Nanoscale metal-organic frameworks for biomedical imaging and drug delivery

Tannic acid-based bio-MOFs with antibacterial and antioxidant properties acquiring non-hemolytic and non-cytotoxic characteristics

Tannic acid (TA) based bio-metal phenolic networks (bio-MPNs) were prepared by using Cu(II), Zn(II), Bi(III), Ce(III), La(III), and Ti(IV) metal ions. TA-based bio-MPNs exhibited wedge-shaped pores between 16.4 and 25.8 nm pore size ranges. The higher gravimetric yield% was achieved for TA-Bi(III), and TA-Ti(IV) bio-MPNs with more than 90 %, and higher surface area was observed for TA-La(IIII) bio-MPNs as 56.2 m2/g with 17.3 nm average pore sizes. All TA-based MPNs are non-hemolytic with less than 5 % hemolysis ratio, whereas TA-based Bio-MPNs do not affect blood clotting with > 90 % blood clotting indexes except for TA-Cu(II) Bio-MPNs at 0.1 mg/mL concentration. Moreover, TA-Bi(III) and TA-Ce(III) Bio-MPNs were found to be safer materials showing no significant toxicity on L929 fibroblast cells at 100 μg/mL concentration, along with TA-based Bio-MPNs prepared with Cu(II), Zn(II), La(III), and Ti(IV) metal ions that could be safely used in in vivo applications at 1 μg/mL concentration. It has been proven by 2 different antioxidant tests that the prepared TA-based Bio-MPNs show antioxidant properties even if their TA-derived antioxidant properties decrease. Furthermore, all types of TA-based Bio-MPNs show great antimicrobial activity depending on the metal ion or microorganism types and the highest antibacterial/antifungal effect was determined for TA-Cu(II), and TA-Zn(II) Bio-MPNs with the lowest MBC/MFC values against Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 10231.

Tight orchestration of wound healing phase through metal-organic compounds

Cutaneous wound healing remains a common health problem. Metal-organic frameworks (MOFs) have emerged as an advanced therapeutic platform for promoted wound healing. However, there is a lack of MOF particles possessing excellent stability, biocompatibility, and reactive oxygen species (ROS) scavenging ability for tight orchestration of wound healing. Herein, we synthetize therapeutic MOF particles named PgC3Zn and employ them as skin sprays for wound repair. At the inflammatory stage, the pH- and ROS-responsive Zn2+ release of PgC3Zn alleviates oxidative stress and exerts antibacterial and anti-inflammatory efficacy. During the proliferation stage, PgC3Zn promote the migration and proliferation of fibroblasts, the re-epithelialization of keratinocytes, and the angiogenesis of endothelial cells. During the remodeling stage, PgC3Zn effectively facilitate the wound closure and collagen deposition. Moreover, multiple endogenous growth factors have been identified to contribute to the wound healing process. Importantly, PgC3Zn exhibit excellent biocompatibility and remarkably accelerate the healing process in both acute and infected rat full-thickness skin wound models in vivo. Consistently, transcriptomic data illustrate the multi-stage and multi-functional regulation effects of PgC3Zn in promoting wound healing. This study proposes versatile and biocompatible PgC3Zn MOF particles with potentials for enhancing the management of acute and infected skin wounds.

Development of Underwater Oleophobic and Underoil Hydrophobic Strontium(II)-Cyclotriphosphazene Hexacarboxylate Framework with Prewetting-Induced Switchable Wettability and Self-Cleanability for Continuous Oil-Water Mixture and Emulsion Separations

Oil spill management presents significant challenges, particularly when addressing spills that occur beneath the water's surface. In this context, Sr-HCPCP (SRMIST-2) is an innovative MOF with underwater oleophobic and underoil hydrophobic properties, incorporating enhanced coordination, a strong affinity for water and hydrophilic strontium, and a nontoxic, eco-friendly, biocompatible, and hydrophobic cyclotriphosphazene. It is designed with switchable wetting properties and exceptional chemical and thermal stability. SRMIST-2 is synthesized via a hydrothermal reaction between strontium nitrate and hexakis(4-carboxylatophenoxy)-cyclotriphosphazene. Its structure consists of edge-sharing {Sr3(COO)6(H2O)3} polyhedra that form 1-D chains, which pair to create 2-D networks that further interact with HCPCP ligands to construct a three-dimensional framework. When coated onto cotton fiber using polydopamine, the resulting CF-PDA-SRMIST-2 demonstrates excellent oil-water separation. Depending on whether it is prewetted with water or oil, it achieves separation efficiencies of 88-99%, with high flux rates (3409 Lm2-h-1 for water and 2840 Lm2-h-1 for oil) and remains effective over 15 cycles. It effectively separates oil-in-water and water-in-oil emulsions with 98% and 95% efficiency, respectively. CF-PDA-SRMIST-2 remains stable under acidic, alkaline, saline, and extreme temperature conditions. Its self-cleaning, amphiphobic properties ensure durability and reusability. With its low-cost, scalability, and eco-friendly nature, CF-PDA-SRMIST-2 is a promising material for sustainable oil spill remediation and environmental protection.

Application of a porous zirconium-based MOF nanoplate as an affinity ECL platform for the detection of protein kinase activity and inhibitor screening

Abnormal kinase expression affects phosphorylation in the human body, which is associated with numerous diseases, including cancer, diabetes mellitus, and Alzheimer's disease. In this study, we synthesized a highly stable, two-dimensional, luminescence-functionalized metal-organic framework with remarkable electrochemiluminescence (ECL) by immobilizing 9,10-Di(p-carboxyphenyl) anthracene (dca) on a zirconium cluster (dca-Zr₁₂) via a strong coordination bond between -COO⁻ and Zr⁴⁺. This novel and simple platform relies on the highly specific identification of phosphate molecules by the ultra-thin dca-Zr₁₂ nanoplate through carboxylate-Zr⁴⁺-phosphate chemistry. The ferrocene-labeled peptide substrate (Fc-S-Peptide) was phosphorylated in the presence of protein kinase A (PKA) and adenosine 5'-triphosphate (ATP), and the resulting phosphopeptide could subsequently be precisely captured by the zirconium sites of the dca-Zr12-modified electrode and, eventually, quench the ECL and gain a signal-off state. This rapid and simple detection strategy was successfully employed to measure PKA activity, with a detection limit as low as 0.35 mU mL-1. Based on the results, it exhibited high selectivity and can be applied for screening PKA inhibitors. The technique was subsequently applied to detect protein kinase activity in drug-stimulated MCF-7 cell lysates, demonstrating its potential for kinase-related investigations. Further, this platform could identify the activity of other kinase types with universal applicability.

Pickering emulsions stabilized by metal-organic framework nanoparticles

Pickering emulsions are attractive formulations due to their simplicity, similar to traditional surfactant-based emulsions, and their potential to create functional materials. Recently, Pickering emulsions stabilized by metal-organic framework (MOF) nanoparticles have garnered significant interest. This Review aims to systematize our knowledge of how MOF nanoparticles stabilize Pickering emulsions, providing fundamental insights for advancing this field. We thoroughly examine the emulsification process of Pickering emulsions stabilized by MOF nanoparticles. Additionally, we detail the superstructures derived from these emulsions, including colloidosomes, hydrogel droplets, 3D honeycomb network structures, molecularly imprinted polymers, monoliths, and micromotors. Finally, we discuss challenges and future research opportunities related to this type of emulsion.

