Zeolitic Imidazolate Framework Research Articles

Characterization of CYP303A1 and its potential application based on ZIF-8 nanoparticle-wrapped dsRNA in Nilaparvata lugens (Stål).

RNA interference (RNAi) technology has been put forward as a promising method for pest control and resistance management. Mining highly efficient lethal genes and constructing stable double-stranded RNA (dsRNA) delivery systems are of great significance to improve the application potential of RNAi technology. In this study, we characterized a molting-related gene, NlCYP303A1, in Nilaparvata lugens that was highly expressed in the cuticle and at the end stages of each instar in nymphs. Silencing the expression of NlCYP303A1 in N. lugens resulted in a deformed phenotype and a significant increase in mortality. Furthermore, interfering with NlCYP303A1 changed the relative expression of key genes in the chitin synthesis and degradation pathway. Finally, we used the nanocarrier zeolitic imidazolate framework-8 (ZIF-8) to load dsNlCYP303A1, forming a complex denoted as dsNlCYP303A1@ZIF-8. The results of both feeding and rice-seedling dip experiments indicated that the expression of NlCYP303A1 was dramatically and persistently suppressed by the dsNlCYP303A1@ZIF-8 treatment, compared with treatment with dsNlCYP303A1, suggesting that ZIF-8 can enhance the interference efficiency as well as the stability of dsNlCYP303A1. Our results demonstrate that the lethal gene NlCYP303A1 can be employed as an excellent target for RNAi technology by loading onto a nano-delivery system, and provide new insights into the creation of innovative pest control approaches. © 2024 Society of Chemical Industry.

Biomimetic super-wetting membranes via in-situ growth and synchronous integration of ZIF nanoleaves (ZIF-Ls) for emulsified oily wastewater purification and catalytic Knoevenagel condensation

To address the increasingly severe oil spill accidents and water contamination, the development of super-wetting membranes with high oil/water separation efficiency is in great demand but remains challenging. The critical challenge lies in the rational design and fabrication of robust rough surface with hierarchical micro/nano-structure. In this study, biomimetic super-wetting polyacrylonitrile composite membrane was developed through in-situ synthesis and synchronous integration of zeolitic imidazolate framework nanoleaves (ZIF-Ls). Thorough investigation was conducted to assess the effect of the ZIF-Ls growth time on membrane morphology and surface wetting property. Incorporating the nanoleaf-like ZIF-Ls onto the surface of the membrane provided the surface with micro/nano rough structure and superamphiphilic/superlyophobic features. The prepared membrane showed great separation capability toward various O/W and W/O emulsions, and could be easily regenerated by employing a simple rinsing and drying procedure with high separation efficiency sustained even after multiple separation cycles. Moreover, the membrane with ZIF-Ls demonstrated outstanding catalytic performance in the Knoevenagel condensation. This study achieves advancements in the development of super-wettable membranes with outstanding performance in separating emulsions and the as-prepared membranes have the potential to serve as promising candidates for practical oily mixture treatment.

Citral Encapsulated into a Zeolite Imidazolate Framework-67 (ZIF-67) Cage via Biomimetic Mineralization as an Efficient Preservative for Long-Term Antimildew Efficacy of Bamboo

Citral Encapsulated into a Zeolite Imidazolate Framework-67 (ZIF-67) Cage via Biomimetic Mineralization as an Efficient Preservative for Long-Term Antimildew Efficacy of Bamboo

Just-in-Time Generation of Nanolabels via In Situ Biomineralization of ZIF-8 Enabling Ultrasensitive MicroRNA Detection on Unmodified Electrodes.

