Fabrication of a microporous Dy(III)-organic framework with polar channels for 5-Fu (fluorouracil) delivery and inhibiting human brain tumor cells

Improving the drug delivery performance of ZIF-8 with amine functionalization as a 5-fluorouracil nanocarrier

This study investigates the effect of amine functional groups in ZIF-8 metal-organic frameworks on the loading and release of 5-fluorouracil (5-FU). The facile and cost-effective solvent-assisted linker exchange (SALE) method was used to exchange 2-methylimidazole (2-MIM) linkers with 3-amino-1,2,4-triazole (Atz) in the ZIF-8 structure, which resulted in a synthesis of ZIF-8A with 22, 53, and 74% Atz exchange, respectively. The prepared nanoparticles were characterized by 1H-NMR, XRD, FT-IR, FE-SEM, UV-Vis spectroscopy, and zeta potential analysis. Drug encapsulation efficiency results showed 12% for 5-FU@ZIF-8 which increased to 48% for 5-FU@ZIF-8A(53%). Also, the results of in-vitro experiments exhibited the pH-responsive behavior of nanocarriers and slower release for 5-FU@ZIF-8A(53%) compared to 5-FU@ZIF-8. The increase in drug encapsulation efficiency and slower release is due to the presence of the amine functional group in the structure, which improves the host-guest interactions between drug molecules and linkers. Moreover, the MTT assay was performed on MCF-7 and HFF-2 cell lines which revealed that 5-FU@ZIF-8A(53%) exhibited more significant cytotoxicity toward cancer cells while less toxicity toward normal cells compared to 5-FU@ZIF-8. These findings highlight the capability of amine-functionalized ZIF-8 as an effective drug delivery system for 5-FU and demonstrate the potential of the facial and low-cost SALE approach as a promising technique in nanocarrier development.

Green Ultrasound-Assisted Synthesis of Rare-Earth-Based MOFs

Rare-earth (RE)-based metal organic frameworks (MOFs) are quickly gaining popularity as flexible functional materials in a variety of technological fields. These MOFs are useful for more than just conventional uses like gas sensors and catalyst materials; in fact, they also show significant promise in emerging technologies including photovoltaics, optical, and biomedical applications. Using yttrium and europium as ionic host centres and dopants, respectively, and 1,3,5-benzenetricarboxylic acid (H3-BTC) as an organic linker, we describe a simple and green approach for the fabrication of RE-MOFs. Specifically, Y-BTCs and Eu-doped Y-BTCs MOFs have been synthesised in a single step using an eco-friendly method that makes use of ultrasound technology. To establish a correlation between the morphological and structural properties and reaction conditions, a range of distinct reaction periods has been employed for the synthetic processes. Detailed analyses of the synthesised samples through powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR) have confirmed the phase formation. Furthermore, thermal analyses such as thermogravimetric analysis (TGA) have been employed to evaluate the thermal stability and structural modifications of the Y-BTC and Eu-doped Y-BTC samples. Finally, the luminescent properties of the synthesised samples doped with Eu3+ have been assessed, providing an evaluation of their characteristics. As a proof of concept, an Eu-doped Y-BTC sample has been applied for the sensing of nitrobenzene as a molecule test of nitro derivatives.

A reliable QSPR model for predicting drug release rate from metal-organic frameworks: a simple and robust drug delivery approach

During the drug release process, the drug is transferred from the starting point in the drug delivery system to the surface, and then to the release medium. Metal-organic frameworks (MOFs) potentially have unique features to be utilized as promising carriers for drug delivery, due to their suitable pore size, high surface area, and structural flexibility. The loading and release of various therapeutic drugs through the MOFs are effectively accomplished due to their tunable inorganic clusters and organic ligands. Since the drug release rate percentage (RES%) is a significant concern, a quantitative structure-property relationship (QSPR) method was applied to achieve an accurate model predicting the drug release rate from MOFs. Structure-based descriptors, including the number of nitrogen and oxygen atoms, along with two other adjusted descriptors, were applied for obtaining the best multilinear regression (BMLR) model. Drug release rates from 67 MOFs were applied to provide a precise model. The coefficients of determination (R2) for the training and test sets obtained were both 0.9999. The root mean square error for prediction (RMSEP) of the RES% values for the training and test sets were 0.006 and 0.005, respectively. To examine the precision of the model, external validation was performed through a set of new observations, which demonstrated that the model works to a satisfactory degree.