Chitosan and carboxymethyl cellulose coated on NH2-UiO-66 as green, biocompatible, nontoxic, and pH-stimuli responsive for levofloxacin delivery: A comparative study

Recently, developing an efficient and green approach to overcoming bacterial resistance in drug delivery systems has remained a significant challenge. This work is supposed to design and create two novel, green, biocompatible nanocarriers by incorporating levofloxacin-loaded NH2-UiO-66 into the chitosan and carboxymethyl cellulose biopolymers. The structural characteristics and antibacterial activity of the synthesized carriers were analyzed using FT-IR, SEM, BET, XRD, TGA-DTA, zeta potential, DLS, swelling analysis, ZOI, MIC, MBC, and MTT techniques. The in vitro release rate of the levofloxacin at acidic and neutral environments from the NH2-UiO-66/levofloxacin/carboxymethyl cellulose was 78±2.1% and 18±1.9% and from the NH2-UiO-66/levofloxacin/chitosan was 86±3.5% and 69±2.9% respectively, over 72 h. Kinetics studies showed that the Corsmeyer-Peppas and Higuchi models predicted the release mechanisms of NH2-UiO-66/levofloxacin/carboxymethyl cellulose (R2=0.97) and NH2-UiO-66/levofloxacin/chitosan nanocarriers R2=0.97, respectively. Additionally, studies of the antibacterial properties showed that two NH2-UiO-66/levofloxacin/carboxymethyl cellulose and NH2-UiO-66/levofloxacin/chitosan nanocarriers were more effective against Staphylococcus aureus bacteria than Escherichia coli bacteria. The MTT assay showed that after 48 h, the NH2-UiO-66/levofloxacin/carboxymethyl cellulose nanocarrier with a concentration of 8 mg/mL exhibited lower cell viability compared to the NH2-UiO-66/levofloxacin/chitosan nanocarrier. Overall, these developed nanocarriers hold promise as advanced drug delivery systems due to their strong antibacterial properties.

Enzyme-loaded Fe3+-doped ZIF-90 particles as catalytic bioreactor hybrids for operating catalytic cascades

Fe3+-doped ZIF-90 (Fe3+-ZIF-90), a metal-organic framework (MOF), was synthesized and characterized. The MOF particles reveal peroxidase-like activity reflected by catalyzing the H2O2 oxidation of 3,3',5,5'-tetramethylbenzidine, TMB, to TMB˙+. Integration of the two enzymes, β-galactosidase, β-Gal, and glucose oxidase, GOx, in the Fe3+-ZIF-90 provides an organized framework allowing the operation of a three-catalyst cascade, where the β-Gal-catalyzed oxidation of lactose yields glucose and galactose, and the resulting glucose is aerobically oxidized by GOx to gluconic acid and H2O2, followed by the Fe3+-ZIF-90-catalyzed H2O2 oxidation of TMB to TMB˙+. The coupled bienzyme/nanozyme cascade in the MOFs is ca. 5-fold enhanced, as compared to a homogeneous mixture of the catalytic constituents. The enhanced catalytic activity of the enzyme cascades in the MOFs is attributed to the confined reaction framework, allowing product channeling across the multienzyme constituents and overcoming diffusion barriers. Moreover, the enzymes, acetylcholine esterase, AChE, and choline oxidase, ChOx, are encapsulated in the confined porous Fe3+-ZIF-90 particles. The catalytic cascade where the neurotransmitter acetylcholine is hydrolyzed by AChE followed by the stepwise ChOx-catalyzed oxidation of choline to betaine and H2O2, and the Fe3+-ZIF-90-catalyzed oxidation of TMB to colored TMB˙+ by H2O2 is demonstrated. The three-catalyst cascade is ca. 5-fold enhanced as compared to the mixture of separated catalysts. The integrated three-catalyst AChE/ChOx/Fe3+-ZIF-90 particles are applied as colorimetric sensors detecting the neurotransmitter acetylcholine and probing AChE inhibitors. The novelty of the systems is reflected by the assembly of multienzyme catalytic Fe3+-ZIF-90 hybrids in confined environments as bioreactor frameworks driving effective biocatalytic cascades.

Carbohydrate polymer-functionalized metal nanoparticles in cancer therapy: A review

Metal nanoparticles have been emerged as promising candidates in cancer therapy because of their large surface area, optical properties and ROS generation. Therefore, these nanoparticles are able to mediate cell death through hyperthermia, photothermal therapy and ROS-triggered apoptosis. The various metal nanoparticles including gold, silver and iron oxide nanostructures have been exploited for the theranostic application. Moreover, precision oncology and off-targeting features can be improved by metal nanoparticles. The modification of metal nanoparticles with carbohydrate polymers including chitosan, hyaluronic acid, cellulose, agarose, starch and pectin, among others can significantly improve their anti-cancer activities. Carbohydrate polymers have been idea for the purpose of drug delivery due to their biocompatibility, biodegradability and increasing nanoparticle stability. In addition, carbohydrate polymers are able to improve drug delivery, cellular uptake and sustained release of cargo. Such nanoparticles are capable of responding to the specific stimuli in the tumor microenvironment including pH and light. Furthermore, the carbohydrate polymer-modified metal nanoparticles can be utilized for the combination of chemotherapy, phototherapy and immunotherapy. Since the biocompatibility and long-term safety are critical factors for the clinical translation of nanoparticles, the modification of metal nanoparticles with carbohydrate polymers can improve this way to the application in clinic.

Metal-Organic Frameworks: Unlocking New Frontiers in Cardiovascular Diagnosis and Therapy

Cardiovascular disease (CVD) is one of the most critical diseases which is the predominant cause of death in the world. Early screening and diagnosis of the disease and effective treatment after diagnosis play an important role in the patient's recovery. Metal-organic frameworks (MOFs), a kind of hybrid ordered micro or meso-porous materials, constructed by metal nodes or clusters with organic ligands, due to their special features like high porosity and specific surface area, open metal sites, or ligand tunability, are widely used in various areas including gas storage, catalysis, sensors, biomedicine. Recently, advances in MOFs are bringing new developments and opportunities for the healthcare industry including the theranostic of CVD. In this review, the applications of MOFs are illustrated in the diagnosis and therapy of CVD, including biomarker detection, imaging, drug delivery systems, therapeutic gas delivery platforms, and nanomedicine. Also, the toxicity and biocompatibility of MOFs are discussed. By providing a comprehensive summary of the role played by MOFs in the diagnosis and treatment of CVDs, it is hoped to promote the future applications of MOFs in disease theranostics, especially in CVDs.

Maltodextrin-driven MOF Nano-antibacterial system for effective targeted bacteria and enhancing photodynamic therapy in bacterial keratitis

The occurrence of bacterial keratitis (BK) presents a significant threat to ocular health, often leading to visual impairment. Currently, conventional antibiotic therapies tend to promote bacterial resistance and lack biocompatibility. Therefore, it is of great significance to develop an alternative product with safe and efficient antimicrobial properties. In this study, we developed a novel smart pH-responsive nano-antibacterial system (PM/Ag-Ce6@ZIF-8) based on a metal-organic framework (MOF), enabling specific bacterial targeting and photodynamic therapy. By utilizing bacteria-specific maltodextrin transport pathway, the intelligent nano-antibacterial modified with maltotriose can accurately discriminate between bacterial infection and normal tissue, specifically target the site of infection, and efficiently accumulate at the infection site to enhance safety and efficacy. Furthermore, the incorporation of silver nanoparticles enhances the effectiveness of MOF photodynamic therapy by effectively eradicating bacteria. The nano-antibacterial system exhibits potent inhibition of biofilm formation as well as antibacterial activity while demonstrating excellent in vitro and in vivo biocompatibility. In an animal model of bacterial keratitis, PM/Ag-Ce6@ZIF-8 exhibits superior antibacterial activity compared to Levofloxacin (LVFX) eye drops, significantly improving therapeutic outcomes for bacterial keratitis in mice. Hence, this intelligent nano-antibacterial platform holds promising potential for clinical applications in treating keratitis.

