PPIH as a poor prognostic factor increases cell proliferation and m6A RNA methylation in hepatocellular carcinoma.

RNA-binding proteins (RBPs) play a crucial role in the biological processes of liver hepatocellular carcinoma (LIHC). Peptidyl-prolyl cis-trans isomerase H (PPIH), an RBP, possesses prolyl isomerase activity and functions as a protein chaperone. The relationship between PPIH and LIHC has not yet been fully elucidated. This study elucidated potential mechanisms through which PPIH affects the prognosis of LIHC. Bioinformatics analysis and in vitro experiments revealed that PPIH expression was higher in LIHC tissues than in normal tissues. PPIH was identified as an independent prognostic factor, with high PPIH expression being associated with worse prognoses. Moreover, PPIH increased the m6A RNA methylation level and promoted cell proliferation by modulating DNA replication and the expression of cell cycle-related genes in LIHC cells. Bioinformatics analysis also revealed that PPIH expression increased immune cell infiltration and the expression of immune checkpoint proteins. Collectively, these findings indicate that PPIH might promote LIHC progression by enhancing the m6A RNA methylation level, increasing cell proliferation, and altering the tumor immune microenvironment. Our study demonstrates that PPIH, as a poor prognostic factor, may lead to LIHC malignancy through multiple pathways. Further in-depth research on this topic is warranted.

Metabolism of Malus halliana Roots Provides Insights into Iron Deficiency Tolerance Mechanisms.

Iron (Fe) deficiency is one of the most common micronutrient imbalances limiting plant growth globally, especially in arid and saline alkali regions due to the decreased availability of Fe in alkaline soils. Malus halliana grows well in arid regions and is tolerant of Fe deficiency. Here, a physiological and metabolomic approach was used to analyze the short-term molecular response of M. halliana roots to Fe deficiency. On the one hand, physiological data show that the root activity first increased and then decreased with the prolongation of the stress time, but the change trend of root pH was just the opposite. The total Fe content decreased gradually, while the effective Fe decreased at 12 h and increased at 3 d. The activity of iron reductase (FCR) increased with the prolongation of stress. On the other hand, a total of 61, 73, and 45 metabolites were identified by GC-MS in three pairs: R12h (Fe deficiency 12 h) vs. R0h (Fe deficiency 0 h), R3d (Fe deficiency 3 d) vs. R0h, and R3d vs. R12h, respectively. Sucrose, as a source of energy, produces monosaccharides such as glucose by hydrolysis, while glucose accumulates significantly at the first (R12h vs. R0h) and third time points (R3d vs. R0h). Carbohydrates (digalacturonate, L-xylitol, ribitol, D-xylulose, glucose, and glycerol) are degraded into pyruvate through glycolysis and pentose phosphate, which participate in the TCA. Glutathione metabolism and the TCA cycle coordinate with each other, actively respond to Fe deficiency stress, and synthesize secondary metabolites at the same time. This study thoroughly examines the metabolite response to plant iron deficiency, highlighting the crucial roles of sugar metabolism, tricarboxylic acid cycle regulation, and glutathione metabolism in the short-term iron deficiency response of apples. It also lays the groundwork for future research on analyzing iron deficiency tolerance.

Identification of mutations in viral proteins involved in cell adaptation using a reverse genetic system of the live attenuated hepatitis A virus vaccine H2 strain.

