Metal-organic Framework Nanoparticles Research Articles

Zinc–cobalt bimetallic metal-organic framework (Zn/Co-MOF) nanoparticles as potent pH stimuli anti-corrosive agent for development of a self-healable epoxy composite coating

The impressive BET-surface area and the design versatility have made Z67(ZIF-67) MOF a potent nanomaterial for anti-corrosion applications. Despite excellent anti-corrosion features the Z67(ZIF-67) suffers poor stability in water media, making it improper for application in polymeric systems. One strategy to enhance the stability of Z67 is its structure modification via a mixed-metal organic framework approach. This study involved the synthesis of a series of Z67 nanoparticles through the incorporation of zinc cation (Zn) at different percentages. Specifically, three different compositions were synthesized: Zn10-Z67, Zn20-Z67, and Zn30-Z67 denoting the addition of 10 %, 20 %, and 30 % molar percent of Zn, respectively. FTIR, FE-SEM, XRD, TEM, ICP-OES, and XPS, as well as BET analyses, were conducted for the Zinc–Cobalt bimetallic MOF structure. Subsequently, the properties attributed to the particles' active and barrier anti-corrosion feature in solution (NaCl) as well as coating (epoxy) phases were investigated. The EIS test performed in the solution phase, after 72h of metal exposure to Zn30-Z67 containing saline media, revealed a 590 % and 30 % increase in total resistance, respectively, compared to the uninhibited sample. Due to the increased stability of Zn10-Z67 in a saline environment, the active corrosion inhibition of the scratched coating containing these particles was increased by approximately 140 % compared to the Z67-containing composite. The incorporation of zinc cations into the structure of Z67 has enhanced the stability and control release features in aqueous environments, thereby enhancing the barrier properties of the epoxy coating. The reduction rate of log|Z|0.01Hz of the Zn10-Z67/EPC was 9 % which was lower than that of the Neat EPC (epoxy coating) (24 %).

The Surface of Colloidal Metal-Organic Framework Nanoparticles Revealed by Vibrational Sum Frequency Scattering Spectroscopy.

Solvation shells strongly influence the interfacial chemistry of colloidal systems, from the activity of proteins to the colloidal stability and catalysis of nanoparticles. Despite their fundamental and practical importance, solvation shells have remained largely undetected by spectroscopy. Furthermore, their ability to assemble at complex but realistic interfaces with heterogeneous and rough surfaces remains an open question. Here, we apply vibrational sum frequency scattering spectroscopy (VSFSS), an interface-specific technique, to colloidal nanocrystals with porous metal-organic frameworks (MOFs) as a case study. Due to the porous nature of the solvent-particle boundary, MOF particles challenge conventional models of colloidal and interfacial chemistry. Their multiweek colloidal stability in the absence of conventional surface ligands suggests that stability may arise in part from solvation forces. Spectra of colloidally stable Zn(2-methylimidazolate)2 (ZIF-8) in polar solvents indicate the presence of ordered solvation shells, solvent-metal binding, and spontaneous ordering of organic bridging linkers within the MOF. These findings help explain the unexpected colloidal stability of MOF colloids, while providing a roadmap for applying VSFSS to wide-ranging colloidal nanocrystals in general.

Iron (II)-based metal-organic framework nanozyme for boosting tumor ferroptosis through inhibiting DNA damage repair and system Xc-

Development of ferroptosis-inducible nanoplatforms with high efficiency and specificity is highly needed and challenging in tumor ferrotherapy. Here, we demonstrate highly effective tumor ferrotherapy using iron (II)-based metal-organic framework (FessMOF) nanoparticles, assembled from disulfide bonds and ferrous ions. The as-prepared FessMOF nanoparticles exhibit peroxidase-like activity and pH/glutathione-dependent degradability, which enables tumor-responsive catalytic therapy and glutathione depletion by the thiol/disulfide exchange to suppress glutathione peroxidase 4, respectively. Upon PEGylation and Actinomycin D (ActD) loading, the resulting FessMOF/ActD-PEG nanoplatform induces marked DNA damage and lipid peroxidation. Concurrently, we found that ActD can inhibit Xc− system and elicit ferritinophagy, which further boosts the ferrotherapeutic efficacy of the FessMOF/ActD-PEG. In vivo experiments demonstrate that our fabricated nanoplatform presents excellent biocompatibility and a high tumor inhibition rate of 91.89%.

