Zeolitic Imidazolate Framework-8 Nanoparticles Research Articles

Sustainable Synthesis of Zeolitic Imidazolate Framework-8 Nanoparticles and Application in the Adsorption of the Drug Chlorhexidine

In an attempt to synthesize nanomaterial concerning chemistry, the sustainable synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles by a low-cost approach through the recycling of waste mother liquors was explored and then indicated the potential to remove chlorhexidine (CHLX) from an aqueous solution. ZIF-8 was produced under solvothermal reaction at 25°C and characterized by Fourier Transform Infrared Spectroscopy, X-ray diffraction, adsorption/desorption of N<sub>2</sub>, dynamic light scattering and contact angle. The water Chemical stability test was conducted using ZIF-8 and it was immersed in pure water for 24 h at room temperature. Batch-type adsorption was used to check the potential of ZIF-8 (first and second generation) for the adsorption of the chlorhexidine with initial chlorhexidine concentration (0.05, 0.06 and 0.07 mol/L), agitation time (1, 3.5 and 6 h) and the mass of nano-adosrbent (0.04, 0.05 and 0.06 g). Process optimization was performed through a Factorial experimental design. The optimum conditions were selected for the nano-adsorbent mass of 0.04 g, agitation time of 1 h and initial chlorhexidine concentration 0.07 mmol/L. The ZIF-8 sustainable synthesis was efficient and generated a crystalline nanomaterial. The result shows that ZIF-8 is stable in water under ambient conditions. The ZIF-8 first generation and ZIF-8 second generation exhibit a high adsorption capacity (27.17 mg/g and 30.96 mg/g). It was found that, under the synthesis conditions, the recycled mother liquor user did not affect the final characteristics of this nanomaterial. The results indicated that the initial concentration of chlorhexidine and nano-adsorbent mass influenced the adsorption capacity. Experimental design provided the process optimum conditions (1 h, 0.04 g of adsorbent mass and 0.07 mmol/L).

A green and facile one-step hydration method based on ZIF-8-PDA to prepare melamine composite sponges with excellent hydrophobicity for oil-water separation

Frequent crude oil spills and illegal discharges of industrial organic pollutants cause serious damage to the ecological environment and considerable loss of valuable resources. Therefore, there is an urgent need to develop efficient strategies to separate and recover oils or reagents from sewage. Herein, a green, facile and rapid one-step hydration method was applied to obtain the composite sponge (ZIF-8-PDA@MS) that monodispersed zeolitic imidazolate framework-8 nanoparticles with high porosity and large specific surface area were firmly loaded onto the melamine sponge by ligand exchange and the self-assembly of dopamine. The water contact angle of ZIF-8-PDA@MS with multiscale hierarchical porous structure could reach 162°, which remained stable over a long period of time and a wide pH range. ZIF-8-PDA@MS displayed excellent adsorption capacities (up to 85.45–168.95 g⋅g−1), and could be reused at least 40 times. Besides, ZIF-8-PDA@MS exhibited remarkable photothermal effect. Simultaneously, Silver nanoparticle-immobilized composite sponges were also prepared via in-situ reduction of silver ions to inhibit bacterial contamination. The composite sponge developed in this work can be used not only for the treatment of industrial sewage, but also for the emergency response of large-scale marine oil spill accidents, which has inestimable practical value for water decontamination.

ZIF-8 Nanoparticles Evoke Pyroptosis for High-Efficiency Cancer Immunotherapy.

Although zeolitic imidazolate framework-8 (ZIF-8) has been applied in various tumor therapies, the intrinsic immunogenicity remains unclear. Here, we initiatively discover that ZIF-8 nanoparticles (NPs) can intrinsically induce pyroptosis by a caspase-1/gasdermin D (GSDMD)-dependent pathway. The pyroptotic cell death is accompanied by necrosis and immunogenic cell death (ICD) simultaneously for efficient in situ immunity initiation. Meanwhile, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), a mitochondrial depolarizing agent, is successfully loaded into ZIF-8 NPs and found to further enhance the pyroptosis process. Collectively, the obtained Pluronic F127-modified CCCP-incorporated ZIF-8 NPs (F127ZIF-8CCCP NPs) activate antitumor immunity and reprogram immunosuppressive tumor microenvironment (TME), realizing high-efficiency tumor growth inhibition. This work will facilitate biomedicine applications of ZIF-8 and provide good inspiration for pyroptosis-induced cancer therapy.