The live attenuated hepatitis A virus vaccine H2 strain was developed by passaging a wild-type H2w isolate in cell cultures. Currently, the mechanism underlying its attenuation phenotype remain largely unknown. In this study, we generated a full-length infectious cDNA clone of the H2 strain using in-fusion techniques. The recovered H2 strain (H2ic) from the cDNA clone exhibited an efficient replication in both the hepatoma cell line Huh7.5.1 and the 2BS cell line used for vaccine production, similar to the parental H2 strain. Additionally, H2ic did not cause disease in Ifnar1-/- C57 mice, consistent with the H2 strain. To explore the cell-adaptive mutations of the H2 strain, chimeric viruses were generated by replacing its non-structural proteins with corresponding regions from H2w using the infectious cDNA clone as a genetic backbone. The chimeric viruses carrying the 3C or 3D proteins from H2w showed decreased replication in Huh7.5.1 and 2BS cell lines compared to H2ic. Other chimeric viruses containing the 2B, 2C, or 3A proteins from H2w failed to be recovered. Furthermore, there were no significant differences in disease manifestation in mice between H2ic and the recovered chimeric viruses. These results demonstrate that adaptive mutations in the 2B, 2C, and 3A proteins are essential for efficient replication of the H2 strain in cell cultures. Mutations in the 3C and 3D proteins contribute to enhanced replication in cell cultures but did not influence the attenuated phenotypes in mice. Together, this study presents the first reverse genetic system of the H2 strain and identifies viral proteins essential for adaptation to cell cultures.

The pharmacokinetics/pharmacodynamics integration of tilmicosin against Mycoplasma synoviae in vitro and in vivo.

Mycoplasma synoviae (MS) infection is a serious threat to poultry industry in China. Tilmicosin is a semisynthetic macrolide antibiotic used only in animals and has shown potential efficacy against MS, but there were no reported articles concerning the pharmacokinetics/pharmacodynamics (PK/PD) interactions of tilmicosin against MS in vitro and vivo. This study aimed to assess the antibacterial activity of tilmicosin against MS in vitro and in vivo using PK/PD model to provide maximal efficacy. The minimum inhibitory concentration (MIC) and killing rates of different drug concentrations were measured using the microdilution method in vitro. Then, tilmicosin was administered orally to the MS-infected chickens at doses of 7.5 and 60 mg/kg, and the PK parameters of tilmicosin in joint dialysates were determined using high-pressure liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) combined with the microdialysis technique. The antibacterial effect (△E) was calculated when the infected chickens were administered a single oral dose of tilmicosin at 4, 7.5, 15, 30, and 60 mg/kg b.w. The PK and PD data were fitted using the Sigmoid Emax model to evaluate the PK/PD interactions of tilmicosin against MS. The bactericidal activity of tilmicosin against MS was concentration dependent. Furthermore, the PK/PD index of AUC0-72h/MIC exhibited the most optimal fitting results (R2 = .98). The MS load decreased by 1, 2, and 3 Log10 CFU/mL, then AUC/MIC was determined as 13.99, 20.53, and 28.23 h, respectively, and the bactericidal effect can be achieved when the dose of MS-infected chickens is at 31.64 mg/kg b.w. The findings of this study hold significant implications for optimizing the treatment regimen for MS infection.

Enhancing Few-Shot CLIP With Semantic-Aware Fine-Tuning.

Learning generalized representations from limited training samples is crucial for applying deep neural networks in low-resource scenarios. Recently, methods based on contrastive language-image pretraining (CLIP) have exhibited promising performance in few-shot adaptation tasks. To avoid catastrophic forgetting and overfitting caused by few-shot fine-tuning, existing works usually freeze the parameters of CLIP pretrained on large-scale datasets, overlooking the possibility that some parameters might not be suitable for downstream tasks. To this end, we revisit CLIP's visual encoder with a specific focus on its distinctive attention pooling layer, which performs a spatial weighted-sum of the dense feature maps. Given that dense feature maps contain meaningful semantic information, and different semantics hold varying importance for diverse downstream tasks (such as prioritizing semantics like ears and eyes in pet classification tasks rather than side mirrors), using the same weighted-sum operation for dense features across different few-shot tasks might not be appropriate. Hence, we propose fine-tuning the parameters of the attention pooling layer during the training process to encourage the model to focus on task-specific semantics. In the inference process, we perform residual blending between the features pooled by the fine-tuned and the original attention pooling layers to incorporate both the few-shot knowledge and the pretrained CLIP's prior knowledge. We term this method as semantic-aware fine-tuning (). is effective in enhancing the conventional few-shot CLIP and is compatible with the existing adapter approach (termed ). Extensive experiments on 11 benchmarks demonstrate that both and significantly outperform the second-best method by + 1.51 % and + 2.38 % in the one-shot setting and by + 0.48 % and + 1.37 % in the four-shot setting, respectively.

