Surface-Functionalized Metal-Organic Frameworks for Binding Coronavirus Proteins

The potential of metal-organic framework MIL-101(Al)-NH2 in the forefront of antiviral protection of cells via interaction with SARS-CoV-2 spike RBD protein and their antibacterial action mediated with hypericin and photodynamic treatment

The global pandemic of SARS-CoV-2 has highlighted the necessity for innovative therapeutic solutions. This research presents a new formulation utilising the metal-organic framework MIL-101(Al)-NH2, which is loaded with hypericin, aimed at addressing viral and bacterial challenges. Hypericin, recognised for its antiviral and antibacterial efficacy, was encapsulated to mitigate its hydrophobicity, improve bioavailability, and utilise its photodynamic characteristics. The MIL-101(Al)-NH2 Hyp complex was synthesised, characterised, and evaluated for its biological applications for the first time. The main objective of this study was to demonstrate the multimodal potential of such a construct, in particular the effect on SARS-CoV-2 protein levels and its interaction with cells. Both in vitro and in vivo experiments demonstrated the effective transport of hypericin to cells that express ACE2 receptors, thereby mimicking mechanisms of viral entry. In addition, hypericin found in the mitochondria showed selective phototoxicity when activated by light, leading to a decrease in the metabolic activity of glioblastoma cells. Importantly, the complex also showed antibacterial efficacy by selectively targeting Gram-positive Staphylococcus epidermidis compared to Gram-negative Escherichia coli under photodynamic therapy (PDT) conditions. To our knowledge, this study was the first to demonstrate the interaction between hypericin, MIL-101(Al)-NH2 and the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, which inhibits cellular uptake and colocalises with ACE2-expressing cells. Therefore, the dual functionality of the complex - targeting the viral RBD and the antibacterial effect via PDT - emphasises its potential to mitigate complications of viral infections, such as secondary bacterial infections. In summary, these results suggest that MIL-101(Al)-NH2 Hyp is a promising multifunctional therapeutic agent for antiviral and antibacterial applications, potentially contributing to the improvement of COVID-19 treatment protocols and the treatment of co-infections.

Protein and peptide confinement within metal-organic materials

Metal-organic materials (MOMs), including both discrete metal-organic cages (MOCs) and metal-organic frameworks (MOFs), are emerging as promising materials for peptide and protein immobilisation. In particular, the ease of synthesis of MOMs alongside their well-defined and modular internal void spaces makes them appealing when considering routes to immobilise and stabilise peptides and proteins outside of biological environments whilst retaining their native activity. Here we review recent advances made in understanding the conformation of peptidic materials confined within MOMs and the enzymes@MOF constructs which show the best enzymatic performance. We highlight opportunities for further advancement in each of these areas and proposed that complementary approaches taken by the MOC and MOF communities might be fruitfully combined to advance our understanding and the development of peptide/protein@MOM applications.

A Potential 3-in-1 Combined AntiSARS-CoV-2 Therapy Using Pulmonary MIL-100(Fe) Formulation

The emergence and rapid propagation of infectious diseases, including the COVID-19 pandemic, has evidenced the vulnerabilities in global health surveillance, the ease of transmission, and the imperative need for effective treatments. In this context, nanomedicines based on metal-organic frameworks (MOFs) have garnered great relevance as promising drug delivery platforms in a large range of complex diseases (e.g., cancer, and infections). However, most research has focused on sensing with scarce examples in antiviral therapies. Hence, here a pioneer combined 3-in-1 effect anti-COVID pulmonary multitherapy based on the mesoporous iron(III) carboxylate MIL-100(Fe) nanoparticles is proposed, with the proven intrinsic MOF effect, associated with favipiravir drug into their porosity and heparin on their external surface. A significant antiviral effect against a real scenario of COVID-19 infection is demonstrated (≈70% inhibition), ensuring a suitable cellular viability. Further, a convenient pulmonary formulation is prepared based on mannitol-based microspheres, testing its safety and biodistribution in healthy mice. No significant side effects are observed, reaching successfully the deep lungs, emphasizing a reduced immunological response compared to their controls. Therefore, these promising results open new horizons for future (pre)clinical trials targeting challenging infectious/pulmonary pathologies, enhancing the feasibility of designing customized therapeutic MOF platforms.