Biodegradable Microneedle Array-Mediated Transdermal Delivery of Dimethyloxalylglycine-Functionalized Zeolitic Imidazolate Framework-8 Nanoparticles for Bacteria-Infected Wound Treatment

Bacteria-infected skin wounds caused by external injuries remain a serious challenge to the whole society. Wound healing dressings, with excellent antibacterial activities and potent regeneration capability, are increasingly needed clinically. Here, we reported a novel functional microneedle (MN) array comprising methacrylated hyaluronic acid (MeHA) embedded with pH-responsive functionalized zeolitic imidazolate framework-8 (ZIF-8) nanoparticles to treat bacteria-infected cutaneous wounds. Antibacterial activity was introduced into Zn-ZIF-8 to achieve sterilization through releasing Zn ions, as well as increased angiogenesis by dimethyloxalylglycine (DMOG) molecules that were distributed within its framework. Furthermore, biodegradable MeHA was chosen as a substrate material carrier to fabricate DMOG@ZIF-8 MN arrays. By such design, DMOG@ZIF-8 MN arrays would not only exhibit excellent antibacterial activity against pathogenic bacteria but also enhance angiogenesis within wound bed by upregulating the expression of HIF-1α, leading to a significant therapeutic efficiency on bacteria-infected cutaneous wound healing. Based on these results, we conclude that this new treatment strategy can provide a promising alternative for accelerating infected wound healing via effective antibacterial activity and ameliorative angiogenesis.

The pH-responsive zeolitic imidazolate framework nanoparticle as a promising immune-enhancing adjuvant for anti-caries vaccine

ObjectivesStreptococcus mutans (S. mutans) is the main aetiologic bacterium of dental caries, whose protein antigen (PAc) has been administered as an anti-caries vaccine. In addition, several fusion proteins or PAc combined with adjuvants were used as anti-caries vaccines to improve the relatively weak immunogenicity of PAc. However, there are no nanoparticle-based adjuvants with good biocompatibility, excellent biodegradability, or the high loading performance of antigens used for anti-caries vaccines. This study aimed to prepare an innovative nanoparticle-based anti-caries vaccine and evaluate immune responses elicited by this vaccine in vitro and in vivo. MethodsIn this study, an anti-caries vaccine was prepared by an antigen of recombinant protein PAc from S. mutans and an adjuvant of zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) synthesized using a hydrothermal method. Then, mice were administrated intranasally by ZIF-8@PAc vaccine, and immune responses were evaluated. ResultsZIF-8 NPs not only greatly improved the internalization of the antigen but also released the PAc protein after degradation of ZIF-8 NPs in lysosomes for the further processing and presentation of antigen-presenting cells. In addition, ZIF-8@PAc induced significantly more potent PAc-specific serum IgG and saliva IgA antibodies, a higher splenocyte proliferation index, higher levels of the cytokines IL-4, IL-6, IL-10, IL-17A and IFN-γ, and a higher percentage of mature DCs and CD4+ memory T cells in vivo. ConclusionsThe ZIF-8 NPs, as an anti-caries vaccine adjuvant-assisted antigen PAc, elicit significantly potent immune responses, aiding in the further prevention of dental caries. Clinical significanceVaccine immunotherapy is an attractive strategy for prevention and treatment of dental caries. The ZIF-8@PAc vaccine can induce significantly high level of immune responses in this study, which indicates great potential for prevention and treatment of caries.

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

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

Synthesis of hydrogels incorporating core–shell structured Fe3O4@ZIF-8 as bio-nanocomposite carriers for drug delivery