Towards a More Efficient Breast Cancer Therapy Using Active Human Cell Membrane-Coated Metal–Organic Frameworks

The recent description of well-defined molecular subtypes of breast cancer has led to the clinical development of a number of successful molecular targets. Particularly, triple-negative breast cancer (TNBC) is an aggressive type of breast cancer with historically poor outcomes, mainly due to the lack of effective targeted therapies. Recent progresses in materials science have demonstrated the impressive properties of metal–organic framework nanoparticles (NPs) as antitumoral drug delivery systems. Here, in a way to achieve efficient bio-interfaces with cancer cells and improve their internalization, benchmarked MIL-100(Fe) NPs were coated with cell membranes (CMs) derived from the human TNBC cell line MDA-MB-468. The prepared CMs-coated metal–organic framework (CMs_MIL-100(Fe)) showed enhanced colloidal stability, cellular uptake, and cytotoxicity in MDA-MB-468 cells compared to non-coated NPs, paving the way for these human CMs-coated MIL-100(Fe) NPs as effective targeted therapies against the challenging TNBC.

Metal-organic framework as nanocarriers for agricultural applications: a review

Agrochemicals are substances used to promote plant growth and eradicate pests; and are essential to meeting the world food demand both qualitatively and quantitatively. Unfortunately, their extensive usage has resulted in certain significant problems, i.e., soil contamination, bioaccumulation, and the development of pest resistance. Consequently, there is a need for a reduced and more regulated usage of agrochemicals. The development of sustainable nanomaterials is encouraged in agricultural nanotechnology to minimize the usage of conventional fertilizers, herbicides, and pesticides. Metal-organic Framework (MOF)s are porous materials made of functional organic ligands and metal nodes or clusters connected by covalent bonds. Researchers are becoming increasingly interested in using MOF in a variety of sectors. The features of engineered MOFs have the potential to be an optimal strategy for producing impressively unique results in agricultural research. They also have advantages in terms of biocompatibility and biodegradability, which can be leveraged to boost the efficiency of traditional agrochemicals administration. Controlled release of agrochemicals offers an innovative solution to decrease the nutrient uptake rates and contamination of the environment. The application of MOF nanoparticles as nanocarriers to modify the loading and release properties of agrochemicals is particularly highlighted in this review.

Biochar decorated with metal–organic framework nanoparticles as robust modifier to manipulate nanofiltration mixed matrix membranes characteristics and performance

UiO-66-NH2 metal–organic framework nanoparticles and carbonaceous biochar prepared from the pyrolysis of Cladophora glomerata alga are introduced as novel modifiers and employed to manipulate polyethersulfone (PES) mixed matrix membranes. The membranes were fabricated through immersion precipitation method and fully assessed through X-ray diffraction pattern, field emission scanning electron microscopy, contact angle, atomic force microscopy, and zeta potential analysis. The membrane performances were also examined by water flux, fouling resistance, and solute rejection. The results indicated that the modified membranes manipulated by 0.2–0.8 wt% of modifier had smoother surfaces than the pristine PES membrane. Moreover, by loading the modifiers in the membrane bulk, the zeta potential was changed from negative to positive values. All the modified membranes revealed superior filtration performance compared to that of the pristine PES membrane. In the modified membrane of the best performance, water flux was increased to up to 85% and contact angle was decreased to 43°. Due to the uniform distribution of modifiers on the membrane surface, and thereby, formation of a barrier layer, up to 98.5% of Reactive Blue 50 dye was rejected by the modified membranes. Salt rejections were also improved in the membranes tailored by the introduced modifiers. Furthermore, through the fouling experiments conducted by humic acid and bovine serum albumin, just 12.9 and 34% reductions in water fluxes were recorded for the modified membrane of the best performance. The experimental results indicated that the higher flux recovery ratios could also be expected for all the membranes modified by the novel hydrophilic modifiers.

Polyphenol-Assisted Biomineralization of Metal-Organic Framework Nanoparticles for Precision Delivery of Therapeutic Proteins to Cancer Cells.