Co2+ coordination-assisted molecularly imprinted covalent organic framework for selective extraction of ochratoxin A.

Covalent organic frameworks (COFs) are attractive materials for sample pretreatment due to their tunable structures and functions. However, the precise recognition of contaminant in complex environmental matrices by COFs remains challenging owing to their insufficient specific active sites. Herein, we report Co2+ coordination-assisted molecularly imprinted flexible COF (MI-COF@Co2+) for selective recognition of ochratoxin A (OTA). The MI-COF@Co2+ was prepared via one-step polymerization of 3,3-dihydroxybenzidine, 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine, Co2+ and template. The flexible units endowed COFs with the self-adaptable ability to regulate the molecular conformation and coordinate with Co2+ to locate the imprinted cavities. The coordination interaction greatly improved the adsorption capacity and selectivity of MI-COF@Co2+ for OTA. The prepared MI-COF@Co2+ was used as solid phase extraction adsorbent for high-performance liquid chromatography determination of OTA with the detection limit of 0.03 ng mL-1 and the relative standard deviation of < 2.5 %. In addition, this method permitted interference-free determination of OTA in real samples with recovery from 89.5 % to 102.8 %. This work provides a simple way to improve the selectivity of COFs for the determination of hazardous compounds in complex environments.

Insulin receptor isoform B is required for efficient proinsulin processing in pancreatic ß cells.

The insulin receptor (INSR, IR) has two isoforms, IRA and IRB, through alternative splicing. However, their distinct functions in vivo remain unclear. Here we generated ß cell-specific IRB knockout (KO) mice (ßIRBKO). The KO mice displayed worsened hyperinsulinemia and hyperproinsulinemia in diet-induced obesity due to impaired proinsulin processing in ß cells. Mechanistically, loss of IRB suppresses eukaryotic translation initiation factor 4G1 (eIF4G1) by stabilizing the transcriptional receptor sterol-regulatory element binding protein 1 (SREBP1). Moreover, excessive autocrine proinsulin in ßIRBKO mice enhances the activity of extracellular signal-regulated kinase (ERK) through the remaining IRA to further stabilize nuclear SREBP1, forming a feedback loop. Collectively, our study paves the way to dissecting the isoform-specific function of IR in vivo and highlights the important roles of IRB in insulin processing and protecting ß cells from lipotoxicity in obesity.

Persistent Luminescence Nanoplatform for Autofluorescence-Free Tracking of Submicrometer Plastic Particles in Plant.

The uptake of plastic particles by plants and their transport through the food chain make great risks to biota and human health. Therefore, it is important to trace plastic particles in the plant. Traditional fluorescence imaging in plants usually suffers significant autofluorescence background. Here, we report a persistent luminescence nanoplatform for autofluorescence-free imaging and quantitation of submicrometer plastic particles in plant. The nanoplatform was fabricated by doping persistent luminescence nanoparticles (PLNPs) onto polystyrene (PS) nanoparticles. Cr3+-doped zinc gallate PLNP was employed as the dopant for autofluorescence-free imaging due to its persistent luminescence nature. In addition, the Ga element in PLNP was used as a proxy to quantify the PS in the plant by inductively coupled plasma mass spectrometry (ICP-MS). Thus, the developed nanoplatform allows not only dual-mode autofluorescence-free imaging (persistent luminescence and laser-ablation ICP-MS) but also ICP-MS quantitation for tracking PS in plant. Application of this nanoplatform in a typical plant model Arabidopsis thaliana revealed that PS mainly distributed in the root (>99.45%) and translocated very limited (<0.55%) to the shoot. The developed nanoplatform has great potential for quantitative tracing of submicrometer plastic particles to investigate the environmental process and impact of plastic particles.