Metal-Organic Frameworks-Based Nanoplatforms for the Theranostic Applications of Neurological Diseases

Neurological diseases are the foremost cause of disability and the second leading cause of death worldwide. Owing to the special microenvironment of neural tissues and biological characteristics of neural cells, a considerable number of neurological disorders are currently incurable. In the past few years, the development of nanoplatforms based on metal-organic frameworks (MOFs) has broadened opportunities for offering sensitive diagnosis/monitoring and effective therapy of neurology-related diseases. In this article, the obstacles for neurotherapeutics, including delayed diagnosis and misdiagnosis, the existence of blood brain barrier (BBB), off-target treatment, irrepressible inflammatory storm/oxidative stress, and irreversible nerve cell death are summarized. Correspondingly, MOFs-based diagnostic/monitoring strategies such as neuroimaging and biosensors (electrochemistry, fluorometry, colorimetry, electrochemiluminescence, etc.) and MOFs-based therapeutic strategies including higher BBB permeability, targeting specific lesion sites, attenuation of neuroinflammation/oxidative stress as well as regeneration of nerve cells, are extensively highlighted for the management of neurological diseases. Finally, the challenges of the present research from perspective of clinical translation are discussed, hoping to facilitate interdisciplinary studies at the intersections between MOFs-based nanoplatforms and neurotheranostics.

A Luminescent Mg-Metal-Organic Framework for Sustained Release of 5-Fluorouracil: Appropriate Host-Guest Interaction and Satisfied Acid-Base Resistance

It is important to achieve a moderate sustained release rate for drug delivery, so it is critical to regulate the host-guest interactions for the rational design of a carrier. In this work, a nano-sized biocompatible metal-organic framework (MOF), Mg(H₂TBAPy)(H₂O)₃·C₄H₈O₂ (TDL-Mg), was constructed by employing π-conjugated 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H₄TBAPy) as a ligand and used for 5-fluorouracil (5-FU) loading (28.2 wt %) and sustained slow release. TDL-Mg exhibits a 3D supramolecular architecture featuring a 1D rectangle channel with a size of 6.2 × 8.1 Ų and a Brunauer-Emmett-Teller surface area of 627 m²·g^-1. Channel microenvironment analysis shows that the rigid H₂TBAPy^2- ligand adopts special torsion to stabilize the channels and offer rich π-binding sites; the partially deprotonated carboxyls not only participate in the formation of strong hydrogen bonds but also create a mild pH buffer environment for biological applications. Suitable host-guest interactions are generated by the synergistic effect of polydirectional hydrogen bonds, multiple π-interactions, and confined channels, which allow 5-FU@TDL-Mg to release 76% of load in 72 h, a medically reasonable rate. Microcalorimetry was used to directly quantify these host-guest interactions with a moderate enthalpy of 22.3 kJ·mol^-1, which provides a distinctive thermodynamic interpretation for understanding the relationship between the MOF design and the drug release rate. Additionally, the nano-sized 5-FU@TDL-Mg can be taken up by mouse breast cancer cells (4T1 cells) for imaging based on the dramatic fluorescence change during the release of 5-FU, exhibiting potential applications in biological systems.

Metal Organic Frameworks as Drug Targeting Delivery Vehicles in the Treatment of Cancer

: In recent years, metal organic frameworks (MOFs) have been widely developed as vehicles for the effective delivery of drugs to tumor tissues. Due to the high loading capacity and excellent biocompatibility of MOFs, they provide an unprecedented opportunity for the treatment of cancer. However, drugs which are commonly used to treat cancer often cause side effects in normal tissue accumulation. Therefore, the strategy of drug targeting delivery based on MOFs has excellent research significance. Here, we introduce several intelligent targeted drug delivery systems based on MOFs and their characteristics as drug-loading systems, and the challenges of MOFs are discussed. This article covers the following types of MOFs: Isoreticular Metal Organic Frameworks (IRMOFs), Materials of Institute Lavoisier (MILs), Zeolitic Imidazolate Frameworks (ZIFs), University of Oslo (UiOs), and MOFs-based core-shell structures. Generally, MOFs can be reasonably controlled at the nanometer size to effectively achieve passive targeting. In addition, different ligands can be modified on MOFs for active or physicochemical targeting. On the one hand, the targeting strategy can improve the concentration of the drugs at the tumor site to improve the efficacy, on the other hand, it can avoid the release of the drugs in normal tissues to improve safety. Despite the challenges of clinical application of MOFs, MOFs have a number of advantages as a kind of smart delivery vehicle, which offer possibilities for clinical applications.