The delivery of proteins into the cytosol holds great promise for cell signaling manipulation and the development of precision medicine. However, this potency is challenged by achieving targeted and controlled delivery, specifically within diseased cells. In this study, we introduce a versatile and effective method for the precision delivery of therapeutic proteins to cancer cells by designing polyphenol-assisted biomineralization of zeolite imidazole framework-8 (ZIF-8). We demonstrate that by leveraging the strong noncovalent binding affinity of epigallocatechin gallate (EGCG) with both proteins and ZIF-8, our approach significantly enhances the biomineralization of ZIF-8, which in turn improves the efficiency of protein encapsulation and intracellular delivery. Moreover, the incorporation of EGCG within ZIF-8 enables controlled degradation of the nanoparticles and the selective release of the encapsulated proteins in cancer cells. This selective release is triggered by the oxidation of EGCG in response to the high levels of reactive oxygen species (ROS) found within cancer cells that destabilize the EGCG/ZIF-8 nanoparticles. We have further demonstrated the ability of EGCG/ZIF-8 to deliver a wide range of proteins into cancer cells, including bacterial virulence protein, to rewire cell signaling and prohibit tumor cell growth in a mouse xenograft model. Our strategy and findings underscore the potential of designing the EGCG/ZIF-8 interface for specific and controlled protein delivery for targeted cancer therapy.

Combined application of surfactants and iron-based metal–organic framework nanoparticles for targeted delivery of insecticides

With the development of smart delivery systems for pesticides, many studies revealed that nanodelivery methods have great potential for use in efficient and sustainable agriculture; however, field application of the nanopesticides is still a challenge. In this study, the application of a chlorfenapyr (CF)-loaded iron-based metal–organic framework (CF@MIL-101-SL) to maize and its control efficacy for Spodoptera frugiperda were investigated in detail. The results showed that, compared with a suspension concentrate of CF (CF-SC), a solution of CF@MIL-101-SL with the surfactant aerosol OT exhibited excellent wetting, deposition and adhesion with maize leaves. The CF@MIL-101-SL NPs exhibited bidirectional translocation in maize, which significantly enhanced the transport of CF to the target tissues. Field trials revealed that CF@MIL-101-SL maintained > 75 % control efficiency after 21 d of spraying, indicating significantly greater insecticidal activity and persistence than CF-SC. Spray application of CF@MIL-101-SL gave high initial deposition rates, long half-lives on tender and old leaves and significantly reduced pesticide drift into the environment. Based on a biosafety assessment, spraying with CF@MIL-101-SL reduced the negative effects of CF on plants during the growth period. In addition, CF@MIL-101-SL increased the survival rate of Harmonia axyridis larvae and reduced the impacts of CF on the growth and intestinal damage of Harmonia axyridis. In summary, these results highlight the advantages of metal–organic framework delivery systems for multidimensional enhancement of pesticide efficacy, persistence, and safety and provide data on field application and the environmental risks of nanodelivery systems.

Integration of metal organic framework nanoparticles into sodium alginate biopolymer-based three-dimensional membrane capsules for the efficient removal of toxic metal cations from water and real sewage

