Towards applications of bioentities@MOFs in biomedicine

Biomimetic functionalized metal organic frameworks as multifunctional agents: Paving the way for cancer vaccine advances

Biomimetic functionalized metal-organic frameworks (Fn-MOFs) represent a cutting-edge approach in the realm of cancer vaccines. These multifunctional agents, inspired by biological systems, offer unprecedented opportunities for the development of next-generation cancer vaccines. The vast surface area, tunable pore size, and diverse chemistry of MOFs provide a versatile scaffold for the encapsulation and protection of antigenic components, crucial for vaccine stability and delivery. This work delves into the innovative design and application of Fn-MOFs, highlighting their role as carriers for immune enhancement and their potential to revolutionize vaccine delivery. By mimicking natural processes, Fn-MOFs, with their ability to be functionalized with a myriad of chemical and biological entities, exhibit superior biocompatibility and stimuli-responsive behavior and facilitate targeted delivery to tumor sites. This review encapsulates the latest advancements in Fn-MOF technology, from their synthesis and surface modification to their integration into stimuli-responsive and combination therapies. It underscores the significance of biomimetic approaches in overcoming current challenges in cancer vaccine development, such as antigen stability and immune evasion. By leveraging the biomimetic nature of Fn-MOFs, this work paves the way for innovative strategies in cancer vaccines, aiming to induce potent and long-lasting immune responses against malignancies.

Advances in Functionalized Biocomposites of Living Cells Combined with Metal-Organic Frameworks

Motivated by the remarkable innate characteristics of cells in living organisms, we have found that hybrid materials that combine bioorganisms with nanomaterials have significantly propelled advancements in industrial applications. However, the practical deployment of unmodified living entities is inherently limited due to their sensitivity to environmental fluctuations. To surmount these challenges, an efficacious strategy for the biomimetic mineralization of living organisms with nanomaterials has emerged, demonstrating extraordinary potential in biotechnology. Among them, innovative composites have been engineered by enveloping bioorganisms with a metal-organic framework (MOF) coating. This review systematically summarizes the latest developments in living cells/MOF-based composites, detailing the methodologies employed in structure fabrication and their diverse applications, such as bioentity preservation, sensing, catalysis, photoluminescence, and drug delivery. Moreover, the synergistic benefits arising from the individual compounds are elucidated. This review aspires to illuminate new prospects for fabricating living cells/MOF composites and concludes with a perspective on the prevailing challenges and impending opportunities for future research in this field.

HP35 Protein in the Mesopore of MIL-101(Cr) MOF: A Model to Study Cotranslocational Unfolding

The immobilization of enzymes in metal-organic framework (MOF) cages is important in biotechnology. In this context, the mechanism of translocation of proteins through the cavities of the MOF and the roles played by confinement and MOF chemistry in giving rise to stable protein intermediates that are otherwise transiently populated in the physiological environment are important questions to be addressed. These unexplored aspects are examined with villin headpiece (HP35) as a model protein confined within a mesopore of MIL-101(Cr) using molecular dynamics simulations. At equilibrium, the protein is located farther from the center of the cavity and closer to the MOF surface. Molecular interactions with the MOF partially unfold helix-1 at its N-terminus. Umbrella sampling simulations inform the range of conformations that HP35 undertakes during translocation from one cavity to another and associated changes in free energy. Relative to its equilibrium state within the cavity, the free energy barrier for the unfolded protein at the cage window is estimated to be 16 kcal/mol. This study of MOF-based protein conformation can also be a general approach to observing intermediates in folding-unfolding pathways.

A novel PEG-mediated approach to entrap hemoglobin (Hb) within ZIF-8 nanoparticles: Balancing crystalline structure, Hb content and functionality

Hemoglobin (Hb)-based oxygen carriers are investigated as a potential alternative or supplement to regular blood transfusions, particularly in critical and life-threatening scenarios. These include situations like severe trauma in remote areas, battlefield conditions, instances where blood transfusion is not feasible due to compatibility concerns, or when patients decline transfusions based on religious beliefs. This study introduces a novel method utilizing poly(ethylene glycol) (PEG) to entrap Hb within ZIF-8 nanoparticles (i.e., Hb@ZIF-8 NPs). Through meticulous screening, we achieved Hb@ZIF-8 NPs with a record-high Hb concentration of 34 mg mL-1. These NPs, sized at 168 nm, displayed exceptional properties: a remarkable 95 % oxyhemoglobin content, excellent encapsulation efficiency of 85 %, and resistance to Hb oxidation into methemoglobin (metHb). The addition of PEG emerged as a crucial factor amplifying Hb entrapment within ZIF-8, especially at higher Hb concentrations, reaching an unprecedented 34 mg mL-1. Importantly, PEG exhibited a protective effect, preventing metHb conversion in Hb@ZIF-8 NPs at elevated Hb concentrations.

Flexible and Free-Standing Metal-Organic Framework Nanowire Paper

Beyond traditional paper, multifunctional nanopaper has received much attention in recent years. Currently, many nanomaterials have been successfully used as building units of nanopaper. However, it remains a great challenge to prepare flexible and freestanding metal-organic framework (MOF) nanopaper owing to the low aspect ratio and brittleness of MOF nanocrystals. Herein, this work develops a flexible and free-standing MOF nanopaper with MOF nanowires as building units. The manganese-based MOF (Mn-MOF) nanowires with lengths up to 100 μm are synthesized by a facile solvothermal method. Through a paper-making technique, the Mn-MOF nanowires interweave with each other to form a three-dimensional architecture, thus creating a flexible and free-standing Mn-MOF nanowire paper. Furthermore, the surface properties can be engineered to obtain high hydrophobicity by modifying polydimethylsiloxane (PDMS) on the surfaces of the Mn-MOF nanowire paper. The water contact angle reaches 130°. As a proof of concept, this work presents two potential applications of the Mn-MOF/PDMS nanowire paper: (i) The as-prepared Mn-MOF/PDMS nanowire paper is compatible with a commercial printer. The as-printed colorful patterns are of high quality, and (ii) benefiting from the highly hydrophobic surfaces, the Mn-MOF/PDMS nanowire paper is able to efficiently separate oil from water.

Nanocomposites Based on Magnetic Nanoparticles and Metal-Organic Frameworks for Therapy, Diagnosis, and Theragnostics

In the last two decades, metal-organic frameworks (MOFs) with highly tunable structure and porosity, have emerged as drug nanocarriers in the biomedical field. In particular, nanoscaled MOFs (nanoMOFs) have been widely investigated because of their potential biocompatibility, high drug loadings, and progressive release. To enhance their properties, MOFs have been combined with magnetic nanoparticles (MNPs) to form magnetic nanocomposites (MNP@MOF) with additional functionalities. Due to the magnetic properties of the MNPs, their presence in the nanosystems enables potential combinatorial magnetic targeted therapy and diagnosis. In this Review, we analyze the four main synthetic strategies currently employed for the fabrication of MNP@MOF nanocomposites, namely, mixing, in situ formation of MNPs in presynthesized MOF, in situ formation of MOFs in the presence of MNPs, and layer-by-layer methods. Additionally, we discuss the current progress in bioapplications, focusing on drug delivery systems (DDSs), magnetic resonance imaging (MRI), magnetic hyperthermia (MHT), and theragnostic systems. Overall, we provide a comprehensive overview of the recent advances in the development and bioapplications of MNP@MOF nanocomposites, highlighting their potential for future biomedical applications with a critical analysis of the challenges and limitations of these nanocomposites in terms of their synthesis, characterization, biocompatibility, and applicability.

