Zeolitic Imidazolate Framework-8 Nanoparticles Research Articles

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.

Trans-Cinnamaldehyde-encapsulated zeolitic imidazolate framework-8 nanoparticle complex solutions to inactivate Escherichia coli O157:H7 on fresh spinach leaves.

This study synthesized and characterized ZIF-8 nanoparticles encapsulated with trans-cinnamaldehyde oil (TC) and evaluated their antimicrobial effectiveness against Escherichia coli O157:H7 on fresh spinach leaves. The antimicrobial activity of different mass ratios of TC-encapsulated ZIF-8 against E. coli O157:H7 (ATCC 43895) strain was assessed and the best mass ratio of 1:2 TC to ZIF-8 identified. Spinach leaves were treated with (1) 0.5TC@ZIF-8_PL nanoparticle complexes solution, (2) 200 ppm chlorine, (3) free TC, and (4) sterilized distilled water (control). All sample groups were rinsed for 1 min, dried in a biosafety cabinet, weighted, and packed in sterilized Whirl-pkTM Stand-Up sampling bags, and stored at 4°C for 15 days for shelf life studies. Samples were dipped into a solution of nanoparticles and another group was sprayed. The quality of spinach samples was assessed by monitoring changes in moisture content (MC), water activity (Aw), color, pH, texture (firmness and work), vitamin C content, total carotenoid, and chlorophyll content. Spinach leaves treated with 0.5TC@ZIF-8_PL had less (p < 0.05) water, total chlorophyll, and total carotenoid losses, with minimal changes in pH. However, treatment did not prevent the color degradation (p > 0.05) and adversely affected spinach firmness. The spinach samples treated with 200 ppm chlorine and free TC had higher (p < 0.05) total chlorophyll degradation than the samples treated with the nanoparticles. The mass ratio of TC-encapsulated ZIF-8 must be readjusted to reduce potential toxicity issues while maintaining the antimicrobial properties. PRACTICAL APPLICATION: Zeolitic imidazolate framework-8 (ZIF-8) nanoparticle complex can be used to encapsulate natural antimicrobials to inhibit growth of pathogens on fresh produce. A 2-log reduction in populations of Escherichia coli O157:H7 on fresh spinach leaves was achieved using trans-cinnamaldehyde at low concentrations. The results can be used to embed the compounds into polymeric films for antimicrobial packaging applications.

Effects of metal-organic framework nanoparticles on the combustion, performance, and emission characteristics of a diesel engine

This study was set to use metal-organic framework nanoparticles in diesel fuel formulation for the first time. Zeolitic imidazolate framework nanoparticles were synthesized using a green technique at room temperature, characterized using various characterization techniques, and used in a diesel-water emulsion fuel at two different concentrations (15 and 30 ppm). The prepared fuel blends were tested in a diesel engine at various loads (25–100% of full-load operation). The effects of fuel composition and engine load were assessed on the behavior of the engine. The combustion and performance parameters of nano-emulsion fuel blends were analogous to those observed for diesel. Nano-emulsion fuels resulted in significantly lower nitrogen oxide emissions than diesel at engine loads up to 75% of full-load operation. Nano-emulsion fuels also markedly outperformed diesel in terms of smoke emission at full-load operation. More specifically, nano-emulsion fuels could result in a significantly lower nitrogen oxide than diesel fuel, with an average reduction of about 15%. These findings were achieved with a slight penalty on the unburned hydrocarbon emissions. The encouraging results obtained in the current preliminary study can serve as an invaluable starting point for future studies to attain a more environmentally friendly diesel combustion process using MOF nanoparticles.

Cecropin-Loaded Zeolitic Imidazolate Framework Nanoparticles with High Biocompatibility and Cervical Cancer Cell Toxicity.

Cecropins (CECs) are insect venom-derived amphiphilic peptides with numerous pharmacological effects, including anti-inflammatory, antibacterial, antiviral, and anti-tumor activities. Cecropins induce tumor cell death by disrupting phospholipid membrane integrity. However, non-specific cytotoxicity and in vivo rapid degradation limit clinical application. Nanotechnologies provide novel strategies for tumor eradication, including nanocarriers that can precisely target drugs to tumor tissue. We report the fabrication of CEC-encapsulated zeolitic imidazolate framework 8 (ZIF-8) nanoparticles (CEC@ZIF-8 NPs) via the preparation of CEC@ZIF-8 NPs in pure water by one-pot stirring. This method yielded morphologically uniform NPs with 20 wt% drug loading capacity and 9% loading efficiency. The NP formulation protected CECs from proteasome degradation, enhanced peptide bioavailability, promoted HeLa tumor cell uptake, and increased antitumor efficacy compared to free CECs. In conclusion, this ZIF-8 encapsulation strategy may enhance the clinical applicability of CECs and other antitumor peptides.