Nanolabels can enhance the detection performance of electrochemical biosensing methods, yet their practical application is hindered by complex preparation, batch-to-batch variability, and poor long-term storage stability. Herein, we present a novel electrochemical method for miRNA detection based on the just-in-time generation of zeolitic imidazolate framework-8 (ZIF-8) nanolabels initiated by nucleic acids. In this design, the target miRNA-21 is captured with magnetic beads and polyadenylated by Escherichia coli Poly(A) polymerase (EPP), producing miRNA-21 molecules with poly(A) tails (miR-21-poly(A)). These molecules are then adsorbed onto a bare gold electrode (AuE) surface via adenine-gold affinity interactions, serving as nucleation sites for the rapid in situ formation of ZIF-8 nanoparticles. The ZIF-8 nanoparticles function as signal labels, impeding electron transfer at the electrode interfaces and thereby generating a notable electrochemical signal. The developed method demonstrated exceptional sensitivity, with a detection limit (LOD) as low as 2.3 aM and a linear detection range from 10 aM to 1000 fM. The practical application of the developed method was validated by using it to evaluate miRNA-21 expression levels in various biological samples, including cell lines, tumor tissues, and clinical blood samples from non-small cell lung cancer (NSCLC) patients. This approach simplifies the detection process by eliminating the need for presynthesized nanomaterials and premodified electrodes. Its simplicity and high sensitivity make this method a promising tool for point-of-care testing and a wide range of biomedical research applications.

Spleen Targeting Nucleic Acid Delivery Vector Based on Metal-Organic Frameworks.

Nucleic acids have attracted increasing attention as drugs due to their fascinating advantages, such as long-term efficacy and ease of preparation compared to proteins. The nucleic acid therapy relies heavily on delivery vectors, which can prevent the degradation of nucleic acids while assisting them in cellular internalization. However, commonly used nonviral vector liposomes easily accumulate in the liver, which can limit their application in extrahepatic diseases. Herein, a potential spleen targeting vector for nucleic acids is developed based on the metal-organic frameworks. The plasmids are encapsulated inside the nanoscale zeolitic imidazolate framework (ZIF) via coprecipitation. The co-encapsulation of the cationic polymer poly(ether imide) (PEI) and the stabilizer polyvinylpyrrolidone (PVP) can significantly improve particle dispersion and stability. The prepared nanoparticles allow efficient transfection in vitro, mainly through clathrin-mediated and caveolae-mediated endocytosis. The biodistribution in mice shows that 46% of the nanoparticles accumulate in the spleen, which is much higher than that of the liposomes. The vector can successfully deliver plasmids to extrahepatic organs for protein synthesis and even induce an immune response. The elaborate ZIF-based nanoparticle may offer a new route for extrahepatic, especially spleen targeting delivery for the nucleic acids.

Atomically dispersed iron sites from eco-friendly microbial mycelium as highly efficient hydrogenation catalyst

Iron, one of the most abundant elements on earth and an essential element for living organisms, plays a crucial role in our daily metabolism. In the field of catalysis, the development of high-performance catalysts based on less toxic iron element is also of significant importance for green chemistry and a sustainable future. To construct Fe-based heterogeneous catalysts with excellent hydrogenation performance, precise modulation of the atomic coordination structure is a key strategy for enhancing catalytic activity. In this study, we present an in-situ coating method for applying a zeolitic imidazolate framework (ZIF) onto the surface of fungal hyphae. The asymmetric coordination structure of Fe1-N3P1 was precisely tailored by utilizing the phosphorus source from the fungus and the nitrogen source in the ZIFs. Detailed characterizations and density functional theory calculations revealed that the incorporation of ZIFs not only increased the specific surface area of catalysts, but also facilitated the dispersion of Fe2P nanoparticles into the Fe1-N3P1 center, making the lowest reaction energy barrier and resulting in the best performance for nitrobenzene hydrogenation when compared to the Fe2P nanoparticles and clusters. This research introduces a novel design concept for constructing asymmetric monoatomic configuration based on the inherent characteristics of natural microorganisms and the exogenous porous coordination polymers.

A hierarchical porous Fe3O4-COOH@H-ZIF-67 composite as magnetic solid-phase extraction adsorbent for benzimidazole pesticides

