Sarah V. Dummert

This work gives insight into rapid, in situ drug encapsulation in ZIF-8, its incorporation into an alginate matrix at 95 wt%, yielding MOF composites with controlled drug release, and preliminary in vitro studies on their antiproliferative activity.

In this study, we explore the interfacing of Photosystem I (PSI) with the metal-organic framework (MOF) ZIF-8 (ZIF = zeolitic imidazolate framework) through encapsulation and surface immobilization methods, aimed at stabilizing PSI through biohybrid composite formation. PSI was successfully encapsulated within ZIF-8 (PSI@ZIF-8) and immobilized on ZIF-8 surfaces (PSI/ZIF-8) using a one-pot synthesis and surface impregnation technique, respectively. Characterization techniques including powder X-ray diffraction, Fourier transform infrared spectroscopy, and high-angle annular dark-field scanning transmission electron microscopy confirmed the formation and first-of-its-kind nanoscale visualization of the PSI/ZIF-8 composites. Spectroscopic analysis revealed that while PSI encapsulation resulted in minor structural changes potentially from scaffolding-induced stress and MOF building blocks, the overall protein integrity was maintained. Our study demonstrates that, in contrast to surface interfacing, ZIF-8 encapsulation provides a protective environment for PSI, enhancing its stability and retaining its functional properties, thereby offering an auspicious approach for the development of biohybrid materials in semi-artificial photosynthesis and other biotechnological applications.

The successful development of a metal-organic framework (MOF)-derived Co/Co₃O₄/C core-shell composite integrated into laser-induced graphitic (LIG) carbon electrodes for electrochemical sensing is reported. The sensors are fabricated via a direct laser scribing technique using a UV laser (355 nm wavelength) to induce the photothermolysis of rationally selected ZIF-67 into the LIG matrix. Electrochemical characterization reveals that the incorporation of the laser-scribed ZIF-67-derived composite on the electrode surface reduces the impedance more than 100 times compared with bare LIG sensors. Comprehensive morphological, structural, and chemical analyses confirm the formation of porous LIG from the laser irradiation of polyimide, while the LIG+ZIF-67-derived composites feature size-controlled and uniformly distributed Co/Co₃O₄ core/shell nanoparticles (NPs) in the semihollow wasp-nest-like carbon matrix from photothermal decomposition of ZIF-67, embedded within the LIG electrode area. The high surface area and porosity of this ZIF-67-derived nitrogen-rich carbon facilitate charge transfer processes, whereas size-controlled Co/Co₃O₄ core/shell NPs offer accessible electrochemical active sites, making these LIG+ZIF-67-derived composite-based sensors promising materials for applications requiring high charge injection capability and low electrode/electrolyte interface impedance. The PI+Z67_L sensor exhibited a 400 times higher specific capacitance (2.4 mF cm^-2) compared to the PI_L sensor (6 μF cm^-2). This laser scribing approach enables the rapid and cost-effective fabrication of high-performance electrochemical sensors enhanced by the integration of tailored MOF-derived composites.

Scaffolds with multiple advantageous biological and structural properties are still a challenge in the field of tissue engineering. The convergence of advanced fabrication techniques and functional materials is key to fulfill this need. Melt electrowriting (MEW) is an additive manufacturing technique that enables the fabrication of microfibrous scaffolds with precisely defined microarchitectures. Here, it is proposed to exploit metal–organic frameworks (MOFs) to efficiently introduce multifunctionalities by combining polycaprolactone (PCL), the gold standard material in MEW, with a silver‐/silver‐chloride‐decorated iron‐based MOF (NH₂‐MIL‐88B(Fe)). This results in highly ordered constructs with antibacterial properties and magnetic resonance imaging (MRI) visibility. Scaffolds with up to 20 wt% MOF are successfully melt‐electrowritten with a fiber diameter of 50 µm. Among these, 5 wt% MOF proves to be the optimal concentration as it exhibits silver‐induced sustained antibacterial efficacy while maintaining PCL cytocompatibility and in vitro immune response. The iron component of the MOF (Fe(III) nodes) renders the composite visible with MRI, thereby enabling scaffold monitoring upon implantation with a clinically accepted method. The combination of MEW and MOFs as tunable additives and cargo carriers opens the way for designing advanced multifunctional scaffolds with a wide range of applications in, e.g., tissue engineering, biosensing and drug delivery.

While there is a tremendous amount of scientific research on metal organic frameworks (MOFs) for gas storage/separation, catalysis and energy storage, the development and application of biocompatible MOFs still poses major challenges. In general, they can be synthesised from various biocompatible linkers and metal ions but particularly cyclodextrins (CDs) as cyclic oligosaccharides are an astute choice for the former. Although the field of CD-MOF materials is still in the early stages and their design and fabrication comes with many hurdles, the benefits coming from CDs built in a porous framework are exciting. Versatile host-guest complexation abilities, high encapsulation capacity and hydrophilicity are among the valuable properties inherent to CDs and offer extended and novel applications to MOFs. In this review, we provide an overview of the state-of-the-art synthesis, design, properties and applications of these materials. Initially, a rationale for the preparation of CD-based MOFs is provided, based on the chemical and structural properties of CDs and including their advantages and disadvantages. Further on, the review exhaustively surveys CD-MOF based materials by categorising them into three sub-classes, namely (i) CD-MOFs, (ii) CD-MOF hybrids, obtained via combination with external materials, and (iii) CD-MOF-derived materials prepared under pyrolytic conditions. Subsequently, CD-based MOFs in practical applications, such as drug delivery and cancer therapy, sensors, gas storage, (enantiomer) separations, electrical devices, food industry, and agriculture, are discussed. We conclude by summarizing the state of the art in the field and highlighting some promising future developments of CD-MOFs.