Sodium alginate (SA) biopolymer has been recognized as an efficient adsorbent material owing to their unique characteristics, including biodegradability, non-toxic nature, and presence of abundant hydrophilic functional groups. Accordingly, in the current research work, UiO-66-OH and UiO-66-(OH)2 metal organic framework (MOF) nanoparticles (NPs) have been integrated into SA biopolymer-based three-dimensional (3-D) membrane capsules (MCs) via a simple and facile approach to remove toxic metal cations (Cu2+ and Cd2+) from water and real sewage. The newly configured capsules were characterized by FTIR, SEM, XRD, EDX and XPS analyses techniques. Exceptional sorption properties of the as-developed capsules were ensured by evaluation of the pertinent operational parameters, i.e., contents of MOF-NPs (1–100 wt%), adsorbent dosage (0.001–0.05 g), content time (0–360 h), pH (1–8), initial concentration of metal cations (5–1000 mg/L) and reaction temperature (298.15–333.15 K) on the eradication of Cu2+ and Cd2+ metal cations. It was found that hydrophilic functional groups (-OH and -COOH) have performed an imperative role in the smooth loading of MOF-NPs into 3-D membrane capsules via intra/inter-molecular hydrogen bonding and van der waals potencies. The maximum monolayer uptake capacities (as calculated by the Langmuir isotherm model) of Cd2+ and Cu2+ by 3-D SGMMCs-OH were 940 and 1150 mg/g, respectively, and by 3-D SGMMCs-(OH)2 were 1375 and 1575 mg/g, respectively, under optimum conditions. The as-developed capsules have demonstrated superior selectivity against targeted metal cations under designated pH and maintained >80 % removal efficiency up to six consecutive treatment cycles. Removal mechanisms of metal cations by the 3-D SGMMCs-OH/(OH)2 was proposed, and electrostatic interaction, ion-exchange, inner-sphere coordination bonds/interactions, and aromatic ligands exchange were observed to be the key removal mechanisms. Notably, FTIR and XPS analysis indicated that hydroxyl groups of Zr-OH and BDC-OH/(OH)2 aromatic linkers played vital roles in Cu2+ and Cd2+ adsorption by participating in inner-sphere coordination interactions and aromatic ligands exchange mechanisms. The as-prepared capsules indicated >70 % removal efficiency of Cu2+ from real electroplating wastewater in the manifestation of other competitive metal ions and pollutants under selected experimental conditions. Thus, it was observed that newly configured 3-D SGMMCs-OH/(OH)2 have offered a valuable discernment into the development of MOFs-based water decontamination 3-D capsules for industrial applications.

Poly-l-lysine modified MOF nanoparticles with pH/ROS sensitive CIP release and CUR triggered photodynamic therapy against drug-resistant bacterial infection

The challenge of drug resistance in bacteria caused by the over use of biotics is increasing during the therapy process, which has attracted great attentions of the clinicians and scientists around the world. Recently, photodynamic therapy (PDT) triggered by photosensitizer (PS) has become a promising treatment method because of its high efficacy, easy operation, and low side effect. Herein, the poly-l-lysine (PLL) modified metal-organic framework (MOF) nanoparticles, ZIF/PLL-CIP/CUR, were synthesized to allow both reactive oxygen species (ROS) responsive drug release and photodynamic effect for synergistic therapy against drug resistant bacterial infections. The PLL was modified on the shell of the zeolite imidazole framework (ZIF) by the ROS-responsive thioketal linker for controllable CIP release. CUR were encapsulated in ZIF as the photosensitizer for blue light mediated photodynamic effect to produce singlet oxygen (1O2) and superoxide anion radical (O2−) for efficient inhibition towards methicillin-resistant Staphylococcus aureus (MRSA). The charge conversion from negative charge (−4.6 mV) to positive charge (2.6 mV) was observed at pH 7.4 and pH 5.5, and 70.9 % CIP was found released at pH 5.5 in the presence of H2O2, which suggests the good biosafety at physiological pH and ROS-responsive drug release of the as-prepared nanoparticle in the bacterial microenvironment. The as-prepared nanoparticles could effectively kill MRSA and disrupt bacterial biofilm by combination of chemo- and photodynamic therapy. In mice model, the as-prepared nanoparticles exhibited excellent biosafety and synergistic effect with 98.81 % healing rate in treatment of MRSA infection, which is considered as a promising candidate in combating drug resistant bacterial infection.

Application of metal–organic frameworks in stomatology

Metal–organic frameworks (MOFs), a new class of porous organic–organic hybrid materials controlled by self-assembly of metal atoms and organic pillars, are attracting considerable interest because of their specific properties. More recently, the advantages of different types of nanoscale metal–organic frameworks for the use of MOF nanoparticles in stomatology have been reported in the literature. This article covers the treatment of oral cancer, surface modification of implants, antibacterial dressings, and treatment of periodontitis and periodontal regeneration. It presents recent applications, future challenges, and prospects for MOFs in stomatology in four areas. It provides an overview of recent advances in the design and application of MOFs in stomatology from their intrinsic properties to different syntheses and their use as smart drug delivery systems or a combination of these.

