A novel detection method for organophosphorus insecticide fenamiphos: Molecularly imprinted electrochemical sensor based on core-shell Co3O4@MOF-74 nanocomposite

Highly sensitive and selective electrochemical detection of catechol using surface molecularly-imprinted film integrated with ratiometric indicator displacement assay

Catechol (CC) is an important environmental pollutant due to its toxicity, non-degradability and widespread distribution. The rapid, sensitive, and selective detection of CC remains a challenging task owing to the coexistence of multiple phenolic pollutants with similar structures and properties in the environment. This article proposed an electrochemical sensing system that combined a molecularly imprinted sensing interface and ratiometric indicator displacement assay (IDA) for sensitive and selective detection of CC. A unique carbon nanotubes (CNTs) interpenetrating ZIF-8 material (CNT@ZIF-8) was successfully prepared and utilized as a support for surface molecular imprinting of CC. As a substrate material, CNT@ZIF-8 increased the electroactive surface area of the electrode, improved electronic conductivity, and promoted the bonding stability of molecularly imprinted polymer (MIP) film on the electrode. The developed sensing interface exhibited excellent adsorption affinity, enrichment ability, and signal transduction ability towards CC. On this basis, a novel IDA method based on ratiometric electrochemical signals was developed using epinephrine (EP) as a competitive indicator. The proposed electrochemical sensing platform had a wide linear range of 1-1000 μM with a detection limit of 0.23 μM and exhibited high anti-interference ability, good repeatability, superior regenerability, and long-term stability. The sensing system was applied to the analysis of CC in tap water and green tea samples, with recoveries of 94.4 %-104 % and 95.7 %-106.7 %, respectively, demonstrating broad practical application prospects. This study not only provides a promising conductive material for surface molecular imprinting and electrochemical sensing but also offers a reliable strategy for the electrochemical detection of CC.

Metal-organic frameworks-molecularly imprinted polymers (MOF-MIP): Synthesis, properties, and applications in detection and control of microorganisms

Microbial contamination poses a significant threat to human health, food safety, and the ecological environment. Its rapid spread and potential pathogenicity create an urgent global challenge for efficient detection and control. However, existing methods have several shortcomings such as traditional techniques like culture methods and polymerase chain reaction (PCR) are time-consuming, while nanomaterials and aptamers often lack selectivity, stability, and affordability. Additionally, conventional disinfectants can be inefficient, lead to drug resistance, and harm the environment. To address these challenges, developing new materials and technologies that are efficient, sensitive, and stable is crucial for microbial detection and control. In this context, metal-organic frameworks (MOF) and molecularly imprinted polymers (MIP) have emerged as promising functional materials due to their unique structural advantages. The high porosity of MOF provides ample imprinting sites for MIP, while MIP enhance selective adsorption and inactivation of target microorganisms by MOF. This synergistic combination results in a composite material that offers a novel solution for microbial detection, significantly improving sensitivity, selectivity, antibacterial efficiency, and environmental friendliness. This paper reviews the synthesis strategies of metal-organic frameworks-molecularly imprinted polymers (MOF-MIP), highlighting their structural properties and innovative applications in microbial detection, which aim to inspire researchers in related fields. Looking ahead, future advancements in material science and biotechnology are expected to lead to widespread use of MOF-MIP composites in food safety, environmental monitoring, medical diagnosis, and public health-providing robust support against microbial pollution. By studying the collaborative mechanisms of MOF and MIP while optimizing design processes will enhance precision speed cost-effectiveness in microbial detection technology significantly contributing to human health and environmental safety.

Ultrasensitive electrochemical sensor for luteolin based on MOFs-derived metal oxide/alloy-doped nitrogen-containing porous carbon composites

As a natural flavonoid with diverse pharmacological activities, luteolin has shown attractive potential in various applications such as drug discovery, food preservation, health care products, and cosmetics. The precise quantification of luteolin is not only crucial for optimizing its therapeutic efficacy, but also for ensuring compliance with safety standards, as its biological activity largely depends on concentration thresholds and excessive intake may lead to adverse reactions. Here, we have successfully developed an electrochemical sensing platform for luteolin using a simple synthesis strategy. The core of this platform lies in the composite of metal oxides/alloys and nitrogen-doped porous carbon obtained after pyrolysis, whose unique porous architecture and rich pyrrolic nitrogen structure provide efficient adsorption sites for luteolin, while the diverse active centers embedded in the composite significantly enhance its electrocatalytic efficacy. The carefully constructed FeCo-NC-800/GCE electrochemical sensing platform exhibits excellent performance in detecting luteolin. More importantly, we have successfully applied this sensing platform to the detection of luteolin in actual samples such as peanut shells, honeysuckle, and chrysanthemum, which verified the accurate identification of luteolin by FeCo-NC-800/GCE in complex environmental backgrounds and demonstrated its great potential in practical applications.

Introducing bimetallic MOF-based electrochemical sensor for voltametric nanogram determination of sulfadimidine: various applications and a comprehensive sustainability assessment

Due to its characteristics and allowable use, the sulphonamide group remains a first-choice treatment for veterinarians when managing multiple veterinary diseases. Unfortunately, long-term consumption of food containing sulphonamide residues can result in harmful effects, especially that sulphonamides are classified in category D. Metal-organic frameworks (MOFs) have demonstrated outstanding selectivity in detecting target components due to their large surface areas and intricate structures. In this study, we present a novel voltammetric approach for determining sulfadimidine (SLD) in veterinary formulations, animal plasma, and animal-derived products, including milk and eggs. We employed a bimetallic Cu/Ni-MOF to modify a carbon paste electrode, utilizing differential pulse voltammetry (DPV) for SLD detection. The morphology of the Cu/Ni-MOF was analyzed to ensure optimal structural characteristics, and experimental conditions were optimized to achieve the best performance. A major advantage of this method is its wide linearity range (100 nM to 100,000 nM) and the ability to detect SLD at nanogram levels, with a LOD of 20 nM and a LOQ of 60 nM. These characteristics demonstrate the fabricated Cu/Ni-MOF's capability to detect SLD at levels below its maximum residue limit (MRL) in plasma, milk, and eggs. Furthermore, the environmental impact of this method was assessed using the RGB 12 metric and compared against the AGREE, Complex GAPI, and BAGI metrics, offering a comprehensive evaluation of its analytical performance and practical advantages. This approach holds promise for curbing antibiotic misuse by providing a straightforward and effective method for SLD detection across multiple matrices.