Biomedical Applications of Metal-Organic Frameworks Revisited

Metal-organic frameworks (MOFs) have been shown to be great alternatives to traditional porous materials in various chemical applications, and they have been very widely studied for biomedical applications in the past decade specifically for drug storage. After our review published in 2011 [Keskin and Kızılel, Ind. Eng. Chem. Res. 2011, 50 (4), 1799-1812, 10.1021/ie101312k], we have witnessed a very fast growth not only in the number and variety of MOFs but also in their usage across a broad spectrum of biomedical fields. With the recent integration of molecular modeling and data science approaches to the experimental studies, biomedical applications of MOFs have been significantly accelerated positioning them as pivotal components in the regenerative medicine, medical imaging, and diagnostics. In this review, we visited the diverse biomedical applications of MOFs considering the recent experimental and computational efforts on drug storage and delivery, bioimaging, and biosensing. We focused on the underlying mechanisms governing the molecular interactions between MOFs and biological systems and discussed both the opportunities and challenges in the field to highlight the potential of MOFs in advanced therapeutics for cancer and neurological diseases.

Folic acid functionalized Ag@MOF(Ag) decorated carboxymethyl starch nanoparticles as a new doxorubicin delivery system with inherent antibacterial activity

Considering the benefits of controlled drug delivery in cancer treatment, as well as the importance of biological macromolecules in this area, herein, the pre-synthesized carboxymethyl starch (CMS) was converted to CMS nanoparticles (CMS NPs) in one easy nanoprecipitation way. Thereafter, the Ag@MOF(Ag) was in situ synthesized in the presence of pre-prepared CMS NPs (CMS NPs/Ag@MOF(Ag)). Eventually, the functionalization with folic acid (FA) obtained the CMS NPs/Ag@MOF(Ag)-FA. The success of the accomplished process was approved by doing several techniques, including FT-IR, XRD, EDX, AFM, etc. The SEM analysis showed a combination of rod-like and spherical-like morphology for the fabricated bio-nanocomposite. The generated CMS NPs/Ag@MOF(Ag)-FA with a surface area of 10.595 m2/g displayed a pore size of 13.666 nm and 82.99 % of doxorubicin (DOX) loading efficiency (DOX@CMS NPs/Ag@MOF(Ag)-FA). The 38.46 % and 58.19 % of loaded DOX were released respectively within 240 h at pH 7.4 and pH 5.0, referring to the pH-responsivity of the constructed system. 27.25 % of inhibitory effects on HeLa cells were obtained for the drug-loaded bio-nanocomposite. The CMS NPs/Ag@MOF(Ag)-FA also displayed an inherent antibacterial activity towards two common gram-negative and gram-positive bacteria. All of these results can contribute to developing polysaccharide-based porous systems in controlled cancer therapy.

Metal-organic frameworks in drug delivery: engineering versatile platforms for therapeutic applications

Recently, metal-organic frameworks (MOFs) have attracted much attention as versatile materials for drug delivery and personalized medicine. MOFs are porous structures made up of metal ions coupled with organic ligands. This review highlights the synthesis techniques used to design MOFs with specific features such as surface area and pore size, and the drug encapsulation within MOFs not only improves their stability and solubility but also allows for controlled release kinetics, which improves therapeutic efficacy and minimizes adverse effects. Furthermore, it discusses the challenges and potential advantages of MOF-based drug delivery, such as MOF stability, biocompatibility, and scale-up production. With further advancements in MOF synthesis, functionalization techniques, and understanding of their interactions using biological systems, MOFs can have significant promise for expanding the area of personalized medicine and improving patient outcomes.