N-/Si-co-doped nanocrystalline diamonds as highly sensitive luminescent thermometers

Diamonds can host a variety of luminescent point defects, such as nitrogen vacancies and silicon vacancies, making them remarkably promising materials for luminescence nanothermometry. They also exhibit desirable characteristics, including low cytotoxicity, good biocompatibility and the benefits of carbon chemistry for tuneable surface functionalization with target molecules. In this work, N-/Si co-doped nanocrystalline diamonds were synthesized via microwave plasma-enhanced chemical vapor deposition under varying methane flow and temperature conditions, aiming for maximum photoluminescence intensity. In-depth analysis of the luminescence characteristics of NV- and SiV- emitting point defects with temperature, based on both experiments and ab initio calculations, suggested the existence of thermal coupling between their states. This coupling enabled ratiometric approaches to be exploited for more sensitive luminescent thermometry. A maximum thermal relative sensitivity of 5.5% K-1 was achieved. This is remarkable for in vitro temperature measurements of biological tissues.

Strengthening Antisense Oligonucleotide-Mediated Anti-Tumor Immunity via Metal-Organic Framework Nanoparticles

Overexpression of checkpoint proteins, such as programmed death ligand one (PD-L1), prevents immune recognition and enables cancer growth. Current monoclonal antibodies that block PD-L1 tend to be fragile, unable to penetrate tumors, and target cancer at later stages, thus leading to inconsistent patient outcomes. Antisense oligonucleotides (ASOs) provide an alternative to decrease PD-L1 expression, but require frequent high dosing due to fast degradation, rapid clearance, and poor cell uptake. To overcome these issues, we harnessed biocompatible metal-organic framework (MOF) nanoparticles, porous nanomaterials comprising metal nodes and organic linkers, to deliver ASOs. Encapsulating ASOs into MOFs enhances their stability and protection during intracellular delivery, leading to reduced PD-L1 expression and downstream immune recognition. Herein, we synthesized three distinct PD-L1-specific ASOs and loaded them individually into zirconium-based nano-sized NU-1000 MOFs, averaging ∼80% encapsulation efficiency. Release of encapsulated ASOs was sustained up to 7 days ex cellulo . MOF encapsulation increased ASO potency and reduced PD-L1 expression ∼ 3-fold and 2-fold in triple negative breast cancer EMT6 and melanoma B16-F10 cells, respectively. We evaluated the impact of MOF-delivered ASOs on PD-L1-expressing immune cells, where we observed ca. 12-fold increases in dendritic cell co-stimulatory marker expression, and amplified T cell activation and proliferation compared to untreated cells (4-fold and 10-fold, respectively). Notably, these changes drove a 3-fold increase in tumor caspase-3 expression, a key mediator for apoptosis. This research highlights how MOFs can be harnessed to bypass ASO limitations without requiring sequence modifications, and offers a broadly applicable platform for improved oligonucleotide delivery for various genes of interest.

Photoactivated Multivariate Metal-Organic Frameworks for On-Demand Drug Release: The Role of Host-Guest Interactions

The development of smart drug delivery vehicles capable of controlled release upon application of an external stimulus is of paramount interest for the next generation of personalized medicine. Herein, we report a series of six multivariate (MTV) MOFs capable of visible light-activated drug delivery. The drug loading capacity and release rates were systematically tuned through variation of the linker ratio between 4,4'-azobenzene dicarboxylic acid (H2ABDA) and 4,4'-(diazene-1,2-diyl)bis(3,5-difluorobenzoic acid) (H2ABDA(3,5-F)). The drug loading capacity, dictated by host-guest interactions, was thoroughly explored via a combined experimental and computational approach using two model drug or drug-like molecules, 5-fluorouracil (5-FU) and Nile Red. Notably, the loading capacity for 5-FU follows a "Goldilocks" profile with a maximum loading at 33% H2ABDA(3,5-F) content. Computational results confirm the existence of a cooperative ligand environment that promotes strong, preferential binding at the tetrahedral/octahedral pore window formed between two H2ABDA and one H2ABDA(3,5-F). Thus, the MTV approach enhanced capacity over the native 100% H2ABDA(3,5-F) and 0% H2ABDA(3,5-F) MOFs. In addition to increased loading, the rate of cargo release upon green light excitation also increased as the percentage of H2ABDA(3,5-F) in the MOF was raised, reaching a maximum release rate of 0.9 ± 0.1% of total cargo per minute for the MOF containing 100% H2ABDA(3,5-F) MOF. The results highlight the promise of MTV MOF design for optimizing drug delivery vehicles with relevant payloads and patient-dictated dosing.

Photoclick surface modification of MOF-808 for galactose-mediated targeted chemotherapy

Controllable surface modification of nanoparticulate drug delivery vectors is key to enhancing specific desirable properties such as colloidal stability, targeting, and stimuli-responsive cargo release. Metal-organic frameworks (MOFs) have been proposed as potential delivery devices, with surface modification achieved by various bioconjugate "click" reactions, including copper-catalysed and strain-promoted azide-alkyne cycloaddition. Herein, we show that photo-induced nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) can be used to surface-modify tetrazole-appended Zr MOFs with maleimides, and vice versa, with the extent of this traceless surface functionalisation controlled by the length of photoirradiation. This "photoclick" surface modification protocol is exemplified by the decorating of carboplatin-loaded MOF-808 with galactose units to target asialoglycoprotein receptors of specific cancer cell types. Targeting towards HepG2 cells, which overexpress these receptors, is indicated by enhanced endocytosis and cytotoxicity in both two- and three-dimensional cell cultures compared to other cell lines. The study shows both the power of the NITEC protocol for functionalisation of MOFs, and also the benefits of carbohydrate targeting in drug delivery vectors, with scope for significant additional work diversifying the surface targeting units available for nanoparticle functionalisation under these mild, biocompatible "photoclick" conditions.

Exploring New Bioorthogonal Catalysts: Scaffold Diversity in Catalysis for Chemical Biology

Bioorthogonal catalysis has revolutionized the field of chemical biology by enabling selective and controlled chemical transformations within living systems. Research has converged on the development of innovative catalyst scaffolds, seeking to broaden the scope of bioorthogonal reactions, boost their efficiency, and surpass the limitations of conventional catalysts. This review provides a comprehensive overview of the latest advancements in bioorthogonal catalyst research based on different scaffold materials. Through an in-depth analysis of fabrication strategies and applications of bioorthogonal catalysts, this review discusses the design principles, mechanisms of action, and applications of these novel catalysts in chemical biology. Current challenges and future directions in exploring the scaffold diversity are also highlighted. The integration of diverse catalyst scaffolds offers exciting prospects for precise manipulation of biomolecules and the development of innovative therapeutic strategies in chemical biology. In addition, the review fills in the gaps in previous reviews, such as in fully summarizing the presented scaffold materials applied in bioorthogonal catalysts, emphasizing the potential impact on advancing bioorthogonal chemistry, and offering prospects for future development in this field.

Innate Immune Activation with Multifunctional Nanoparticles for Cancer Immunotherapy

Immune checkpoint blockade (ICB) has revolutionized the treatment of many cancers by leveraging the immune system to combat malignancies. However, its efficacy is limited by the immunosuppressive tumor microenvironment and other regulatory mechanisms of the immune system. Innate immune modulators (IIMs) provide potent immune activation to complement adaptive immune responses and help overcome resistance to ICB. This minireview provides an overview of IIMs and their roles in antitumor immune responses and summarizes recent advances in developing nanotechnology to enhance the delivery of IIMs to tumors for potentiating cancer immunotherapy and mitigating systemic toxicity. We discuss innovative nanoparticle platforms for the delivery of IIMs targeting the cyclic GMP-AMP synthase-stimulator of interferon genes pathway, the toll-like receptor pathway, and the retinoic acid-inducible gene I-like receptor pathway. We review the preliminary clinical readouts of representative IIM nanoptherapeutics and highlight the development of multifunctional nanoparticles for combination treatments of IIMs with conventional treatment mdoalities such as chemotherapy, radiotherapy, photodynmic therapy, and tumor antigens. Finally, we summarize the lessons learned from the existing systems, the challenges in the field, and future perspectives for this exciting field of nanotherapeutics for cancer immunotherapy.