Metal-Organic Framework-Mediated Delivery of Nucleic Acid across Intact Plant Cells

Plant synthetic biology is applied in sustainable agriculture, clean energy, and biopharmaceuticals, addressing crop improvement, pest resistance, and plant-based vaccine production by introducing exogenous genes into plants. This technique faces challenges delivering genes due to plant cell walls and intact cell membranes. Novel approaches are required to address this challenge, such as utilizing nanomaterials known for their efficiency and biocompatibility in gene delivery. This work investigates metal-organic frameworks (MOFs) for gene delivery in intact plant cells by infiltration. Hence, small-sized ZIF-8 nanoparticles (below 20 nm) were synthesized and demonstrated effective DNA/RNA delivery into Nicotiana benthamiana leaves and Arabidopsis thaliana roots, presenting a promising and simplified method for gene delivery in intact plant cells. We further demonstrate that small-sized ZIF-8 nanoparticles protect RNA from RNase degradation and successfully silence an endogenous gene by delivering siRNA in N. benthamiana leaves.

Predicting Spin-Dependent Phonon Band Structures of HKUST-1 Using Density Functional Theory and Machine-Learned Interatomic Potentials

The present study focuses on the spin-dependent vibrational properties of HKUST-1, a metal-organic framework with potential applications in gas storage and separation. Employing density functional theory (DFT), we explore the consequences of spin couplings in the copper paddle wheels (as the secondary building units of HKUST-1) on the material's vibrational properties. By systematically screening the impact of the spin state on the phonon bands and densities of states in the various frequency regions, we identify asymmetric -COO- stretching vibrations as being most affected by different types of magnetic couplings. Notably, we also show that the DFT-derived insights can be quantitatively reproduced employing suitably parametrized, state-of-the-art machine-learned classical potentials with root-mean-square deviations from the DFT results between 3 cm-1 and 7 cm-1. This demonstrates the potential of machine-learned classical force fields for predicting the spin-dependent properties of complex materials, even when explicitly considering spins only for the generation of the reference data used in the force-field parametrization process.

Enhancing Bone Regeneration through CDC20-Loaded ZIF-8 Nanoparticles Wrapped in Erythrocyte Membranes with Targeting Aptamer

In the context of bone regeneration, nanoparticles harboring osteogenic factors have emerged as pivotal agents for modulating the differentiation fate of stem cells. However, persistent challenges surrounding biocompatibility, loading efficiency, and precise targeting ability warrant innovative solution. In this study, a novel nanoparticle platform founded upon the zeolitic imidazolate framework-8 (ZIF-8) is introduced. This new design, CDC20@ZIF-8@eM-Apt, involves the envelopment of ZIF-8 within an erythrocyte membrane (eM) cloak, and is coupled with a targeting aptamer. ZIF-8, distinguished by its porosity, biocompatibility, and robust cargo transport capabilities, constitutes the core framework. Cell division cycle protein 20 homolog (CDC20) is illuminated as a new target in bone regeneration. The eM plays a dual role in maintaining nanoparticle stability and facilitating fusion with target cell membranes, while the aptamer orchestrates the specific recruitment of bone marrow mesenchymal stem cells (BMSCs) within bone defect sites. Significantly, CDC20@ZIF-8@eM-Apt amplifies osteogenic differentiation of BMSCs via the inhibition of NF-κB p65, and concurrently catalyzes bone regeneration in two bone defect models. Consequently, CDC20@ZIF-8@eM-Apt introduces a pioneering strategy for tackling bone defects and associated maladies, opening novel avenues in therapeutic intervention.

Organophosphate Detoxification and Acetylcholinesterase Reactivation Triggered by Zeolitic Imidazolate Framework Structural Degradation

Organophosphate (OP) toxicity is related to inhibition of acetylcholinesterase (AChE) activity, which plays a key role in the neurotransmission process. In this work, we report the ability of different zinc zeolitic imidazolate frameworks (ZIFs) to behave as potential antidotes against OP poisoning. The Zn-L coordination bond (L = purine, benzimidazole, imidazole, or 2-methylimidazole) is sensitive to the G-type nerve agent model compounds diisopropylfluorophosphate (DIFP) and diisopropylchlorophosphate, leading to P-X (X = F or Cl) bond breakdown into nontoxic diisopropylphosphate. P-X hydrolysis is accompanied by ZIF structural degradation (Zn-imidazolate bond hydrolysis), with the concomitant release of the imidazolate linkers and zinc ions representing up to 95% of ZIF particle dissolution. The delivered imidazolate nucleophilic attack on the OP@AChE adduct gives rise to the recovery of AChE enzymatic function. P-X bond breakdown, ZIF structural degradation, and AChE reactivation are dependent on imidazolate linker nucleophilicity, framework topology, and particle size. The best performance is obtained for 20 nm nanoparticles (NPs) of Zn(2-methylimidazolate)2 (sod ZIF-8) exhibiting a DIFP degradation half-life of 2.6 min and full recovery of AChE activity within 1 h. 20 nm sod ZIF-8 NPs are not neurotoxic, as proven by in vitro neuroblastoma cell culture viability tests.

Synthetic Biohybrids of Red Blood Cells and Cascaded-Enzymes@ Metal-Organic Frameworks for Hyperuricemia Treatment

Hyperuricemia, caused by an imbalance between the rates of production and excretion of uric acid (UA), may greatly increase the mortality rates in patients with cardiovascular and cerebrovascular diseases. Herein, for fast-acting and long-lasting hyperuricemia treatment, armored red blood cell (RBC) biohybrids, integrated RBCs with proximal, cascaded-enzymes of urate oxidase (UOX) and catalase (CAT) encapsulated within ZIF-8 framework-based nanoparticles, have been fabricated based on a super-assembly approach. Each component is crucial for hyperuricemia treatment: 1) RBCs significantly increase the circulation time of nanoparticles; 2) ZIF-8 nanoparticles-based superstructure greatly enhances RBCs resistance against external stressors while preserving native RBC properties (such as oxygen carrying capability); 3) the ZIF-8 scaffold protects the encapsulated enzymes from enzymatic degradation; 4) no physical barrier exists for urate diffusion, and thus allow fast degradation of UA in blood and neutralizes the toxic by-product H2 O2 . In vivo results demonstrate that the biohybrids can effectively normalize the UA level of an acute hyperuricemia mouse model within 2 h and possess a longer elimination half-life (49.7 ± 4.9 h). They anticipate that their simple and general method that combines functional nanomaterials with living cell carriers will be a starting point for the development of innovative drug delivery systems.