Self-evolving persistent luminescence nanoprobes for autofluorescence-free ratiometric imaging and on-demand enhanced chemodynamic therapy of pulmonary metastatic tumors.

Precise imaging-guided therapy of a pulmonary metastasis tumor is of great significance for tumor management and prognosis. Persistent luminescence nanoparticles (PLNPs) are promising probes due to their in situ excitation-free and low-background imaging characteristics. However, most of the PLNP-based probes cannot intelligently distinguish between normal and tumor tissues or balance the needs of targeted accumulation and rapid metabolism, resulting in false positive signals and potential side effects. Besides, the luminescence intensity of single-emissive PLNPs is affected by external factors. Herein, we report a self-evolving double-emissive PLNP-based nanoprobe ZGMC@ZGC-TAT for pulmonary metastatic tumor imaging and therapy. Acid-degradable green-emitting PLNPs (ZGMC) with good afterglow performance and therapeutic potential are synthesized by systematic optimization of dopants. Ultra-small red-emitting PLNPs (ZGC) are then prepared as imaging and reference probes. The two PLNPs are finally covalently coupled and further modified with a cell-penetrating peptide (TAT) to obtain ZGMC@ZGC-TAT. Dual emission ensures a stable luminescence ratio (I700/I537) independent of probe concentration, test voltage and time gate. ZGMC degrades and phosphorescence disappears in a tumor microenvironment (TME), resulting in an increase in I700/I537, thus enabling tumor-specific ratiometric imaging. Cu2+ and Mn2+ released by ZGMC degradation achieve GSH depletion and enhance CDT, effectively inhibiting tumor cell proliferation. Meanwhile, the size of ZGMC@ZGC-TAT decreases sharply, and the resulting ZGC-TAT further causes nuclear pyknosis and quickly clear metabolism. The developed ZGMC@ZGC-TAT turns non-targeted lung aggregation of nanomaterials into a unique advantage, and integrates TME-triggered phosphorescence and size self-evolution, and on-demand therapeutic functions, showing outstanding prospects in precise imaging and efficient treatment of pulmonary metastatic tumors.

Persistent production of multiple active species with copper doped zinc gallate nanoparticles for light-independent photocatalytic degradation of organic pollutants.

Photocatalysis is considered as an environmentally friendly and sustainable method as it can produce active species to degrade pollutants. However, its applications are hindered by the turbidity of pollutants and the requirements for continuous or repeated in situ irradiation. To avoid the need for continuous in situ irradiation in the photocatalytic process, herein we report the doping of Cu(II) ions into zinc gallate (ZnGa2O4) as traps to capture photo-generated electrons. In this way, long lifetime charge release and separation were effectively achieved for the persistent degradation of organic dyes in wastewater. The Cu(II) doped ZnGa2O4 (ZGC) nanoparticles with a small size about 7.7 nm synthesized via a hydrothermal method exhibited a persistent photocatalytic activity with continuous production of reactive oxygen species for at least 96 h without in situ irradiation due to its unique electronic structure and carrier transport path, and enabled to degrade 82.2 % of rhodamine B in 1 h. Further investigation revealed that the doped Cu(II) ions occupied the octahedral sites of ZGC and highly increased the persistent production and availability of active species for the persistent degradation of organic dyes under pre-illuminated conditions.

Engineering of molecularly imprinted cavity within 3D covalent organic frameworks: An innovation for enhanced extraction and removal of microcystins.

