Parametric study on the mixed solvent synthesis of ZIF-8 nano- and micro-particles for CO adsorption: A response surface study

A simple one step synthesis of magnetic-optical dual functional ZIF-8 in a sodalite phase for magnetically guided targeting bioimaging and drug delivery

Functionalized metal-organic frameworks (MOFs) that integrate targeted tumor imaging and drug delivery are expected to significantly enhance the therapeutic efficacy of cancer. However, the complicated synthesis process has greatly limited their utilization in clinical application. Herein, a one-step simple method was used to construct novel multifunctional MOFs by co-loading doxorubicin (DOX) and Fe3O4 into the ZIF-8 with sodalite topology. DOX serves as a fluorescence imaging reagent and an anticancer drug and Fe3O4 is used as a magnetic resonance imaging and magnetic targeting anticancer reagent. The fabricated DOX/Fe3O4@ZIF-8 nanocomposite showed excellent fluorescence and magnetic resonance imaging performances in tumors. Moreover, DOX/Fe3O4@ZIF-8 can be accumulated in tumors via a magnetic targeting effect and tumor growth could be inhibited in vivo due to the release of DOX. Additionally, the apoptosis process of DOX/Fe3O4@ZIF-8 on HepG2 cells is well investigated. Overall, DOX/Fe3O4@ZIF-8 synthesized in simple one step can be used for simultaneous targeted bioimaging and cancer therapy.

Metal-Organic Frameworks as bio- and heterogeneous catalyst supports for biodiesel production

As biodiesel (BD)/Fatty Acid Alkyl Esters (FAAE) is derived from vegetable oils and animal fats, it is a cost-effective alternative fuel that could complement diesel. The BD is processed from different catalytic routes of esterification and transesterification through homogeneous (alkaline and acid), heterogeneous and enzymatic catalysis. However, heterogeneous catalysts and biocatalysts play an essential role towards a sustainable alternative to homogeneous catalysts applied in biodiesel production. The main drawback is the supporting material. To overcome this, currently, Metal-Organic Frameworks (MOFs) have gained significant interest as supports for catalysts due to their extremely high surface area and numerous binding sites. This review focuses on the advantages of using various MOFs structures as supports for heterogeneous catalysts and biocatalysts for the eco-friendly biodiesel production process. The characteristics of these materials and their fabrication synthesis are briefly discussed. Moreover, we address in a general way basic items ranging from biodiesel synthesis to applied catalysts, giving great importance to the enzymatic part, mainly to the catalytic mechanism in esterification/transesterification reactions. We provide a summary with recommendations based on the limiting factors.

ZIF-8 metal organic framework composites as hydrogen evolution reaction photocatalyst: A review of the current state

In the past decade, extensive research has been devoted to synthesis of ZIF-8 materials for catalytic applications. As physico-chemical properties are synthesis-dependent, this review explores different synthesis strategies based the solvent and solvent-free synthesis of zeolitic imidazole framework. Accordingly, the effect of several parameters on the ZIF-8 synthesis were discussed including solvent, deprotonating agents, precursors ratio is delivered. Additionally, the advantages and disadvantages of each synthesis have been discussed and assessed. ZIF-8 textural and structural properties justify its wide use as a stable high surface area MOF in aqueous catalytic reactions. This review includes the applicatios of ZIF-8 materials in photocatalytic hydrogen evolution reaction (HER). The efficiency of the reviewed materials was fairly assessed. Finally, Limitations, drawbacks and future challenges were fully debated to ensure the industrial viability of the ZIFs.

Peptide-Mediated Synthesis of Zeolitic Imidazolate Framework-8: Effect of Molecular Hydrophobicity, Charge Number and Charge Location

Three amphiphilic peptides with varied molecular hydrophobicity, charge number and charge location have been designed as regulators to modulate the crystal growth of zeolitic imidazolate framework-8 (ZIF-8). All three peptides can interact with ZIF-8 to inhibit {100} facet growth and produce truncated cubic crystals. The peptide's molecular hydrophobicity plays a dominant role in defining the final morphology and size of the ZIF-8 crystals. The peptides with less charge and higher hydrophobicity can promote nuclei formation and crystal growth to give smaller ZIF-8 crystals. However, the charge located in the center of the molecular hydrophobic region has little effect on the crystal nucleation and growth due to the shielding of its charge by molecular aggregation. The study provides insights into the effect of molecular charge and hydrophobicity on ZIF-8 crystal growth and is helpful for guiding the molecular design for regulating the synthesis of metal-organic framework materials.

Expanding the ZIFs Repertoire for Biological Applications with the Targeted Synthesis of ZIF-20 Nanoparticles

Owing to their facile synthesis, tailorable porosity, diverse compositions, and low toxicity, zeolitic imidazolate framework (ZIF) nanoparticles (NPs) have emerged as attractive platforms for a variety of biologically relevant applications. To date, a small subset of ZIFs representing only two topologies and very few linker chemistries have been studied in this realm. We seek to expand the bio-design space for ZIF NPs through the targeted synthesis of a hierarchically complex ZIF based on two types of cages, ZIF-20, with lta topology. This study demonstrates the rapid synthesis and size tunability of ZIF-20 particles across the micro and nanoregimes via microwave heating and the use of a modulating agent. To evaluate the utility of ZIF particles for biological applications, we examine their stability in biologically relevant media and demonstrate biocompatibility with A549 human epithelial cells. Further, the ability to encapsulate and release methylene blue, a therapeutic and bioimaging agent, is validated. Importantly, ZIF-20 NPs display a unique behavior relative to previously studied ZIFs based on their specific structural and chemical features. This finding highlights the need to expand the design space across the broader ZIFs family, to exploit a wider range of relevant properties for biological applications and beyond.

Electrospun Nylon 6,6/ZIF-8 Nanofiber Membrane for Produced Water Filtration

This study develops electrospun nylon 6,6 nanofiber membrane (NFM), incorporating zeolitic imidazolate framework-8 (ZIF-8) as the additive for produced water (PW) filtration. Electrospun NFM is suitable to be used as a filter, especially for water treatment, since it has a huge surface area to volume ratio, high porosity, and great permeability compared to the conventional membranes. These properties also enhance its competitiveness to be used as reverse osmosis pre-treatment, as the final stage of PW treatment water reuse purpose. However, the fouling issue and low mechanical strength of NFM reduces hydraulic performance over time. Therefore, this study employs ZIF-8 as an additive to improve nylon 6,6 NFM properties to reduce fouling and increase membrane tensile strength. Results show that the optimum loading of ZIF-8 was at 0.2%. This loading gives the highest oil rejection (89%), highest steady-state pure water permeability (1967 L/(m2·h·bar)), 2× higher than untreated nylon 6,6 NFM with tensile strength 5× greater (3743 MPa), and a steady-state permeability of 1667 L/(m2·h·bar) for filtration of real produced water.