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Ensuring food safety continues to be one of the major global challenges. For effective food safety monitoring, fast, sensitive, portable, and efficient food safety detection strategies must be devised. Metal organic frameworks (MOFs) are porous crystalline materials that have attracted attention for use in high-performance sensors for food safety detection owing to their advantages such as high porosity, large specific surface area, adjustable structure, and easy surface functional modification. Immunoassay strategies based on antigen-antibody specific binding are one of the important means for accurate and rapid detection of trace contaminants in food. Emerging MOFs and their composites with excellent properties are being synthesized, providing new ideas for immunoassays. This article summarizes the synthesis strategies of MOFs and MOF-based composites and their applications in the immunoassays of food contaminants. The challenges and prospects of the preparation and immunoassay applications of MOF-based composites are also presented. The findings of this study will contribute to the development and application of novel MOF-based composites with excellent properties and provide insights into advanced and efficient strategies for developing immunoassays., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

With the rapid growth of the economy, people are increasingly reliant on energy sources. However, in recent years, the energy crisis has gradually intensified. As a clean energy source, methane has garnered widespread attention for its development and utilization. This study employed both large-scale computational screening and machine learning to investigate the adsorption and diffusion properties of thousands of metal–organic frameworks (MOFs) in six gas binary mixtures of CH4 (H2/CH4, N2/CH4, O2/CH4, CO2/CH4, H2S/CH4, He/CH4) for methane purification. Firstly, a univariate analysis was conducted to discuss the relationships between the performance indicators of adsorbents and their characteristic descriptors. Subsequently, four machine learning methods were utilized to predict the diffusivity/selectivity of gas, with the light gradient boosting machine (LGBM) algorithm emerging as the optimal one, yielding R2 values of 0.954 for the diffusivity and 0.931 for the selectivity. Furthermore, the LGBM algorithm was combined with the SHapley Additive exPlanation (SHAP) technique to quantitatively analyze the relative importance of each MOF descriptor, revealing that the pore limiting diameter (PLD) was the most critical structural descriptor affecting molecular diffusivity. Finally, for each system of CH4 mixture, three high-performance MOFs were identified, and the commonalities among high-performance MOFs were analyzed, leading to the proposals of three design principles involving changes only to the metal centers, organic linkers, or topological structures. Thus, this work reveals microscopic insights into the separation mechanisms of CH4 from different binary mixtures in MOFs. [ABSTRACT FROM AUTHOR]

• A magnetic-fluorescent immunosensing platform for efficient detection of ZEN in cereal products was developed. • MIL-53(Al)@AuNPs heterogeneous composite were facilely synthesized to prepare fluorescent signal probe. • The capture probe (MNPs-mAbs) was used to capture the target ZEN rapidly and simplify the immunoassay process. • This MOF-based magnetic-fluorescent immunoassay can rapidly detect ZEN contaminant with a LOD of 0.0035 ng/mL. Rapid, sensitive, specific and stable detection of mycotoxin in food remains an extremely crucial issue. Herein, a magnetic-fluorescent immunosensing platform for the detection of zearalenone (ZEN) was proposed. The platform utilized Au nanoparticles (AuNPs) heterogeneous fluorescent metal–organic framework (MIL-53(Al)@AuNPs) labeled with ZEN-bovine serum albumin (ZEN-BSA) as signal probe and ZEN mono-antibodies coupled with magnetic NPs (MNPs-mAbs) as capture probe. Specifically, the heterogenization of AuNPs on the MIL-53(Al) surface improved its biocompatibility, and facilitated the loading of ZEN-BSA conjugates. The MNPs-mAbs could rapidly capture the target ZEN, simplify the immunoassay process and further improve the detection efficiency. The established competitive magnetic-fluorescent immunosensing platform had a wider linear response to ZEN in the range of 0.001–100 ng/mL with a lower limit of detection (LOD) at 0.0035 ng/mL, and could finish the whole detection process within 20 min, showing great potential for rapid and sensitive detection of food contaminants. [ABSTRACT FROM AUTHOR]