Hapten prediction, monoclonal antibody preparation, and development of an immunochromatographic assay for the detection of fenamiphos

Fenamiphos (FENA) is an organophosphorus insecticide, and its residues in fruits, vegetables, and the environment have raised concerns. Therefore, it is very important to develop a simple, rapid, and accurate method for FENA detection. In this study, a novel FENA hapten was designed and predicted based on computer-aided simulation technology, and high-performance anti-FENA monoclonal antibodies were screened using a matrix effect-enhanced screening method, with a half-maximal inhibitory concentration of 1.269 ng/mL. Furthermore, a colloidal gold immunochromatographic assay (ICA) was established for the detection of FENA, with calculated limits of detection of 1.030 μg/kg, 0.515 μg/kg, 0.250 ng/mL, and 0.405 μg/kg in oranges, cowpeas, river water, and soil. Spiked recovery experiments and real sample validation showed that the detection results from the ICA and LC-MS/MS were consistent, with a CV < 10 %, indicating that the ICA had good accuracy and stability and shows promise as a rapid screening method for FENA in fruits, vegetables, and the environment.

Plasmonic Porous ZIF-8/Au NPs Platforms: A Complex Matrix Enhances SERS Substrate for Micromolar-Trace Detection of Several Analytes

Surface-enhanced Raman scattering (SERS) is an advantageous method for organic chemical and biological sensing. Benzoic acid, benzisothiazolinone, and thiram are common model compounds used to study the interaction of toxic substances with metal surfaces using SERS spectroscopy. Metal-organic frameworks, with their high porosity and large surface area, have recently received a lot of attention in sensing applications. Plasmonic porous structures are promising SERS substrates because of their high broadband charge-transfer resonance and reproducibility of fabrication. Furthermore, the exceptional enhancement of the electromagnetic field makes plasmonic nanomaterials ideal SERS substrates. In this study, we developed SERS substrates based on ZIF-8/Au NPs through a self-assembly process that forms stacked layers. The ZIF-8/Au NPs substrate demonstrated a remarkable ability to enhance Raman scattering, enabling ultrasensitive detection of various target molecules at micromolar concentrations. These attributes establish it as a promising SERS substrate for biosensing applications.

Ultrasensitive quantification of neonicotinoid thiamethoxam in environment using MOF-derived CuCo2O4/3D rGO based electrochemical sensor integrated with optimized neural network

Accurate quantification of neonicotinoid insecticides is pivotal to ensure environmental safety by examining and mitigating their potential harmful effects on pollinators and aquatic ecosystems. In this scenario, detection of neonicotinoid insecticide, thiamethoxam (TMX), is significant for safeguarding ecological balance and human health. Hence, we developed a highly sensitive electrochemical sensor for detection of TMX in environmental samples, utilizing a novel nanocomposite with superior electrocatalytic properties and integrating an optimized neural network for accurate data analysis. The nanocomposite was synthesized via sonochemical approach, combining metal-organic framework (MOF)-derived spinel copper cobaltite (M-CuCo₂O₄) with three-dimensional reduced graphene oxide (3DrGO). Important characterizations were performed on prepared M-CuCo₂O₄/3DrGO composite and was immobilized on a screen-printed carbon electrode (SPCE) for electrochemical investigations. The synergistic effects of M-CuCo₂O₄ and 3DrGO enabled M-CuCo₂O₄/3DrGO/SPCE to achieve exceptional performance towards TMX detection. The sensor exhibited low limit of detection (LOD) of 0.6 nM and wide linear range of 0.15-174.52 μM. Furthermore, neural network model demonstrated excellent accuracy in estimating TMX concentrations, achieving a root mean square error (RMSE) of 2.01 and mean absolute error (MAE) of 1.33. The sensor showed remarkable stability and reliability in real samples including agricultural wastewater, red soil, and brown rice, highlighting its practical applicability for TMX monitoring in environmental and agricultural contexts.

Redefining Metal Organic Frameworks in Biosensors: Where Are We Now?

As a broad class of porous nanomaterials, metal organic frameworks (MOFs) exhibit unique properties, such as broad tunability, high stability, atomically well-defined structure, and ordered uniform porosity. These features facilitate the rational design of MOFs as an outstanding nanomaterial candidate in biosensing, therapeutics delivery, and catalysis applications. Recently, novel modifications of the MOF nanoarchitecture and incorporation of synergistic guest materials have been investigated to achieve well-tailored functional design, gradually bridging the fundamental gap between structure and targeted activity. Specifically, the burgeoning studies of MOF-based high-performance biosensors have aimed to achieve high sensitivity, selectivity, and stability for a large variety of analytes in different sensing matrices. In this review, we elaborate the key roles of MOF nanomaterials in biosensors, including their high stability as a protective framework for biomolecules, their intrinsic sensitivity-enhancing functionalities, and their contribution of catalytic activity as a nanozyme. By examining the main structures of MOFs, we further identify varied structural engineering approaches, such as precursor tuning and guest molecule incorporation, that elucidate the concept of the structure-activity relationship of MOFs. Furthermore, we highlight the unique applications of MOF nanomaterials in electrochemical and optical biosensors for enhanced sensor performances. Finally, the challenges and future perspectives of developing next-generation MOF nanomaterials for biosensor applications are discussed.

Graphdiyne biomaterials: from characterization to properties and applications

Graphdiyne (GDY), the sole synthetic carbon allotrope with sp-hybridized carbon atoms, has been extensively researched that benefit from its pore structure, fully conjugated surfaces, wide band gaps, and more reactive C≡C bonds. In addition to the intrinsic features of GDY, engineering at the nanoscale, including metal/transition metal ion modification, chemical elemental doping, and other biomolecular modifications, endowed GDY with a broader functionality. This has led to its involvement in biomedical applications, including enzyme catalysis, molecular assays, targeted drug delivery, antitumor, and sensors. These promising research developments have been made possible by the rational design and critical characterization of GDY biomaterials. In contrast to other research areas, GDY biomaterials research has led to the development of characterization techniques and methods with specific patterns and some innovations based on the integration of materials science and biology, which are crucial for the biomedical applications of GDY. The objective of this review is to provide a comprehensive overview of the biomedical applications of GDY and the characterization techniques and methods that are essential in this process. Additionally, a general strategy for the biomedical research of GDY will be proposed, which will be of limited help to researchers in the field of GDY or nanomedicine.

