Biocatalytic transformations in living organisms, such as multi-enzyme catalytic cascades, proceed in different cellular membrane-compartmentalized organelles with high efficiency. Nevertheless, it ...remains challenging to mimicking biocatalytic cascade processes in natural systems. Herein, we demonstrate that multi-shelled metal-organic frameworks (MOFs) can be used as a hierarchical scaffold to spatially organize enzymes on nanoscale to enhance cascade catalytic efficiency. Encapsulating multi-enzymes with multi-shelled MOFs by epitaxial shell-by-shell overgrowth leads to 5.8~13.5-fold enhancements in catalytic efficiencies compared with free enzymes in solution. Importantly, multi-shelled MOFs can act as a multi-spatial-compartmental nanoreactor that allows physically compartmentalize multiple enzymes in a single MOF nanoparticle for operating incompatible tandem biocatalytic reaction in one pot. Additionally, we use nanoscale Fourier transform infrared (nano-FTIR) spectroscopy to resolve nanoscale heterogeneity of vibrational activity associated to enzymes encapsulated in multi-shelled MOFs. Furthermore, multi-shelled MOFs enable facile control of multi-enzyme positions according to specific tandem reaction routes, in which close positioning of enzyme-1-loaded and enzyme-2-loaded shells along the inner-to-outer shells could effectively facilitate mass transportation to promote efficient tandem biocatalytic reaction. This work is anticipated to shed new light on designing efficient multi-enzyme catalytic cascades to encourage applications in many chemical and pharmaceutical industrial processes.
Owing to the progressive development of metal–organic‐frameworks (MOFs) synthetic processes and considerable potential applications in last decade, integrating biomolecules into MOFs has recently ...gain considerable attention. Biomolecules, including lipids, oligopeptides, nucleic acids, and proteins have been readily incorporated into MOF systems via versatile formulation methods. The formed biomolecule‐MOF hybrid structures have shown promising prospects in various fields, such as antitumor treatment, gene delivery, biomolecular sensing, and nanomotor device. By optimizing biomolecule integration methods while overcoming existing challenges, biomolecule‐integrated MOF platforms are very promising to generate more practical applications.
Integrating biomolecules into metal–organic‐frameworks (MOFs) has recently gain considerable attention, owing to the progressive development of the synthesis of MOFs in the last decade. Biomolecules, including lipids, oligopeptides, nucleic acids, and proteins are readily incorporated into MOF systems via versatile formulation methods. The formed biomolecule‐MOF hybrid structures show promising prospects in various fields, such as antitumor treatment, gene delivery, biomolecular sensing, and nanomotor device.
Zeolitic imidazolate frameworks (ZIFs), a subclass of metal–organic frameworks (MOFs) built with tetrahedral metal ions and imidazolates, offer permanent porosity and high thermal and chemical ...stabilities. While ZIFs possess some attractive physical and chemical properties, it remains important to enhance their functionality for practical application. Here, an overview of the extensive strategies which have been developed to improve the functionality of ZIFs is provided, including linker modifications, functional hybridization of ZIFs via the encapsulation of guest species (such as metal and metal oxide nanoparticles and biomolecules) into ZIFs, and hybridization with polymeric matrices to form mixed matrix membranes for industrial gas and liquid separations. Furthermore, the developed strategies for achieving size and shape control of ZIF nanocrystals are considered, which are important for optimizing the textural characteristics as well as the functional performance of ZIFs and their derived materials/hybrids. Moreover, the recent trends of using ZIFs as templates for the derivation of nanoporous hybrid materials, including carbon/metal, carbon/oxide, carbon/sulfide, and carbon/phosphide hybrids, are discussed. Finally, some perspectives on the potential future research directions and applications for ZIFs and ZIF‐derived materials are offered.
Zeolitic imidazolate frameworks (ZIFs), offer permanent porosity and high thermal and chemical stabilities. The developed strategies for enhancing the functionality of ZIFs, including linker functionalization and hybridization with guest species and polymers, are discussed. Finally, the utilization of ZIFs as templates for fabricating nanoporous hybrid materials and the future trends and prospects in the functionalization of ZIFs are examined.
Because of their efficiency, selectivity, and environmental sustainability, there are significant opportunities for enzymes in chemical synthesis and biotechnology. However, as the three-dimensional ...active structure of enzymes is predominantly maintained by weaker noncovalent interactions, thermal, pH, and chemical stressors can modify or eliminate activity. Metal–organic frameworks (MOFs), which are extended porous network materials assembled by a bottom-up building block approach from metal-based nodes and organic linkers, can be used to afford protection to enzymes. The self-assembled structures of MOFs can be used to encase an enzyme in a process called encapsulation when the MOF is synthesized in the presence of the biomolecule. Alternatively, enzymes can be infiltrated into mesoporous MOF structures or surface bound via covalent or noncovalent processes. Integration of MOF materials and enzymes in this way affords protection and allows the enzyme to maintain activity in challenge conditions (e.g., denaturing agents, elevated temperature, non-native pH, and organic solvents). In addition to forming simple enzyme/MOF biocomposites, other materials can be introduced to the composites to improve recovery or facilitate advanced applications in sensing and fuel cell technology. This review canvasses enzyme protection via encapsulation, pore infiltration, and surface adsorption and summarizes strategies to form multicomponent composites. Also, given that enzyme/MOF biocomposites straddle materials chemistry and enzymology, this review provides an assessment of the characterization methodologies used for MOF-immobilized enzymes and identifies some key parameters to facilitate development of the field.