Integrating g-C3N4 nanosheets with MOF-derived porous CoFe2O4 to form an S-scheme heterojunction for efficient pollutant degradation via the synergy of photocatalysis and peroxymonosulfate activation

When confronted with wastewater that is characterized by complex composition, stable molecular structure, and high concentration, relying solely on photocatalytic technology proves inadequate in achieving satisfactory degradation results. Therefore, the integration of other highly efficient degradation techniques has emerged as a viable approach to address this challenge. Herein, a novel strategy was employed whereby the exfoliated g-C3N4 nanosheets (CNs) with exceptional photocatalytic performance, were intimately combined with porous rod-shaped cobalt ferrite (CFO) through a co-calcination process to form the composite CFO/CNs, which exhibited remarkable efficacy in the degradation of various organic pollutants through the combination of photocatalysis and Fenton-like process synergistically, exemplified by the representative case of tetracycline hydrochloride (TCH, 200 mL, 50 mg/L). Specifically, under 1 mM of peroxymonosulfate (PMS) and illumination conditions, 50 mg of 1CFO/9CNs achieved a TCH removal ratio of ∼90% after 60 min of treatment. Furthermore, this work comprehensively investigated the influence of various factors, including catalyst and PMS dosages, solution pH, and the presence of anions and humate, on the degradation efficiency of pollutants. Besides, quenching experiments and EPR tests confirmed the establishment of an S-scheme heterojunction between CNs and CFO, which facilitated the effective spatial separation of photoexcited charge carriers and preserved the potent redox potential of photogenerated electrons and holes. This work offers a valuable reference for the integration of photocatalysis with the PMS-based Fenton-like process.

Living virus-based nanohybrids for biomedical applications

Living viruses characterized by distinctive biological functions including specific targeting, gene invasion, immune modulation, and so forth have been receiving intensive attention from researchers worldwide owing to their promising potential for producing numerous theranostic modalities against diverse pathological conditions. Nevertheless, concerns during applications, such as rapid immune clearance, altering immune activation modes, insufficient gene transduction efficiency, and so forth, highlight the crucial issues of excessive therapeutic doses and the associated biosafety risks. To address these concerns, synthetic nanomaterials featuring unique physical/chemical properties are frequently exploited as efficient drug delivery vehicles or treatments in biomedical domains. By constant endeavor, researchers nowadays can create adaptable living virus-based nanohybrids (LVN) that not only overcome the limitations of virotherapy, but also combine the benefits of natural substances and nanotechnology to produce novel and promising therapeutic and diagnostic agents. In this review, we discuss the fundamental physiochemical properties of the viruses, and briefly outline the basic construction methodologies of LVN. We then emphasize their distinct diagnostic and therapeutic performances for various diseases. Furthermore, we survey the foreseeable challenges and future perspectives in this interdisciplinary area to offer insights. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Fabrication of Oriented Polycrystalline MOF Superstructures

The field of metal-organic frameworks (MOFs) has progressed beyond the design and exploration of powdery and single-crystalline materials. A current challenge is the fabrication of organized superstructures that can harness the directional properties of the individual constituent MOF crystals. To date, the progress in the fabrication methods of polycrystalline MOF superstructures has led to close-packed structures with defined crystalline orientation. By controlling the crystalline orientation, the MOF pore channels of the constituent crystals can be aligned along specific directions: these systems possess anisotropic properties including enhanced diffusion along specific directions, preferential orientation of guest species, and protection of functional guests. In this perspective, we discuss the current status of MOF research in the fabrication of oriented polycrystalline superstructures focusing on the specific crystalline directions of orientation. Three methods are examined in detail: the assembly from colloidal MOF solutions, the use of external fields for the alignment of MOF particles, and the heteroepitaxial ceramic-to-MOF growth. This perspective aims at promoting the progress of this field of research and inspiring the development of new protocols for the preparation of MOF systems with oriented pore channels, to enable advanced MOF-based devices with anisotropic properties.

A Micrometric Transformer: Compositional Nanoshell Transformation of Fe3+ -Trimesic-Acid Complex with Concomitant Payload Release in Cell-in-Catalytic-Shell Nanobiohybrids

Nanoencapsulation of living cells within artificial shells is a powerful approach for augmenting the inherent capacity of cells and enabling the acquisition of extrinsic functions. However, the current state of the field requires the development of nanoshells that can dynamically sense and adapt to environmental changes by undergoing transformations in form and composition. This paper reports the compositional transformation of an enzyme-embedded nanoshell of Fe3+ -trimesic acid complex to an iron phosphate shell in phosphate-containing media. The cytocompatible transformation allows the nanoshells to release functional molecules without loss of activities and biorecognition, while preserving the initial shell properties, such as cytoprotection. Demonstrations include the lysis and killing of Escherichia coli by lysozyme, and the secretion of interleukin-2 by Jurkat T cells in response to paracrine stimulation by antibodies. This work on micrometric Transformers will benefit the creation of cell-in-shell nanobiohybrids that can interact with their surroundings in active and adaptive ways.

Trajectory in biological metal-organic frameworks: Biosensing and sustainable strategies-perspectives and challenges

The ligand attribute of biomolecules to form coordination bonds with metal ions led to the discovery of a novel class of materials called biomolecule-associated metal-organic frameworks (Bio-MOFs). These biomolecules coordinate in multiple ways and provide versatile applications. Far-spread bio-ligands include nucleobases, amino acids, peptides, cyclodextrins, saccharides, porphyrins/metalloporphyrin, proteins, etc. Low-toxicity, self-assembly, stability, designable and selectable porous size, the existence of rigid and flexible forms, bio-compatibility, and synergistic interactions between metal ions have led Bio-MOFs to be commercialized in industries such as sensors, food, pharma, and eco-sensing. The rapid growth and commercialization are stunted by absolute bio-compatibility issues, bulk morphology that makes it rigid to alter shape/porosity, longer reaction times, and inadequate research. This review elucidates the structural vitality, biocompatibility issues, and vital sensing applications, including challenges for incorporating bio-ligands into MOF. Critical innovations in Bio-MOFs' applicative spectrum, including sustainable food packaging, biosensing, insulin and phosphoprotein detection, gas sensing, CO2 capture, pesticide carriers, toxicant adsorptions, etc., have been elucidated. Emphasis is placed on biosensing and biomedical applications with biomimetic catalysis and sensitive sensor designing.

A versatile MOF-derived theranostic for dual-miRNA controlled accurate cancer cell recognition and photodynamic therapy

Precise detection and monitoring of microRNAs (miRNAs) in living tumor cells is significant for the prompt diagnosis of cancer and provides important information for treatment of cancer. A significant challenge is developing methods for imaging different miRNAs simultaneously to further enhance diagnostic and treatment accuracy. In this work, a versatile MOF-derived theranostic system (DAPM) was constructed using photosensitive metal-organic frameworks (PMOF, PM) and a DNA AND logic gate (DA). The DAPM exhibited excellent biostability and enabled sensitive detection of miR-21 and miR-155, achieving a low limit of detection (LOD) for miR-21 (89.10 pM) and miR-155 (54.02 pM). The DAPM probe generated a fluorescence signal in tumor cells where miR-21 and miR-155 co-existed, demonstrating the enhanced ability of tumor cell recognition. Additionally, the DAPM achieved efficient ROS generation and concentration-dependent cytotoxicity under light irradiation, providing effective photodynamic therapy for anti-tumors. The proposed DAPM theranostic system enables accurate cancer diagnosis, and provides spatial and temporal information for PDT.