Advances and Challenges in Molecularly Imprinted Electrochemical Sensors for Application in Environmental, Biomedicine, and Food Safety

Molecularly imprinted electrochemical sensors (MIECSs) are a specialized class of sensors based on molecularly imprinted derivative materials (MIDPs), which have been extensively applied in environmental monitoring, biomedicine, and food safety, allowing for high selectivity and sensitivity in detecting target molecules. This review provides an in-depth exploration of the most innovative and successful nanomaterials employed for modifying imprinted polymers, highlighting their crucial role in enhancing sensor performance, including carbon-based nanomaterials, meal derivatives, magnetic nanomaterials, polymeric and composite nanomaterials. In addition to reviewing advances in derivative materials design, this article delves into the current challenges facing molecularly imprinted sensors, such as issues related to template removal, nonspecific binding, and fabrication reproducibility. These challenges limit the practical application of MIECSs, particularly in complex real-world environments. The review also discusses representative applications of these sensors, including environmental monitoring, biomedicine and food safety, which demonstrate their versatility and potential. Finally, the review outlines future research directions aimed at overcoming these challenges. This includes strategies for improving the stability and reusability of MIECSs, enhancing their selectivity and sensitivity, and developing novel imprinting techniques. By addressing these issues, researchers can pave the way for the next generation of electrochemical sensors, which will be more robust, reliable, and suitable for a wide range of industrial and clinical applications.

Emerging carbonaceous material based on residual grape seed applied in selective and sensitive electrochemical detection of fenamiphos

Fenamiphos (FNP) is a pesticide applied for soil pest control, particularly nematodes, and sucking insects, including aphids and thrips. Despite its use being banned in several countries due to its highly toxic nature for living beings, including mammals, because of its acetylcholine-inhibiting action, it is still marketed for use in agriculture. Therefore, a carbon paste electrode modified with residual grape seed biochar (bSU), served as an electrochemical sensor (E-bSU) for the quantification of fenamiphos in grape juice, tap water, and river water samples. The bSU underwent comprehensive characterization employing elemental, morphological, and spectroscopic analysis techniques. The impact of electrode modification and the electrochemical behavior of the FNP were systematically assessed through cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. The biochar manifested a microporous surface adorned with dispersed functional groups, enhancing its affinity for organic compounds, particularly the investigated pesticide. Electrode modification and the optimization of analysis parameters resulted in a notable 6-fold amplification of the electrochemical signal of FNP relative to initial conditions, underscoring the efficacy of the E-bSU. The developed methodology attained limits of detection and quantification of 0.3 and 0.9 nmol L⁻1, respectively. Repeatability and reproducibility assays demonstrated relative standard deviations below 5%, underscoring the reliability of the applied electrode. The sensor showcased recoveries ranging from 99.75% to 109.9% across the analyzed samples, highlighting the utility of this selective, stable, and reproducible sensor for fenamiphos determination.

Recent advances on metal-organic framework-based electrochemical sensors for determination of organic small molecules

Metal-organic frameworks (MOFs) are an extraordinarily versatile class of porous materials renowned for their intricate three-dimensional skeletal architectures and exceptional chemical properties. These extraordinary attributes have pushed MOFs into the vanguard of diverse disciplines such as microporous conduction, catalysis, separation, biomedical engineering, and electrochemical sensing. The focus of this review is to offer a comprehensive summary of recent advancements in designing MOF-based electrochemical sensors for detecting organic small molecules. offer a comprehensive survey of the recent progress in the methodologies adopted for the construction of MOF composites, covering template-assisted synthesis, Modification in synthesis, and post-synthesis modification. In addition, we discuss the practical application of MOF-based electrochemical sensors in the detection of organic small molecules. Our findings highlight the superior electrochemical sensing capabilities of these novel composites compared to those of their pristine counterparts. In conclusion, we provide a condensed perspective on the potential future trajectories in this domain, underscoring the impetus for continued enquiry and enhancement of MOF composite assemblies. With sustained investigation, the horizon appears bright for electrochemical sensing of small organic molecules and their myriad applications.

Hazardous Materials from Threats to Safety: Molecularly Imprinted Polymers as Versatile Safeguarding Platforms

Hazards associated with highly dangerous pollutants/contaminants in water, air, and land resources, as well as food, are serious threats to public health and the environment. Thus, it is imperative to detect or decontaminate, as risk-control strategies, the possible harmful substances sensitively and efficiently. In this context, due to their capacity to be specifically designed for various types of hazardous compounds, the synthesis and use of molecularly imprinted polymers (MIPs) have become widespread. By molecular imprinting, affinity sites with complementary shape, size, and functionality can be created for any template molecule. MIPs' unique functions in response to external factors have attracted researchers to develop a broad range of MIP-based sensors with increased sensitivity, specificity, and selectivity of the recognition element toward target hazardous compounds. Therefore, this paper comprehensively reviews the very recent progress of MIPs and smart polymer applications for sensing or decontamination of hazardous compounds (e.g., drugs, explosives, and biological or chemical agents) in various fields from 2020 to 2024, providing researchers with a rapid tool for investigating the latest research status.

Effective inhibition of chloride ion interference in photocatalytic process by negatively charged molecularly imprinted photocatalyst: Behavior and mechanism

The ubiquitous chloride ions (Cl-) in water seriously interfere with pollutant oxidation and inevitably generate undesirable chlorinated byproducts. In this study, we report for the first time that a negatively charged molecularly imprinted photocatalyst (MIP) can effectively inhibit Cl- interference and suppress the production of chlorination byproducts (the yield of chloroacetic acid was only 16 % of the bare photocatalyst system) while ensuring efficient degradation of target pollutants, thereby greatly improving the safety of the pollutant degradation process. Taking antibiotics as target pollutant, we investigated the mechanism of action of MIP by comparing the antibiotic degradation pathways, fate of photogenerated active species and production of reactive chlorine species (RCS) in the MIP and bare photocatalyst system. The mechanism by which MIP inhibits Cl- interference was mainly based on a synergy between electrostatic repulsion and steric hindrance induced by the specific capture of antibiotics in imprinted cavity, which effectively suppressed the production of RCS and hindered the participation of RCS in antibiotics degradation. In addition, MIP showed good compatibility with common cations, anions and organic matter, and performed well within a broad pH range in various water environments. Thus, the negatively charged MIP provides a feasible approach for the safe and efficient removal of pollutants in Cl- containing water.