Due to its high porosity and excellent pH-sensitive breakdown, the zeolitic imidazolate framework-8 (ZIF-8) has been investigated as a drug delivery vehicle. To increase the magnetic property of ZIF-8 nanoparticles, Fe3O4 nanoparticles (Fe3O4 NPs) were encapsulated to form a core–shell structure (Fe3O4@ZIF-8). The core–shell particles were then incorporated into a hydrogel to increase biocompatibility. The Fe3O4@ZIF-8-incorporated hydrogel nanocomposite (Fe3O4@ZIF-8 hydrogel) was then studied for in vitro cytotoxicity for drug delivery applications. Transmission electron microscopy images confirmed the core–shell structure of the synthesized Fe3O4@ZIF-8 with a central Fe3O4 core and a shell of nano-sized ZIF-8. The specific surface area of the obtained Fe3O4@ZIF-8 was 821 m2 g–1 with a pore volume of 0.36 cm3 g–1. The effect of the prepared Fe3O4@ZIF-8 on cell viability (mouse fibroblast, L929 cell line) was investigated using an MTT (3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide) assay. The Fe3O4@ZIF-8 and pure ZIF-8 showed a 50% inhibitory concentration at 28.2 + 1.0 and 11.2 + 6.6 µg mL–1, respectively. A chitosan/pluronic F-127 hydrogel incorporating Fe3O4@ZIF-8 was successfully prepared and showed over 75% cell viability compared to the fresh culture medium. Overall results indicated the safety of using chitosan/pluronic F-127 vehicles containing Fe3O4@ZIF-8 as a carrier for drug delivery systems.

Effects of zeolitic imidazolate framework-8 nanoparticles on physicomechanical properties and microstructure of limestone calcined clay cement mortar

The limitations of limestone calcined clay cement (LC3) include its low mechanical strength and high drying shrinkage, in addition to its durability, which has not been addressed well in previous studies. Therefore, the objective of the present study was to investigate the feasibility of enhancing the durability and physical and mechanical properties of LC3 mortar by incorporating zeolitic imidazolate framework-8 (ZIF-8) nanoparticles. Six mixes of LC3 mortar with 0, 0.1, 0.3, 0.5, 0.7, and 0.9 wt% ZIF-8 were prepared and tested. The microstructure of the LC3-ZIF-8 mortar was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The optimal ZIF-8 content was 0.5 wt%, at which the workability was significantly reduced, and the tensile and flexural strengths were increased. Although the LC3-ZIF-8 mortar exhibited a lower compressive strength than the unmodified LC3 mortar, the former had higher flexural and tensile strengths because of the positive effect of ZIF-8 on promoting calcium hydroxide (CH) and monocarboaluminate (Mc). These findings were consistent with the SEM, XRD, and Raman spectroscopy results. The water absorption and drying shrinkage rates of the LC3-ZIF-8 mortar were lower than those of the unmodified LC3 mortar owing to the modification of the LC3 mortar pore structure upon the addition of ZIF-8 nanoparticles. This study provides a better insight into the feasibility of utilizing ZIF-8 nanoparticles as reinforcement for LC3-based materials.

Preparation and characterization of novel cellulose based adsorbent with ultra-high methylene blue adsorption performance

Although zeolitic imidazole framework-8 (ZIF-8) has been widely used as the organic dye adsorbent, a suitable carrier is needed to solve the issues of low stability and poor dispersibility in water. Poly(acrylic acid) was grafted onto cellulose to prepare MAA aerogel with more active sites for MB adsorption which was applied as the carrier for ZIF-8. Here, ZIF-8/MAA composite aerogel was prepared by in situ growing the ZIF-8 nanoparticles onto the walls of the pores of MAA aerogel. The prepared adsorbent was characterized by SEM, FTIR, and TG analysis. A series of adsorption experiments were carried out to optimize the various parameters affecting MB adsorption behaviors (the adsorbent dosage, solution pH, initial MB concentration, adsorption time, and adsorption temperature). The experimental data for the adsorption process followed a pseudo-secondary kinetic model, more in line with the Langmuir isotherm (R2 = 0.992), with a maximum adsorption capacity of 1492.99 mg/g. The prepared adsorbent exhibited great reusability even after five repeated cycles of adsorption-regeneration. The adsorption mechanism was discussed in depth. Thus, the prepared ZIF-8/MAA aerogel can be used as an environmentally friendly, efficient, stable and reusable adsorbent for MB in wastewater treatment.

“Non-cytotoxic” doses of metal-organic framework nanoparticles increase endothelial permeability by inducing actin reorganization