A hierarchical porous structural magnetic zeolite imidazolate framework-67 composite (Fe3O4-COOH@H-ZIF-67) was prepared through directly mixing the H-ZIF-67 and glutaric anhydride functionalized Fe3O4 nanospheres, of which the H-ZIF-67 was synthesized through a double template pore size regulation method. The successful preparation of Fe3O4-COOH@H-ZIF-67 composite was confirmed based on the material characterization using different techniques. The prepared composite was applied in the efficient removal of four benzimidazole pesticides (BZDs) in water using magnetic solid-phase extraction (MSPE) process. The results of static and dynamic adsorption experiments indicate that the adsorption of BZDs on Fe3O4-COOH@H-ZIF-67 follow pseudo-second-order kinetics, the Langmuir model fitted well with the adsorption data (R2 are all higher than 0.9969), and the maximum adsorption capacity for BZDs are 7.44–31.11 mg/g. Meanwhile, the adsorption mechanism study indicate that both hydrogen bonding and coordination play important roles during the adsorption process of BZDs. Finally, the developed MSPE method was combined with HPLC analysis and applied in the removal of BZDs from simulated pesticides wastewater. The removal rate was 82.76–96.18 %, and the treated samples met the requirements of the maximum residue limits of CBZ in the national standard GB 21523–2008. In addition, the adsorbent can be used at least three times and the extraction efficiency changed within 3 % after being stored in dry atmosphere at room temperature for 90 days. The results of this work manifested that Fe3O4-COOH@H-ZIF-67 composite can be used for removal and analysis of BZDs in complex samples.

Trimetallic ZIFs-derived nanoarchitecture for portable wireless electrochemical determination of chlorogenic acid in natural medicine and food samples

In this paper, a novel trimetallic zeolitic imidazolate frameworks (ZnCoMn-ZIFs) was successfully synthesized by a facile one-pot method at room temperature, which was further used to prepare a triatomic site anchored in N-doped carbon (Co2MnN8@C) hybrid nanostructure via a pyrolysis method. The synthesized Co2MnN8@C was modified on the screen-printed carbon electrode, and the modified electrode was used for the portable wireless sensitive determination of chlorogenic acid (CGA) by differential pulse voltammetry. The Co2MnN8@C exhibited large surface area and excellent catalytic activity with increasing Co and Mn sites, which could selectively combine with CGA to enhance the sensitivity of the electrochemical sensor. Under the optimized conditions, the constructed sensor had wider linear ranges for CGA analysis from 0.05–10.0 μmol/L and 10.0–100.0 μmol/L with a detection limit of 0.0075 μmol/L (3S0/S). The sensor was successfully applied to detect CGA in natural medicine and food samples with satisfied recoveries. Therefore, the proposed strategy may stimulate the exploration of trimetallic ZIFs with more active sites for the development of sensitive electrochemical sensors.

Efficient, chlorine-free, and durable alkaline seawater electrolysis enabled by MOF-derived nanocatalysts

The development of cost-effective, scalable, and non-precious based bifunctional catalysts that can efficiently catalyze the sluggish oxygen and hydrogen evolution reactions (OER and HER) in the highly corrosive seawater medium is challenging, yet vital to realize a practical seawater electrolyzer. In this work, we demonstrate a nickel-exchanged zeolitic imidazolate framework (Ni@ZIF67)-derived nickel-cobalt-cobalt oxide nanoparticles embedded amorphous carbon (Ni–Co–CoO@C) nanocomposite as an efficient, chloride-resistant, and stable bifunctional catalyst in alkaline seawater. The OER and HER activities are meticulously characterized by comparing nanocomposites prepared at different pyrolysis temperatures. Ni@ZIF67 pyrolyzed at 700 °C (NZ700) exhibits the lowest OER overpotential (281 mV @ 10 mA cm−2) whereas that pyrolyzed at 500 °C reveals the lowest HER overpotential (196 mV @ 50 mA cm−2) in alkaline seawater. The NZ700||NZ700 cell also exhibits the lowest overall splitting voltage in alkaline seawater (1.72 V @ 20 mA cm−2). Detailed post-electrolysis studies are also carried out to explore the origin of the electrocatalytic activities. Furthermore, a zero-gap, flow-cell type alkaline seawater electrolyzer prototype has been fabricated to demonstrate the viability of our catalysts.

Meso/Microporous Single-Atom Catalysts with Curved Fe-N4 sites Boost the Oxygen Reduction Reaction Activity.