Fabrication of granular three-dimensional graphene oxide/UiO-66 adsorbent for high uranium adsorption: Density functional theory and fixed bed column studies

This study presents a thorough investigation of the novel application of graphene oxide (GO) modified with melamine formaldehyde to fabricate granular three-dimensional GO (3D-GO), followed by the introduction of UiO-66 doping (3D-GO/U) for high uranium (U) adsorption. The U(VI) adsorption isotherms revealed that 3D-GO/U-10 with 10 % UiO-66 incorporation exhibited an impressive adsorption capacity of 375.5 mg g-1 and remained high U(VI) sorption performance in wide pH range. The introduction of UiO-66 to 3D-GO (3D-GO/U-10) led to the deagglomeration of the UiO-66 particles. The in situ surface-enhanced-Raman-spectroscopy-analysis and density-functional-theory simulations showed the symmetric metal center site Zr-O2 on UiO-66 was discovered to exhibit the highest adsorption energy (-3.21 eV) for U(VI) species due to the electrons transfer from the oxygen atom to U(VI) drives the covalent bonding between the symmetric metal center sites Zr-O2 and U(VI) on 3D-GO/U-10. The 3D-GO/U-10 was regenerated using a 0.1 M Na2CO3/0.01 M H2O2 solution and achieved up to 89.7 % U(VI) removal in the 5th cycle. The continuous flow column experiments results revealed 3D-GO/U-10 can regenerate and maintain a U(VI) removal capacity of ∼76 % for up to 4 cycles column experiments. Therefore, 3D-GO/U-10 exhibits great potential for removing U(VI) from water bodies.

Metal-Organic Frameworks: Unconventional Nanoweapons against COVID

The SARS-CoV-2 (COVID-19) pandemic outbreak led to enormous social and economic repercussions worldwide, felt even to this date, making the design of new therapies to combat fast-spreading viruses an imperative task. In the face of this, diverse cutting-edge nanotechnologies have risen as promising tools to treat infectious diseases such as COVID-19, as well as challenging illnesses such as cancer and diabetes. Aside from these applications, nanoscale metal-organic frameworks (nanoMOFs) have attracted much attention as novel efficient drug delivery systems for diverse pathologies. However, their potential as anti-COVID-19 therapeutic agents has not been investigated. Herein, we propose a pioneering anti-COVID MOF approach by studying their potential as safe and intrinsically antiviral agents through screening various nanoMOF. The iron(III)-trimesate MIL-100 showed a noteworthy antiviral effect against SARS-CoV-2 at the micromolar range, ensuring a high biocompatibility profile (90% of viability) in a real infected human cellular scenario. This research effectively paves the way toward novel antiviral therapies based on nanoMOFs, not only against SARS-CoV-2 but also against other challenging infectious and/or pulmonary diseases.

The Promise and Potential of Metal-Organic Frameworks and Covalent Organic Frameworks in Vaccine Nanotechnology

The immune system's complexity and ongoing evolutionary struggle against deleterious pathogens underscore the value of vaccination technologies, which have been bolstering human immunity for over two centuries. Despite noteworthy advancements over these 200 years, three areas remain recalcitrant to improvement owing to the environmental instability of the biomolecules used in vaccines─the challenges of formulating them into controlled release systems, their need for constant refrigeration to avoid loss of efficacy, and the requirement that they be delivered via needle owing to gastrointestinal incompatibility. Nanotechnology, particularly metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), has emerged as a promising avenue for confronting these challenges, presenting a new frontier in vaccine development. Although these materials have been widely explored in the context of drug delivery, imaging, and cancer immunotherapy, their role in immunology and vaccine-related applications is a recent yet rapidly developing field. This review seeks to elucidate the prospective use of MOFs and COFs for biomaterial stabilization, eliminating the necessity for cold chains, enhancing antigen potency as adjuvants, and potentializing needle-free delivery of vaccines. It provides an expansive and critical viewpoint on this rapidly evolving field of research and emphasizes the vital contribution of chemists in driving further advancements.

Advances in Nanomaterials and Composites Based on Mesoporous Materials as Antimicrobial Agents: Relevant Applications in Human Health

Nanotechnology has emerged as a cornerstone in contemporary research, marked by the advent of advanced technologies aimed at nanoengineering materials with diverse applications, particularly to address challenges in human health. Among these challenges, antimicrobial resistance (AMR) has risen as a significant and pressing threat to public health, creating obstacles in preventing and treating persistent diseases. Despite efforts in recent decades to combat AMR, global trends indicate an ongoing and concerning increase in AMR. The primary contributors to the escalation of AMR are the misuse and overuse of various antimicrobial agents in healthcare settings. This has led to severe consequences not only in terms of compromised treatment outcomes but also in terms of substantial financial burdens. The economic impact of AMR is reflected in skyrocketing healthcare costs attributed to heightened hospital admissions and increased drug usage. To address this critical issue, it is imperative to implement effective strategies for antimicrobial therapies. This comprehensive review will explore the latest scientific breakthroughs within the metal-organic frameworks and the use of mesoporous metallic oxide derivates as antimicrobial agents. We will explore their biomedical applications in human health, shedding light on promising avenues for combating AMR. Finally, we will conclude the current state of research and offer perspectives on the future development of these nanomaterials in the ongoing battle against AMR.