The scarcity of selective adsorbents for efficient extraction and removal of microcystins (MCs) from complex samples greatly limits the precise detection and effective control of MCs. Three-dimensional covalent organic frameworks (3D COFs), characterized by their large specific surface areas and highly ordered rigid structure, are promising candidates, but suffer from lack of specific recognition. Herein, we design to engineer molecularly imprinted cavities within 3D COFs via molecularly imprinted technology, creating a novel adsorbent with exceptional selectivity, kinetics and capacity for the efficient extraction and removal of MCs. As proof-of-concept, a new CC bond-containing 3D COF, designated JNU-7, is designed and prepared for copolymerization with methacrylic acid, the pseudo template L-arginine and ethylene dimethacrylate to yield the JNU-7 based molecularly imprinted polymer (JNU-7-MIP). The JNU-7-MIP exhibits a great adsorption capacity (156 mg g-1) for L-arginine. Subsequently, the JNU-7-MIP based solid-phase extraction coupled with high performance liquid chromatography-mass spectrometry achieves low detection limit of 0.008 ng mL-1, wide linear range of 0.025-100 ng mL-1, high enrichment factor of 186, rapid extraction of 10 min, and good recoveries of 92.4%-106.5% for MC-LR. Moreover, the JNU-7-MIP can rapidly remove the MC-LR from 1 mg L-1 to levels (0.26-0.35 µg L-1) lower than the WHO recommended limit for drinking water (1 µg L-1). This work reveals the considerable potential of 3D COF based MIPs as promising adsorbents for the extraction and removal of contaminants in complex real samples.

Tuning the planarity of molecularly imprinted covalent organic frameworks for selective extraction of ochratoxin A in alcohol samples.

Here, we report a monomer planarity modulation strategy for room-temperature constructing molecularly imprinted-covalent organic frameworks (MI-COFs) for selective extraction of ochratoxin A (OTA). 2,4,6-triformylphloroglucinol (Tp) was used as basic building block, while three amino monomers with different planarity were employed as modulators to explore the effect of planarity on the selectivity of MI-COFs. The MI-TpTapa constructed from Tp and the lowest planarity of monomer Tapa gave the highest selectivity for OTA, and was further used as the adsorbent for dispersed-solid phase extraction (DSPE) of OTA in alcohol samples. Coupling MI-TpTapa based DSPE with high-performance liquid chromatography allowed the matrix-effect free determination of OTA in alcohol samples with the limit of detection of 0.023 µg kg-1 and the recoveries of 91.4-97.6%. The relative standard deviation (RSD, n = 6) of intra and inter day was <3.2%. This work provides a new way to construct MI-COFs for selective extraction of hazardous targets.

Microbial-induced carbonate precipitation effectively prevents Pb2+ migration through the soil profile: Lab experiment and model simulation.

Due to the inappropriate disposal of waste materials containing lead (Pb) and irrigation with sewage containing Pb, the migration of Pb2+ within the soil profile has been extensively investigated. The conventional Pb2+ block method is challenging to implement due to its complex operational procedures and high construction costs. To address this issue, this study introduces the microbial-induced carbonate precipitation (MICP) technique as a novel approach to impede the migration of Pb2+ in the soil profile. Soil acclimatization with urea resulted in an increased proportion of urease-producing microorganisms, including Bacillus, Paenibacillus, and Planococcaceae, along with heightened expression of urea-hydrolyzing genes (UreA, UreB, UreC, and UreG). This indicates that urea-acclimatized soil (Soil-MICP) possesses the potential to induce carbonate precipitation. Batch Pb2+ fixation experiments confirmed that the fixation efficiency of Soil-MICP on Pb2+ exceeded that of soil without MICP, attributed to the MICP process within the Soil-MICP group. Dynamic migration experiments revealed that the MICP reaction transformed exchangeable lead into carbonate-bound Pb, effectively impeding Pb2+ migration in the soil profile. Additionally, the migration rate of Pb2+ in Soil-MICP was influenced by varying urea amounts, pH levels, and pore flow rates, leading to a slowdown in migration. The Two-site sorption model aptly described the Pb2+ migration process in the Soil-MICP column. This study aims to elucidate the MICP biomineralization process, uncover the in-situ blocking mechanism of MICP on lead in soil, investigate the impact of Pb on key genes involved in urease metabolism, enhance the comprehension of the chemical morphology of lead mineralization products, and provide a theoretical foundation for MICP technology in preventing the migration of Pb2+ in soil profiles.