Boosted photocatalytic hydrogen evolution of S-scheme N-doped CeO2-δ@ZnIn2S4 heterostructure photocatalyst

The advancement of highly effective heterojunction photocatalysts with improved charge separation and transfer has become a crucial scientific perspective for utilizing solar energy. In this study, we developed the S-scheme heterostructure by depositing N-doped CeO2-δ (NC) nanoparticles onto two-dimensional ZnIn2S4 (ZIS) nanosheets via hydrolysis strategy for significantly enhanced photocatalytic hydrogen evolution reaction. The optimal H2 generation rate of ∼ 798 μmol g-1 h-1 was achieved for NC-3@ZIS under solar light irradiation, which is about 18 and 2 times higher than those of pristine CeO2 (∼44 μmol g-1 h-1) and ZIS (∼358 μmol g-1 h-1), respectively. The photogenerated electrons from NC interact with the photogenerated holes of ZIS driven by an internal electric field, confirmed by In-situ KPFM, DFT calculation, and XPS results. According to EPR and photoelectrochemical measurements, NC-3@ZIS composite shows dramatically high separation efficiency of photogenerated charge carriers. This study provides a new approach for developing non-noble metal S-scheme heterojunctions with enhanced photocatalytic hydrogen evolution.

Efficient Electrochemical Sensing of Chlorpromazine with a Composite of Multiwalled Carbon Nanotubes and a Thiacalix[4]arene-Based Metal-Organic Framework

Chlorpromazine (CPMZ) is a representative drug for the treatment of psychiatric disorders. Excessive use of CPMZ could result in some serious health problems, and therefore, construction of a sensitive electrochemical sensor for CPMZ detection is greatly significant for human health. Herein, a feasible electrochemical method for the detection of CPMZ was provided. To design a suitable electrode surface modifier, a new two-dimensional (2D) thiacalix[4]arene-based metal-organic framework was designed and synthesized under solvothermal conditions, namely, [Co(TMPA)Cl2]MeOH·2EtOH·2H2O (Co-TMPA). Afterward, a series of composite materials was prepared by combining Co-TMPA with highly conductive carbon materials. Markedly, Co-TMPA/MWCNT-2@GCE (GCE = glassy carbon electrode, MWCNT = multiwalled carbon nanotube) exhibited the best electrocatalytic performance for CPMZ detection due to the synergistic effect between MWCNT and Co-TMPA. Particularly, it featured a low limit of detection (8 nM) and a wide linear range (0.05 to 1350 μM) in quantitative determination of CPMZ. Meanwhile, the sensor possessed excellent stability, selectivity, and reproducibility. Importantly, Co-TMPA/MWCNT-2@GCE was employed to analyze CPMZ in urine and serum with satisfactory recoveries (98.87-102.17%) and relative standard deviations (1.44-3.80%). Furthermore, the electrochemical detection accuracy of the Co-TMPA/MWCNT-2@GCE sensor was verified with the ultraviolet-visible spectroscopy technique. This work offers a promising sensor for the efficient analysis of drug molecules.

Recent and emerging trends of metal-organic frameworks (MOFs)-based sensors for detecting food contaminants: A critical and comprehensive review

Interest in the use of sensors based on metal-organic frameworks (MOFs) to detect food pollutants has been growing recently due to the desirable characteristics of MOFs, including uniform structures, large surface area, ultrahigh porosity and easy-to-functionalize surface. Fundamentally, this review offers an excellent solution using MOFs-based sensors (e.g., fluorescent, electrochemical, electrochemiluminescence, surface-enhanced Raman spectroscopy, and colorimetric sensors) to detect food contaminants such as pesticide residues, mycotoxins, antibiotics, food additives, and other hazardous candidates. More importantly, their application scenarios and advantages in food detection are also introduced in more detail. Therefore, this systematic review analyzes detection limits, linear ranges, the role of functionalities, and immobilized nanoparticles utilized in preparing MOFs-based sensors. Additionally, the main limitations of each sensing type, along with the enhancement mechanisms of MOFs in addressing efficient sensing are discussed. Finally, the limitations and potential trends of MOFs-based materials in food contaminant detection are also highlighted.

Recent Advances in Metal-Organic Framework (MOF)-Based Composites for Organic Effluent Remediation

Environmental pollution caused by organic effluents emitted by industry has become a worldwide issue and poses a serious threat to the public and the ecosystem. Metal-organic frameworks (MOFs), comprising metal-containing clusters and organic bridging ligands, are porous and crystalline materials, possessing fascinating shape and size-dependent properties such as high surface area, abundant active sites, well-defined crystal morphologies, and huge potential for surface functionalization. To date, numerous well designated MOFs have emerged as critical functional materials to solve the growing challenges associated with water environmental issues. Here we present the recent progress of MOF-based materials and their applications in the treatment of organic effluents. Firstly, several traditional and emerging synthesis strategies for MOF composites are introduced. Then, the structural and functional regulations of MOF composites are presented and analyzed. Finally, typical applications of MOF-based materials in treating organic effluents, including chemical, pharmaceutical, textile, and agricultural wastewaters are summarized. Overall, this review is anticipated to tailor design and regulation of MOF-based functional materials for boosting the performance of organic effluent remediation.

Extremozyme-Based Biosensors for Environmental Pollution Monitoring: Recent Developments

Extremozymes combine high specificity and sensitivity with the ability to withstand extreme operational conditions. This work presents an overview of extremozymes that show potential for environmental monitoring devices and outlines the latest advances in biosensors utilizing these unique molecules. The characteristics of various extremozymes described so far are presented, underlining their stability and operational conditions that make them attractive for biosensing. The biosensor design is discussed based on the detection of photosynthesis-inhibiting herbicides as a case study. Several biosensors for the detection of pesticides, heavy metals, and phenols are presented in more detail to highlight interesting substrate specificity, applications or immobilization methods. Compared to mesophilic enzymes, the integration of extremozymes in biosensors faces additional challenges related to lower availability and high production costs. The use of extremozymes in biosensing does not parallel their success in industrial applications. In recent years, the "collection" of recognition elements was enriched by extremozymes with interesting selectivity and by thermostable chimeras. The perspectives for biosensor development are exciting, considering also the progress in genetic editing for the oriented immobilization of enzymes, efficient folding, and better electron transport. Stability, production costs and immobilization at sensing interfaces must be improved to encourage wider applications of extremozymes in biosensors.