Cytotoxicity of nanoparticles is routinely characterized by biochemical assays such as cell viability and membrane integrity assays. However, these approaches overlook cellular biophysical properties including changes in the actin cytoskeleton, cell stiffness, and cell morphology, particularly when cells are exposed to “non-cytotoxic” doses of nanoparticles. Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs), a member of metal–organic framework family, has received increasing interest in various fields such as environmental and biomedical sciences. ZIF-8 NPs may enter the blood circulation system after unintended oral and inhalational exposure or intended intravenous injection for diagnostic and therapeutic applications, yet the effect of ZIF-8 NPs on vascular endothelial cells is not well understood. Here, the biophysical impact of “non-cytotoxic” dose ZIF-8 NPs on human aortic endothelial cells (HAECs) is investigated. We demonstrate that “non-cytotoxic” doses of ZIF-8 NPs, pre-defined by a series of biochemical assays, can increase the endothelial permeability of HAEC monolayers by causing cell junction disruption and intercellular gap formation, which can be attributed to actin reorganization within adjacent HAECs. Nanomechanical atomic force microscopy and super resolution fluorescence microscopy further confirm that “non-cytotoxic” doses of ZIF-8 NPs change the actin structure and cell morphology of HAECs at the single cell level. Finally, the underlying mechanism of actin reorganization induced by the “non-cytotoxic” dose ZIF-8 NPs is elucidated. Together, this study indicates that the “non-cytotoxic” doses of ZIF-8 NPs, intentionally or unintentionally introduced into blood circulation, may still pose a threat to human health, considering increased endothelial permeability is essential to the progression of a variety of diseases. From a broad view of cytotoxicity evaluation, it is important to consider the biophysical properties of cells, since they can serve as novel and more sensitive markers to assess nanomaterial’s cytotoxicity.

Injectable self-healing polysaccharide hydrogel loading CuS and pH-responsive DOX@ZIF-8 nanoparticles for synergistic photothermal-photodynamic-chemo therapy of cancer

The injectable self-healing polysaccharide hydrogel was prepared by the formation of Schiff base bonds between aldehyde-modified methylcellulose (MCCHO) and carboxymethyl chitosan (CMC). The copper sulfide nanoparticles (CuS NPs) and pH-sensitive doxorubicin-loaded zeolitic imidazolate frameworks nanoparticles ([email protected] NPs) were prepared and could be well-dispersed into the hydrogel system. The presence of CuS NPs can achieve photothermal therapy (PTT) for tumors under the irradiation of the near-infrared (NIR) laser. Moreover, CuS NPs can generate photodynamic effects under NIR irradiation, converting oxygen into toxic reactive oxygen species (ROS) and presenting efficient photodynamic therapy (PDT). The [email protected] NPs can be decomposed under an intracellular acidic environment and realize the controlled release of DOX. The injectable self-healing hydrogel loading CuS and [email protected] NPs can achieve synergistic photothermal-photodynamic-chemo therapy for tumors and will inspire the researchers to construct a platform from hydrogel combined with multifunctional nanomaterials to realize the effective multimodal therapy for tumor.

Preparation of ZIF-67@DTMS NPs/Epoxy composite coating and its anti-corrosion performance for Q235 carbon steel in 3.5 wt% NaCl solution

In this work, dodecyltrimethoxysilane (DTMS)-modified zeolitic imidazolate frameworks nanoparticles (ZIF-67@DTMS NPs) were prepared and added into epoxy (EP) matrix to fabricate composite coating. The anti-corrosion performance and adhesive force of ZIF-67@DTMS/EP coating were measured with electrochemical impedance spectroscopy and pull-off tests. The results show that compared to pure EP coating, the impedance modulus of ZIF-67@DTMS/EP composite coating is significantly enhanced. The prepared ZIF-67@DTMS NPs as nanofillers can significantly improve the corrosion resistance and the adhesion of EP coating. In addition, the diffusion coefficient of aggressive species in the coatings were determined by molecular dynamics simulations, and the influence mechanism of ZIF-67@DTMS NPs on the anti-corrosion performance of epoxy coating was explored. The ZIF-67@DTMS NPs could combine with EP tightly through forming hydrogen bond. Meanwhile, these NPs could fill in the holes in the EP coating and then block the transmission channel of aggressive species, which enhances the barrier of coatings to the access of aggressive species, then improves the anticorrosion performance of coatings.

Hybrid Benzimidazole-Dichloroimidazole Zeolitic Imidazolate Frameworks Based on ZIF-7 and Their Application in Mixed Matrix Membranes for CO2/N2 Separation.