Homochiral BINOL-Based Metal-Organic Frameworks for Luminescence Sensing of Hydrobenzoin Enantiomers

Luminescent chiral metal-organic frameworks (CMOFs) are promising candidates for the enantioselective sensing of important chiral molecules. Herein, we report the synthesis and characterization of Zn and Cd CMOFs based on 1,1'-bi-2-naphthol (BINOL)-derived 3,3',6,6'-tetra(benzoic acids), H4L-OEt and H4L-OH. Four CMOFs, Zn-L-OEt, Zn-L-OH, Cd-L-OEt, and Cd-L-OH, based on these ligands were crystallographically characterized. Zinc cations form 8-connected (8-c) penta-metallic secondary building units (SBUs), while cadmium cations form 4-c trimetallic SBUs. These SBUs are linked by 4-c L-OEt and L-OH ligands to form noninterpenetrated 4, 8-c 4,8T41 zinc CMOFs (Zn-L-OEt and Zn-L-OH) and 2-fold interpenetrated 4-c diamondoid (dia) cadmium CMOFs (Cd-L-OEt and Cd-L-OH), respectively. At a ligand concentration of 24 μM, H4L-OEt and H4L-OH showed negligible luminescent quenching by RR- and SS-hydrobenzoin (HB) enantiomers with Stern-Völmer constants of 29-89 M-1. In contrast, CMOFs displayed efficient quenching by HB enantiomers with Stern-Völmer constants of 583-1200 M-1, due to significant HB preconcentration in CMOF channels via favorable host-guest interactions between CMOF frameworks and HB molecules. The CMOFs demonstrated luminescence quenching selectivity for RR-HB over SS-HB, with Zn-L-OEt exhibiting the highest quenching ratio (Ksv(RR)/Ksv(SS)) of 1.624. This work highlights the potential of CMOFs in enantioselective sensing applications.

Harnessing Large Language Models to Collect and Analyze Metal-Organic Framework Property Data Set

This research focused on the efficient collection of experimental metal-organic framework (MOF) data from scientific literature to address the challenges of accessing hard-to-find data and improving the quality of information available for machine learning studies in materials science. Utilizing a chain of advanced large language models (LLMs), we developed a systematic approach to extract and organize MOF data into a structured format. Our methodology successfully compiled information from more than 40,000 research articles, creating a comprehensive and ready-to-use data set. Specifically, data regarding MOF synthesis conditions and properties were extracted from both tables and text and then analyzed. Subsequently, we utilized the curated database to analyze the relationships between synthesis conditions, properties, and structure. Through machine learning, we identified the existence of a gap between simulation data and experimental data, and further analysis revealed the factors contributing to this discrepancy. Additionally, we leveraged the extracted synthesis condition data to develop a synthesis condition recommender system. This system suggests optimal synthesis conditions based on the provided precursors, offering a practical tool to refine synthesis strategies. This underscores the importance of experimental datasets in advancing MOF research.

Anchoring Catalytic Metal Nodes within a Single-Crystalline Pyrazolate Metal-Organic Framework for Efficient Heterogeneous Catalysis

The synthesis of single-crystalline and robust pyrazolate metal-organic frameworks (Pz-MOFs) capable of facilitating challenging organic transformations is fundamentally significant in catalysis. Here we demonstrate a metal-node-based catalytic site anchoring strategy by synthesizing a single-crystalline and robust Pz-MOF (PCN-1004). PCN-1004 features one-dimensional (1D) copper-Pz chains interconnected by well-organized ligands, forming a porous three-dimensional (3D) network with two types of 1D open channels. Notably, PCN-1004 displays exceptional stability in aqueous solutions across a broad pH range (1 to 14), attributed to the robust copper-Pz coordination bond. Significantly, PCN-1004 functions as an outstanding catalyst in cross dehydrogenative coupling reactions for constructing C-O/C-S bonds, even in the absence of directing groups, achieving yields of up to ~99 %, with long cycle lives and high substrate compatibility. PCN-1004 outperforms all previously reported porphyrin-based homogeneous and heterogeneous catalysts. Control experiments and computations elucidate the pivotal catalytic role of the copper-Pz chains and reveal a free radical pathway for the reaction. This work not only demonstrates the successful implementation of a metal-node-based catalytic site anchoring strategy for the efficient catalysis of challenging organic transformations but also highlights the synergistic effect of a robust framework, 1D open channels, and active sites in enhancing catalytic efficiency within MOFs.

Proton-Mediated Dynamic Nestling of DNA Payloads Within Size-Matched MOFs Nanochannels for Smart Intracellular Delivery

With sequence-programmable biological functions and excellent biocompatibility, synthetic functional DNA holds great promise for various biological applications. However, it remains a challenge to simultaneously retain their biological functions while protecting these fragile oligonucleotides from the degradation by nucleases abundant in biological circumstances. Herein, a smart delivery system for functional DNA payloads is developed based on proton-mediated dynamic nestling of cytosine-rich DNA moieties within the precisely size-matched nanochannels of highly crystalline metal-organic frameworks (MOFs): At neutral pH, cytosine-rich DNA strands exhibit a flexible single-stranded state and can be accommodated by MOFs nanochannels with a size of ca. 2.0 nm; while at acidic conditions, the protonation of cytosine-rich strands weakens their interaction with the nanochannels, and the tendency to form four-stranded structures drives these DNA strands out of the nanochannels. Results confirm the successful protection of DNA payloads from enzymatic hydrolysis by the MOFs nanochannels, and the delicate coupling of the endocytosis processes and the proton-responsive Cytosine-rich DNA/MOFs systems realized the efficient intracellular delivery of DNA payloads. Furthermore, with a complementary sequence to the telomere overhangs, direct imaging of telomeres and the nucleus is successfully achieved with the proton-mediated DNA/MOFs system.

Metal-Organic Framework Thin Films as Drug Delivery Systems

Selective metal-organic frameworks (MOFs) have been studied as promising candidates for biomedical applications, especially as drug delivery systems due to their exceptional structural properties. This work reports the detailed methods to prepare an iron-containing MOF, MIL-88B(Fe), on functionalized gold and medical-grade stainless steel surfaces for drug delivery. We present a general procedure for preparing a novel drug carrier that can potentially be used as drug-eluting stent coatings.

Dynamic pH‐Responsive Release and Biological Impact of In Situ Quercetin‐Modified MIL‐101(Fe)‐NH2

A successful investigation was conducted on the in situ modification of MIL‐101(Fe)‐NH2 with quercetin and its controlled release under various pH conditions. MIL‐101(Fe)‐NH2 was synthesized using an electrochemical method at room temperature (15 volts, 30 min). The formation of the material was confirmed through comprehensive analyses, including PXRD, FTIR, and TGA. Nitrogen sorption isotherm measurements revealed that Qu@MIL‐101(Fe)‐NH2 exhibited a smaller surface area compared to MIL‐101(Fe)‐NH2, with both materials classified as mesoporous. Transmission electron microscopy (TEM) clearly depicted the materials’ octahedral microspindle morphology. The cumulative percent release (CPR) of quercetin from Qu@MIL‐101(Fe)‐NH2 over 72 h was determined to be 53.45 % at pH 1.2, 19.48 % at pH 4.8, and 5.87 % at pH 7.4. Notably, quercetin release in the acidic microenvironment representative of cancer cells (pH 4.8) was nearly four times higher than under physiological conditions (pH 7.4). Kinetic release studies indicated that quercetin release from Qu@MIL‐101(Fe)‐NH2 followed the Ritger‐Peppas kinetic model, suggesting non‐Fickian diffusion. The MIL‐101(Fe)‐NH2 nanocarriers, with in situ‐loaded quercetin, demonstrated promising potential for pH‐triggered drug release. Additionally, the safety of MIL‐101(Fe)‐NH2 in biological models and the anticancer efficacy of quercetin were evaluated in vitro using two liver cancer cell lines.