Biochemical transformations of inorganic nanomedicines in buffers, cell cultures and organisms

The field of nanomedicine is rapidly evolving, with new materials and formulations being reported almost daily. In this respect, inorganic and inorganic-organic composite nanomaterials have gained significant attention. However, the use of new materials in clinical trials and their final approval as drugs has been hampered by several challenges, one of which is the complex and difficult to control nanomaterial chemistry that takes place within the body. Several reviews have summarized investigations on inorganic nanomaterial stability in model body fluids, cell cultures, and organisms, focusing on their degradation as well as the influence of corona formation. However, in addition to these aspects, various chemical reactions of nanomaterials, including phase transformation and/or the formation of new/secondary nanomaterials, have been reported. In this review, we discuss recent advances in our understanding of biochemical transformations of medically relevant inorganic (composite) nanomaterials in environments related to their applications. We provide a refined terminology for the primary reaction mechanisms involved to bridge the gaps between different disciplines involved in this research. Furthermore, we highlight suitable analytical techniques that can be harnessed to explore the described reactions. Finally, we highlight opportunities to utilize them for diagnostic and therapeutic purposes and discuss current challenges and research priorities.

A selenoureido-iminoglycolipid transported by zeolitic-imidazolate framework nanoparticles: a novel antioxidant therapeutic approach

A selenium-containing metal-organic framework with remarkable antioxidant capacity and ROS-scavenging activity was constructed by a controlled de novo encapsulation approach of a glycoconjugate mimetic, specifically a sp2-iminoglycolipid bearing a selenoureido fragment (DSeU), within a zeolitic-imidazolate framework exoskeleton. Biocompatible and homogeneous nanosized particles of ∼70 nm (DSeU@ZIF8) were obtained, which could be efficiently internalized in cells, overcoming the poor solubility in biological media and limited bioavailability of glycolipids. The ZIF-particle served as nanocarrier for the intracellular delivery of the selenocompound to cells, promoted by the acidic pH inside endosomes/lysosomes. As demonstrated by in vitro studies, the designed DSeU@ZIF8 nanoparticles displayed a high antioxidant activity at low doses; lower intracellular ROS levels were observed upon the uptake of DSeU@ZIF8 by human endothelial cells. Even more interesting was the finding that these DSeU@ZIF8 particles were able to reverse to a certain level the oxidative stress induced in cells by pre-treatment with an oxidizing agent. This possibility of modulating the oxidative stress in living cells may have important implications in the treatment of diverse pathological complications that are generally accompanied with elevated ROS levels.

Histidine-Rich Protein Accelerates the Biomineralization of Zeolitic Imidazolate Frameworks for In Vivo Protein Delivery

Biomineralization of metal-organic frameworks (MOFs) provides a powerful approach for intracellular protein delivery, enabling the study of biological function and therapeutic potential of proteins. However, the potency of this approach is largely challenged by the low efficiency of current strategies for interfacing proteins with MOFs for biomineralization and intracellular delivery. Here, we report a versatile and convenient biomineralization strategy for the rapid encapsulation and enhanced delivery of proteins using MOFs, accelerated by histidine-rich proteins. We demonstrate that the histidine-rich green fluorescent protein (H39GFP) can accelerate the biomineralization of MOFs by promoting the coordination between proteins and metal ions, leading to enhanced protein delivery efficiency up to 15-fold. Moreover, we show that the delivery of H39GFP-fused cytotoxic ribonuclease and bacterial-derived RAS protease can effectively inhibit tumor cell growth. The strategy of promoting the biomineralization of MOFs via histidine-rich proteins for enhanced intracellular delivery could be expanded to other biomacromolecules, advancing their therapeutic potential and the biomedical scope of MOFs.

Tunable metal-organic frameworks assist in catalyzing DNAzymes with amplification platforms for biomedical applications

Various binding modes of tunable metal organic frameworks (MOFs) and functional DNAzymes (Dzs) synergistically catalyze the emergence of abundant functional nanoplatforms. Given their serial variability in formation, structural designability, and functional controllability, Dzs@MOFs tend to be excellent building blocks for the precise "intelligent" manufacture of functional materials. To present a clear outline of this new field, this review systematically summarizes the progress of Dz integration into MOFs (MOFs@Dzs) through different methods, including various surface infiltration, pore encapsulation, covalent binding, and biomimetic mineralization methods. Atomic-level and time-resolved catalytic mechanisms for biosensing and imaging are made possible by the complex interplay of the distinct molecular structure of Dzs@MOF, conformational flexibility, and dynamic regulation of metal ions. Exploiting the precision of DNAzymes, MOFs@Dzs constructed a combined nanotherapy platform to guide intracellular drug synthesis, photodynamic therapy, catalytic therapy, and immunotherapy to enhance gene therapy in different ways, solving the problems of intracellular delivery inefficiency and insufficient supply of cofactors. MOFs@Dzs nanostructures have become excellent candidates for biosensing, bioimaging, amplification delivery, and targeted cancer gene therapy while emphasizing major advancements and seminal endeavors in the fields of biosensing (nucleic acid, protein, enzyme activity, small molecules, and cancer cells), biological imaging, and targeted cancer gene delivery and gene therapy. Overall, based on the results demonstrated to date, we discuss the challenges that the emerging MOFs@Dzs might encounter in practical future applications and briefly look forward to their bright prospects in other fields.

Copper(II)-MOFs for bio-applications

The recent development and implementation of copper-based metal-organic frameworks in biological applications are reviewed. The advantages of the presence of copper in MOFs for relevant applications such as drug delivery, cancer treatment, sensing, and antimicrobial are highlighted. Advanced composites such as MOF-polymers are playing critical roles in developing materials for specific applications.

Nanosized Silk-Magnesium Complexes for Tissue Regeneration

Metal ions provide multifunctional signals for cell and tissue functions, including regeneration. Inspired by metal-organic frameworks (MOFs), nanosized silk protein aggregates with a high negative charge density are used to form stable silk-magnesium ion complexes. Magnesium ions (Mg ions) are added directly to silk nanoparticle solutions, inducing gelation through the formation of silk-Mg coordination complexes. The Mg ions are released slowly from the nanoparticles through diffusion, with sustained release via tuning the degradation or dissolution of the nanosized silk aggregates. Studies in vitro reveal a dose-dependent influence of Mg ions on angiogenic and anti-inflammatory functions. Silk-Mg ion complexes in the form of hydrogels also stimulate tissue regeneration with a reduced formation of scar tissue in vivo, suggesting potential utility in tissue regeneration.

Detachable MOF-Based Core/Shell Nanoreactor for Cancer Dual-Starvation Therapy With Reversing Glucose and Glutamine Metabolisms

Tumor-dependent glucose and glutamine metabolisms are essential for maintaining survival, while the accordingly metabolic suppressive therapy is limited by the compensatory metabolism and inefficient delivery efficiency. Herein, a functional metal-organic framework (MOF)-based nanosystem composed of the weakly acidic tumor microenvironment-activated detachable shell and reactive oxygen species (ROS)-responsive disassembled MOF nanoreactor core is designed to co-load glycolysis and glutamine metabolism inhibitors glucose oxidase (GOD) and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES) for tumor dual-starvation therapy. The nanosystem excitingly improves tumor penetration and cellular uptake efficiency via integrating the pH-responsive size reduction and charge reversal and ROS-sensitive MOF disintegration and drug release strategy. Furthermore, the degradation of MOF and cargoes release can be self-amplified via additional self-generation H2 O2 mediated by GOD. Last, the released GOD and BPTES collaboratively cut off the energy supply of tumors and induce significant mitochondrial damage and cell cycle arrest via simultaneous restriction of glycolysis and compensatory glutamine metabolism pathways, consequently realizing the remarkable triple negative breast cancer killing effect in vivo with good biosafety via the dual starvation therapy.