Zeolitic-imidazolate frameworks (ZIFs) are among the most efficient precursors for the synthesis of atomically dispersed Fe-N/C materials, which are promising catalysts for enhancing the performance of Zn-air batteries (ZABs) and proton exchange fuel cells (PEMFCs). However, existing ZIF-derived Fe-N/C electrocatalysts mostly consist of microporous materials, leading to insufficient mass transport and inadequate battery/cell performance. In this study, we synthesize an atomically dispersed meso/microporous Fe-N/C material with curved Fe-N4 active sites, denoted as FeSA-N/TC, through the pyrolysis of hemin-modified ZIF films on ZnO nanorods, obtained from the self-assembly reaction between Zn2+ from ZnO hydrolysis and 2-methylimidazole. Density functional theory calculations demonstrate that the curved Fe-N4 active sites can weaken the intermediate adsorptions, resulting in lower free energy barriers and enhanced performance during oxygen reduction reaction (ORR). Specifically, FeSA-N/TC exhibits exceptional ORR performance with half-wave potentials of 0.925 V in alkaline media and 0.825 V in acidic media. When used as the cathodic catalyst in PEMFCs and ZABs, FeSA-N/TC achieves high peak power densities (H2-O2 PEMFC: 1100 mW cm-2; H2-Air PEMFC: 715 mW cm-2; liquid-state ZAB: 228 mW cm-2; solid-state ZAB: 112 mW cm-2), demonstrating its feasibility and efficiency in practical applications.

Meso/Microporous Single‐Atom Catalysts with Curved Fe‐N4 sites Boost the Oxygen Reduction Reaction Activity

Zeolitic‐imidazolate frameworks (ZIFs) are among the most efficient precursors for the synthesis of atomically dispersed Fe‐N/C materials, which are promising catalysts for enhancing the performance of Zn‐air batteries (ZABs) and proton exchange fuel cells (PEMFCs). However, existing ZIF‐derived Fe‐N/C electrocatalysts mostly consist of microporous materials, leading to insufficient mass transport and inadequate battery/cell performance. In this study, we synthesize an atomically dispersed meso/microporous Fe‐N/C material with curved Fe‐N4 active sites, denoted as FeSA‐N/TC, through the pyrolysis of hemin‐modified ZIF films on ZnO nanorods, obtained from the self‐assembly reaction between Zn2+ from ZnO hydrolysis and 2‐methylimidazole. Density functional theory calculations demonstrate that the curved Fe‐N4 active sites can weaken the intermediate adsorptions, resulting in lower free energy barriers and enhanced performance during oxygen reduction reaction (ORR). Specifically, FeSA‐N/TC exhibits exceptional ORR performance with half‐wave potentials of 0.925 V in alkaline media and 0.825 V in acidic media. When used as the cathodic catalyst in PEMFCs and ZABs, FeSA‐N/TC achieves high peak power densities (H2‐O2 PEMFC: 1100 mW cm–2; H2‐Air PEMFC: 715 mW cm–2; liquid‐state ZAB: 228 mW cm–2; solid‐state ZAB: 112 mW cm–2), demonstrating its feasibility and efficiency in practical applications.

Hierarchical Engineering on Built‐In Electric Field of Bimetallic Zeolitic Imidazolate Derivatives Towards Amplified Dielectric Loss

AbstractConstruction of built‐in electric field (BIEF) in nanohybrids has been demonstrated as an efficacious strategy to boost the dielectric loss by facilitating oriented transfer and transition of charges, thus optimizing the electromagnetic wave absorption property. However, the specific influence of BIEF on interface polarization needs to explore thoroughly and the BIEF strength should be further augmented. Herein, several dielectric systems incorporated Mott–Schottky heterojunctions and hollow structures are designed and constructed, where bimetallic zeolitic imidazolate framework are employed to derive Cu‐ZnO Mott–Schottky heterojunctions, and hierarchical structures and BIEF are further enriched by introducing hollow structure and reduced graphene oxide. The well‐established “double” BIEF verified by theoretical calculation and hollow engineering can regulate the conductivity, and enhance the polarization relaxation effectively. Especially, there always coexisted both enhanced charge separation and reversed charge distribution in this “double” BIEF, boosting the interface polarization. Attributing to the synergy of well‐matched impedance and amplified dielectric loss, the obtained hybrids exhibited superior absorption (reflection loss of −46.29 dB and an ultra‐wide effective absorption bandwidth of 7.6 GHz at only 1.6 mm). This work proves an innovative model for dissecting dielectric loss mechanisms and pioneers a novel strategy to explore advanced absorbers through enhancing BIEF.