Preparation of antimicrobial composite from Arabic gum-grafted-poly(p-phenylene diamine)/MOF(Fe) decorated with Cu nanoparticles as a unique nanobiosorbent for removal of cloxacillin antibiotic

The growth of the world population has led to an increase in the demand for fresh water. Water pollution is often caused by hasty urbanization without proper management of hazardous waste. Therefore, it is vital to implement new methods to remove pollutants from water. In the current study, an antimicrobial nanocomposite adsorbent composed of Arabic gum-grafted-poly(para phenylene diamine) (AG-g-PpPA) decorated with metal-organic framework and copper nanoparticles (AG-g-PpPA@MOF(Fe)/Cu) was synthesized via in-situ copolymerization. The nanocomposite was utilized for eliminating the antibiotic cloxacillin from water solutions. The effects of different factors were analyzed, including pH, the quantity of adsorbent, contact time, and preliminary cloxacillin concentrations. Ideal parameters were pH 7, 5 mg adsorbent dosage, 10 min contact time, and an initial 500 mg/L cloxacillin concentration. The adsorption process followed the Freundlich isotherm equation, with a maximum adsorption ability of 400 mg/g. The kinetics information appropriately fits a pseudo-second-order model. Thermodynamic calculation showed the adsorption occurred spontaneously. The nanocomposite also displayed antibacterial action in contradiction to Escherichia coli and Staphylococcus aureus. Additionally, the adsorbent could be recovered and reused effectively. The excellent adsorption ability highlights the potential of AG-g-PpPA@MOF(Fe)/Cu adsorbent for eliminating pharmaceutical pollutants from wastewater.

UiO-66 metal–organic framework nanoparticles as electrocatalysis for direct sodium borohydride fuel cells

UiO-66 metal–organic framework nanoparticles as electrocatalysis for direct sodium borohydride fuel cells

Zeta Potential and Size Analysis of Zeolitic Imidazolate Framework-8 Nanocrystals Prepared by Surfactant-Assisted Synthesis.

The crystal nucleation and growth mechanism of monodispersed metal-organic framework nanoparticles were studied using time-resolved light dynamic, electrokinetic, and powder X-ray diffraction methods. We confirmed that zeolitic imidazolate framework-8 (ZIF-8) nanocrystals follow a nonclassical crystal growth pathway, where a fast nucleation occurs with dense liquid clusters or nanocrystals forming spontaneously when two precursors are mixed. We also explored the zeta potential and solvodynamic size changes of ZIF-8 prepared by a surfactant-assisted synthesis. Three modulators, including 1-methylimidazole (1-mIm), tris(hydroxymethyl)aminomethane (THAM), and (1-hexadecyl)trimethylammonium bromide (CTAB), were studied. We found that 1-mIm dramatically increases the rate of nucleation of ZIF-8. With an increasing amount of 1-mIm, which functions as a coordination modulator, the size increases, and the zeta potential of ZIF-8 decreases. Whereas THAM, as both a coordination and a deprotonation modulator, increases the size and zeta potential of ZIF-8 simultaneously, CTAB, as a long alkyl cationic surfactant, mainly adsorbs on the surface of ZIF-8, and the zeta potential of the formed ZIF-8 is controlled by the amount of CTAB in solution compared with its critical micelle concentration. Overall, we reveal that the modulator type and concentration can be used to control the size and zeta potential of the dispersed ZIF-8 nanocrystals in a colloid system. The experiments also enable identification of the nucleation and crystal growth processes of ZIF-8. The findings will be applicable to other nanocrystals in colloid systems, which are used for heterogeneous catalysis and guest molecular loadings.

Erythrocyte Membrane Camouflaged Nanotheranostics for Optical Molecular Imaging-Escorted Self-Oxygenation Photodynamic Therapy.