Application and Development Prospect of Nanoscale Iron Based Metal-Organic Frameworks in Biomedicine

Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe2+/Fe3+ exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.

Construction of Immobilized Enzymes with Yeast and Metal-Organic Frameworks for Enhanced Biocatalytic Activities

Metal-organic frameworks (MOFs) have become promising host materials for enzyme immobilization and protection. Herein, ZIF-8 nanocubes were successfully self-assembled onto yeast as a biological template to obtain hybrid Y@ZIF-8. The size, morphology, and loading efficiency of ZIF-8 nanoparticles assembled on yeast templates can be well-regulated by adjusting the various synthetic parameters. Particularly, the amount of water significantly affected the particle size of ZIF-8 assembled on yeast. Through using a cross-linking agent, the relative enzyme activity of Y@ZIF-8@t-CAT could be greatly enhanced and remained the highest even after seven consecutive cycles, with improved cycling stability, as compared to that of Y@ZIF-8@CAT. In addition to the effect of the physicochemical properties of Y@ZIF-8 on the loading efficiency, the temperature tolerance, pH tolerance, and storage stability of Y@ZIF-8@t-CAT were also systematically investigated. Importantly, the catalytic activity of free catalase was decreased to 72% by 45 days, while the activity of the immobilized catalase remained above 99%, suggesting good storage stability. The present work demonstrates that yeast-templated ZIF-8 nanoparticles have a high potential to be used as biocompatible immobilization materials and are promising candidates for the preparation of effective biocatalysts in biomedicine applications.

Amino Acid-Coated Zeolitic Imidazolate Framework for Delivery of Genetic Material in Prostate Cancer Cell

Metal-organic frameworks (MOFs) are currently under progressive development as a tool for non-viral biomolecule delivery. Biomolecules such as proteins, lipids, carbohydrates, and nucleic acids can be encapsulated in MOFs for therapeutic purposes. The favorable physicochemical properties of MOFs make them an attractive choice for delivering a wide range of biomolecules including nucleic acids. Herein, a green fluorescence protein (GFP)-expressing plasmid DNA (pDNA) is used as a representative of a biomolecule to encapsulate within a Zn-based metal-organic framework (MOF) called a zeolitic imidazolate framework (ZIF). The synthesized biocomposites are coated with positively charged amino acids (AA) to understand the effect of surface functionalization on the delivery of pDNA to prostate cancer (PC-3) cells. FTIR and zeta potential confirm the successful preparation of positively charged amino acid-functionalized derivatives of pDNA@ZIF (i.e., pDNA@ZIF_AA). Moreover, XRD and SEM data show that the functionalized derivates retain the pristine crystallinity and morphology of pDNA@ZIF. The coated biocomposites provide enhanced uptake of genetic material by PC-3 human prostate cancer cells. The AA-modulated fine-tuning of the surface charge of biocomposites results in better interaction with the cell membrane and enhances cellular uptake. These results suggest that pDNA@ZIF_AA can be a promising alternative tool for non-viral gene delivery.

Dual-targeting lanthanide-ICG-MOF nanoplatform for cancer Theranostics: NIR II luminescence imaging guided sentinel lymph nodes surgical navigation

Sentinel lymph node imaging is important for breast tumor staging and prediction of postoperative metastasis. However, clinical sentinel lymph node imaging has limitations such as low specificity, low contrast, and short retention time. The combination of bio-conjugates chemistry and luminescence technology may achieve the specific targeting effect. In this research, we designed a dual-targeting composite nanoprobe (∼50 nm) using a metal-organic framework (MOF) as carrier, loaded with lanthanide and ICG, and combined with hyaluronic acid and folic acid to detect metastatic lymph nodes. The coupled hyaluronic acid and folic acid can target to the tumor cells and dentritic cells with a dual-targeting effect. The FA-HA/ZIF-8@ICG nanoprobes can accumulate rapidly in sentinel lymph node with a stronger luminescence intensity (1.6 times) than that of normal popliteal lymph nodes in vivo, thus distinguish metastatic sentinel lymph node from normal effectively. Furthermore, due to the MOF carrier, the integrated lanthanide and near-infrared dye by transferring the absorbed excitation energy from ICG to Nd³⁺ can enhance the signal-to-background ratio of NIR II imaging and have long retention time in vivo imaging. Finally, the FA-HA/ICG@Ln@ZIF-8 nanoplatform increased the penetration depth and contrast of imaging, prolonged the retention time, and achieved the sentinel lymph nodes surgical resection. This study has important implications for lymph node imaging and surgical navigation.

Preservation of Proteins in Human Plasma through Metal-Organic Framework Encapsulation

Traditional cold chain systems of collection, transportation, and storage of biofluid specimens for eventual analysis pose a huge financial and environmental burden. These systems are impractical in pre-hospital and resource-limited settings, where refrigeration and electricity are not reliable or even available. Here, we develop an innovative technology using metal-organic frameworks (MOFs), a novel class of organic-inorganic hybrids with high thermal stability, as encapsulates for preserving the integrity of protein biomarkers in biofluids under ambient or non-refrigerated storage conditions. We encapsulate prostate-specific antigen (PSA) in whole patient plasma using hydrophilic zeolitic imidazolate framework-90 (ZIF-90) for preservation at 40 °C for 4 weeks and eventual on-demand reconstitution for antibody-based assays with recovery above 95% compared to storage at -20 °C. Without ZIF-90 encapsulation, only 10-30% of the PSA immunoactivity remained. Furthermore, we demonstrate encapsulation of multiple cancer biomarker proteins in whole patient plasma using ZIF-8 or ZIF-90 encapsulants for eventual on-demand reconstitution and analysis after 1 week at 40 °C. Overall, MOF encapsulation of patient biofluids is important as climate change may be affecting the stability and increase costs of maintaining biospecimen cold chain custody for the collection, transportation, and storage of biospecimens prior to analysis or for biobanking regardless of any countries' affluence.

Targeting telomerase utilizing zeolitic imidazole frameworks as non-viral gene delivery agents across different cancer cell types

Telomerase, a ribonucleoprotein coded by the hTERT gene, plays an important role in cellular immortalization and carcinogenesis. hTERT is a suitable target for cancer therapeutics as its activity is highly upregulated in most of cancer cells but absent in normal somatic cells. Here, by employing the two Metal-Organic Frameworks (MOFs), viz. ZIF-C and ZIF-8, based biomineralization we encapsulate Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 plasmid system that targets hTERT gene (CrhTERT) in cancer cells. When comparing the two biocomposites, ZIF-C shows the better loading capacity and cell viability. The loaded plasmid in ZIF-C is highly protected against enzymatic degradation. CrhTERT@ZIF-C is efficiently endocytosed by cancer cells and the subcellular release of CrhTERT leads to telomerase knockdown. The resultant inhibition of hTERT expression decreases cellular proliferation and causing cancer cell death. Furthermore, hTERT knockdown shows a significant reduction in tumour metastasis and alters protein expression. Collectively we show the high potential of ZIF-C-based biocomposites as a promising general tool for gene therapy of different types of cancers.