Understanding water reaction pathways to control the hydrolytic reactivity of a Zn metal-organic framework

Metal-organic frameworks (MOFs) are a class of porous materials that are of topical interest for their utility in water-related applications. Nevertheless, molecular-level insight into water-MOF interactions and MOF hydrolytic reactivity remains understudied. Herein, we report two hydrolytic pathways leading to either structural stability or framework decomposition of a MOF (ZnMOF-1). The two distinct ZnMOF-1 water reaction pathways are linked to the diffusion rate of incorporated guest dimethylformamide (DMF) molecules: slow diffusion of DMF triggers evolution of the initial MOF into a water-stable MOF product exhibiting enhanced water adsorption, while fast exchange of DMF with water leads to decomposition. The starting MOF, three intermediates from the water reaction pathways and the final stable MOF have been characterized. The documentation of two distinct pathways counters the stereotype that water exposure always leads to destruction or degradation of water-sensitive MOFs, and demonstrates that water-stable MOFs with improved adsorption properties can be prepared via controlled solvent-triggered structural rearrangement.

Metal ion formulations for diabetic wound healing: Mechanisms and therapeutic potential

Metals are vital in human physiology, which not only act as enzyme catalysts in the processes of superoxide dismutase and glucose phosphorylation, but also affect the redox process, osmotic adjustment, metabolism and neural signals. However, metal imbalances can lead to diseases such as diabetes, which is marked by chronic hyperglycemia and affects wound healing. The hyperglycemic milieu of diabetes impairs wound healing, posing significant challenges to patient quality of life. Wound healing encompasses a complex cascade of hemostasis, inflammation, proliferation, and remodeling phases, which are susceptible to disruption in hyperglycemic conditions. In recent decades, metals have emerged as critical facilitators of wound repair by enhancing antimicrobial properties (e.g., iron and silver), providing angiogenic stimulation (copper), promoting antioxidant activity and growth factor synthesis (zinc), and supporting wound closure (calcium and magnesium). Consequently, research has pivoted towards the development of metal ion-based therapeutics, including innovative formulations such as nano-hydrogels, nano-microneedle dressings, and microneedle patches. Prepared by combining macromolecular materials such as chitosan, hyaluronic acid and sodium alginate with metals, aiming at improving the management of diabetic wounds. This review delineates the roles of key metals in human physiology and evaluates the application of metal ions in diabetic wound management strategies.

Nanoscale Mixed-Ligand Metal-Organic Framework for X-ray Stimulated Cancer Therapy

Concurrent localized radiotherapy and systemic chemotherapy are standards of care for many cancers, but these treatment regimens cause severe adverse effects in many patients. Herein, we report the design of a mixed-ligand nanoscale metal-organic framework (nMOF) with the ability to simultaneously enhance radiotherapeutic effects and trigger the release of a potent chemotherapeutic under X-ray irradiation. We synthesized a new functional quaterphenyl dicarboxylate ligand conjugated with SN38 (H2QP-SN) via a hydroxyl radical-responsive covalent linkage. Because of the similar length of QP-SN and bis(p-benzoato)porphyrin (DBP) ligands, QP-SN was incorporated into Hf-DBP nMOF to afford a novel multifunctional mixed-ligand Hf-DBP-QP-SN nMOF with good biocompatibility. Hf-DBP-QP-SN not only enhances radiation damage to tumors via a unique radiotherapy-radiodynamic therapy (RT-RDT) process but also increases ·OH generation from radiolysis with electron-dense Hf12 secondary building units (SBUs) to release SN38 from Hf-DBP-QP-SN for chemotherapy. Elevated levels of hydrogen peroxide in the tumor microenvironment further stimulate the release of SN38 by enhancing ·OH generation under X-ray irradiation. With low doses of X-ray irradiation, Hf-DBP-QP-SN suppressed the growth of CT26 colon and 4T1 breast tumors by 93.5% and 95.2%, respectively, without any sign of general toxicity. Our study highlights the potential of using ionizing radiation-mediated chemistry for on-demand activation of nanotherapeutics for synergistic radiotherapy and chemotherapy without causing severe adverse effects.

Cooperative Immobilization of Transition-Metal Clusters into Kagome-Type Metal-Organic Framework for C2H2/CO2 Separation

There has long been a pursuit for a metal-organic framework (MOF)-based adsorbent for various hydrocarbon separations. Herein, we utilized simple trimesic acid and 1,2,4-triazole, together with the heterometallic strategy to produce two quaternary MOFs with a kgm-type structure. The cooperative coordination allows the immobilization of metal clusters into the pore channels, creating an appropriate pore size and high density of open metal sites. The resulting material shows excellent C2H2/CO2 separation performance with good stability.

Multifunctional Nanomaterials Mediate Cholesterol Depletion for Cancer Treatment

Cholesterol is an essential membrane component, and the metabolites from cholesterol play important biological functions to intricately support cancer progression and dampen immune responses. Preclinical and clinical studies have demonstrated the role of cholesterol metabolism regulation on inhibiting tumor growth, remodeling the immunosuppressive tumor microenvironment (TME), and enhancing anti-tumor immunity. In this minireview, we discuss complex cholesterol metabolism in tumors, its important role in cancer progression, and its influences on immune cells in the TME. We provide an overview of recent advances in cancer treatment through regulating cholesterol metabolism. We discuss the design of cholesterol-altering multifunctional nanomaterials to regulate oxidative stress, modulate immune checkpoints, manipulate mechanical stress responses, and alter cholesterol metabolic pathways. Additionally, we examine the interactions between cholesterol metabolism regulation and established cancer treatments with the aim of identifying efficient strategies to disrupt cholesterol metabolism and synergistic combination therapies for effective cancer treatment.

Impact of photoaging on the chemical and cytotoxic properties of nanoscale zeolitic imidazolate framework-8

This study investigated the influence of photoaging on a nanoscale metal-organic framework (MOF), truncated rhombic dodecahedron nano-zeolitic imidazolate framework-8 (nZIF-8), focusing on its oxidative stress, inflammation, and implications for pulmonary diseases. We observed significant photodegradation-induced transformations in nZIF-8, characterized by a reduction in particle size from 200.5 to 101.4 nm and notable structural disintegration after prolonged exposure to simulated solar radiation. This alteration resulted in a marked decrease in oxidative cytotoxicity in BEAS-2B cells, which was attributed to changes in surface properties and reduced reactive oxygen species (ROS) production. Gene expression analysis further revealed a decrease in cytotoxic and inflammatory responses, which potentially lowers the risk of chronic obstructive pulmonary disease (COPD). Aged nZIF-8 also showed diminished capacity to induce pro-inflammatory cytokines and influence COPD-related gene expression, reducing its potential to exacerbate COPD pathogenesis. Our findings highlight the critical need for comprehensive safety evaluations of these materials, while considering their long-term environmental and biological impacts. The diminished cytotoxicity and inflammatory potential of aged nZIF-8 highlighted its enhanced suitability for broader applications, indicating that photoaging may lead to safer and more sustainable material utilization.

Quantitative in Vivo Molecular MRI

Molecular magnetic resonance imaging (MRI) combines chemistry, chemical biology, and imaging techniques to track molecular events non-invasively. Quantitative molecular MRI aims to provide meaningful, reproducible numerical measurements of molecular processes or biochemical targets within the body. In this review, the classifications of molecular MRI probes based on their signal-generating mechanism and functionality are first described. From there, the primary considerations for in vitro characterization and in vivo validation of molecular MRI probes, including how to avoid pitfalls and biases are discussed. Then, recommendations on imaging acquisition protocols and analysis methods to establish quantitative relationships between MRI signal change induced by the probes and the molecular processes of interest are provided. Finally, several representative case studies are highlighted that incorporate these features. Quantitative molecular MRI is a multidisciplinary research area incorporating expertise in chemical biology, inorganic chemistry, molecular probes, imaging physics, drug development, pathobiology, and medicine. The purpose of this review is to provide guidance to chemists developing MR imaging probes and methods in terms of in vitro and in vivo validation to accelerate the translation of these new quantitative tools for non-invasive imaging of biological processes.