Synergetic Enzyme-Incorporated Metal-Organic Framework and Polyoxometalate Nanozyme: Achieving Stable Tandem Catalysis for Organic Photoelectrochemical Transistor Bioanalysis.

Organic photoelectrochemical transistor (OPECT) has emerged as a promising technique for biomolecule detection, yet its operational rationale remains limited due to its short development time. This study introduces a stable tandem catalysis protocol by synergizing the enzyme-incorporated metal-organic frameworks (E-MOFs) with polyoxometalate (POM) nanozyme for sensitive OPECT bioanalysis. The zeolitic imidazolate framework-8 (ZIF-8) acts as the skeleton to protect the encapsulated glucose oxidase (GOx), allowing the stable catalytic generation of H2O2. With peroxidase-like activity, a phosphotungstic acid hydrate (PW12) is then able to utilize the H2O2 to induce the biomimetic precipitation on the photogate, ultimately resulting in the altered device characteristics for quantitative detection. This work reveals the potential and versatility of an engineered enzymatic system as a key enabler to achieve novel OPECT bioanalysis, which is believed to offer a feasible framework to explore new operational rationale in optoelectronic and bioelectronic detection.

Pd modified by Fe-Nx confined in N-doped carbon with hierarchical mesoporous structure for the highly efficient semi-hydrogenation of phenylacetylene

The removal of small amounts of phenylacetylene from styrene is a crucial step in the production of high-quality styrene feedstocks. In the presence of a large amount of styrene and a small amount of phenylacetylene, achieving and maintaining high selectivity of styrene remains a significant challenge. In this work, a catalyst denoted as Pd1.25-Fe-N-C/VC was designed and synthesized with remarkably low Pd loading (the actual Pd content was 0.96 wt%). The catalyst exhibited a satisfactory selectivity for styrene (>95 %) and maintained high selectivity levels (>90 %) in the semi-hydrogenation of phenylacetylene even with prolonged reaction time. Pd nanoparticles (NPs) were well distributed and securely anchored onto the Fe-N-C/VC support with a hierarchical mesoporous structure, which obtained from the pyrolysis of a hexagonal star-like Fe-doped zeolitic imidazolate framework with vitamin C surfactant (Fe-doped ZIF/VC). The remarkable catalytic properties may be partly ascribed to the effective synergy effect of the uniformly well-dispersed Fe-Nx (x represents the coordination number) with Pd active centers, which could modulate the adsorption kinetics of the reactant alkynes and alkenes and thus enhancing the selectivity towards styrene. Meanwhile, the hierarchical mesoporous structure is beneficial for the mass transfer, which can effectively promote the interactions between the reactants and active centers. Possible mechanism for the selective hydrogenation of phenylacetylene catalyzed by Pd1.25-Fe-N-C/VC was also illustrated. Moreover, the Pd1.25-Fe-N-C/VC catalyst exhibited sustained catalytic activity and selectivity even after four continuous cycle tests, showing notable reusability and stability. This work may offer a promising approach for creating highly efficient Pd-based catalysts with remarkably low Pd loading for phenylacetylene semi-hydrogenation.

Fabrication of natural enzyme-covered / amino-modified Pd-Pt bimetallic-doped zeolitic imidazolate framework for ultrasensitive detection of metabolites.

The present article introduced an natural enzyme-covered/amino-modified Pd-Pt bimetallic-doped zeolitic imidazolate framework (NAPPZ) for ultrasensitive and specific detection of glucose. The dodecahedral nanomaterial zeolitic imidazolate framework (ZIF-8)-loaded Pd-Pt bimetallic nanoparticles endowed the composite with peroxidase-like activity. The modification with glucose oxidase (GOx) facilitated the rapid access of H2O2 produced through glucose oxidation to the Pd-Pt nanoparticles vicinity reducing diffusion. GOx specifically catalyzes the transformation of glucose into H2O2, which then H2O2 rapidly migrates to the Pd-Pt nanoparticles, catalyzing the oxidation of colorless o-phenylenediamine into the orange-yellow product 2,3-diaminophenazine. Based on the aforementioned cascade reaction, the NAPPZ and NAPPZ based on ChOx were utilized for detecting glucose in human urine samples and cholesterol in milk, respectively. The NAPPZ strategy presented a broad detection range (20-1100μmol L-1) and a low detection limit (15.9μmol L-1) for glucose, and the NAPPZ based on ChOx strategy approach offered a broad detection range (10-500μmol L-1) and low detection limit (6.4μmol L-1) for cholesterol. Therefore, this novel method holds significant potential in the areas of clinical diagnostics and food safety.