• A smartphone-assisted fluorescence-colorimetric immunosensing platform was proposed. • NH 2 -UiO-66@PtNPs was exploited to construct a fluorescence-colorimetric signal probe. • The multi-mode immunosensing microarray showed satisfactory results of AMD detection. • The efficient, visual and portable method showed great potential in food analysis. Amantadine (AMD) is an antiviral drug used to treat animal-based infectious diseases such as avian influenza. However, its illegal use in animal-derived food industries endangers human health. Therefore, an efficient, portable, and visual sensor to detect AMD in food is crucial for ensuring food safety. A multifunctional nanocomposite NH 2 -UiO-66@PtNPs was exploited to design a smartphone-assisted fluorescence-colorimetric immunosensing microarray for multidimensional detection of AMD in animal-derived foods. Platinum nanoparticles (NPs) were immobilized on a Zr-based metal–organic framework (NH 2 -UiO-66). Pt NPs exhibited peroxidase-like activity, whereas NH 2 -UiO-66 stabilized Pt NPs and improved the colorimetric signal of the sensor. Moreover, the fluorescence ligand NH 2 -BDC in NH 2 -UiO-66 was released via alkaline hydrolysis, amplifying the fluorescence signal and improving detection sensitivity. The smartphone-assisted color recognition system accurately identified the color changes of the microarray. The immunocompetitive reaction of AMD and the antibody (Ab) in the microarray NH 2 -UiO-66@PtNPs@Ab 2 allowed the quantitative and visual detection of AMD in a wide concentration range (0.1–1000 ng/mL) with high sensitivity [limit of detection = 0.0022 ng/mL (fluorescence), 0.069 ng/mL (colorimetric), and 0.68 ng/mL (smartphone)]. This detection strategy was verified in AMD-spiked food samples with satisfactory recoveries (82.0–103.0%) and stability (RSD: ≤7.1%, n = 3), showing its great potential for visual screening and portable detection of other food contaminants. [ABSTRACT FROM AUTHOR]

[Display omitted] • In silico screening was performed for the dynamic adsorption of O 2 and N 2. • K O2 and the metal type of the MOFs were critical factors for O 2 /N 2 separation. • Transition-metal-based MOFs were more conducive to the selective adsorption of O 2 over N 2. • Three strategies are proposed to design MOFs for O 2 /N 2 separation. It remains a great challenge to separate O 2 from N 2 at room temperature. Pressure swing adsorption (PSA) technology is a potential candidate, and the development of high-efficiency adsorbents for O 2 /N 2 separation at room temperature has attracted a great deal of interest. In this work, machine learning (ML)-assisted high-throughput computational screening (HTCS) techniques were performed to screen the dynamic adsorption of O 2 and N 2 in 6,013 computation-ready experimental metal–organic frameworks (CoRE-MOFs) , including the competitive adsorption of O 2 and the diffusion of pure N 2 and O 2 , to identify the best materials for O 2 /N 2 separation. First, based on HTCS, we established the relationships between the structural/energetic descriptors with the performance indicators. Three machine learning (ML) algorithms were then applied to predict the performance indicators of MOFs. In addition, the relative importance of the structural/energetic descriptors and metal center type in MOFs toward the separation performance was evaluated, indicating that the metal center type of MOFs is a key factor for the separation of O 2 /N 2. Transition metal elements were determined to have highest importance by ML. Moreover, the 13 best MOFs were identified for the dynamic adsorption of O 2 from the air. Finally, three types of design strategies could significantly improve the performance of MOFs, such as regulating the topology and alternating the metal node and organic linker. The combination of HTCS, ML, and design strategies from bottom to top provide powerful microscopic insights for the development of MOF adsorbents for the separation of O 2 at room temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rapid mechanochemical synthesis of Co(AIP)(BPY) 0.5 at the gram scale. • Co(AIP)(BPY) 0.5 –25 with CH 4 uptake of 1.03 mmol/g and CH 4 /N 2 selectivity of 7.3. • The separation is due to the difference in geometrical structures of CH 4 and N 2. Efficient capture dilute methane (CH 4) from nitrogen (N 2) is of significant importance in both environment and economical aspects. However, CH 4 /N 2 separation is still a great challenge in gas separation field limited by their close physical properties. Herein, we developed the mechanochemical synthesis of a cobalt-based pillar-layer metal–organic framework, Co(AIP)(BPY) 0.5 , for adsorption separation of CH 4 /N 2 mixture. This synthetic method allowed Co(AIP)(BPY) 0.5 accessible rapidly and sustainably at the gram scale. By varying the grinding time, a series of mechanochemically synthesized Co(AIP)(BPY) 0.5 products were obtained and CO 2 adsorption measurements confirmed that Co(AIP)(BPY) 0.5 –25 obtained by grinding for 25 min had the highest porosity. Then CH 4 /N 2 adsorption and separation of the resulting Co(AIP)(BPY) 0.5 –25 was studied. CH 4 and N 2 uptakes of Co(AIP)(BPY) 0.5 –25 were 1.03 and 0.26 mmol/g at 298 K and 5 bar, showing preferential adsorption of CH 4 over N 2 and the CH 4 /N 2 selectivity with 7.3. Meanwhile, the excellent potential separation ability of CH 4 /N 2 mixtures with different concentrations on Co(AIP)(BPY) 0.5 –25 was confirmed by simulated breakthrough experiments. Molecular simulations revealed that spheroidal CH 4 molecules were located in the center of the pores while most of linear N 2 molecules were only distributed near the walls of the pores due to the difference in geometrical structures. This work provides an example of rapid mechanochemical synthesis of Co(AIP)(BPY) 0.5 within short time for separating CH 4 /N 2 mixture. [ABSTRACT FROM AUTHOR]