Hypoxic tumor microenvironment (TME) hampers the application of oxygen (O2 )-dependent photodynamic therapy (PDT) in solid tumors. To address this problem, a biomimetic nanotheranostics (named MMCC@EM) is developed for optical molecular imaging-escorted self-oxygenation PDT. MMCC@EM is synthesized by encapsulating chlorin e6 (Ce6) and catalase (CAT) in metal-organic framework (MOF) nanoparticles with erythrocyte membrane (EM) camouflage. Based on the biomimetic properties of EM, MMCC@EM efficiently accumulates in tumor tissues. The enriched MMCC@EM achieves TME-activatable drug release, thereby releasing CAT and Ce6, and this process can be monitored through fluorescence (FL) imaging. In addition, endogenous hydrogen peroxide (H2 O2 ) will be decomposed by CAT to produce O2 , which can be reflected by the measurement of intratumoral oxygen concentration using photoacoustic (PA) imaging. Such self-oxygenation nanotheranostics effectively mitigatetumor hypoxia and improve the generation of singlet oxygen (1 O2 ). The 1 O2 disrupts mitochondrial function and triggers caspase-3-mediated cellular apoptosis. Furthermore, MMCC@EM triggers immunogenic cell death (ICD) effect, leading to an increased infiltration of cytotoxic T lymphocytes (CTLs) into tumor tissues. As a result, MMCC@EM exhibits good therapeutic effects in 4T1-tumor bearing mice under the navigation of FL/PA duplex imaging.

Enhanced carbohydrate-based plastic performance by incorporating cerium-based metal-organic framework for food packaging application

The development of biodegradable active packaging films with hydrophobic characteristics is vital for extending the shelf life of food and reducing the reliance on petroleum-based plastics. In this study, novel hydrophobic cerium-based metal-organic framework (Ce-MOF) nanoparticles were successfully synthesized. The Ce-MOF nanoparticles were then incorporated into the cassava starch matrix at varying concentrations (0.5 %, 1.5 %, 3 %, and 4 % w/w of total solid) to fabricate cassava-based active packaging films via the solution casting technique. The influence of Ce-MOF on the morphology, thermal attributes, and physicochemical properties of the cassava film was subsequently determined through further analyses. Biomedical analysis including antioxidant activity and the cellular morphology evaluation in the presence of the films was also conducted. The results demonstrated that the consistent dispersion of Ce-MOF nanofillers within the cassava matrix led to a significant enhancement in the film's crystallinity, thermal stability, antioxidant activity, biocompatibility, and hydrophobicity. The introduction of Ce-MOF also contributed to the film's reduced water solubility. Considering these outcomes, the developed cassava/Ce-MOF films undoubtedly have significant potential for active food packaging applications.

Manifestation of UiO-66-Zr MOF-enabled photocatalytic membranes for successive separation and degradation of dye mixtures in water remediation

The use of metal-organic framework (MOF) nanoparticles both as a separation-enhancer and as a photocatalyst has been demonstrated by suitably embedding them into polysulfone (PSU) membranes. These MOF-nanoparticles with Zr-metal and 2-aminoterephthalic-ligand, namely UiO-66-NH2, are synthesized via solvothermal and embedded into the PSU-membranes via solvent-casting process, confirmed via XRD and IR analysis. The skin-deep presence of MOFs and enhancements in the depth of pore-channels within membrane are confirmed through FESEM images. A favorable surface-charge and hydrophilic nature of the MOF-membrane are confirmed via zeta-surface potential and water contact angle analysis, respectively. Consequently, the water-flux efficacy of the optimized MOF-embedded membrane is estimated to be ∼59 L/m2h, while it is ∼20 L/m2h for pristine-membrane. The flux of MOF-membrane against the dye solutions containing rhodamine B (RhB), Congo red (CR), and their mixtures (RhB+CR) is estimated to be ∼39.9, 42.7 and 28.8 L/m2h, which is ∼3.6 times more than the pristine-membrane. Correspondingly, a rejection of ∼81.6, 77.6, and (87.2+79.2%) is estimated for RhB, CR and RhB+CR, respectively, which is ∼2.3 times higher the pristine-membrane. Furthermore, under sunlight irradiation, the MOF-membrane degrades ∼10.1, 7.1 and (7.3+4.2%) of RhB, CR and (RhB+CR) dyes, respectively. The parameters indicating regenerative efficiency, such as flux recovery ratio, reversible, irreversible, and total fouling are found to be enhanced for MOF-membranes compared to pristine-membrane. Overall, the incorporation of MOFs as additives enhances both separation and regeneration efficiency of membranes through photocatalytic process. This process holds promise as a reliable strategy for developing smart-membranes for energy-efficient real-time water treatment applications.

