX was incorporated and released faster due to its affinity for the coating material. A set of complementary solid state nuclear magnetic resonance (ssNMR) experiments including 1H-1H and 13C-27Al two-dimensional NMR, was used to gain a deep understanding on the multiple interactions involved in the MIL-100(Al) core-shell system. To do so, 13C-labelled shells were synthesized. This study paves the way towards a methodology to assess the nanoMOF component localization at a molecular scale and to investigate the nanoMOF physicochemical properties, which play a main role on their biological applications.

Iron-Based Metal-Organic Frameworks in Drug Delivery and Biomedicine

Metal-organic frameworks (MOFs) are crystalline materials comprising metal centers and organic linkers that feature structural rigidity and functional flexibility. These attractive materials offer large surface areas, high porosity, and good chemical stability; they have shown promise in chemistry (H₂ separation and catalysis), magnetism, and optics. They have also shown potential for drug delivery following the demonstration in 2006 that chromium-based MOFs can be loaded with ibuprofen. Since then, iron-based MOFs (Fe-MOFs) have been shown to offer high drug loading and excellent biocompatibility. The present review focuses on the synthesis and surface modifications of Fe-MOFs as well as their applications in drug delivery and biomedicine.

Stimuli-responsive metal-organic framework nanoparticles for controlled drug delivery and medical applications

Stimuli-responsive metal-organic framework nanoparticles, NMOFs, provide a versatile platform for the controlled release of drugs and biomedical applications. The porous structure of NMOFs, their biocompatibility, low toxicity, and efficient permeability turn the NMOFs into ideal carriers for therapeutic applications. Two general methods to gate the drug-loaded NMOFs and to release the loads were developed: by one method, the loaded NMOFs are coated or surface-modified with stimuli-responsive gates being unlocked in the presence of appropriate chemical (e.g., ions or reducing agents), physical (e.g., light or heat), or biomarker (e.g., miRNA or ATP) triggers. By a second approach, the drug-loaded NMOFs include encoded structural information or co-added agents to induce the structural distortion or stimulate the degradation of the NMOFs. Different chemical triggers such as pH changes, ions, ATP, or redox agents, and physical stimuli such as light or heat are applied to degrade the NMOFs, resulting in the release of the loads. In addition, enzymes, DNAzymes, and disease-specific biomarkers are used to unlock the gated NMOFs. The triggered release of drugs for cancer therapy, anti-blood clotting, and the design of autonomous insulin-delivery systems ("artificial pancreas") are discussed. Specifically, multi-drug carrier systems and functional NMOFs exhibiting dual and cooperative therapeutic functions are introduced. The future perspectives and applications of stimuli-responsive particles are addressed.

Metal-organic frameworks for virus detection

Virus severely endangers human life and health, and the detection of viruses is essential for the prevention and treatment of associated diseases. Metal-organic framework (MOF), a novel hybrid porous material which is bridged by the metal clusters and organic linkers, has become a promising biosensor platform for virus detection due to its outstanding properties including high surface area, adjustable pore size, easy modification, etc. However, the MOF-based sensing platforms for virus detection are rarely summarized. This review systematically divided the detection platforms into nucleic acid and immunological (antigen and antibody) detection, and the underlying sensing mechanisms were interpreted. The nucleic acid sensing was discussed based on the properties of MOF (such as metal ion, functional group, geometry structure, size, porosity, stability, etc.), revealing the relationship between the sensing performance and properties of MOF. Moreover, antibodies sensing based on the fluorescence detection and antigens sensing based on molecular imprinting or electrochemical immunoassay were highlighted. Furthermore, the remaining challenges and future development of MOF for virus detection were further discussed and proposed. This review will provide valuable references for the construction of sophisticated sensing platform for the detection of viruses, especially the 2019 coronavirus.

Bioengineering of nano metal-organic frameworks for cancer immunotherapy

Immunotherapy techniques, such as immune checkpoint inhibitors, chimeric antigen receptor (CAR) T cell therapies and cancer vaccines, have been burgeoning with great success, particularly for specific cancer types. However, side effects with fatal risks, dysfunction in tumor microenvironment and low immune response rates remain the bottlenecks in immunotherapy. Nano metal-organic frameworks (nMOFs), with an accurate structure and a narrow size distribution, are emerging as a solution to these problems. In addition to their function of temporospatial delivery, a large library of their compositions, together with flexibility in chemical interaction and inherent immune efficacy, offers opportunities for various designs of nMOFs for immunotherapy. In this review, we overview state-of-the-art research on nMOFs-based immunotherapies as well as their combination with other therapies. We demonstrate that nMOFs are predominantly customized for vaccine delivery or tumor-microenvironment modulation. Finally, a prospect of nMOFs in cancer immunotherapy will be discussed.