Optimization and verification of selective removal of organophosphate esters from wastewater by molecularly imprinted adsorbent

Tributyl phosphate (TNBP), a new type of flame retardant, is an emerging pollutant and has been frequently detected in various matrices such as wastewater. Efficient removal of TNBP is critical for wastewater treatment. In this study, molecularly imprinted polymer (MIP) was prepared using precipitation polymerization for selective adsorption of TNBP. The results showed that MIP had a porous structure and formed effective imprinting cavities, which was primarily responsible for its superior adsorption ability. The adsorption of TNBP by MIP was carried out following both the pseudo-secondary kinetic model and the Langmuir isothermal adsorption model. MIP adsorbed TNBP rapidly and reached adsorption equilibrium within 30 min with 923 μmol g-1 at 298 K. The adsorption capacity and adsorption rate of MIP were respectively 2 and 5.49 times those of non-molecularly imprinted polymers. In addition, MIP could effectively counter disturbances from external parameters like temperature and pH, exhibiting strong environmental flexibility. MIP can specifically adsorb organophosphate esters, and can selectively adsorb TNBP under the interference of coexisting contaminants such as1,3-diphenylguanidine and isazofos. In actual bodies of water, MIP's highly selective adsorption of TNBP retains its advantage. The selective adsorption of MIP was mainly due to the common phosphate skeleton, and the specific substituent of organophosphate esters played an important role in the imprinting process. Hydrogen bonding might be involved in the polymerization process of TNBP with acrylamide and the adsorption process of TNBP by MIP.MIP exhibited good reuse efficiency, the total adsorption capacity decreased by no more than 25% after 7 reuse cycles. This study provides a simple and efficient method for selective removal of organophosphate from wastewater.

Emerging trends in sensors based on molecular imprinting technology: Harnessing smartphones for portable detection and recognition

Molecular imprinting technology (MIT) has become a promising recognition technology in various fields due to its specificity, high efficiency, stability and eco-friendliness in the recognition of target. Molecularly imprinted polymers (MIPs), known as 'artificial receptors', are shown similar properties to natural receptors as a biomimetic material. The selectivity of recognition for targets can be greatly improved when MIPs are introduced into sensors, as known that MIPs, are suitable for the pretreatment and analysis of trace substances in complex matrix samples. At present, various sensors has been developed by the combination with MIPs for detecting and identifying trace compounds, biological macromolecules or other substances, such as optical, electrochemical and piezoelectric sensors. Smart phones, with their built-in sensors and powerful digital imaging capabilities, provide a unique platform for the needs of portability and instant detection. MIP sensors based on smart phones are expected to become a new research direction in the future. This review discusses the latest applications of MIP sensors in the field of detection and recognition in recent years, summarizes the frontier progress of MIP sensor research based on smart phones in the past two years, and points out the challenges, limitations and future development prospects.

Dual-functional molecularly imprinted doped carbon dot based on metal-organic frameworks for tetracycline adsorption and determination

A carbon dot (CD) was prepared by using tryptophan as a single carbon source and demonstrated its good selective fluorescence quenching effect on tetracycline (TC). The modified metal-organic frameworks (MOF) NH2-MIL-101 was chosen as matrix, doped with CD, molecularly imprinted polymer (MIP) prepared with TC as the template, and finally CD-MOF-MIP complexes (CD@MIP) was synthesized. For comparison, MIP were also prepared without CD as well as non-imprinted polymers and their ability was tested, respectively. CD@MIP is a nanomaterial with bright fluorescence under the irradiation of ordinary UV equipment (λ = 360 nm), which has a fast and stable fluorescence quenching for TC and a good linear relationship for TC in the concentration range 0-400 μmol L-1. The quantum yield of CD@MIP was 12.75% and the 3σ limit of detection (LOD) for CD@MIP was 0.59 μmol L-1. The maximum adsorption capacity of CD@MIP reached 304.6 mg g-1 and the adsorption equilibrium was reached after about 75 min. The adsorption of CD@MIP to tetracycline spiked in milk samples reached 90.0 mg g-1 within 2 h, which was much higher than that of NIP (48.4 mg g-1) under the same conditions, as demonstrated by high performance liquid chromatography (HPLC). The results obtained showed that CD@MIP combined the high adsorption capacity of MOF, the specific adsorption of molecular imprinting and the fluorescence properties of CD, can determine and rapidly removeTC in the environment.

Highly-oxidizing Au@MnO2-X nanozymes mediated homogeneous electrochemical detection of organophosphorus independent of dissolved oxygen

Traditional oxidase-like (OXD) nanozymes rely primarily on O2-mediated superoxide anion (O2·-) process for catalytic oxidation and organophosphorus (Ops) detection. While during the actual detection process, the concentration of O2 is inconstant that can be easily changed with the external environment, distorting detection results. Herein, highly-oxidizing Au@MnO2-X nanozymes with core-shell nanostructure are designed which trigger substantial electron transfer from inner Au core to outer ultrathin MnO2-X layer. According to experimental and theoretical calculations, the core-shell nanostructure and ultrathin MnO2-X of Au@MnO2-X result in the large surface defects, high oxygen vacancies and MnIII ratios. The specially structured Au@MnO2-X nanozymes are therefore highly-oxidizing and the catalytic oxidation can be completed merely through electrons transferring instead of the O2-mediated O2·- process. Based on this, an oxygen independent and ultrasensitive nanozyme-based sensor is established using homogeneous electrochemistry (HEC), its Ops is detected at a LOD of 0.039 ng mL-1. Combined with the UV-vis spectrum of 3,3',5,5'-tetramethylbenzidine (TMB), the linear discriminant analysis of five Ops i.e., Ethion, Omethoate, Diazinon, Chlorpyrifos methyl and Dipterex has achieved superior discrimination results. Therefore, HEC based on strong oxidizing nanozymes provide a new avenue for the development of high-performance electrochemical sensors and demonstrate potential applicability to pesticide residue determination in real samples.

Application and Development Prospect of Nanoscale Iron Based Metal-Organic Frameworks in Biomedicine

Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe2+/Fe3+ exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.