An amino and triazole-containing metal-organic framework: cellobiose sensing and its catalytic conversion under mild conditions

A novel metal-organic framework functionalized with amino and triazole moieties, namely Zn-TDA, has been synthesized. It represents the first example of a MOF-based sensor for highly selective sensing of cellobiose over other saccharides. Furthermore, Zn-TDA was used as a catalyst for the conversion of cellobiose to 5-hydroxymethylfurfural (5-HMF), achieving an excellent yield of 68.7% within 90 min under mild conditions.

Applications of Metal-Organic Frameworks (MOFs) in Drug Delivery, Biosensing, and Therapy: A Comprehensive Review

The porous materials known as metal-organic frameworks (MOFs) stand out for their enormous surface area, adaptable pore size and shape, and structural variety. These characteristics make them well-suited for various applications, especially in healthcare. This review thoroughly summarizes recent studies on the use of MOFs in drug delivery, biosensing, and therapeutics. MOFs may encapsulate medications, target certain cells or tissues, and regulate their release over time. Additionally, MOFs have the potential to be used in biosensing applications, allowing for the selective detection of chemical and biological substances. MOFs' optical or electrical characteristics may be modified to make biosensors that track physiological data. MOFs show potential for targeted drug delivery and the regulated release of therapeutic substances in cancer treatment. In addition, they may work as potent antibacterial agents, providing a less dangerous option than traditional antibiotics that increase antibiotic resistance. For practical applications, further research is required as well as more consideration for the problems with toxicity and biocompatibility. In addition to addressing the difficulties and promising possibilities in this area, this study intends to provide insights into the potential of MOFs in healthcare for drug delivery, biosensing, and treatment. Despite several essential reviews in this area, it was necessary to look into the most recent research on drug delivery, biosensing, and therapy as a combined concept.

Metal-organic frameworks in oral drug delivery

Metal-organic frameworks (MOFs) offer innovative solutions to the limitations of traditional oral drug delivery systems through their unique combination of metal ions and organic ligands. This review systematically examines the structural properties and principles of MOFs, setting the stage for their application in drug delivery. It discusses various classes of MOFs, including those based on zirconium, iron, zinc, copper, titanium, aluminum, potassium, and magnesium, assessing their drug-loading capacities, biocompatibility, and controlled release mechanisms. The effectiveness of MOFs is illustrated through case studies that highlight their capabilities in enhancing drug solubility, providing protection against the harsh gastrointestinal environment, and enabling precise drug release. The review addresses potential challenges, particularly the toxicity concerns associated with MOFs, and calls for further research into their biocompatibility and interactions with biological systems. It concludes by emphasizing the potential of MOFs in revolutionizing oral drug delivery, highlighting the critical need for comprehensive research to harness their full potential in clinical applications.

Drug delivery based exosomes uptake pathways

Most cells secrete a material called extracellular vesicles (EVs), which play a crucial role in cellular communication. Exosomes are one of the most studied types of EVs. Recent research has shown the many functions and substrates of cellular exosomes. Multiple studies have shown the efficacy of exosomes in transporting a wide variety of cargo to their respective target cells. As a result, they are often utilized to transport medicaments to patients. Natural exosomes as well as exosomes modified with other compounds to enhance transport capabilities have been employed. In this article, we take a look at how different types of exosomes and modified exosomes may transport different types of cargo to their respective targets. Exosomes have a lot of potential as drug delivery vehicles for many synthetic compounds, proteins, nucleic acids, and gene repair specialists because they can stay in the body for a long time, are biocompatible, and can carry natural materials. A good way to put specific protein particles into exosomes is still not clear, though, and the exosomes can't be used in many situations yet. The determinants for exosome production, as well as ways for loading certain therapeutic molecules (proteins, nucleic acids, and small compounds), were covered in this paper. Further study and the development of therapeutic exosomes may both benefit from the information collected in this review.

Synthesis and evaluation of nanosized aluminum MOF encapsulating Umbelliferon: assessing antioxidant, anti-inflammatory, and wound healing potential in an earthworm model

Nanoporous aluminum metal-organic framework (Al-MOF) was synthesized via solvothermal methods and employed as a carrier matrix for in vitro drug delivery of Umbelliferon (Um). The encapsulated Um was gradually released over seven days at 37 °C, using simulated body fluid phosphate-buffered saline (PBS) at pH 7.4 as the release medium. The drug release profile suggests the potential of Al-MOF nanoparticles as effective drug delivery carriers. Structural and chemical analyses of Um-loaded Al-MOF nanoparticles (Um-Al MOF) were conducted using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), and ultraviolet-visible (UV-Vis) spectroscopy. Thermal gravimetric analysis (TGA) was employed to investigate the thermal stability of the Al-MOF nanoparticles, while Transmission Electron Microscopy (TEM) was utilized to assess their morphological features. Um-Al MOF nanoparticles demonstrated notable antioxidant and anti-inflammatory properties compared to Um and Al-MOF nanoparticles individually. Moreover, they exhibited significant enhancement in wound healing in an earthworm model. These findings underscore the potential of Al-MOF nanoparticles as a promising drug delivery system, necessitating further investigations to explore their clinical applicability.

Cyclodextrin in drug delivery: Exploring scaffolds, properties, and cutting-edge applications

Cyclodextrins (CDs) are unique cyclic compounds that can form inclusion complexes via host-guest complexation with a wide range of molecules, thereby altering their physicochemical properties. These molecules offer the formation of inclusion complexes without the formation of covalent bonds, making them suitable for a variety of applications in pharmaceutical and biomedical fields. Due to their supramolecular host-guest properties, CDs are being utilized in the fabrication of biomaterials, metal-organic frameworks, and nano-drug carriers. Additionally, CDs in combination with biomolecules are biocompatible and can deliver nano to macromolecules at the site of drug actions. However, the availability of free hydroxyl groups and a simple crosslinking process for supramolecular fabrication show immense opportunities for researchers in the field of tissue engineering and biomedical applications. In this review article, we have covered the historical development, various types of chemical frameworks, unique chemical and physical properties, and important applications of CDs in drug delivery and biomedical sciences.

A review on synthesis of MOF-derived carbon composites: innovations in electrochemical, environmental and electrocatalytic technologies

Carbon composites derived from Metal-Organic Frameworks (MOFs) have shown great promise as multipurpose materials for a range of electrochemical and environmental applications. Since carbon-based nanomaterials exhibit intriguing features, they have been widely exploited as catalysts or catalysts supports in the chemical industry or for energy or environmental applications. To improve the catalytic performance of carbon-based materials, high surface areas, variable porosity, and functionalization are thought to be essential. This study offers a thorough summary of the most recent developments in MOF-derived carbon composite synthesis techniques, emphasizing innovative approaches that improve the structural and functional characteristics of the materials. Their uses in electrochemical technologies, such as energy conversion and storage, and their function in environmental electrocatalysis for water splitting and pollutant degradation are also included in the debate. This review seeks to clarify the revolutionary effect of carbon composites formed from MOFs on sustainable technology solutions by analyzing current research trends and innovations, opening the door for further advancements in this rapidly evolving sector.

A fast and simple procedure for the synthesis of a zinc and 1,4-benzene dicarboxylic acid metal-organic framework and its evaluation as a sorbent for dispersive micro solid phase extraction of pesticide residues

In this work, Zn-1,4-benzenedicarboxylate metal-organic framework was synthesized by a simple hydrothermal process and used in dispersive micro solid phase extraction of some pesticide from various fruit juice and water samples. Seven widely consumed pesticides in agriculture (chlorpyrifos, haloxyfop-R-methyl, oxadiazon, diniconazole, clodinafop-propargyl, fenpropathrin, and fenaxoprop-p-ethyl) were selected as target analytes. In this work, dispersive micro solid phase extraction was followed by a liquid phase microextraction method to achieve more enrichment of the analytes, and the enriched analytes were quantified using a gas chromatography-flame ionization detector. The sorbent was authenticated by Fourier transform infrared spectrophotometry, X-ray diffraction, energy dispersive X-ray analysis, and scanning electron microscope imaging. The factors affecting the extraction efficiency of the developed method were investigated, and the validation of the method under the optimized extraction conditions presented satisfactory results for precision and trueness, with limits of detection and quantification in the ranges of 0.50-0.90 and 1.5-2.7 μg L-1, respectively. Enrichment factors and extraction recoveries were in the ranges of 239-392% and 47-78%, respectively. One river water and some fruit and vegetable juice samples were analyzed by the recommended method, and the obtained recoveries were between 90% and 102%.