Drug-Loaded Lipid-Coated Hybrid Organic-Inorganic "Stealth" Nanoparticles for Cancer Therapy

Hybrid porous nanoscale metal organic frameworks (nanoMOFs) made of iron trimesate are attracting increasing interest as drug carriers, due to their high drug loading capacity, biodegradability, and biocompatibility. NanoMOF surface modification to prevent clearance by the innate immune system remains still challenging in reason of their high porosity and biodegradable character. Herein, FDA-approved lipids and poly(ethylene glycol) (PEG)-lipid conjugates were used to engineer the surface of nanoMOFs by a rapid and convenient solvent-exchange deposition method. The resulting lipid-coated nanoMOFs were extensively characterized. For the first time, we show that nanoMOF surface modification with lipids affords a better control over drug release and their degradation in biological media. Moreover, when loaded with the anticancer drug Gem-MP (Gemcitabine-monophosphate), iron trimesate nanoMOFs acted as “Trojan horses” carrying the drug inside cancer cells to eradicate them. Most interestingly, the PEG-coated nanoMOFs escaped the capture by macrophages. In a nutshell, versatile PEG-based lipid shells control cell interactions and open perspectives for drug targeting.

Designing Magnetic NanoMOFs for Biomedicine: Current Trends and Applications

Metal–organic frameworks (MOFs) have shown a great potential in biomedicine due to their promising applications in different fields, including drug delivery, thermometry, theranostics etc. In this context, the development of magnetic sub-micrometric or nanometric MOFs through miniaturization approaches of magnetic MOFs up to the nanoscale still represents a crucial step to fabricate biomedical probes, especially in the field of theranostic nanomedicine. Miniaturization processes have to be properly designed to tailor the size and shape of particles and to retain magnetic properties and high porosity in the same material, fundamental prerequisites to develop smart nanocarriers integrating simultaneously therapeutic and contrast agents for targeted chemotherapy or other specific clinical use. An overview of current trends on the design of magnetic nanoMOFs in the field of biomedicine, with particular emphasis on theranostics and bioimaging, is herein envisioned.

Glycyrrhetinic acid modified MOFs for the treatment of liver cancer

Liver cancer remains a major cause of cancer-related death across the globe. Nano medicines have emerged as promising candidates to improve liver cancer chemotherapy. In this study, a glycyrrhetinic acid (GA) modified metal-organic framework-based drug delivery system (GA-MOFs) was developed to enhance the liver targeting ability of 5-FU. The physicochemical properties of GA-MOFs regarding particle size, size distribution and morphology were evaluated. The results showed that the obtained 5-FU@GA-MOFs had an octahedral structure, a uniform particle size distribution, and a diameter of ∼200 nm. In vitro release experiments demonstrated that 5-FU@GA-MOFs exhibited a pH-dependent release pattern. MTT assays indicated that 5-FU-loaded GA-MOFs showed greater cytotoxicity towards HepG2 cells when compared to 5-FU alone at the same dose. In vivo tissue distribution demonstrated that the 5-FU@GA-MOFs significantly increased the accumulation of 5-FU in the liver. In vivo imaging analysis further manifested the liver targeting ability of GA-MOFs. Taken together, these results suggested that GA-modified MOFs showed promising potential as liver-targeting nanocarriers for the delivery of anti-tumor drugs.

Metal-Organic Material Polymer Coatings for Enhanced Gas Sorption Performance and Hydrolytic Stability under Humid Conditions

Physisorbent metal-organic materials (MOMs) have shown benchmark performance for highly selective CO₂ capture from bulk and trace gas mixtures. However, gas stream moisture can be detrimental to both adsorbent performance and hydrolytic stability. One of the most effective methods to solve this issue is to transform the adsorbent surface from hydrophilic to hydrophobic. Herein, we present a facile approach for coating MOMs with organic polymers to afford improved hydrophobicity and hydrolytic stability under humid conditions. The impact of gas stream moisture on CO₂ capture for the composite materials was found to be negligible under both bulk and trace CO₂ capture conditions with significant improvements in regeneration times and energy requirements.