Metal-Organic Frameworks as Sensors for Human Amyloid Diseases

Metal-organic frameworks (MOFs) are versatile compounds with emergent applications in the fabrication of biosensors for amyloid diseases. They hold great potential in biospecimen protection and unprecedented probing capabilities for optical and redox receptors. In this Review, we summarize the main methodologies employed in the fabrication of MOF-based sensors for amyloid diseases and collect all available data in the literature related to their performance (detection range, limit of detection, recovery, time of analysis, among other parameters). Nowadays, MOF sensors have evolved to a point where they can, in some cases, outperform technologies employed in the detection of several amyloid biomarkers (amyloid β peptide, α-synuclein, insulin, procalcitonin, and prolactin) present in biological fluids, such as cerebrospinal fluid and blood. A special emphasis has been given by researchers on Alzheimer's disease monitoring to the detriment of other amyloidosis that are underexploited despite their societal relevance (e.g., Parkinson's disease). There are still important obstacles to overcome in order to selectively detect the various peptide isoforms and soluble amyloid species associated with Alzheimer's disease. Furthermore, MOF contrast agents for imaging peptide soluble oligomers in living humans are also scarce (if not nonexistent), and action in this direction is unquestionably required to clarify the contentious link between the amyloidogenic species and the disease, guiding research toward the most promising therapeutic strategies.

Metal-Organic Framework-Based Materials for Wastewater Treatment: Superior Adsorbent Materials for the Removal of Hazardous Pollutants

In previous years, different pollutants, for example, organic dyes, antibiotics, heavy metals, pharmaceuticals, and agricultural pollutants, have been of note to the water enterprise due to their insufficient reduction during standard water and wastewater processing methods. MOFs have been found to have potential toward wastewater management. This Review focused on the synthesis process (such as traditional, electrochemical, microwave, sonochemical, mechanochemical, and continuous-flow spray-drying method) of MOF materials. Moreover, the properties of the MOF materials have been discussed in detail. Further, MOF materials' applications for wastewater treatment (such as the removal of antibiotics, organic dyes, heavy metal ions, and agricultural waste) have been discussed. Additionally, we have compared the performances of some typical MOFs-based materials with those of other commonly used materials. Finally, the study's current challenges, future prospects, and outlook have been highlighted.

Virus Management Using Metal-Organic Framework-Based Technologies

The eradication and isolation of viruses are two concurrent approaches to protect ourselves from viral infections and diseases. The quite versatile porous materials called metal-organic frameworks (MOFs), have recently emerged as efficient nanosized tools to manage viruses, and several strategies to accomplish these tasks have been developed. This review describes these strategies employing nanoscale MOFs against SARS-CoV-2, HIV-1, tobacco mosaic virus, etc., which include the sequestration by host-guest penetration inside pores, mineralization, design of a physical barrier, controlled delivery of organic and inorganic antiviral drugs or bioinhibitors, photosensitization of singlet oxygen, and direct contact with inherently cytotoxic MOFs.

Nanosized metal-organic frameworks as unique platforms for bioapplications

Metal-organic frameworks (MOFs) are extremely versatile materials, which serve to create platforms with exceptional porosity and specific reactivities. The production of MOFs at the nanoscale (NMOFs) offers the possibility of creating innovative materials for bioapplications as long as they maintain the properties of their larger counterparts. Due to their inherent chemical versatility, synthetic methods to produce them at the nanoscale can be combined with inorganic nanoparticles (NPs) to create nanocomposites (NCs) with one-of-a-kind features. These systems can be remotely controlled and can catalyze abiotic reactions in living cells, which have the potential to stimulate further research on these nanocomposites as tools for advanced therapies.

Vancomycin-Loaded Fe3O4/MOF-199 Core/Shell Cargo Encapsulated by Guanidylated-β-Cyclodextrine: An Effective Antimicrobial Nanotherapeutic

This study describes an efficient antimicrobial drug delivery system composed of iron oxide magnetic nanoparticles (Fe₃O₄ NPs) coated by an MOF-199 network. Then, the prepared vancomycin (VAN)-loaded carrier was fully packed in a lattice of beta-cyclodextrin (BCD). For cell adhesion, beta-cyclodextrin has been functionalized with guanidine (Gn) groups within in situ synthetic processes. Afterward, drug loading efficiency and the release patterns were investigated through precise analytical methods. Confocal microscopy has shown that the prepared cargo (formulated as [VAN@Fe₃O₄/MOF-199]BCD-Gn) could be attached to the Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacterial cells in a higher rate than the individual VAN. The presented system considerably increased the antibacterial effects of the VAN with a lower dosage of drug. The cellular experiments such as the zone of inhibition and optical density (OD₆₀₀) have confirmed the enhanced antibacterial effect of the designed cargo. In addition, the MIC/MBC (minimum inhibitory and bactericidal concentrations) values have been estimated for the prepared cargo compared to the individual VAN, revealing high antimicrobial potency of the VAN@Fe₃O₄/MOF-199]BCD-Gn cargo.

DUCNP@Mn-MOF/FOE as a Highly Selective and Bioavailable Drug Delivery System for Synergistic Combination Cancer Therapy

Heterostructures comprising lanthanide-doped upconversion nanoparticles (DUCNPs) and metal-organic frameworks (MOFs) are emerging as promising nanosystems for integrating medical diagnosis and treatment. Here, the DUCNP@Mn-MOF nanocarrier was developed, which showed good efficiency for loading and delivering a cytotoxic antitumor agent (3-F-10-OH-evodiamine, FOE). The combined advantages of the pH-responsive and peroxidase-like properties of Mn-MOF and the unique optical features of DUCNPs granted the DUCNP@Mn-MOF/FOE system synergistic chemodynamic and chemotherapeutic effects. The DUCNP@Mn-MOF nanocarrier effectively overcame the intrinsic limitations of FOE, such as its unfavorable physicochemical properties and limited in vivo potency. This complexed nanosystem was responsive to the tumor microenvironment and showed excellent tumor targeting capability. Thus, DUCNP@Mn-MOF/FOE exhibited highly selective and bioavailable drug delivery properties and is promising for cancer therapy. In a mouse breast cancer model, DUCNP@Mn-MOF/FOE inhibited tumor growth without significant toxicity. Therefore, the proposed nanosystem represents a promising theragnostic platform for multimodal combination diagnosis and therapy of tumors.

Targeted in vitro gene silencing of E2 and nsP1 genes of chikungunya virus by biocompatible zeolitic imidazolate framework

Chikungunya fever caused by the mosquito-transmitted chikungunya virus (CHIKV) is a major public health concern in tropical, sub-tropical and temperate climatic regions. The lack of any licensed vaccine or antiviral agents against CHIKV warrants the development of effective antiviral therapies. Small interfering RNA (siRNA) mediated gene silencing of CHIKV structural and non-structural genes serves as a potential antiviral strategy. The therapeutic efficiency of siRNA can be improved by using an efficient delivery system. Metal-organic framework biocomposits have demonstrated an exceptional capability in protecting and efficiently delivering nucleic acids into cells. In the present study, carbonated ZIF called ZIF-C has been utilized to deliver siRNAs targeted against E2 and nsP1 genes of CHIKV to achieve a reduction in viral replication and infectivity. Cellular transfection studies of E2 and nsP1 genes targeting free siRNAs and ZIF-C encapsulated siRNAs in CHIKV infected Vero CCL-81 cells were performed. Our results reveal a significant reduction of infectious virus titre, viral RNA levels and percent of infected cells in cultures transfected with ZIF-C encapsulated siRNA compared to cells transfected with free siRNA. The results suggest that delivery of siRNA through ZIF-C enhances the antiviral activity of CHIKV E2 and nsP1 genes directed siRNAs.

