Metal-organic frameworks (MOFs) as effectual diagnostic and therapeutic tools for cancer

Metal-organic frameworks (MOFs) are a class of multifunctional organometallic compounds that include metal ions combined with assorted organic linkers. Recently, these compounds have received widespread attention in medicine, due to their exceptional qualities, including a wide surface area, high porosity, outstanding biocompatibility, non-toxicity, etc. Such characteristic qualities make MOFs superb candidates for biosensing, molecular imaging, drug delivery, and enhanced cancer therapies. This review illustrates the key attributes of MOFs and their importance in cancer research. The structural and synthetic aspects of MOFs are briefly discussed with primary emphasis on diagnostic and therapeutic features, as well as their performance and significance in modern therapeutic methods and synergistic theranostic strategies including biocompatibility. This review offers cumulative scrutiny of the widespread appeal of MOFs in modern-day oncological research, which may stimulate further explorations.

Plasma Meets MOFs: Synthesis, Modifications, and Functionalities

As a porous and network materials consisting of metals and organic ligands, metal-organic frameworks (MOFs) have become one of excellent crystalline porous materials and play an important role in the era about materials science. Plasma, as a useful tool for stimulating efficient reactions under many conditions, and the plasma-assisted technology gets more attractions and endows MOFs more properties. Based on its feature, the research about the modifications and functionalities of MOFs have been developing a certain extent. This review contains a description of the methods for plasma-assisted modification and synthesis of MOFs, with specifically focusing on the plasma-assisted potential for modifications and functionalities of MOFs. The different applications of plasma-assisted MOFs were also presented.

Hybrid liposome/metal-organic framework as a promising dual-responsive nanocarriers for anticancer drug delivery

In this work, liposome-coated iron (III) benzene-1,3,5-tricarboxylate (Fe-BTC) metal-organic framework is examined as a promising pH/Ultrasound dual-responsive nanocarriers for doxorubicin (DOX) delivery. The successful coating of the MOF particles (Lip-Fe-BTC) with the phospholipid bilayer (PBL) was established by direct fusion into the synthesized liposomes. The liposome coating was verified using several techniques, including dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS measurements showed an increase in the average particle diameter of liposomes from 150 nm to 163.1 nm for Lip-Fe-BTC particles. The Fe-BTC particles had the highest average particle diameter (287.3 nm). These results demonstrated that the PBL reduced the aggregation of the particles and improved their dispersity in the release medium. The TGA results demonstrated the MOF's excellent thermal stability. Furthermore, the nanocarrier's loading efficiency and capacity were determined to be ~90% and ~13.5 wt%, respectively. The in-vitro DOX release experiments demonstrated that the DOX-loaded Fe-BTC and liposome-coated Fe-BTC particles showed good pH and US dual-responsive capability, making them promising nanocarriers for drug delivery. The application of US enhanced DOX release from both Fe-BTC and liposome-coated Fe-BTC. In the case of Fe-BTC-DOX particles, the application of US enhanced the DOX release to around 38% and 67%, at pH levels of 7.4 and 5.3, respectively. Similarly, DOX release from the Lip-Fe-BTC-DOX particles reached ~35% and ~53%, at pH levels of 7.4 and 5.3, respectively. The MTT assay showed the biocompatibility and low cytotoxicity of these nanocarriers below 100 µg/ml.

Acid-Degradable Hydrogen-Generating Metal-Organic Framework for Overcoming Cancer Resistance/Metastasis and Off-Target Side Effects

The development of stimuli-responsively degradable porous carriers for both controlled drug release and high biosafety is vitally important to their clinical translation, but still challenging at present. A new type of porphyrin-iron metal organic framework (Fe-MOF) nanocrystals is engineered here as acid-degradable drug carrier and hydrogen donor by the coordination between porphyrin and zero-valence Fe atom. Fe-MOF nanocrystals exhibit excellent acid-responsive degradation for H₂ generation and simultaneous release of the loaded drug for combined hydrogen-chemotherapy of cancer multidrug resistance (MDR) and metastasis and for local hydrogen eradication of the off-target induced toxic side effects of the drug to normal cells/tissues. Mechanistically, released H₂ assists chemotherapeutic drug to efficiently inhibit cancer metastasis by immunoactivating intratumoral M1-phenotype macrophages and consequently downregulating the expression of metastasis-related matrix metalloproteinase-2 (MMP-2) and can also downregulate the expressions of both P-glycoprotein (P-gp) protein and adenosine triphosphate (ATP) in MDR cancer cells to sensitize chemotherapeutic drug for enhanced damage to mitochondria and DNA. High anti-MDR/antimetastasis efficacies and high biocompatibility endow Fe-MOF nanocrystals and the Fe-MOF-based nanomedicine with high potential for clinical translation.

Metal-Organic Framework-Based Stimuli-Responsive Systems for Drug Delivery

With the rapid development of nanotechnology, stimuli-responsive nanomaterials have provided an alternative for designing controllable drug delivery systems due to their spatiotemporally controllable properties. As a new type of porous material, metal-organic frameworks (MOFs) have been widely used in biomedical applications, especially drug delivery systems, owing to their tunable pore size, high surface area and pore volume, and easy surface modification. Here, recent progress in MOF-based stimuli-responsive systems is presented, including pH-, magnetic-, ion-, temperature-, pressure-, light-, humidity-, redox-, and multiple stimuli-responsive systems for the delivery of anticancer drugs. The remaining challenges and suggestions for future directions for the rational design of MOF-based nanomedicines are also discussed.

Bio-related applications of porous organic frameworks (POFs)

Porous organic frameworks (POFs) are promising candidates for bio-related applications. This review highlights the recent progress in POF-based bioapplications, including drug delivery, bioimaging, biosensing, therapeutics, and artificial shells. These encouraging performances suggest that POFs used for bioapplications deserve more attention in the future.

Defective Metal-Organic Frameworks

The targeted incorporation of defects into crystalline matter allows for the manipulation of many properties and has led to relevant discoveries for optimized and even novel technological applications of materials. It is therefore exciting to see that defects are now recognized to be similarly useful in tailoring properties of metal-organic frameworks (MOFs). For instance, heterogeneous catalysis crucially depends on the number of active catalytic sites as well as on diffusion limitations. By the incorporation of missing linker and missing node defects into MOFs, both parameters can be accessed, improving the catalytic properties. Furthermore, the creation of defects allows for adding properties such as electronic conductivity, which are inherently absent in the parent MOFs. Herein, progress of the rapidly evolving field of the past two years is overviewed, putting a focus on properties that are altered by the incorporation and even tailoring of defects in MOFs. A brief account is also given on the emerging quantitative understanding of defects and heterogeneity in MOFs based on scale-bridging computational modeling and simulations.

Magnetic nanoscale metal–organic frameworks for magnetically aided drug delivery and photodynamic therapy

Dual drug doping of magnetic nanoscale metal–organic frameworks facilitates magnetically directed chemotherapy and light activated therapy.