Afterglow Performance of Phenylenevinylene-Based Semiconducting Polymer Nanoparticles Doped with Photosensitizers Containing Electron-Withdrawing Groups.

It is usually believed that doping with photosensitizers capable of generating singlet oxygen (1O2) plays a pivotal role in enhancing the afterglow performance of semiconducting polymer nanoparticles (SPNs). However, the effect of doping photosensitizer bearing electron-withdrawing groups has not been reported. Here we report the effect of doping with six photosensitizers possessing different electron-withdrawing groups on the afterglow performance of SPNs using poly[(9,9-di(2-ethylhexyl)-9H-fluo-rene-2,7-vinylene)-co-(1-methoxy-4-(2-ethylhexyloxy)-2,5-phenylenevinylene)] (PF-MEHPPV) as substrate. It was found that the afterglow performance of SPNs was significantly influenced by doping with photosensitizers bearing electron-withdrawing groups. For the doped photosensitizers with strong electron-withdrawing groups, the stronger the electron-withdrawing ability of the group, the worse of the afterglow performance of the SPN regardless of the 1O2 generation ability of the photosensitizer. When the doped photosensitizer exhibited weak or none electron-withdrawing effect, the 1O2 generation ability of the photosensitizer played a dominant role on the afterglow performance of the SPNs. This work deepens the understanding of the design and synthesis of SPNs with different afterglow properties.

ALKBH5-mediated m6A modification of IL-11 drives macrophage-to-myofibroblast transition and pathological cardiac fibrosis in mice.

Cardiac macrophage contributes to the development of cardiac fibrosis, but factors that regulate cardiac macrophages transition and activation during this process remains elusive. Here we show, by single-cell transcriptomics, lineage tracing and parabiosis, that cardiac macrophages from circulating monocytes preferentially commit to macrophage-to-myofibroblast transition (MMT) under angiotensin II (Ang II)-induced hypertension, with accompanying increased expression of the RNA N6-methyladenosine demethylases, ALKBH5. Meanwhile, macrophage-specific knockout of ALKBH5 inhibits Ang II-induced MMT, and subsequently ameliorates cardiac fibrosis and dysfunction. Mechanistically, RNA immunoprecipitation sequencing identifies interlukin-11 (IL-11) mRNA as a target for ALKBH5-mediated m6A demethylation, leading to increased IL-11 mRNA stability and protein levels. By contrast, overexpression of IL11 in circulating macrophages reverses the phenotype in ALKBH5-deficient mice and macrophage. Lastly, targeted delivery of ALKBH5 or IL-11 receptor α (IL11RA1) siRNA to monocytes/macrophages attenuates MMT and cardiac fibrosis under hypertensive stress. Our results thus suggest that the ALKBH5/IL-11/IL11RA1/MMT axis alters cardiac macrophage and contributes to hypertensive cardiac fibrosis and dysfunction in mice, and thereby identify potential targets for cardiac fibrosis therapy in patients.

Size-Dependent Deformation and Competition H-Bond Site-Induced Individual Fluorescence Response of a Single-Crystal Three-Dimensional Covalent Organic Framework.