Adsorption of sodium dodecyl benzene sulfonate on zeolitic imidazolate framework-8 synthesized using surfactant-free microemulsion as template

While surfactants created great convenience for the development of society, the abuse use of surfactants also brought about severe challenges, such as contamination to the environment and life, inactivation and degradation of nanomaterials due to the blockage of active sites. To this end, a surfactant-free microemulsion (SFME) was utilized here for the first time to prepare nanoscale zeolitic imidazolate framework-8 (ZIF-8) material for surfactant removal from wastewater. The results demonstrated that SFME can effectively control the crystal size of ZIF-8 nanoparticles, just like surfactant-based microemulsion (SBME) system, with a uniform particle size distribution from 20 to 40 nm, smaller and more integral than that was obtained by conventional solvothermal method. Nano ZIF-8 material can efficiently remove surfactant from the wastewater by adsorption, especially for anionic surfactants (sodium dodecyl benzene sulfonate (SDBS)). The adsorption of SDBS on nano ZIF-8 well fitted the pseudo-second order kinetic model and Langmuir adsorption model, with the highest adsorption capacity of 548 mg/g at 318 K. Compared with ZIF-8 based on SBME, ZIF-8 based on SFME showed higher adsorption capacity to SDBS, because of larger surface area and pore volume. The data of zeta potential, FT-IR, XPS and SEM-EDS revealed that the adsorption of SDBS on ZIF-8 not only involves the electrostatic attraction but also hydrophobic interaction including π-π and dispersion force interactions. The current study provides a simple, energy-efficient, green and sustainable route of synthesizing nano ZIFs, without worrying about the secondary pollution, and the as-synthesized can be used as a high-efficient adsorbent to remove the pollutant from water.

MXene Quantum Dot/Zeolitic Imidazolate Framework Nanocarriers for Dual Stimulus Triggered Tumor Chemo-Phototherapy.

It is critical to construct stimuli-responsive multifunctional nanoparticles for the drug delivery system for cancer treatment. Zeolitic imidazolate framework-8 (ZIF-8) has a large specific surface area and decomposes quickly under acidic conditions, which presents an excellent potential in pH-sensitive drug carriers. However, the mere chemotherapeutic drug loaded into ZIF-8 is a monotherapy and may restrict the therapeutic efficacy of malignancies. In this work, an effective nanoparticle-based delivery platform is established to simultaneously encapsulate doxorubicin (DOX) and MXene quantum dot (MQD) in ZIF-8 nanoparticles (MQD@ZIF-8/DOX). Under near-infrared (NIR) laser (808 nm) and UV light (365 nm) irradiation, MQD@ZIF-8 demonstrates a high photothermal conversion efficiency and reactive oxygen species (ROS) production, which shows excellent photothermal therapy and photodynamic therapy effects. Furthermore, the release of DOX-loaded into MQD@ZIF-8 nanoparticles is significantly increased under NIR laser irradiation and at pH 5.6, indicating that acidic conditions and NIR laser irradiation can be effectively combined to stimulate the drug release. The cellular experiments show that MQD@ZIF-8/DOX has an obvious killing effect on HeLa cells and achieves the combined anti-tumor effect of chemotherapy and phototherapy.

Nonflammable, robust and recyclable hydrophobic zeolitic imidazolate frameworks/sponge with high oil absorption capacity for efficient oil/water separation

Developing robust sponge-based materials with high oil capacity and excellent flame resistance for oil spill cleanup is significant. Herein, a highly hydrophobic composite sponge material for oil-water separation, containing a melamine-formaldehyde (MF) sponge substrate and zeolitic imidazolate framework-8 (ZIF-8) coating was fabricated through the simple amino-assisted in-situ growth of ZIF-8 onto the strut surface of MF sponge. The successful integration of MF sponge and ZIF-8 nanoparticles in one composite material was confirmed by scanning electron microscopy, X-ray diffraction and nitrogen sorption. The synergistic effect of the MF substrate and ZIF-8 coating significantly improved its flame resistance. Combining the advantage of the MF substrate and the hydrophobic ZIF-8 nanocrystals, the ZIF-8/MF composite sponge showed high porosity and good hydrophobicity with a water contact angle of 130°. A high adsorption capacity towards various oils was achieved in the range of 76–164 g g−1. Besides, the ZIF-8/MF composite sponge exhibited excellent separation performance for light oil/heavy oil-water mixtures via adsorption and/or gravity-driven separation. In addition, owing to its compressibility and mechanical stability, the ZIF-8/MF composite sponge could be easily regenerated by a simple squeezing method and showed excellent recyclability for the oil adsorption. These features make the ZIF-8/MF composite sponge promising for highly efficient oil-water separation.