Research progress on MOFs and their derivatives as promising and efficient electrode materials for electrocatalytic hydrogen production from water

Hydrogen energy is considered to be the most potential "ultimate energy source" due to its high combustion calorific value, cleanliness, and pollution-free characteristics. Furthermore, the production of hydrogen via the electrolysis of water has the advantages of simplicity, high efficiency, environmentally safe, and high-purity hydrogen. However, it is also associated with issues such as high-power consumption for the reaction and limited large-scale application of noble metal catalysts. Metal-organic frameworks (MOFs) are porous composite materials composed of metal ions and organic functional groups through orderly coordination with large specific surface areas and large porosity. Herein, we focus on the research status of MOFs and their transition metal derivatives for electrocatalytic water splitting to produce hydrogen and briefly describe the reaction mechanism and evaluation parameters of the electrocatalytic hydrogen evolution and oxygen evolution reactions. Furthermore, the relationship between the catalytic behavior and catalytic activity of different MOF-based catalysts and their morphology, elemental composition, and synthetic strategy is analyzed and discussed. The reasons for the excellent activity and poor stability of the original MOF materials for the electrolysis of water reaction are shown through analysis, and using various means to improve the catalytic activity by changing the electronic structure, active sites, and charge transfer rate, MOF-based catalysts were obtained. Finally, we present perspectives on the future development of MOFs for the electrocatalytic decomposition of water.

Nanoscale designing of metal organic framework moieties as efficient tools for environmental decontamination

Environmental pollutants, being a major and detrimental component of the ecological imbalance, need to be controlled. Serious health issues can get intensified due to contaminants present in the air, water, and soil. Accurate and rapid monitoring of environmental pollutants is imperative for the detoxification of the environment and hence living beings. Metal-organic frameworks (MOFs) are a class of porous and highly diverse adsorbent materials with tunable surface area and diverse functionality. Similarly, the conversion of MOFs into nanoscale regime leads to the formation of nanometal-organic frameworks (NMOFs) with increased selectivity, sensitivity, detection ability, and portability. The present review majorly focuses on a variety of synthetic methods including the ex situ and in situ synthesis of MOF nanocomposites and direct synthesis of NMOFs. Furthermore, a variety of applications such as nanoabsorbent, nanocatalysts, and nanosensors for different dyes, antibiotics, toxic ions, gases, pesticides, etc., are described along with illustrations. An initiative is depicted hereby using nanostructures of MOFs to decontaminate hazardous environmental toxicants.

Latest insights on separation and storage of carbon compounds in buildings towards sustainable environment: Recent innovations, challenges, future perspectives and application of machine learning

Throughout the past few decades, scientific agencies have paid a lot of attention to environmental issues such as acid rain, water poisoning, and global warming. In order to solve these environmental problems, metal-organic frameworks (MOFs), which are made up of metal ions and/or clusters attached to organic ligands, have shown some promise. With a focus on the usage of MOFs, this paper examines the most recent developments, difficulties, and potential future directions in the separation and storage of carbon compounds in buildings for a sustainable environment. The importance of using MOFs in decarbonizing water systems and lowering environmental concerns in buildings is highlighted in the research. It addresses the most recent developments in the use of MOFs for renewable energy, such as the elimination of dangerous gases like CO2 and CH4 from water systems. The article also looks at how MOFs might be used to decarbonize water systems in structures, with a focus on how carbon-containing compounds are stored chemically and physically using artificial neural network models. MOFs are a potential solution for renewable energy and environmental remediation in buildings because they have special physical and chemical characteristics like adjustable pores, high porosity, and tiny pore size. The report offers insights into existing treatments and invites academics to investigate MOFs' potential for resolving environmental problems in order to create a sustainable environment in buildings.

Voltammetric sensing of Cd(II) at ZIF-8/GO modified electrode: Optimization and field measurements

In this work, a metal-organic framework/graphene oxide (MOF(ZIF-8)/GO) nanocomposite was utilized for the electroanalysis of trace level of Cd(II) after modification of a cheap graphite rod electrode (GRE). After closed circuit process on the modified electrode, the differential pulse anodic stripping voltammetry (DPASV) technique was used for measuring of Cd(II). In optimal conditions, the sensor showed a linear dependence of current with concentration range 0.1-30 ppb for Cd(II). Moreover, limit of detection 0.03 ppb were obtained. Besides good selectivity, the sensor also indicated good reproducibility (below 5%). Moreover, the sensor showed satisfactory sensing performance in river, dam and wastewater samples with recovery ranging from 97.2% to 102.4%. Additionally, possible interfering cations were examined, but no significant interference was found. For the detection of trace Cd(II) in real matrices, this sensor illustrated other good merits like high stability, rapidity and simplicity.

Cyclodextrin-metal-organic frameworks in molecular delivery, detection, separation, and capture: An updated critical review

Metal-organic frameworks (MOFs) are coordination compounds with tuneable structures and controllable functions. However, the biological toxicity of traditional MOFs materials is often inevitable, making their application in the biological field have many limitations. Therefore, frontier research increasingly focuses on developing biocompatible MOFs materials. Cyclodextrins (CDs), derived from starch, are favored by various biomaterials due to their good biosafety and are often seen in the preparation and application of MOFs materials. This review describes the features of MOFs materials, and the various preparation methods of CD-MOFs are analyzed in detail from the perspective of CD classification. Additionally, the promising applications of CD-MOFs materials for delivery, detection, separation, and capture of active molecules in recent studies are systematically discussed and summarized. In terms of safety, the CD-MOFs materials are meticulously summarized. Finally, this review presents the challenges and future prospects regarding the current CD-MOFs-based materials, which will shed new light on the application of such materials in various fields.

The elimination and extraction of organosulfur compounds from real water and soil samples using metal organic framework/graphene oxide as a novel and efficient nanocomposite

In the present work, an efficient metal organic framework/graphene oxide (MOF-801/GO) sorbent was fabricated and employed for the detection of organosulfur pesticides (OSPs) in real samples using gas chromatography-flame photometric detection (GC-FPD). The optimal extraction parameters for the suggested solid-phase extraction (SPE) include sorbent amount (60 mg), extraction solvent (acetonitrile) and extraction time (5 min). The linear dynamic ranges and detection limits for organosulfur pesticides (OSPs) samples under above extraction conditions were ranged from 0.5 to 300 μg L^-1 and 0.1-1.1 μg L^-1, respectively. Moreover, the proposed SPE/GC-FDP method was applied for the analysis of pesticides in different real environmental water and soil samples. The obtained recoveries of the analytes in were between 92.0 and 106.8% and relative standard deviation (RSD) values were lower than 9.2%. The application of the MOF-801/GO as a sorbent in dSPE of OSPs analytes showed to be reliable, fast and sensible methodology for pesticides monitoring in different environmental samples.