Tryptophan-Modulated Nanoscale Metal-Organic Framework for Coordinated Loading of Biomolecules for Cascade Production of Reactive Oxygen and Nitrogen Species

Owing to the high surface area and porosity, metal-organic frameworks (MOFs) could be utilized as both nanocarriers of biopharmaceuticals and nanoreactors to organize cascade biological reactions with great potential in cancer treatment. However, nanoscale MOFs suitable for biomedical applications rely on harsh preparation conditions. Here, we utilized tryptophan to modulate the morphology and optical properties of zeolitic imidazolate framework-8 (ZIF-8) as nanocarrier to efficiently encapsulate the enzyme and mRNA. Under room temperature in an aqueous solution, tryptophan would coordinate with zinc ions to form ZIF-8:Trp with a decreased size from the μm range to sub-200 nm. In addition, cargo release could be monitored in real time via fluorescence red-shift effects. Besides being used as nanocarriers of biomolecules, ZIF-8:Trp could also be utilized as nanoreactors to induce cascade reactions to produce reactive oxygen and nitrogen species. Overall, this nanosized ZIF-8:Trp could provide a new strategy for preparation of cascade bioreactions and provide new insight for gas therapy.

Aggregation kinetics of polystyrene nanoplastics in gastric environments: Effects of plastic properties, solution conditions, and gastric constituents

Nanoplastics are inevitably ingested into human gastric environment, wherein their aggregation kinetics and interactions with gastric constituents remain unclear. This study investigated the early-stage (20 min) and long-term (1-6 h) aggregation kinetics of four commonly-found polystyrene nanoplastics (PSNPs) including NP100 (100-nm), A-NP100 (100-nm, amino-modified), C-NP100 (100-nm, carboxyl-modified), and NP500 (500-nm) under gastric conditions. Five simulated human gastric fluids (SGFs) including SGF1-3 (0-3.2 g/L pepsin and 34.2 mM NaCl), SGF4 (400 mM glycine), and SGF5 (nine constituents), three pH (2, fasted state; 3.5, late-fed state; and 5, early-fed state), and 1-100 mg/L PSNPs were examined. Aggregation rates ranked NP100 > A-NP100 ≈ C-NP100 > NP500, SGF5 > SGF4 > SGF3 > SGF2 > SGF1, and pH 2 > 3.5 > 5. Increasing PSNP concentration enhanced aggregation rate up to 13.82 nm/s. Aggregation behavior generally followed the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Pepsin, glycine, and proteose-peptone strongly influenced PSNP stability via electrostatic interaction and steric hindrance imparted by protein corona. Freundlich isotherm suggested that PSNPs adsorbed organic constituents following lysozyme > porcine bile > proteose-peptone > pepsin > glycine > D-glucose, inducing changes in constituent structure and PSNP properties. These findings provide insights on the transport of nanoplastics in the gastric environments.

Structural-Functional Pluralistic Modification of Silk Fibroin via MOF Bridging for Advanced Wound Care

Silk fibroin (SF) is widely used to fabricate biomaterials for skin related wound caring or monitoring, and its hydrogel state are preferred for their adaptability and easy to use. However, in-depth development of SF hydrogel is restricted by their limited mechanical strength, increased risk of infection, and inability to accelerate tissue healing. Therefore, a structure-function pluralistic modification strategy using composite system of metal organic framework (MOF) as bridge expanding SF's biomedical application is proposed. After developing the photocuring and bonding SF hydrogel, a MOF drug-loading system is utilized to enhance hydrogel's structural strength while endowing its antibacterial and angiogenic properties, yielding a multifunctional SF hydrogel. The synergy between the MOF and SF proteins at the secondary structure level gives this hydrogel reliable mechanical strength, making it suitable for conventional wound treatment, whether for closing incisions quickly or acting as adhesive dressings (five times the bonding strength of ordinary fibrin glue). Additionally, with the antibacterial and angiogenic functions getting from MOF system, this modified SF hydrogel can even treat ischemic trauma with cartilage exposure. This multiple modification should contribute to the improvement of advanced wound care, by promoting SF application in the production of tissue engineering materials.

CaZnO-based nanoghosts for the detection of ssDNA, pCRISPR and recombinant SARS-CoV-2 spike antigen and targeted delivery of doxorubicin

Overexpression of proteins/antigens and other gene-related sequences in the bodies could lead to significant mutations and refractory diseases. Detection and identification of assorted trace concentrations of such proteins/antigens and/or gene-related sequences remain challenging, affecting different pathogens and making viruses stronger. Correspondingly, coronavirus (SARS-CoV-2) mutations/alterations and spread could lead to overexpression of ssDNA and the related antigens in the population and brisk activity in gene-editing technologies in the treatment/detection may lead to the presence of pCRISPR in the blood. Therefore, the detection and evaluation of their trace concentrations are of critical importance. CaZnO-based nanoghosts (NGs) were synthesized with the assistance of a high-gravity technique at a 1,800 MHz field, capitalizing on the use of Rosmarinus officinalis leaf extract as the templating agent. A complete chemical, physical and biological investigation revealed that the synthesized NGs presented similar morphological features to the mesenchymal stem cells (MSCs), resulting in excellent biocompatibility, interaction with ssDNA- and/or pCRISPR-surface, through various chemical and physical mechanisms. This comprise the unprecedented synthesis of a fully inorganic nanostructure with behavior that is similar to MSCs. Furthermore, the endowed exceptional ability of inorganic NGs for detective sensing/folding of ssDNA and pCRISPR and recombinant SARS-CoV-2 spike antigen (RSCSA), along with in-situ hydrogen peroxide detection on the HEK-293 and HeLa cell lines, was discerned. On average, they displayed a high drug loading capacity of 55%, and the acceptable internalizations inside the HT-29 cell lines affirmed the anticipated MSCs-like behavior of these inorganic-NGs.

Nanoscale MOFs: From synthesis to drug delivery and theranostics applications

Since the first report in 1989, Metal-Organic Frameworks (MOFs) self-assembled from metal ions or clusters, as well as organic linkers, have attracted extensive attention. Due to their flexible composition, large surface areas, modifiable surface properties, and their degradability, there has been an exponential increase in the study of MOFs materials, specifically in drug delivery system areas such as infection, diabetes, pulmonary disease, ocular disease, imaging, tumor therapy, and especially cancer theranostics. In this review, we discuss the trends in MOFs biosafety, from "green" synthesis to applications in drug delivery systems. Firstly, we present the different "green" synthesis approaches used to prepare MOFs materials. Secondly, we detail the methods for the functional coating, either through grafting targeting units, poly(ethylene glycol) (PEG) chains or by using cell membranes. Then, we discuss drug encapsulation strategies, host-guest interactions, as well as drug release mechanisms. Lastly, we report on the drug delivery applications of nanoscale MOFs. In particular, we discuss MOFs-based imaging techniques, including magnetic resonance imaging (MRI), photoacoustic imaging (PAI), positron emission tomography (PET), and fluorescence imaging. MOFs-based cancer therapy methods are also presented, such as photothermal therapy (PTT), photodynamic therapy (PDT), radiotherapy (RT), chemotherapy, and immunotherapy.