ZIF-8 nanoparticles induce neurobehavioral disorders through the regulation of ROS-mediated oxidative stress in zebrafish embryos

Zeolite imidazolate framework-8 (ZIF-8) is a nanomaterial of metal-organic frameworks (MOFs), which have various applications in drug delivery and water pollution remediation. However, little is known about its developmental neurotoxicity in aquatic organisms, especially on the low-level exposure. In the present study, we investigated the toxic effects of ZIF-8 NPs on the neuron development, behavioral traits, oxidative stress and gene expression in zebrafish embryos. Firstly, our results showed that ZIF-8 induced significantly embryonic malformations and abnormal development of nervous system in zebrafish embryos with a concentration-dependent manner. Meanwhile, the locomotor behavior was obviously inhibited while the anxiety behavior was greatly increased after ZIF-8 exposure. Secondly, the levels of ROS and antioxidant enzyme activities (CAT, SOD and MDA) together with AChE and ATPase were substantially increased in the ZIF-8 exposed groups. At the molecular level, ZIF-8 NPs could down-regulate the expression profiles of neural development-related genes (gap43, synapsin 2a and neurogenin 1) and PD-like related genes (dj-1, dynactin and parkin), but up-regulate the expression levels of neuro-inflammatory genes (nox-1, glip1a and glip1b) in larval zebrafish. In addition, we further explored the molecular mechanism of neurotoxicity induced by ZIF-8 with pharmacological experiments. The results showed that specific inhibition of ROS-mediated oxidative stress by the astaxanthin could reverse the expression patterns of ATPase, AChE and neurodevelopmental genes. Moreover, astaxanthin can partially rescue the ZIF-8-modulated locomotor behavior. Taken together, our results demonstrated that ZIF-8 had the potential to cause neurotoxicity in zebrafish embryos. These informations presented in this study will help to elucidate the molecular mechanisms of ZIF-8 nanoparticles exposure in zebrafish, which providing a scientific evaluation of its safety to aquatic ecosystems.

Buffet-style Cu(II) for enhance disulfiram-based cancer therapy

Studies have shown that disulfiram (DSF) can combine with Cu2+ to form bis(N, N-diethyldithiocarbamate) copper(II) complex (CuET) as antitumor drugs. However, there is insufficient endogenous Cu2+ dose to eradicate cancer cells selectively. Inspired by the buffet, we use Cu2+ doped hollow zeolitic imidazolate framework nanoparticles (HZIFCu) as the carrier and equipped with DSF and indocyanine green (ICG) and targeted by folic acid (FA) (D&I@HZIFCu-FA) to enhance DSF-based cancer therapy. D&I@HZIFCu-FA could effectively supply Cu2+ by a buffet-style, assisting the “DSF-to-CuET” transformation in the tumor. Additionally, self-supply Cu2+ could convert H2O2 into ·OH by triggering a Fenton-like reaction for chemo-dynamic therapy, and ICG achieves photothermal therapy for tumors under laser irradiation. This work provides a buffet-style for Cu2+ to make DSF a strong candidate for cancer treatment by combining chemotherapy, chemo-dynamic therapy, and photothermal therapy and inspires more research about its applications in tumor therapy.

Microvesicle-camouflaged biomimetic nanoparticles encapsulating a metal-organic framework for targeted rheumatoid arthritis therapy