MOFs-based Fe@YAU-101/GCE electrochemical sensor platform for highly selective detecting trace multiplex heavy metal ions

The construction of sensors with specific recognition functions can easily, sensitively and efficiently detect heavy metal ions, which is a demand in the field of electrochemical sensing and an important topic in the detection of environmental pollutants. An electrochemical sensor based on MOFs composites was developed for sensing of multiplex metal ions. The large surface area, adjustable porosities and channels in MOFs facilitate successful loading of sufficient quantities highly active units. The active units and pore structures of MOFs are regulated and synergetic with each other to enhance the electrochemical activity of MOFs composites. Thus, the selectivity, sensitivity and reproducibility of MOFs composites have been improved. Fortunately, after characterization, Fe@YAU-101/GCE sensor with strong signal was successfully constructed. In the presence of target metal ions in solution, the Fe@YAU-101/GCE can efficiently and synchronously identify Hg²⁺, Pb²⁺, and Cd²⁺. The detection limits (LOD) are 6.67 × 10^-10 M(Cd²⁺), 3.33 × 10^-10 M(Pb²⁺) and 1.33 × 10^-8 M (Hg²⁺), and are superior to the permissible limits set by the National Environmental Protection Agency. The electrochemical sensor is simple without sophisticated instrumentation and testing processes, hence promising for practical applications.

High-Performance Detection of Exosomes Based on Synergistic Amplification of Amino-Functionalized Fe3O4 Nanoparticles and Two-Dimensional MXene Nanosheets

Exosomes derived from cancer cells have been recognized as a promising biomarker for minimally invasive liquid biopsy. Herein, a novel sandwich-type biosensor was fabricated for highly sensitive detection of exosomes. Amino-functionalized Fe₃O₄ nanoparticles were synthesized as a sensing interface with a large surface area and rapid enrichment capacity, while two-dimensional MXene nanosheets were used as signal amplifiers with excellent electrical properties. Specifically, CD63 aptamer attached Fe₃O₄ nanoprobes capture the target exosomes. MXene nanosheets modified with epithelial cell adhesion molecule (EpCAM) aptamer were tethered on the electrode surface to enhance the quantification of exosomes captured with the detection of remaining protein sites. With such a design, the proposed biosensor showed a wide linear range from 10² particles μL^-1 to 10⁷ particles μL^-1 for sensing 4T1 exosomes, with a low detection limit of 43 particles μL^-1. In addition, this sensing platform can determine four different tumor cell types (4T1, Hela, HepG2, and A549) using surface proteins corresponding to aptamers 1 and 2 (CD63 and EpCAM) and showcases good specificity in serum samples. These preliminary results demonstrate the feasibility of establishing a sensitive, accurate, and inexpensive electrochemical sensor for detecting exosome concentrations and species. Moreover, they provide a significant reference for exosome applications in clinical settings, such as liquid biopsy and early cancer diagnosis.

Molecularly imprinted self-buffering double network hydrogel containing bi-amidoxime functional groups for the rapid hydrolysis of organophosphates

The development of high-performance catalyst materials with high catalytic activity for the hydrolysis of organophosphorus toxicants without additional pH buffer conditions has become an urgent need for practical application. Here, a multifunctional molecularly imprinted polymer double network hydrogel (MIP-DN) material has been prepared by integrating the first polymer network containing the functional group of bi-amidoxime as the catalytic active center and the cationic polymer polyethyleneimine (PEI) with pH buffer function as the main component of the second network. Advantageously, the resultant MIP-DN hydrogel showed excellent catalytic performance without additional pH buffer conditions, exhibiting a half-life of 25 min for the hydrolysis of paraoxon in pure water. Together with multi-functions of high catalytic activity, self-buffering function and excellent processability, the MIP-DN hydrogel prepared in this work provides a new strategy for the preparation of catalytic materials with practical application value toward toxic organophosphates.

An ultrasensitive electrochemical biosensor for bisphenol A based on aptamer-modified MrGO@AuNPs and ssDNA-functionalized AuNP@MBs synergistic amplification

Bisphenol A (BPA) is a harmful endocrine disruptor, sensitive and rapid quantification of BPA is highly desirable. In this work, a novel synergistic signal-amplifying electrochemical biosensor was developed for BPA detection by using a recognition probe (RP) constructed by BPA aptamer modified gold nanoparticles-loaded magnetic reduced graphene oxide (Aptamer-MrGO@AuNPs), and a signal probe (SP) constructed by BPA aptamer-complementary single-stranded DNA (ssDNA) functionalized methylene blue (MB)-loaded gold nanoparticle (ssDNA-AuNP@MBs). The RP and SP can self-assemble to form a stable RP-SP complex through complementary base pairing. The current intensity of the biosensor correlates with the number of RP-SP complexes. In the presence of BPA, the BPA aptamer can capture BPA with high selectivity and affinity, form an RP-BPA complex and dissociate the RP-SP complex to release SP, resulting in a decrease in the current signal intensity of the biosensor. A single AuNP could be loaded with multiple BPA aptamers and MBs, which improves the recognition efficiency and enhances the signal intensity. Due to the magnetic properties of MrGO@AuNPs, the magnetic separation and adsorption of RP or RP-SP complex is very convenient, enabling all reaction processes to be carried out in solution, which not only improves the mass transfer efficiency, but also simplifies the operation. Under optimal conditions, the developed biosensor had a detection limit as low as 0.141 pg/mL and had been successfully applied to the detection of real environmental water samples. Therefore, the synergistic signal amplification strategy of RP and SP has potential value in the detection of trace pollutants in the water environment.

Biogenic synthesis of reduced graphene oxide decorated with silver nanoparticles (rGO/Ag NPs) using table olive (olea europaea) for efficient and rapid catalytic reduction of organic pollutants

In this work, graphene oxide (GO) sheets were prepared via a facile electrochemical exfoliation of graphite in acidic medium and subsequent oxidation with potassium permanganate. The GO sheets were employed for preparation of reduced GO adorned with nanosized silver (rGO/Ag NPs) using green reduction of GO and Ag(I) via olive fruit extract as a reducing and immobilizing agent. The crystal phase, morphology, and nanostructure of the prepared catalyst were characterized by XRD, SEM, EDX, UV-Vis and Raman spectroscopy techniques. The as-prepared rGO/Ag NPs showed superior catalytic performance towards the complete reduction (up to 99%) of 4-nitrophenol (4-NPH) to 4-aminophenol (4-APH) and rhodamine B (RhB) to Leuco RhB within 180 s using NaBH₄ at ambient condition. The rate constant (k) values were found to be 0.021 and 0.022 s^-1 for 4-NPH and RhB reduction, respectively. In addition, the regenerated catalyst could be reused after seven cycles without losing any apparent catalytic efficiency. Accounting for the excellent catalytic capability, chemical stability and environment-friendly synthesis protocol, the rGO/Ag NPs has great potential working as a heterogeneous catalyst in the transforming harmful organic contaminants into less harmful or harmless compounds.