Co-delivery of epirubicin and letrozole using a metal-organic framework nanoparticle in breast cancer therapy

Combination chemotherapy is a viable approach for cancer treatment in clinics when dealing with multidrug-resistant cancer. The difficulty of concentrating medications in drug-resistant cancers remains a substantial issue, making it challenging to get sufficient multi-drug delivery into tumour cells to enhance the synergetic therapeutic effect. To enhance combination therapy, we fabricated metal-organic framework (MOF) nanoparticles (NPs) that co-deliver letrozole (Let) and epirubicin (Epi). We created UIO-66@NH2-based MOFs to achieve desired encapsulation efficiencies of 82.93 ± 2.13 for Let and 66.84 ± 1.25 for Epi. The drug release profile revealed that the release rate of Let and Epi from the nanoparticles was pH-dependent, with a significant increase in acidic environments. This indicated the adaptive release capability of UIO-66-Let/Epi@NH2 in the breast cancer milieu. The nanoparticle size and entrapment efficiency were more stable at 4 °C as compared to 25 °C. Additionally, cellular assays demonstrated that a MOF loaded with Let and Epi increased the rate of apoptosis in MCF-7 cells compared to Let, Epi, and their combination (Let + Epi). The UIO-66-Let/Epi@NH2 group showed increased expression levels of Caspase3, Caspase9, and Mfn1 genes while the expression levels of MMP-3 and MMP-9 genes decreased. The effectiveness of the formulation in inducing apoptosis was confirmed by the results of DAPI staining microscopy and flow cytometry analysis. The higher apoptotic rate and toxicity of the Let/Epi-loaded UIO-66@NH2 MOF may be due to its greater delivery effectiveness into cancer cells. This article describes a novel MOF nanocarrier for the co-delivery of Let and Epi to treat breast cancer. The results demonstrate the potential of MOF nanocarriers as stimuli-responsive co-delivery systems for various drugs.

‘Three Birds With One Stone’ functionalized metal–organic frameworks for facile and efficient chemiluminescent immunoassays

The luminol–H2O2 system is crucial in the field of chemiluminescence (CL) analysis. However, luminol exhibits improved solubility and luminescence only in an alkaline environment, and its preparation process is cumbersome. This inconvenience highlights the need for developing a simple and universally applicable method in this regard. This study integrates luminol and a catalyst into metal–organic frameworks (MOFs) for fabrication of functionalised MOF nanoparticles. Further, PEGylated hematin (PEG = polyethylene glycol) was prepared. This modification with PEG enhanced the catalytic properties of hematin and facilitated the formation of zeolitic imidazole framework-8 nanoparticles. Furthermore, the built-in catalyst enhanced the CL in terms of strength and persistence. These MOF nanoparticles were used as signal markers to fabricate a sandwich-type CL immunosensor for detection of carcinoembryonic antigen, which is a disease marker, following which highly satisfactory analytical test results are obtained. This approach of integrating luminophores and catalysts offers a new idea for generating novel materials in the CL analysis field.

DNA-Directed Assembly of Hierarchical MOF-Cellulose Nanofiber Microbioreactors with "Branch-Fruit" Structures.

Assembling metal-organic frameworks (MOFs) into ordered multidimensional porous superstructures promises the encapsulation of enzymes for heterogeneous biocatalysts. However, the full potential of this approach has been limited by the poor stability of enzymes and the uncontrolled assembly of MOF nanoparticles onto suitable supports. In this study, a novel and exceptionally robust Ni-imidazole-based MOF was synthesized in water at room temperature, enabling in situ enzyme encapsulation. Based on this MOF platform, we developed a DNA-directed assembly strategy to achieve the uniform placement of MOF nanoparticles onto bacterial cellulose nanofibers, resulting in a distinctive "branch-fruit" structure. The resulting hybrid materials demonstrated remarkable versatility across various catalytic systems, accommodating natural enzymes, nanoenzymes, and multienzyme cascades, thus showcasing enormous potential as universal microbioreactors. Furthermore, the hierarchical composites facilitated rapid diffusion of the bulky substrate while maintaining the enzyme stability, with ∼3.5-fold higher relative activity compared to the traditional enzyme@MOF immobilized in bacterial cellulose nanofibers.