The Rise of Electroactive Materials in Face Masks for Preventing Virus Infections

Air-transmitted pathogens may cause severe epidemics, posing considerable threats to public health and safety. Wearing a face mask is one of the most effective ways to prevent respiratory virus infection transmission. Especially since the new coronavirus pandemic, electroactive materials have received much attention in antiviral face masks due to their highly efficient antiviral capabilities, flexible structural design, excellent sustainability, and outstanding safety. This review first introduces the mechanism for preventing viral infection or the inactivation of viruses by electroactive materials. Then, the applications of electrostatic-, conductive-, triboelectric-, and microbattery-based materials in face masks are described in detail. Finally, the problems of various electroactive antiviral materials are summarized, and the prospects for their future development directions are discussed. In conclusion, electroactive materials have attracted great attention for antiviral face masks, and this review will provide a reference for materials scientists and engineers in antiviral materials and interfaces.

Constructing Physiological Defense Systems against Infectious Disease with Metal-Organic Frameworks: A Review

The swift and deadly spread of infectious diseases, alongside the rapid advancement of scientific technology in the past several centuries, has led to the invention of various methods for protecting people from infection. In recent years, a class of crystalline porous materials, metal-organic frameworks (MOFs), has shown great potential in constructing defense systems against infectious diseases. This review addresses current approaches to combating infectious diseases through the utilization of MOFs in vaccine development, antiviral and antibacterial treatment, and personal protective equipment (PPE). Along with an updated account of MOFs used for designing defense systems against infectious diseases, directions are also suggested for expanding avenues of current MOF research to develop more effective approaches and tools to prevent the widespread nature of infectious diseases.

Enhanced adsorption capacity of ZIF-8 for chemical warfare agent simulants caused by its morphology and surface charge

The effective separation of toxic chemicals, including chemical warfare agents (CWAs), from the environment via adsorption is of great importance because such chemicals pose a significant threat to humans and ecosystems. To this end, the development of effective porous adsorbents for CWA removal has received significant attention. Understanding the specific interactions between adsorbents and CWAs must precede for the development of effective adsorbents. Herein, we report the relationship between the adsorption capacity of porous ZIF-8 and its morphological and surface characteristics. Four types of ZIF-8, which have different morphologies (such as cubic, rhombic dodecahedron, and leaf- and plate-shaped samples), were selectively prepared. The four types of ZIF-8 were found to have different surface charges owing to dissimilarly exposed components on the surfaces and additionally incorporated components. The specific surface charges of ZIF-8 were found to be closely related to their adsorption capacities for CWA simulants such as 2-chloroethyl ethyl sulfide (CEES) and dimethyl methyl phosphonate (DMMP). Cubic ZIF-8, with the most positive surface charge among four ZIF-8 samples, exhibited the highest adsorption capacity for CEES and DMMP via the effective polar interaction. Moreover, ZIF-8 exhibited excellent recyclability without losing its adsorption capacity and without critical morphological or structural changes.

Quantifying Ligand Binding to the Surface of Metal-Organic Frameworks

The binding of molecules to the exterior surface of metal-organic frameworks (MOFs) is not a well-understood phenomenon. Herein, the surface chemistry of three MOFs, UiO-66, MIL-88B-NH₂, and ZIF-8, is investigated using dye-displacement experiments. MOF particle surfaces were modified with ligand-appended BODIPY dyes. The ability of the coordinated dyes to be displaced by a variety of exogenous ligands was measured by ultraviolet-visible spectroscopy. This method allowed for measurement of apparent binding constants for different ligands to the MOF surface. As might be expected, ligand affinity was dependent on the nature of the underlying metal-ligand composition of the MOF. This work provides a quantitative evaluation of ligand binding to MOF surfaces and important insights for the modulation, modification, and manipulation of MOFs.