BackgroundMethotrexate (MTX) has been highlighted for Rheumatoid arthritis (RA) treatment, however, MTX does not accumulate well at inflamed sites, and long-term administration in high doses leads to severe side effects. In this study, a novel anti-RA nanoparticle complex was designed and constructed, which could improve the targeted accumulation in inflamed joints and reduce side effects.ResultsHere, we prepared a pH-sensitive biomimetic drug delivery system based on macrophage-derived microvesicle (MV)-coated zeolitic imidazolate framework-8 nanoparticles that encapsulated the drug methotrexate (hereafter MV/MTX@ZIF-8). The MV/MTX@ZIF-8 nanoparticles were further modified with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[folate (polyethylene glycol)-2000] (hereafter FPD/MV/MTX@ZIF-8) to exploit the high affinity of folate receptor β for folic acid on the surface of activated macrophages in RA. MTX@ZIF-8 nanoparticles showed high DLE (~ 70%) and EE (~ 82%). In vitro study showed that effective drug release in an acidic environment could be achieved. Further, we confirmed the activated macrophage could uptake much more FPD/MV/MTX@ZIF-8 than inactivated cells. In vivo biodistribution experiment displayed FPD/MV/MTX@ZIF-8 nanoparticles showed the longest circulation time and best joint targeting. Furthermore, pharmacodynamic experiments confirmed that FPD/MV/MTX@ZIF-8 showed sufficient therapeutic efficacy and safety to explore clinical applications.ConclusionsThis study provides a novel approach for the development of biocompatible drug-encapsulating nanomaterials based on MV-coated metal-organic frameworks for effective RA treatment.Graphical

Stem Cell Membrane-Encapsulated Zeolitic Imidazolate Framework-8: A Targeted Nano-Platform for Osteogenic Differentiation.

Mesenchymal stem cells (MSCs) have been recognized as one of the most promising pharmaceutical multipotent cells, and a key step for their wide application is to safely and efficiently regulate their activities. Various methods have been proposed to regulate the directional differentiation of MSCs during tissue regeneration, such as nanoparticles and metal ions. Herein, nanoscale zeolitic imidazolate framework-8 (ZIF-8), a Zn-based metal-organic framework, is modified to direct MSCs toward an osteoblast lineage. Specifically, ZIF-8 nanoparticles are encapsulated using stem cell membranes (SCMs) to mimic natural molecules and improve the biocompatibility and targeted ability toward MSCs. SCM/ZIF-8 nanoparticles adjust the sustained release of Zn2+ , and promote their specific internalization toward MSCs. The internalized SCM/ZIF-8 nanoparticles show excellent biocompatibility, and increase MSCs' osteogenic potentials. Moreover, RNA-sequencing results elucidate that the activated cyclic adenosine 3,5-monophosphate (cAMP)-PKA-CREB signaling pathway can be dominant in accelerating osteogenic differentiation. In vivo, SCM/ZIF-8 nanoparticles greatly promote the formation of new bone tissue in the femoral bone defect detected by 3D micro-CT, hematoxylin and eosin staining, and Masson staining after 4 weeks. Overall, the SCM-derived ZIF-8 nanostructures achieve the superior targeting ability, biocompatibility, and enhanced osteogenesis, providing a constructive design for tissue repair.

ZIF-8 nanoparticles coated with macrophage-derived microvesicles for sustained, targeted delivery of dexamethasone to arthritic joints

Dexamethasone sodium phosphate (Dex) is widely used in the clinic for the treatment of rheumatoid arthritis. However, it circulates in the blood for a short time and it is linked to a high risk of severe side effects caused by repeated dosing. Here, we encapsulated Dex onto zeolitic imidazolate framework-8 (ZIF-8) to prepare metal–organic framework nanoparticles with high drug loading efficiency. To prevent clearance by the mononuclear phagocyte system and extend time in circulation, the nanoparticles were also camouflaged with macrophage-derived microvesicles (MV) to obtain the biomimetic drug delivery system MV/Dex/ZIF-8. In vitro and in vivo experiments showed that the nanosystem had high drug loading and encapsulation efficiency, high stability, and long circulation time, and it permitted sustained drug release longer in inflamed joint tissues. Our study provides new insights into designing camouflaged drug carriers to prevent their phagocytosis and prolong their time in circulation.

Stability of ZIF-8 Nanoparticles in Most Common Cell Culture Media.

Zeolite imidazolate framework-8 (ZIF-8) is a promising platform for drug delivery, and information regarding the stability of ZIF-8 nanoparticles in cell culture media is essential for proper interpretation of in vitro experimental results. In this work, we report a quantitative investigation of the ZIF-8 nanoparticle’s stability in most common cell culture media. To this purpose, ZIF-8 nanoparticles containing sterically shielded nitroxide probes with high resistance to reduction were synthesized and studied using electron paramagnetic resonance (EPR). The degradation of ZIF-8 in cell media was monitored by tracking the cargo leakage. It was shown that nanoparticles degrade at least partially in all studied media, although the degree of cargo leakage varies widely. We found a strong correlation between the amount of escaped cargo and total concentration of amino acids in the environment. We also established the role of individual amino acids in ZIF-8 degradation. Finally, 2-methylimidazole preliminary dissolved in cell culture media partially inhibits the degradation of ZIF-8 nanoparticles. The guidelines for choosing the proper cell culture medium for the in vitro study of ZIF-8 nanoparticles have been formulated.