Mixed-linker zeolitic imidazolate frameworks (ZIFs) with the sodalite (sod) topology type and based on ZIF-7 have been prepared by direct synthesis from the mixtures of benzimidazole (BzIm) and 4,5-dichloroimidazole (dcIm). Incorporation of dcIm into the ZIF-7 structure gives ZIF-7/COK-17 hybrids with rhombohedral symmetry that do not show the “open-to-closed form” structural transition upon solvent removal exhibited by ZIF-7. They show Type I isotherms for low molecular weight gases and high affinity for CO2 even at low partial pressures. Synthesis under mild conditions gives ZIF nanoparticles (250–400 nm) suitable for incorporation into mixed matrix membranes (MMMs): these were prepared with both glassy (Matrimid) and rubbery (PEBAX 1657) polymers. Permeation tests at 298 K and 1.2 bar reveal that the incorporation of Zn(BzIm0.55dcIm0.45)2 nanoparticles at up to ca. 12 wt % gives defect-free membranes with enhanced CO2 permeability in both polymer matrices, with retention of selectivity (Matrimid) or with an enhancement in selectivity that is most pronounced for the smaller nanoparticles (PEBAX). The membrane with the best performance exhibits a selectivity of ca. 200 for CO2/N2 (a 4-fold increase compared to the pure polymer) and a CO2 permeability of 64 Barrer. At the relatively low loadings investigated, the MMMs’ performance obeys the Maxwell model, and the intrinsic property of diffusivity of the ZIFs can be extracted as a result.

Reduction/pH-responsive disassemblable MOF-microbial nanohybrid for targeted tumor penetration and synergistic therapy

Nanomedicine that combines nanomaterials and nanotechnologies has been attracting intensive attention for tumor treatment and achieved significant advances. However, their therapeutic efficiency is still limited by the passive circulating and enrichment of the currently widely used nanomaterial carries. Instead, an active nanomaterial carrier with tumor-taxis-like behavior holds the potential to further leap tumor targeting and therapeutic efficiency. Herein, for the first time, we show that a tumor microenvironment responsive disassemblable approach, based on tumor-targeted Escherichia coli bacteria linked with degradable zeolitic imidazolate framework-8 (ZIF-8) through disulfide bond-contained polymers, can deliver multiple drugs into deep tumor tissue. The carried ZIF-8 nanoparticles will detach from the Escherichia coli via disulfide bond breakage under high concentration glutathione in tumor sites. Furthermore, the small size ZIF-8 nanoparticles can penetrate whole tumor tissue and release drug molecules (doxycycline and indocyanine green) upon pH-responsive degradation. Under light irradiation, indocyanine green generates reactive oxygen species and mild hyperthermia, realizing a photodynamic/photothermal/chemical synergistic therapy along with the doxycycline. In a mouse model, the as-prepared microbial nanohybrid accumulates and releases the therapeutics throughout the tumor tissue and shows a better tumor inhibition efficacy compared to the ZIF-8 and non-disassemblable ZIF-8/microbial platforms. Thus, this work may establish a new strategy for enhancing tumor penetration and targeting and improving treatment efficiency of nanomaterials through a tumor microenvironment responsive disassemblable microbial nanohybrid.

Engineering Poly(ethylene glycol) Nanoparticles for Accelerated Blood Clearance Inhibition and Targeted Drug Delivery.

Surface modification with poly(ethylene glycol) (PEGylation) is an effective strategy to improve the colloidal stability of nanoparticles (NPs) and is often used to minimize cellular uptake and clearance of NPs by the immune system. However, PEGylation can also trigger the accelerated blood clearance (ABC) phenomenon, which is known to reduce the circulation time of PEGylated NPs. Herein, we report the engineering of stealth PEG NPs that can avoid the ABC phenomenon and, when modified with hyaluronic acid (HA), show specific cancer cell targeting and drug delivery. PEG NPs cross-linked with disulfide bonds are prepared by using zeolitic imidazolate framework-8 NPs as templates. The reported templating strategy enables the simultaneous removal of the template and formation of PEG NPs under mild conditions (pH 5.5 buffer). Compared to PEGylated liposomes, PEG NPs avoid the secretion of anti-PEG antibodies and the presence of anti-PEG IgM and IgG did not significantly accelerate the blood clearance of PEG NPs, indicating the inhibition of the ABC effect for the PEG NPs. Functionalization of the PEG NPs with HA affords PEG NPs that retain their stealth properties against macrophages, target CD44-expressed cancer cells and, when loaded with the anticancer drug doxorubicin, effectively inhibit tumor growth. The innovation of this study lies in the engineering of PEG NPs that can circumvent the ABC phenomenon and that can be functionalized for the improved and targeted delivery of drugs.