Thiol-Amino Bifunctional Metal-Organic-Framework-Based Membrane Regulating Hydrophobic Sites for Selective Separation of Artesunate

The selective separation and purification of artesunate (ARU) and artemisinin (ART) using zirconium-based metal-organic frameworks (MOF), especially UiO-66 MOF, are receiving increasing attention. In this study, tunable "hydrophobic" sites of thiol (-SH) were introduced to amino-functionalized MOFs (UiO-66-NH2) to fabricate a thiol-amino bifunctional UiO-66/polyvinylidene fluoride (PVDF)-blended membrane (S1-UiO/PVDF-DPIM) via the delayed-phase-inversion method for selective separation of ARU/ART. The adsorption results indicated that the modification of UiO-66-NH2 with thiol can indeed increase the ARU adsorption. The thiol-functional MOF (S1-UiO-66-NH2) was chosen as the optimal thiol-amino bifunctional MOF, as it possessed the maximum ARU adsorption capacity (111.14 mg g-1) and the highest selective-separation factor (α = 51.84). The ATR FT-IR dynamic spectrum disclosed the recognition mechanism, indicating that incorporating thiol groups into a hydrophilic MOF as hydrophobic sites can boost adsorption efficiency. Moreover, the static-selective permeation results showed that the S1-UiO/PVDF-DPIM preferentially transfers ARU when mixed with ART, even achieving complete ARU/ART separation. The most crucial aspect was the introduction of a hydrophobic core of -SH and new spontaneously formed disulfide bonds to S1-UiO/PVDF-DPIM, creating alternated hydrogen bonds and hydrophobic interactions. This work provides an alternative strategy to prepare hydrophobic-hydrophilic MOF-based membranes for the highly efficient and selective separation of complex analogue systems.

Noteworthy synthesis strategies and applications of metal-organic frameworks for the removal of emerging water pollutants from aqueous environment

17 global Sustainable Development Goals (SDGs) were established through the adoption of the 2030 Agenda for Sustainable Development by all United Nations members. Clean water and sanitation (SDG 6) and industry, innovation, and infrastructure (SDG 9) are the SDGs focus of this work. Of late, various new companies delivering metal-organic frameworks (MOFs) have blossomed and moved the field of adsorption utilizing MOFs to another stage. Inside this unique circumstance, this article aims to catch recent advancements in the field of MOFs and the utilizations of MOFs relate to the expulsion of arising contaminations that present huge difficulties to water quality because of their steadiness and possible damage to environments and human wellbeing. Customary water treatment techniques regularly neglect to eliminate these poisons, requiring the advancement of novel methodologies. This study overviews engineering techniques for controlling MOF characteristics for better flexibility, stability, and surface area. A current report on MOFs gathered new perspectives that are amicably discussed in emergent technologies and extreme applications towards environmental sectors. Various applications in many fields that exploit MOFs are being fostered, including gas storage, fluid separation, adsorbents, catalysis, medication delivery, and sensor utilizations. The surface area of a wide range of MOFs ranges from 103 to 104 m2/g, which exceeds the standard permeability of several material designs. MOFs with extremely durable porosity are more significant in their assortment and variety than other classes of porous materials. The work outlines the difficulties encountered in the synthesis steps and suggests ways to make use of MOFs' value in a variety of contexts. This caters to creating multivariate systems enclosed with numerous functionalities, leading to the synthesis of MOFs that offer a synergistic blend of in-built properties and exclusive applications. Additionally, the MOF-related future development opportunities and challenges are discussed.

Zirconium-Based Metal-Organic Frameworks with Free Hydroxy Groups for Enhanced Perfluorooctanoic Acid Uptake in Water

Perfluorooctanoic acid (PFOA) is a highly recalcitrant organic pollutant, and its bioaccumulation severely endangers human health. While various methods are developed for PFOA removal, the targeted design of adsorbents with high efficiency and reusability remains largely unexplored. Here the rational design and synthesis of two novel zirconium-based metal‒organic frameworks (MOFs) bearing free ortho-hydroxy sites, namely noninterpenetrated PCN-1001 and twofold interpenetrated PCN-1002, are presented. Single crystal analysis of the pure ligand reveals that intramolecular hydrogen bonding plays a pivotal role in directing the formation of MOFs with free hydroxy groups. Furthermore, the transformation from PCN-1001 to PCN-1002 is realized. Compared to PCN-1001, PCN-1002 displays higher chemical stability due to interpenetration, thereby demonstrating an exceptional PFOA adsorption capacity of up to 632 mg g-1 (1.53 mmol g-1), which is comparable to the reported record values. Moreover, PCN-1002 shows rapid kinetics, high selectivity, and long-life cycles in PFOA removal tests. Solid-state nuclear magnetic resonance results and density functional theory calculations reveal that multiple hydrogen bonds between the free ortho-hydroxy sites and PFOA, along with Lewis acid-base interaction, work collaboratively to enhance PFOA adsorption.

Drug carrier wonders: Synthetic strategies of zeolitic imidazolates frameworks (ZIFs) and their applications in drug delivery and anti-cancer activity

With the rapid advancement of nanotechnology, stimuli-responsive nanomaterials have emerged as a feasible choice for the designing of controlled drug delivery systems. Zeolitic imidazolates frameworks are a subclass of Metal-organic frameworks (MOFs) that are recognized by their excellent porosity, structural tunability and chemical modifications make them promising materials for loading targeted molecules and therapeutics agents. The biomedical industry uses these porous materials extensively as nano-carriers in drug delivery systems. These MOFs not only possess excellent targeted imaging ability but also cause the death of tumor cells drawing considerable attention in the current framework of anticancer drug delivery systems. In this review, the outline of stability, porosity, mechanism of encapsulation and release of anticancer drug have been reported extensively. In the end, we also discuss a brief outline of current challenges and future perspectives of ZIFs in the biomedical world.

Efficient Removal of Greenhouse Gases: Machine Learning-Assisted Exploration of Metal-Organic Framework Space

Global warming is a crisis that humanity must face together. With greenhouse gases (GHGs) as the main factor causing global warming, the adoption of relevant processes to eliminate them is essential. With the advantages of high specific surface area, large pore volume, and tunable synthesis, metal-organic frameworks (MOFs) have attracted much attention in GHG storage, adsorption, separation, and catalysis. However, as the pool of MOFs expands rapidly with new syntheses and discoveries, finding a suitable MOF for a particular application is highly challenging. In this regard, high-throughput computational screening is considered the most effective research method for screening a large number of materials to discover high-performance target MOFs. Typically, high-throughput computational screening generates voluminous and multidimensional data, which is well suited for machine learning (ML) training to improve the screening efficiency and explore the relationships between the multidimensional data in depth. This Review summarizes the general process and common methods for using ML to screen MOFs in the field of GHG removal. It also addresses the challenges faced by ML in exploring the MOF space and potential directions for the future development of ML for MOF screening. This aims to enhance the understanding of the integration of ML and MOFs in various fields and broaden the application and development ideas of MOFs.

Photophysics of fluorescent nanoparticles based on organic dyes - challenges and design principles

Fluorescent nanoparticles have become attractive for bioanalysis and imaging, due to their high brightness and photostability. Many different optical materials have been applied in fluorescent nanoparticles with a broad range of properties and characteristics. One appealing approach is the incorporation of molecular organic fluorophores in nanoparticles with the intention of transferring their known attractive solution-state properties directly to the nanoparticles. However, as molecular dyes are packed closely together in the nanoparticles their interactions most often result in fluorescence quenching and change in spectral properties making this approach challenging. In this perspective we will first discuss the origins of quenching and spectral shifts observed in dye based nanoparticles. On this background, we will then describe various designs of dye based NPs and how they address the challenges of dye-dye interactions and quenching. Our aim is to provide a general framework for understanding the supramolecular mechanisms that determine the photophysics of dye based nanoparticles. This framework of molecular photophysics and its relation to the internal structure of dye based nanoparticles can hopefully serve to assist rational design and optimization of new and improved dye based nanoparticles.