Zeolitic Imidazolate Framework-8 Nanoparticles Exhibit More Severe Toxicity to the Embryo/Larvae of Zebrafish (Danio rerio) When Co-Exposed with Cetylpyridinium Chloride

The combined application of nanoparticles and surfactants has attracted tremendous attention in basic research and industry. However, knowledge of their combined toxicity remains scarce. In this study, we exposed zebrafish embryos to cetylpyridinium chloride (CPC, a cationic surfactant, at 0 and 20 μg/L), zeolitic imidazolate framework nanoparticles (ZIF-NPs, at 0, 30, and 60 mg/L), and their mixtures until 120 h post-fertilization (hpf). Within the used concentration range, both single and combined exposures exhibited limited effects on the survival and hatching of zebrafish. However, the combined exposure of ZIF-NPs and CPC caused more severe effects on the heart rate at both 48 and 72 hpf. The combined exposure also induced significant hyperactivity (i.e., increasing the average swimming velocity) and oxidative stress in zebrafish larvae (at 120 hpf), although all single exposure treatments exhibited limited impacts. Furthermore, the level of reactive oxygen species (or malondialdehyde) exhibited a significantly positive correlation with the heart rate (or average swimming velocity) of zebrafish, suggesting that oxidative stress plays a role in mediating the combined toxicity of CPC and ZIF-NPs to zebrafish. Our findings suggest that the interaction of CPC and ZIF-NPs should not be ignored when assessing the potential risks of their mixtures.

Dual-crosslinked networks of superior stretchability and toughness polyacrylamide-carboxymethylcellulose hydrogel for delivery of alendronate

Hydrogels have been widely applied in biomedical, bionic, and intelligent devices. However, pure hydrogels suffer from poor elasticity and mechanical properties, which severely limit their application. Employing dual-crosslinked networks, comprising simultaneous existence of chemical and physical crosslinks, is an effective approach to circumvent these limitations. In this study, the zeolitic imidazolate framework-8 (ZIF-8) and alendronate loaded ZIF-8 (Aln@ZIF-8) nanoparticles were synthesized by one-pot method. Then, by incorporating ZIF-8 or Aln@ZIF-8 nanoparticles, the dual-crosslinked hydrogel consisting of hydrophilic polyacrylamide (PAM), carboxymethyl cellulose (CMC) was developed. Furthermore, the mechanical properties were measured using a universal testing machine. The results showed that the hydrogel exhibited superior tensile properties, compression properties, storage modulus (G′), and loss modulus (G″) in 10 wt% ZIF-8 nanoparticles. Therefore, considering the superior mechanical properties, the 10 wt% hydrogels were selected as promising candidates as Aln delivery carriers with a high loading capacity (63.83%) and a longer releasing profile (6 d), which might be a potential application in tissue engineering.

ZIF-8 channeled and coordination-bridging two-dimensional WS2 membrane for efficient organic solvent nanofiltration

Zeolitic imidazolate framework-8 (ZIF-8)/WS2 composite 2D membranes were constructed by in-situ growth of ZIF-8 in the interlayer of WS2 laminar membrane. The growth of ZIF-8 nanoparticles in WS2 membrane expanded the interlayer spacing, and endowed WS2 membrane with fixed interlayer spacing by coordination-bridges between WS2 and ZIF-8, which made ZIF-8/WS2 membrane possess not only high solvent permeance but also excellent stability in organic solvents. Isopropanol (IPA) permeance through ZIF-8/WS2 membrane reached 272 L/m2·h·bar, which was about 1.6 times higher than that through pristine WS2 membrane, and the rejection rates for Direct Black 38 (DB38), Congo Red (CR) and Rose Bengal (RosB) were 99%, 99% and 30% respectively. Furthermore, the IPA permeance through ZIF-8/WS2 membrane was almost unchanged after soaking in IPA for 192 h, and IPA permeance and rejection rate for DB 38 changed slightly during 100 h of cross-flow filtration, demonstrating remarkable stability of ZIF-8/WS2 membranes in organic solvents and a promising application potential in organic solvent nanofiltration.