Identifying synthetic variables influencing the reproducible microfluidic synthesis of ZIF nano- and micro-particles

The reproducible synthesis of nano- and -micro particles is a critical step in multiple synthetic and industrial processes. Microfluidic synthesis offers numerous advantages for development of precise, reliable, and industrially useful synthesis protocols. However, the influence of different synthetic variables on reproducibility in microfluidic synthesis is underexplored. In this work, we systematically study the influence of key synthetic parameters on the microfluidic synthesis of four Zeolitic Imidazolate Frameworks (ZIFs): ZIF-7, ZIF-8, ZIF-9, and ZIF-67. Utilizing a coiled tube microfluidic setup, we explore the influence of key synthetic parameters such as reagent concentration, stoichiometry, aging time, and nine modulators (pH-altering agents, surfactants, and polar polymers). Most importantly, we evaluate the impact of these variables in combination with the role of mixing, using the Dean flow model. Lastly, we focus on the reproducibility problems that a coiled reactor presents at specific flowrates and how these problems can be recognized and avoided. Overall, the insights collected from this work inform the design of synthetic protocols and enhance material reproducibility and control in microfluidic nano- and micro-particle synthesis.

Reshaped Local and Systemic Immune Responses Triggered by a Biomimetic Multifunctional Nanoplatform Coordinating Multi-Pathways for Cancer Therapy.

Immunotherapy has fundamentally transformed the clinical cancer treatment landscape; however, achieving intricate and multifaceted modulation of the immune systems remains challenging. Here, a multipathway coordination of immunogenic cell death (ICD), autophagy, and indoleamine 2,3-dioxygenase-1 (IDO1) was achieved by a biomimetic nano-immunomodulator assembled from a chemotherapeutic agent (doxorubicin, DOX), small interfering RNA (siRNA) molecules targeting IDO1 (siIDO1), and the zeolitic imidazolate framework-8 (ZIF-8). After being camouflaged with a macrophage membrane, the biomimetic nanosystem, named mRDZ, enriched in tumors, which allowed synergistic actions of its components within tumor cells. The chemotherapeutic intervention led to a compensatory upregulation in the expression of IDO1, consequently exerting an inhibitory effect on the reactive oxygen species (ROS) and autophagic responses triggered by DOX and ZIF-8. Precise gene silencing of IDO1 by siIDO1 alleviated its suppressive influence, thereby facilitating increased ROS production and improved autophagy, ultimately bolstering tumor immunogenicity. mRDZ exhibited strong capability to boost potent local and systemic antitumor immune responses with a feature of memory, which led to the effective suppression of the growth, lung metastasis, and recurrence of the tumor. Serving as an exemplary model for the straightforward and potent reshaping of the immune system against tumors, mRDZ offers valuable insights into the development of immunomodulatory nanomaterials for cancer therapy.

Tuning of Particle Size of Zeolitic Imidazolate Framework-7 via Rapid Synthesis Duration for CH4 Adsorption

In this work, zeolite imidazolate framework-7 (ZIF-7) nanoparticles are synthesized via a solvothermal method and rapid synthesis durations of 1 h and 3 h. The effect of the synthesis duration on the structural properties of ZIF-7 was characterized by XRD and FESEM analyses. Subsequently, CH4 single gas adsorption over ZIF-7 nanoparticles was examined using the volumetric method at room temperature and pressure ranging from 2 to 9 bar. The results showed that the synthesized ZIF-7 adsorbents were highly crystalline with a well-defined and homogeneous particle size distribution of 50–60 nm. It was found that increasing the synthesis duration from 1 h to 3 h did not amend the structure and morphology of the resultant samples significantly, mainly due to the short synthesis duration. Meanwhile, the CH4 adsorbed by ZIF-7 nanoparticles increased with rising pressure for both samples, and the ZIF-7 nanoparticles synthesized at 3 h showed a greater adsorption capacity than that of 1 h, mainly due to its higher crystallinity and well-developed pore structure. The ZIF-7 synthesized at 3 h demonstrated an adsorption capacity up to 2.2 mol/kg, which was higher than those values reported in the literature for micron-sized ZIF-7 samples. The CH4 gas adsorption behavior of ZIF-7 nanoparticles synthesized at 1 h and 3 h were well predicted by the Langmuir isotherm model, with coefficients of determination, R2, of 0.9994 and 0.9982, respectively.

