Phase dependent encapsulation and release profile of ZIF-based biocomposites

Amperometric sensor based on ZIF/g-C3N4/RGO heterojunction nanocomposite for hydrazine detection

A dense  zeolitic imidazolate framework (ZIF) nanosheet is for the first time molded by reduced graphite oxide (RGO) and graphitic carbon nitride (g-C₃N₄) to fabricate an original 2D/2D/2D heterojunction (ZIF/g-C₃N₄/RGO nanohybrid), which is pipetted onto carbon cloth electrode (CCE) (ZIF/g-C₃N₄/RGO/CCE) as an electrochemical sensor. Profiting from the renowned synergistic and coupling effects, the resulting nanohybrid endows excellent electrocatalytic activity towards hydrazine. Amperometric detection reveals that the hybrid sensor possesses a low detection limit of 32 nM (S/N = 3) in a monitoring range of 0.0001 to 1.0386 mM, along with a high sensitivity 93.71 μA mM^-1 cm^-2. Importantly, the minimum detection concentration of hydrazine in the actual sample is lower than the maximum allowable limit of the World Health Organization (WHO) and has high reproducibility (RSD = 4.82%). As expected, the high sensing capability  of ZIF/g-C₃N₄/RGO combines the advantages of abundant surface-active sites and high conductivity along with 2D interfaces between ZIF, g-C₃N₄, and RGO nanosheets. This study provides a promising to expand 2D-based ternary nanojunction as a bridge for promoting sensing performance.Graphical abstract.

Can 3D electron diffraction provide accurate atomic structures of metal–organic frameworks?

Structure determination by continuous rotation electron diffraction can be as feasible and accurate as single crystal X-ray diffraction without the need for large crystals.

Three-dimensional electron diffraction for porous crystalline materials: structural determination and beyond

Porous crystalline materials such as zeolites, metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have attracted great interest due to their well-defined pore structures in molecular dimensions. Knowing the atomic structures of porous materials is crucial for understanding their properties and exploring their applications. Many porous materials are synthesized as polycrystalline powders, which are too small for structure determination by X-ray diffraction. Three-dimensional electron diffraction (3DED) has been developed for studying such materials. In this Minireview, we summarize the recent developments of 3DED methods and demonstrate how 3DED revolutionized structural analysis of zeolites, MOFs, and COFs. Zeolites and MOFs whose structures remained unknown for decades could be solved. New approaches for design and targeted synthesis of novel zeolites could be developed. Moreover, we discuss the advances of structural analysis by 3DED in revealing the unique structural features and properties, such as heteroatom distributions, mixed-metal frameworks, structural flexibility, guest-host interactions, and structure transformation.

In situ assembled ZIF superstructures via an emulsion-free soft-templating approach

Assembling well-defined MOF superstructures remains challenging as it requires easily removable hard templates or readily available immiscible solutions for an emulsion-based soft-template approach. In this work, a single-step emulsion-free soft templating approach is reported to spontaneously prepare hollow ZIF-8 and ZIF-67 colloidosomes with no further purification. These superstructures can load different enzymes regardless of the size and charge with a high encapsulation efficiency of 99%. We envisage that this work will expand the repertoires of MOF superstructures by the judicious selection of precursors and the reaction medium.

Zeolite-Like Boron Imidazolate Frameworks (BIFs): Synthesis and Application

This review is devoted to discussion of the latest advances in design and applications of boron imidazolate frameworks (BIFs) that are a particular sub-family of zeolite-like metal–organic frameworks family. A special emphasis is made on nanostructured hybrid materials based on BIF matrices and their modern applications, especially in environment remediation and energy conversion.

Modulation of metal-azolate frameworks for the tunable release of encapsulated glycosaminoglycans

Glycosaminoglycans (GAGs) are biomacromolecules necessary for the regulation of different biological functions. In medicine, GAGs are important commercial therapeutics widely used for the treatment of thrombosis, inflammation, osteoarthritis and wound healing. However, protocols for the encapsulation of GAGs in MOFs carriers are not yet available. Here, we successfully encapsulated GAG-based clinical drugs (heparin, hyaluronic acid, chondroitin sulfate, dermatan sulfate) and two new biotherapeutics in preclinical stage (GM-1111 and HepSYL proteoglycan) in three different pH-responsive metal-azolate frameworks (ZIF-8, ZIF-90, and MAF-7). The resultant GAG@MOF biocomposites present significant differences in terms of crystallinity, particle size, and spatial distribution of the cargo, which influences the drug-release kinetics upon applying an acidic stimulus. For a selected system, heparin@MOF, the released therapeutic retained its antithrombotic activity while the MOF shell effectively protects the drug from heparin lyase. By using different MOF shells, the present approach enables the preparation of GAG-based biocomposites with tunable properties such as encapsulation efficiency, protection and release.

ZIF-C for targeted RNA interference and CRISPR/Cas9 based gene editing in prostate cancer

Metal–organic-frameworks for gene therapy in prostate cancer – ZIF-C based delivery of RNA interference and CRISPR/Cas9 causes host gene expression knockdown. Coating with a green tea phytochemical enhances uptake and increases cancer cytotoxicity.

Current status and future prospects of metal–organic frameworks at the interface of dye-sensitized solar cells

In this Frontier Article recent progresses and challenges at the interface of metal–organic frameworks and dye-sensitized solar cells are highlighted and discussed.

Magnetically responsive horseradish peroxidase@ZIF-8 for biocatalysis

A porous model bioreactor is obtained combining zeolitic imidazolate framework ZIF-8 with horseradish peroxidase and iron oxide magnetic nanoparticles in a one-pot process, in water at room temperature.