Sequential Regulation of Local Reactive Oxygen Species by Ir@Cu/Zn-MOF Nanoparticles for Promoting Infected Wound Healing

Most antimicrobials treat wound infections by an oxidation effect, which is induced by the generation of reactive oxygen species (ROS). However, the potential harm of the prolonged high level of ROS should not be ignored. In this study, we presented a novel cascade-reaction nanoparticle, Ir@Cu/Zn-MOF, to effectively regulate the ROS level throughout the healing progress of the infected wound. The nanoparticles consisted of a copper/zinc-modified metal-organic framework (Cu/Zn-MOF) serving as the external structure and an inner core composed of Ir-PVP NPs, which were achieved through a process known as "bionic mineralization". The released Cu2+ and Zn2+ from the shell structure contributed to the production of ROS, which acted as antimicrobial agents during the initial stage. With the disintegration of the shell, the Ir-PVP NP core was gradually released, exhibiting the property of multiple antioxidant enzyme activities, thereby playing an important role in clearing excessive ROS and alleviating oxidative stress. In a full-layer infected rat wound model, Ir@Cu/Zn-MOF nanoparticles presented exciting performance in promoting wound healing by clearing the bacteria and accelerating neovascularization as well as collagen deposition. This study provided a promising alternative for the repair of infected wounds.

A Robust Pyrazolate Metal-Organic Framework for Efficient Catalysis of Dehydrogenative C-O Cross Coupling Reaction

Construction of robust heterogeneous catalysts with atomic precision is a long-sought pursuit in the catalysis field due to its fundamental significance in taming chemical transformations. Herein, we present the synthesis of a single-crystalline pyrazolate metal-organic framework (MOF) named PCN-300, bearing a lamellar structure with two distinct Cu centers and one-dimensional (1D) open channels when stacked. PCN-300 exhibits exceptional stability in aqueous solutions across a broad pH range from 1 to 14. In contrast, its monomeric counterpart assembled through hydrogen bonding displays limited stability, emphasizing the role of Cu-pyrazolate coordination bonds in framework robustness. Remarkably, the synergy of the 1D open channels, excellent stability, and the active Cu-porphyrin sites endows PCN-300 with outstanding catalytic activity in the cross dehydrogenative coupling reaction to form the C-O bond without the "compulsory" ortho-position directing groups (yields up to 96%), outperforming homogeneous Cu-porphyrin catalysts. Moreover, PCN-300 exhibits superior recyclability and compatibility with various phenol substrates. Control experiments reveal the synergy between the Cu-porphyrin center and framework in PCN-300 and computations unveil the free radical pathway of the reaction. This study highlights the power of robust pyrazolate MOFs in directly activating C-H bonds and catalyzing challenging chemical transformations in an environmentally friendly manner.

Exosomes encapsulated in hydrogels for effective central nervous system drug delivery

The targeted delivery of pharmacologically active molecules, metabolites, and growth factors to the brain parenchyma has become one of the major challenges following the onset of neurodegeneration and pathological conditions. The therapeutic effect of active biomolecules is significantly impaired after systemic administration in the central nervous system (CNS) because of the blood-brain barrier (BBB). Therefore, the development of novel therapeutic approaches capable of overcoming these limitations is under discussion. Exosomes (Exo) are nano-sized vesicles of endosomal origin that have a high distribution rate in biofluids. Recent advances have introduced Exo as naturally suitable bio-shuttles for the delivery of neurotrophic factors to the brain parenchyma. In recent years, many researchers have attempted to regulate the delivery of Exo to target sites while reducing their removal from circulation. The encapsulation of Exo in natural and synthetic hydrogels offers a valuable strategy to address the limitations of Exo, maintaining their integrity and controlling their release at a desired site. Herein, we highlight the current and novel approaches related to the application of hydrogels for the encapsulation of Exo in the field of CNS tissue engineering.

Construction of a novel near-infrared fluorescent Nile blue@MOF nanoprobe for imaging mitochondrial ATP in living cells

A near-infrared fluorescent nanoprobe consisting of Nile blue-capped ZIF-90 is first proposed for real-time imaging of mitochondrial ATP. Owing to the strong binding of ATP with Zn2+, the structure of the probe is disrupted, leading to the release of fluorescent NB.

Understanding Cu(i) local environments in MOFs via63/65Cu NMR spectroscopy

The field of metal-organic frameworks (MOFs) includes a vast number of hybrid organic and inorganic porous materials with wide-ranging applications. In particular, the Cu(i) ion exhibits rich coordination chemistry in MOFs and can exist in two-, three-, and four-coordinate environments, which gives rise to many structural motifs and potential applications. Direct characterization of the structurally and chemically important Cu(i) local environments is essential for understanding the sources of specific MOF properties. For the first time, 63/65Cu solid-state NMR has been used to investigate a variety of Cu(i) sites and local coordination geometries in Cu MOFs. This approach is a sensitive probe of the local Cu environment, particularly when combined with density functional theory calculations. A wide range of structurally-dependent 63/65Cu NMR parameters have been observed, including 65Cu quadrupolar coupling constants ranging from 18.8 to 74.8 MHz. Using the data from this and prior studies, a correlation between Cu quadrupolar coupling constants, Cu coordination number, and local Cu coordination geometry has been established. Links between DFT-calculated and experimental Cu NMR parameters are also presented. Several case studies illustrate the feasibility of 63/65Cu NMR for investigating and resolving inequivalent Cu sites, monitoring MOF phase changes, interrogating the Cu oxidation number, and characterizing the product of a MOF chemical reaction involving Cu(ii) reduction to Cu(i). A convenient avenue to acquire accurate 65Cu NMR spectra and NMR parameters from Cu(i) MOFs at a widely accessible magnetic field of 9.4 T is described, with a demonstrated practical application for tracking Cu(i) coordination evolution during MOF anion exchange. This work showcases the power of 63/65Cu solid-state NMR spectroscopy and DFT calculations for molecular-level characterization of Cu(i) centers in MOFs, along with the potential of this protocol for investigating a wide variety of MOF structural changes and processes important for practical applications. This approach has broad applications for examining Cu(i) centers in other weight-dilute systems.

Microfluidic-assisted formulation of cell membrane-camouflaged anisotropic nanostructures

Anisotropic gold (Au) nanostructures have been widely explored for various nanomedicine applications. While these nanomaterials have shown great promise for disease theranostics, particularly for cancer diagnosis and treatment, the utilization and clinical translation of anisotropic Au nanostructures have been limited by their high phagocytic uptake and clearance and low cancer targeting specificity. Numerous efforts have thus been made toward mitigating these challenges. Many conventional strategies, however, rely on all-synthetic materials, involve complex chemical processes, or have low product throughput and reproducibility. Herein, by integrating cell membrane coating and microfluidic technologies, a high-throughput bioinspired approach for synthesizing biomimetic anisotropic Au nanostructures with minimized phagocytic uptake and improved cancer cell targeting is reported. Through continuous hydrodynamic flow focusing, mixing, and sonication, Au nanostructures are encapsulated within the macrophage and cancer cell membrane vesicles effectively. The fabricated nanostructures are uniform and highly stable in serum. Importantly, the macrophage membrane vesicle-encapsulated Au nanostructures can be preferentially internalized by breast cancer cells, but not by macrophages. Overall, this study has demonstrated the feasibility of employing an integrated microfluidic-sonication technique to formulate uniform and highly stable biomimetic anisotropic nanostructures for enhanced cancer theranostic applications.