Understanding the individual fluorescence response mechanism of covalent organic frameworks (COFs) at a single-crystal level is of great significance for the rational design of COF-based microsensors but unreachable because all previous COF-based sensors are performed with average fluorescence response behavior of various sized polycrystalline COFs. Herein, we design to explore the fluorescence response of a monodisperse single-crystal COF and further reveal the individual heterogeneity of the response mechanism. Three-dimensional single-crystal COF-301 (SCOF-301) with an intramolecular H-bond-induced excited-state intramolecular proton-transfer effect is selected as a proof-of-concept SCOF. With ethanol, benzene, and ammonia as model analytes, three different deformation and competition H-bond site-induced fluorescence response mechanisms related to crystal size are revealed. Small single particles of SCOF-301 (SSCOF-301) exhibit a more flexible structure, leading to the dominant role of deformation in the fluorescence response of small-sized SSCOF-301. The decreasing flexibility of SSCOF-301 with the increase of crystal size results in involvement of competition of the H-bond site to the fluorescence response besides deformation. Further increase of the crystal size makes the large-sized SSCOF-301 difficult to deform; thus, the competition of the H-bond site dominates the fluorescence response. This work provides a deep understanding of the individual fluorescence response mechanism of COFs to guide the design of a functional COF sensor with suitable size and mechanism for different structural analytes.

Integrating molecular imprinting into flexible covalent organic frameworks for selective recognition and efficient extraction of aflatoxins.

Covalent organic frameworks (COFs) are promising adsorbents for extraction, but their selectivity for molecular recognition remains a challenging issue due to the very limited structural design with rigid structure. Herein, we report an elegant strategy for the design and synthesis of molecularly imprinted flexible COFs (MI-FCOFs) via one-pot reaction between the flexible building block of 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine and linear 4-phenylenediamine for selective extraction of aflatoxins. The flexible chain structure enabled the developed MI-FCOF to adjust the shape and conformation of frameworks to suit the template molecule, giving high selectivity for aflatoxins recognition. Moreover, MI-FCOF with abundant imprinted sites and function groups exhibited an exceptional adsorption capacity of 258.4 mg g-1 for dummy template which is 3 times that of no-imprinted FCOF (NI-FCOF). Coupling MI-FCOF based solid-phase extraction with high-performance liquid chromatography gave low detection limits of 0.003-0.09 ng mL-1 and good precision with relative standard deviations ≤ 6.7% for the determination of aflatoxins. Recoveries for the spiked rice, corn, wheat and peanut samples were in the range of 85.4%- 105.4%. The high selectivity of the developed MI-FCOF allows matrix-free determination of AFTs in food samples. This work offers a new way to the design of MI-FCOF for selective molecular recognition.

Pore Size Adjustment Strategy for the Fabrication of Molecularly Imprinted Covalent Organic Framework Nanospheres at Room Temperature for Selective Extraction of Zearalenone in Cereal Samples.

Covalent organic frameworks (COFs) are attractive adsorbents for sample pretreatment due to their unique structure and properties. However, the selectivity of COFs for the extraction of hazardous compounds is still limited due to the lack of specific interactions between COFs and targets. Herein, we report a pore size adjustment strategy for room-temperature synthesis of molecularly imprinted COF (MICOF) for selective extraction of zearalenone (ZEN) in complex food samples. The three-dimensional building block tetra(4-aminophenyl) methane was used as a functional monomer, while dialdehyde monomers with different numbers of benzene ring were used to adjust the pore size of MICOF to match with the size of ZEN molecules. The prepared MICOF gave the largest adsorption capacity of 177.2 mg g-1 and the highest imprinting factor of 10.1 for ZEN so far. MICOF was used as the adsorbent for dispersed solid-phase extraction in combination with high-performance liquid chromatography for the determination of trace ZEN in cereals. The high selectivity of the developed method allows simple aqueous standard calibration for the matrix effect-free determination of ZEN in food samples. The limit of detection and the recoveries of the developed method were 0.21 µg kg-1 and 93.7-101.4%, respectively. The precision for the determination of ZEN was less than 3.8% (RSD, n = 6). The developed method is promising for the selective determination of ZEN in complex matrices.