Encapsulating well-defined nanoparticle catalysts into porous materials to form a core–shell nanostructure can enhance the durability, selectivity, or reactivity of the catalysts and even provide ...additional functionalities to the catalysts. Using metal–organic frameworks (MOFs) as the encapsulating porous materials has drawn great interest recently because MOFs, as a class of crystalline nanoporous materials, have well-defined pore structures and unique chemical properties. Also, the structures and properties of MOFs are tunable. In this perspective review, we examine recent progress in the development of synthetic methods for metal@MOF core–shell nanostructures as catalysts. Potential directions in the field are also discussed.
Monodisperse Cu and Cu2O nanoparticles (NPs) are synthesized using tetradecylphosphonic acid as a capping agent. Dispersing the NPs in chloroform and hexane at room temperature results in the ...formation of hollow Cu2O NPs and Cu@Cu2O core/shell NPs, respectively. The monodisperse Cu2O NPs are used to fabricate hybrid solar cells with efficiency of 0.14% under AM 1.5 and 1 Sun illumination.
Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely ...explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine‐functionalized Zr metal–organic framework (MOF), UiO‐66‐NH2 (Pt@UiO‐66‐NH2) as a multifunctional catalyst in the one‐pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO‐66‐NH2, Pt@UiO‐66‐NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO‐66, and Pd@UiO‐66‐NH2. Pt@UiO‐66‐NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO‐66‐NH2). To our knowledge, this work demonstrates the first examples of one‐pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
In tandem: Platinum nanoclusters (PtNCs) encapsulated in amine‐functionalized UiO‐66‐NH2 (Pt@UiO‐66‐NH2) act as a multifunctional catalyst in the one‐pot tandem synthesis of nitrones. By the cooperative interplay between the selective hydrogenation activity provided by PtNCs and Lewis acidity/basicity/nanoconfinement provided by the MOF, Pt@UiO‐66‐NH2 exhibits remarkable activity and selectivity.
We have developed a general synthetic route to encapsulate small molecules in monodisperse zeolitic imid-azolate framework-8 (ZIF-8) nanospheres for drug delivery. Electron microscopy, powder X-ray ...diffraction, and elemental analysis show that the small-molecule-encapsulated ZIF-8 nanospheres are uniform 70 nm particles with single-crystalline structure. Several small molecules, including fluorescein and the anticancer drug camptothecin, were encapsulated inside of the ZIF-8 framework. Evaluation of fluorescein-encapsulated ZIF-8 nanospheres in the MCF-7 breast cancer cell line demonstrated cell internalization and minimal cytotoxicity. The 70 nm particle size facilitates cellular uptake, and the pH-responsive dissociation of the ZIF-8 framework likely results in endosomal release of the small-molecule cargo, thereby rendering the ZIF-8 scaffold an ideal drug delivery vehicle. To confirm this, we demonstrate that camptothecin encapsulated ZIF-8 particles show enhanced cell death, indicative of internalization and intracellular release of the drug. To demonstrate the versatility of this ZIF-8 system, iron oxide nanoparticles were also encapsulated into the ZIF-8 nanospheres, thereby endowing magnetic features to these nanospheres.
Highly luminescent metal–organic frameworks (LMOFs) have received great attention for their potential use in energy-efficient general lighting devices such as white-light-emitting diodes (WLEDs); ...however, achieving strong emission with controllable color, especially high-quality white light, remains a considerable challenge. Herein, we present a new strategy to encapsulate in situ multiple dyes into nanocrystalline ZIF-8 pores to form an efficient dyes@MOF system. Using this strategy, we build three models, namely, multiphase single-shell dye@ZIF-8, single-phase single-shell dyes@ZIF-8, and single-phase multishell dyes@ZIF-8, to systematically and fine-tune the white emission color by varying the components and concentration of encapsulated dyes. The study of these three models demonstrates the importance of the multishell structure, which can effectively reduce the interactions such as Förster resonance energy transfer (FRET) between encapsulated dyes. This energy transfer would otherwise be unavoidable in a single-shell setting, which often reduces the efficiency of white-light emission in the dyes@MOF system. This approach offers a new perspective not only for fine-tuning the emission color within nanoporous dyes@MOFs but also for fabricating MOF nanocrystals that are easily solution-processable. The strategy may also facilitate the development of other types of MOF–guest nanocomposite systems.
ABSTRACT
Introduction: In this study we explored the efficacy of nerve hydrodissection for mild‐to‐moderate carpal tunnel syndrome (CTS). Methods: Thirty‐four participants were randomly assigned to ...an intervention group or a control group. One 5‐ml dose of normal saline was injected into the intracarpal and subcutaneous regions in subjects of both groups, respectively. The primary outcome measure was the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) score. Secondary outcomes were cross‐sectional area of the median nerve and electrophysiological studies. Assessments were performed before the injection and at 1, 2, 3, and 6 months postintervention. Results: Compared with the control group, the intervention group showed significantly greater improvement at the second and third posttreatment months according to BCTQ severity score and at all time‐points for cross‐sectional area of the median nerve (P < 0.01). Discussion: Our study demonstrates the therapeutic effects of nerve hydrodissection for mild‐to‐moderate CTS. Muscle Nerve 59:174–180, 2019
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