Boosting Protein Encapsulation through Lewis-Acid-Mediated Metal-Organic Framework Mineralization: Toward Effective Intracellular Delivery

Encapsulation of biomolecules using metal-organic frameworks (MOFs) to form stable biocomposites has been demonstrated to be a valuable strategy for their preservation and controlled release, which has been however restricted to specific electrostatic surface conditions. We present a Lewis-acid-mediated general in situ strategy that promotes the spontaneous MOF growth on a broad variety of proteins, for the first time, regardless of their surface nature. We demonstrate that MOFs based on cations exhibiting considerable inherent acidity such as MIL-100(Fe) enable efficient biomolecule encapsulation, including elusive alkaline proteins previously inaccessible by the well-developed in situ azolate-based MOF encapsulation. Specifically, we prove the MIL-100(Fe) scaffold for the encapsulation of a group of proteins exhibiting very different isoelectric points (5 < pI < 11), allowing triggered release under biocompatible conditions and retaining their activity after exposure to denaturing environments. Finally, we demonstrate the potential of the myoglobin-carrying biocomposite to facilitate the delivery of O₂ into hypoxic human lung carcinoma A549 cells, overcoming hypoxia-associated chemoresistance.

Conformation-Stabilized Amorphous Nanocoating for Rational Design of Long-Term Thermostable Viral Vaccines

Despite the great potency of vaccines to combat infectious diseases, their global use is hindered by a lack of thermostability, which leads to a constant need for cold-chain storage. Here, aiming at long-term thermostability and eliminating cold-chain requirements of bioactive vaccines, we propose that efforts should focus on tailoring the conformational stability of vaccines. Accordingly, we design a nanocoating composed of histidine (His)-coordinated amorphous Zn and 2-methylimidazolate complex (His-aZn-mIM) on single nanoparticles of viral vaccines to introduce intramolecular coordinated linkage between viruses and the nanocoatings. The coordinated nanocoating enhances the rigidity of proteins and preserves the vaccine's activity. Importantly, integrating His into the original Zn-N coordinative environment symbiotically reinforces its tolerance to biological and hydrothermal solutions, resulting in the augmented thermostability following the Hofmeister effect. Thus, even after storage of His-aZn-mIM encapsulated Human adenovirus type 5 (Ad5@His-aZn-mIM) at 25 °C for 90 d, the potency loss of the coated Ad5 is less than 10%, while the native Ad5 becomes 100% ineffective within one month. Such a nanocoating gains thermostability by forming an ultrastable hydration shell, which prevents viral proteins from unfolding under the attack of hydration ions, providing a conformational stabilizer upon heat exposure. Our findings represent an easy-access biomimetic platform to address the long-term vaccine storage without the requirement of a cold chain.

A review of synthesis, fabrication, and emerging biomedical applications of metal-organic frameworks

The overwhelming potential of porous coordination polymers (PCP), also known as Metal-Organic Frameworks (MOFs), especially their nanostructures for various biomedical applications, have made these materials worth investigating for more applications and uses. MOFs unique structure has enabled them for most applications, particularly in biomedical and healthcare. A number of very informative review papers are available on the biomedical applications of MOFs for the reader's convenience. However, many of those reviews focus mainly on drug delivery applications, and no significant work has been reported on other MOFs for biomedical applications. This review aims to present a compact and highly informative global assessment of the recent developments in biomedical applications (excluding drug-delivery) of MOFs along with critical analysis. Researchers have recently adopted both synthetic and post-synthetic routes for the fabrication and modification of MOFs that have been discussed and analyzed. A critical review of the latest reports on the significant and exotic area of bio-sensing capabilities and applications of MOFs has been given in this study. In addition, other essential applications of MOFs, including photothermal therapy, photodynamic therapy, and antimicrobial activities, are also included. These recently grown emergent techniques and cancer treatment options have gained attention and require further investigations to achieve fruitful outcomes. MOF's role in these applications has been thoroughly discussed, along with future challenges and valuable suggestions for the research community that will help meet future demands.

A comparative study of the toxic effect of ZIF-8 and ZIF-L on the colonization and decomposition of shaded outdoor mice carrions by arthropods

Metal–organic frameworks (MOFs) are promising materials for several applications. Thus, they have been intensively reported and commercialized by several international companies. However, little is known about the fate and risk of MOFs to living organisms. Here, the toxic effect of two Zinc (Zn)-based MOFs; zeolitic imidazolate frameworks (ZIF-8) and leaf-like ZIF (ZIF-L), was tested to investigate the impact of the postmortem period of mice carrions and arthropods which found in decomposing carrions. The data analysis revealed an increase in zinc content over time. Toxicology in forensics studies biological materials for the presence of poisons, such as pharmaceuticals. The toxicology report can provide important details about the types of chemicals present in a person and whether the amount of those substances is in line with a therapeutic dose or exceeds a dangerous level. These findings conclude the possible fate and impact after mortality. This study presents the first study of the toxic effect of ZIFs materials using mice carrions and arthropods (Sarcophaga sp. Larvae) via morphological and microscopic studies compared with control, providing important biological information could aid in the environmental impact of the toxic level of MOF materials.

Recent advances in nanoarchitectures of monocrystalline coordination polymers through confined assembly

Various kinds of monocrystalline coordination polymers are available thanks to the rapid development of related synthetic strategies. The intrinsic properties of coordination polymers have been carefully investigated on the basis of the available monocrystalline samples. Regarding the great potential of coordination polymers in various fields, it becomes important to tailor the properties of coordination polymers to meet practical requirements, which sometimes cannot be achieved through molecular/crystal engineering. Nanoarchitectonics offer unique opportunities to manipulate the properties of materials through integration of the monocrystalline building blocks with other components. Recently, nanoarchitectonics has started to play a significant role in the field of coordination polymers. In this short review, we summarize recent advances in nanoarchitectures based on monocrystalline coordination polymers that are formed through confined assembly. We first discuss the crystallization of coordination polymer single crystals inside confined liquid networks or on substrates through assembly of nodes and ligands. Then, we discuss assembly of preformed coordination polymer single crystals inside confined liquid networks or on substrates. In each part, we discuss the properties of the coordination polymer single crystals as well as their performance in energy, environmental, and biomedical applications.

Metal-organic frameworks as a therapeutic strategy for lung diseases

Lung diseases remain a global burden today. Lower respiratory tract infections alone cause more than 3 million deaths worldwide each year and are on the rise every year. In particular, with coronavirus disease raging worldwide since 2019, we urgently require a treatment for lung disease. Metal organic frameworks (MOFs) have a broad application prospect in the biomedical field due to their remarkable properties. The unique properties of MOFs allow them to be applied as delivery materials for different drugs; diversified structural design endows MOFs with diverse functions; and they can be designed as various MOF-drug synergistic systems. This review concentrates on the synthesis design and applications of MOF based drugs against lung diseases, and discusses the possibility of preparing MOF-based inhalable formulations. Finally, we discuss the chances and challenges of using MOFs for targeting lung diseases in clinical practice.