Three birds with one stone: A nano zeolitic imidazolate framework-luciferase-antimicrobial peptide biocomposite-based biosensing platform for improving enzyme stability, detection sensitivity, and sterilization effect

Adenosine triphosphate-driven bioluminescence (ATP-BL) biosensors were widely employed for on-site screening of bacteria. However, unstable luciferase with strict storage conditions limited its field detection. Moreover, the traditional ATP-BL biosensors lacked the sterilization effect. In this study, a robust and multifunctional zeolitic imidazolate framework-90 decorated with luciferase and polyethylene glycol–antimicrobial peptides (ZIF-90@Luc-AMP) was prepared. It could not only enhance the activity and stability of luciferase at ambient temperatures (≥1 month) but also sensitively detect target bacteria via the bioluminescence (BL) method and kill them (three birds with one stone). During the detection process, the target pathogen Escherichia coli O157:H7 (E. coli O157:H7) was specifically captured on a phage-modified stir bar and formed a sandwich complex with ZIF-90@Luc-AMP. With the synergistic bacteriolysis of ZIF-90@Luc-AMP and the phage, the captured E. coli O157:H7 was decomposed and emitted adenosine triphosphate (ATP), achieving the sterilization effect. Meanwhile, the introduced luciferase catalyzed ATP to produce a BL signal, which was proportional to the concentration of E. coli O157:H7. Combining ZIF-90@Luc-AMP and a phage-labeled stir bar for target recognition and enrichment, the entire analytical process could be easily manipulated within 30 min with a low limit of detection (20 CFU/mL) through a portable ATP bioluminescent meter. The multifunctional ZIF-90@Luc-AMP biosensor with high stability, specificity, and sensitivity was also appropriate for rapid pathogen screening and antibacterial application in the wild.

Balanced adsorption and oxidation in a porous P, N-doped carbon prepared by melt-salt-mediated strategy for enhanced fenton-like reaction

The activation of persulfate oxidation processes using carbon-based catalysts is attractive for eliminating persistent aromatic organic pollutants in wastewater treatment. Herein, N and P co-doped carbonaceous (NPC) catalysts with an ultrahigh surface area were synthesized using a melt-salt-mediated strategy, employing Zeolitic Imidazolate Framework-8 as a self-sacrificing template. The NPC(1:1) carbon, prepared under optimized conditions, exhibited the highest surface area of 2001.5 m2/g, characterized by the highest number of defects and a high dispersion of N (1.89 %) and P (0.30 %) atoms on the carbon. This carbon catalyst exhibited a high capacity for adsorption and potential for activating persulfates in the removal of p-Nitrophenol (p-NP). Experimental data indicate a balance between adsorption and oxidation in the NPC(1:1)/PDS/p-NP system, with the highest catalytic removal rate achieved through moderate pre-adsorption of p-NP. Evidence from quenching, electron paramagnetic resonance (EPR), and amperometric i-t experiments suggests that the NPC(1:1)/PDS system primarily degrades p-NP through an electron transfer pathway. Defects in carbon and graphitic N were identified as catalytic sites. These defects resulted in an electron-deficient state, which leads to the activation of PDS and graphitic N was more reactive than both pyridinic and pyrrolic N in the adsorption of PDS molecules. Additionally, P-containing groups such as C-P-O, C-O-P, and C3-P were pinpointed as active sites on the carbons through DFT calculations. The intermediates during p-NP degradation were identified, and possible degradation pathways were proposed. A toxicity analysis indicated a significant reduction in overall toxicity following the oxidation treatment. This study provides innovative insights into the balance between adsorption and catalytic activity in porous carbon-activated persulfate oxidation reactions, thereby aiding in the development of enhanced oxidation catalysts for environmental remediation.