The Effect of Surface Composition on the Selective Capture of Atmospheric CO2 by ZIF Nanoparticles: The Case of ZIF-8.

We performed theoretical studies of CO2 capture in atmospheric conditions by the zeolitic imidazolate framework-8 (ZIF-8) via classical Monte Carlo (MC) simulations with Metropolis sampling and classical molecular dynamics (MD) simulations in the NVT and NPT ensembles and different thermodynamic conditions. The ZIF-8 framework was described by varying unit cell dimensions in the presence of pure gases of CO2, N2, O2, Ar, and H2O steam as well as binary mixtures of CO2:N2 and CO2:H2O in s 1:1 concentration. Different chemical compositions of the framework surface was considered to provide an accurate treatment of charge and charge distribution in the nanoparticle. Hence, surface groups were represented as unsaturated zinc atom (Zn+2), 2-methylimidazole (mImH), and deprotonated 2-methylimidazole (mIm-). Force field reparameterization of the surface sites was required to reproduce the interactions of the gas molecules with the ZIF-8 surface consistent with quantum mechanics (QM) calculations and Born-Oppenheimer molecular dynamics (BOMD). It was observed that ZIF-8 selectively captures CO2 due to the negligible concentrations of N2, O2, Ar, and H2O. These molecules spontaneously migrate to the inner pores of the framework. At the surface, there is a competitive interaction between H2O, CO2, and N2, for the positively charged ZIF-8 nanoparticle with a large binding energy advantage for water molecules (on average -62, -15, and -8 kcal/mol respectively). For the neutral ZIF-8 nanoparticle, the water molecules dominate the interactions due to the occurrence of hydrogen bond with the imidazolate groups at the surface. Simulations of binary mixtures of CO2/water steam and CO2/N2 were performed to investigate binding competition between these molecules for the framework positively charged and neutral surfaces. It was found that water molecules drastically block the interaction between CO2 molecules and the framework surface, decreasing CO2 capture in the central pore, and CO2 molecules fully block the interaction between N2 molecules and the framework. These findings show that CO2 capture by ZIF-8 is possible in atmospheric environments only upon dehydration of the atmospheric gas. It further shows that ZIF-8 capture of CO2 from the atmospheric environment is dependent on thermodynamic conditions and can be increased by decreasing temperature and/or increasing pressure.

Electrospun zinc-based metal organic framework loaded-PVA/chitosan/hyaluronic acid interfaces in antimicrobial composite nanofibers scaffold for bone regeneration applications

Metal−Organic Frameworks (MOFs)-loaded electrospun nanofibers have paid much attention to biomedical applications; particularly zeolitic imidazolate framework-8 (ZIF-8) or (Zn-MOF). Electrospun ZIF-8-loaded polyvinyl alcohol/chitosan/hyaluronic acid (ZIF-8@PVA/CH/HA) nanofibrous are constructed, which integrate synthetic nanomaterials with biocompatible mats for bone regeneration. Multifunctional PVA/CH/HA scaffolds embedded with ZIF-8 were fabricated by electrospinner. SEM confirmed the petal shape with a smooth surface for ZIF-8 nanoparticles and successful synthesis of ZIF-8@PVA/CH/HA NFs endowed with excellent morphological structure. The chemical configuration was obtained for all fabricated scaffolds using FTIR and XRD analyses. NFs mats containing ZIF-8 ratios ranged (0, 0.4 and 0.8%, w/v) offered slow-sustained swelling % in water up to 9 days, and gradual weight loss % in PBS (80% degradation rate after more than a week), compared to unloaded ZIF-8 scaffold. Moreover, the results demonstrated that the scaffolds with 0.8% ZIF-8 (PVA/CH/HA/0.8% ZIF-8) recorded sustainable release for ≥6 days; while other scaffolds with (0, 0.2 and 0.4% w/v) ZIF-8 exhibited releasing of ZIF-8 for only 24 h. The treatment of platform with 0.8% MOF showed proficient antimicrobial activities against + G/–G bacteria, pathogens, and fungal cells. The current results refer to the capability of utilizing PVA/CH/HA/ZIF-8 NFs as biomaterials for bone/tissue regeneration, presently.

Therapy of spinal cord injury by folic acid polyethylene glycol amine-modified zeolitic imidazole framework-8 nanoparticles targeted activated M/Ms.