Effective reduction of nitric oxide over a core-shell Cu-SAPO-34@Fe-MOR zeolite catalyst

In this study, a core-shell catalyst of Cu-SAPO-34@Fe-MOR was successfully prepared through a silica-sol adhesion method, and its performance for selective catalytic reduction of nitric oxide by NH₃ (NH₃-SCR) was evaluated in detail. The Fe-MOR coating has not only increased the high-temperature activity and broadened the reaction temperature window of Cu-SAPO-34 to a large extent, but also increased the hydrothermal stability of Cu-SAPO-34 markedly. It is demonstrated that a strong synergistic interaction effect exists between Cu²⁺ and Fe³⁺ ions and promotes the redox cycle and oxidation-reduction ability of copper ions, which greatly accelerates the catalytic performance of the core-shell Cu-SAPO-34@Fe-MOR catalyst. Abundant isolated Cu²⁺ ions and Fe³⁺ ions on the ion exchange sites performing NO _x reduction at low and high temperature region lead to the broad reaction temperature window of Cu-SAPO-34@Fe-MOR. In addition, more weakly adsorbed NO _x species formed and the increased number of Lewis acid sites may also contribute to the higher catalytic performance of Cu-SAPO-34@Fe-MOR. On the other hand, the better hydrothermal ageing stability of Cu-SAPO-34@Fe-MOR is related to its lighter structural collapse, fewer acidic sites lost, more active components (Cu²⁺ and Fe³⁺) maintained, and more monodentate nitrate species formed in the core-shell catalyst after hydrothermal ageing. Last, the mechanism study has found that both Langmuir-Hinshelwood ("L-H") and Eley-Rideal ("E-R") mechanisms play an essential role in the catalytic process of Cu-SAPO-34@Fe-MOR, and constitute another reason for its higher activity compared with that of Cu-SAPO-34 (only "L-H" mechanism).

A signal-on electrochemical DNA biosensor based on exonuclease III-assisted recycling amplification

DNA electrochemical detection technology has attracted tremendous interest in recent years. However, a facile and sensitive method for the detection of the disease indicators or genes is still waiting. Herein, we constructed a signal-on electrochemical platform for detecting the manganese superoxide dismutase (MnSOD) gene by incorporating a redox electrochemical signal probe (methylene blue) and exonuclease III-assisted target recycling signal amplification strategy. The sensor was prepared by self-assembly of a capture DNA probe of thiol-modified on GCE with gold electrodeposition. In the presence of target DNA, the exonuclease III can cleave the duplexes formed by the target DNA and the redox-labeled hairpin probes, release the target DNA and produce a residual sequence. The target DNA can continue to hybridize with the hairpin probe for the next cycle of amplification. The residual sequence hybridized with the surface-immobilized capture probes on AuNPs-modified GCE to generate a significantly amplified redox current. In particular, the redox current value of the resultant sensor showed a linear relationship with MnSOD gene concentration in the range of 1-10⁴ pM with the detection limit as low as 0.3 pM. Furthermore, the sensor has excellent specificity and can distinguish single-base mismatch from perfectly matched target DNA. The sensor is fast in operation, and simple in design for detecting different DNA sequences or DNA identification by selecting the appropriate probe sequence, thus shedding light on a good promising application when encountering disease outbreaks or for the early clinical diagnosis of gene-related diseases.

Molecularly imprinted voltammetric sensor sensibilized by nitrogen-vacancy graphitized carbon nitride and Ag-MWCNTs towards the detection of acetaminophen

The overdose of acetaminophen (AP) can cause serious acute liver injury even the irreversible liver necrosis. The quantitative detection of AP is of great significance not only for clinical applications but also for the quantity control of its pharmaceutical formulations. In this paper, a sensitive molecularly imprinted voltammetric sensor towards AP was constructed based on synergistic enhancement of nitrogen-vacancy graphitized carbon nitride (NV-g-C₃ N₄ ) and carboxylated MWCNTs loaded with silver nanoparticles (Ag-MWCNTs). The powder X-Ray diffraction spectrum, field emission scanning and transmission electron microscopes, cyclic voltammetry (CV), and electrochemical impedance spectrum were used to characterize the composites. The results show that NV-g-C₃ N₄ and Ag-MWCNTs closely embedded each other, forming loose porous hybrid structure by hydrogen bond. The prepared sensor molecular imprinting polymer (MIP)/C₃ N₄ /Ag-CNTs/GCE shows a strong synergistic enhancement of electroanalytical response by CV and differential pulse voltammetry (DPV) tests when compared with NV-g-C₃ N₄ /GCE, Ag-CNTs/GCE, and MIP/GCE. Through the optimization of the ratio of monomer and template, electropolymerization cycle, elution cycle, incubation time, and pH, linear ranges of 0.007-5 and 5-100 μM were found with the limit of detection of 2.33 nM by DPV. Moreover, its selectivity towards AP was satisfied when compared with detection towards ascorbic acid, dopamine, and glucose. The recovery range of 96.3%-100.5% was obtained in the spiked human serum and urine samples with the SD below 3.0%. In addition, the prepared sensor shows great detecting robustness with good anti-interference, reproducibility, and stability.

Constructing 3D magnetic flower-like Fe3O4@SiO2@Co3O4@BiOCl heterojunction photocatalyst for degrading rhodamine B

In this work, the 3D magnetic flower-like Fe₃O₄@SiO₂@Co₃O₄@BiOCl heterojunction photocatalyst was successfully prepared. The combination of BiOCl with Co₃O₄ favored to increase specific surface area and separate photo-generated carriers of the resulting composite, resulting in the improvement of catalytic efficiency. The photocatalytic activities of Fe₃O₄@SiO₂@Co₃O₄@BiOCl were researched in details. In 50 min of visible light, the degradation efficiency for rhodamine B (RhB) of Fe₃O₄@SiO₂@Co₃O₄@BiOCl was 98.41%. It still maintained 94.22% even after three tests. Furthermore, the photodegradation mechanisms were also investigated, indicating that the improved efficiency was ascribed to the superior separation of photo-induced electron-hole pairs. This study supplies a new perception to fabricate photocatalysts for actual uses.