Excessively activated microglia/macrophages (M/Ms) re-establish the proinflammatory microenvironment that exacerbates motor and/or sensory dysfunction after spinal cord injury (SCI). Thus, proinflammatory M/Ms-suppressed treatments may be effective strategies for SCI. However, the utilization of anti-inflammatory drugs for clinical approaches and biomedical research has side effects, such as nephrotoxicity and hepatotoxicity. In this study, we fabricated folic acid-polyethylene glycol (FA-PEG) amine-modified zeolitic imidazole framework-8 (ZIF-8) nanoparticles (FA-PEG/ZIF-8) and found that it effectively restored function in vivo. FA-PEG/ZIF-8 treatment significantly eliminated proinflammatory M/Ms without targeting other nerve cells and downregulated inflammation in the injured lesion. Furthermore, FA-PEG/ZIF-8 caused little toxicity in SCI mice compared to normal mice. These results suggest that FA-PEG/ZIF-8 has the potential to help recover from early-stage SCI by suppressing proinflammatory M/Ms.

Dual targeted zeolitic imidazolate framework nanoparticles for treating metastatic breast cancer and inhibiting bone destruction

Tumor bone metastasis is still difficult to cure despite the development of various treatment strategies. Drug delivery systems can improve the poor biological distribution of anticancer drugs in tumors. But only a very small number of nanoparticles can cross the physiological barrier to reach the tumor. In addition, the progression of bone metastasis is influenced by tumor cells, osteoclasts and bone matrix. To address these problems, a bone and tumor dual targeted nanocarrier was developed by utilizing NF-κB inhibitor loaded into zeolitic imidazolate framework-8 (ZIF-8) (CZ), which was then coated with hyaluronic acid/alendronate (HA/ALN). The CZ prepared by two-step method had high loading capacity, and the loading efficiency of Cur was to be 47.55 ± 4.03%. HA/ALN functionalization avoided explosive release of reagents and improved the stability of nanoparticles. The dual targeted ZIF-8 nanoparticle (CZ@HA/ALN) had a pH-triggered drug release performance, which effectively inhibited breast cancer cells growth and osteoclastogenesis in vitro. Uptake experiments showed that the conjugation of ALN with HA did not affect targeting ability of HA. Moreover, HA/ALN functionalized nanoparticles were more aggregated at bone metastasis sites than HA functionalized nanoparticles. CZ@HA/ALN could block the PD-1 immune check point, leading to Raw 264.7 cells differentiation into anti-tumor macrophage rather than osteoclast. The antitumor experiments in vivo exhibited that the dual targeted ZIF-8 nanoparticle effectively inhibited bone resorption and tumor progress, thereby improving the bone microenvironment. Therefore, this single but versatile nanoparticle provided a promising therapeutic scheme for bone metastasis treatment.

Mechanical, hydration, and microstructural behavior of cement paste incorporating Zeolitic imidazolate Framework-67 (ZIF-67) nanoparticles

Zeolitic imidazolate frameworks (ZIFs) have recently emerged as attractive materials for several applications including the building and construction sector. Unlike most other 2D nanomaterials, ZIFs usually possess high porosity and specific surface area. In this work, the feasibility and compatibility of utilizing a small percentage of ZIF-67 (0–0.9 wt.%) as an additive to cement-based materials has been investigated. The mineralogy, morphology, and microstructure of the cement paste ZIF-67 composites were characterized using different techniques (i.e., SEM-EDX, Raman, and XRD). The compressive and direct tensile strengths, water absorption, dry density, and calorimetry heat flow tests of the cement paste ZIF-67 composites were also evaluated. The results revealed that the optimum content of ZIF-67 is 0.5 wt.% at which the composite exhibited 44.8 % and 113 % improvements in the compressive and direct tensile strengths, respectively, relative to the control mix at 28 days. These improvements are attributed to the production of crystalline CSH and sheet-like CH induced by the addition of ZIF-67 nanoparticles. The results also revealed that the dry density increased while the water absorption and total porosity decreased with increasing the nanoparticle content. A calorimetry heat flow test revealed that the addition of ZIF-67 nanoparticles decreased the time needed to reach the silicate and aluminate states while increasing the maximal heat flow. The findings reported in this study could lead to a new industrial application where improved mechanical and hydration properties of cement-based materials are achieved through the addition of tiny fractions of ZIFs nanoparticles.