RESUMO
Residue of sulfamethazine (SMZ), a typical short-acting drug to prevent bacterial infections, in food is a threat to human health. A ternary heterogeneous metal-organic framework hybrid (Zn/Fe-MOF@PDANSs) of Zn-TCPP-MOF, MIL-101 (Fe) and polydopamine nanoparticles (PDANSs) was proposed to establish an aptasensor for the sensitive and selective detection of SMZ. In this sensor, Zn-TCPP-MOF and FAM emitted fluorescence at 609 nm and 523 nm, respectively, and the fluorescence of FAM-ssDNA could be quenched when it was adsorbed on the surface of MOF hybrid. In the presence of SMZ, the fluorescence of FAM-ssDNA recovered due to the dropping from MOF hybrid, while the fluorescence of MOF hybrid remained. With this strategy, a wide concentration range and high sensitivity of SMZ were detection. And the ternary Zn/Fe-MOF@PDANSs sensor exhibited more excellent performance than binary Zn/Fe-MOF aptasensor. In addition, the sensor showed pleasurable selectivity, and was utilized for SMZ determination in authentic chicken and pork samples, implying the fascinating potential in practical application.
RESUMO
The development of new sensors for on-site food toxin monitoring that combine extraction, analytes distinction and detection is important in resource-limited environments. Surface-enhanced Raman scattering (SERS)-based signal readout features fast response and high sensitivity, making it a powerful method for detecting mycotoxins. In this work, a SERS-based assay for the detection of multiple mycotoxins is presented that combines extraction and subsequent detection, achieving an analytically relevant detection limit (â¼ 1 ng/mL), which is also tested in corn samples. This sensor consists of a magnetic-core and mycotoxin-absorbing polydopamine-shell, with SERS-active Au nanoparticles on the outer surface. The assay can concentrate multiple mycotoxins, which are identified through multiclass partite least squares analysis based on their SERS spectra. We developed a strategy for the analysis of multiple mycotoxins with minimal sample pretreatment, enabling in situ analytical extraction and subsequent detection, displaying the potential to rapidly identify lethal mycotoxin contamination on site.
Assuntos
Contaminação de Alimentos , Ouro , Nanopartículas Metálicas , Micotoxinas , Análise Espectral Raman , Zea mays , Micotoxinas/análise , Micotoxinas/química , Análise Espectral Raman/métodos , Análise Espectral Raman/instrumentação , Contaminação de Alimentos/análise , Ouro/química , Nanopartículas Metálicas/química , Zea mays/química , Zea mays/microbiologia , Limite de DetecçãoRESUMO
Ethyl carbamate (EC) is a carcinogen widely found in the fermentation process of Baijiu. Herein, we construct a molecularly imprinted polymers/MXene/cobalt (II) based zeolitic imidazolate frameworks (MIP/MXene/ZIF-67) nano-enzyme sensor for the detection of EC during Baijiu production. The ZIF-67 is synthesized in situ on the MXene nanosheets to provide a superior catalytic activity to H2O2 and amplify the electrochemical signal. The MIP is prepared by the polymerization reaction to recognize EC. Owing to the interaction between EC and EC-MIP, the interferences are effectively eliminated, greatly improving the accuracy of the expected outcome. This approach attains an ultrasensitive assay of EC ranging from 8.9 µg/L to 44.5 mg/L with detection limit of 0.405 µg/L. The accuracy of this method is confirmed by the recovery experiment with good recoveries from 95.07% to 107.41%. This method is applied in natural EC analyses, and the results are consistent with certified gas chromatograph- mass spectrometer.
Assuntos
Técnicas Eletroquímicas , Contaminação de Alimentos , Impressão Molecular , Uretana , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Uretana/análise , Uretana/química , Contaminação de Alimentos/análise , Catálise , Polímeros Molecularmente Impressos/química , Limite de DetecçãoRESUMO
In this study, we devised a photothermally stable phytochemical dye by leveraging alizarin in conjunction with the metal-organic framework ZIF-8 (AL@ZIF-8). The approach involved grafting alizarin into the microporous structure of ZIF-8 through physical adsorption and hydrogen-bonding interactions. AL@ZIF-8 significantly enhanced the photostability and thermostability of alizarin. The nanoparticles demonstrate substantial color changes in various pH environments, showcasing their potential for meat freshness monitoring. Furthermore, we introduced an intelligent film utilizing poly(vinyl alcohol)-sodium alginate-AL@ZIF-8 (PA-SA-ZA) for detecting beef freshness. The sensor exhibited a superior water contact angle (52.34°) compared to the alizarin indicator. The color stability of the film was significantly enhanced under visible and UV light (ΔE < 5). During beef storage, the film displayed significant color fluctuations correlating with TVB-N (R2=0.9067), providing precise early warning signals for assessing beef freshness.
Assuntos
Alginatos , Colorimetria , Álcool de Polivinil , Alginatos/química , Animais , Álcool de Polivinil/química , Bovinos , Colorimetria/métodos , Antraquinonas/química , Embalagem de Alimentos/instrumentação , Compostos Fitoquímicos/química , Carne Vermelha/análise , Estruturas Metalorgânicas/químicaRESUMO
The importance of food quality and safety lies in ensuring the best product quality to meet consumer demands and public health. Advanced technologies play a crucial role in minimizing the risk of foodborne illnesses, contamination, drug residue, and other potential hazards in food. Significant materials and technological advancements have been made throughout the food supply chain. Among them, quantum dots (QDs), as a class of advanced nanomaterials with unique physicochemical properties, are progressively demonstrating their value in the field of food quality and safety. This review aims to explore cutting-edge research on the different applications of QDs in food quality and safety, including encapsulation of bioactive compounds, detection of food analytes, food preservation and packaging, and intelligent food freshness indicators. Moreover, the modification strategies and potential toxicities of diverse QDs are outlined, which can affect performance and hinder applications in the food industry. The findings suggested that QDs are mainly used in analyte detection and active/intelligent food packaging. Various food analytes can be detected using QD-based sensors, including heavy metal ions, pesticides, antibiotics, microorganisms, additives, and functional components. Moreover, QD incorporation aided in improving the antibacterial and antioxidant activities of film/coatings, resulting in extended shelf life for packaged food. Finally, the perspectives and critical challenges for the productivity, toxicity, and practical application of QDs are also summarized. By consolidating these essential aspects into this review, the way for developing high-performance QD-based nanomaterials is presented for researchers and food technologists to better capitalize upon this technology in food applications.
Assuntos
Pontos Quânticos , Contaminação de Alimentos/prevenção & controle , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Qualidade dos Alimentos , Pontos Quânticos/toxicidadeRESUMO
The onset of Alzheimer's disease is related to neuron damage caused by massive deposition of Aß in the brain. Recent studies suggest that excessive Aß in the brain mainly comes from peripheral blood, and BBB is the key to regulate Aß in and out of the brain. In this study, we explored the pathogenesis of AD from the perspective of Aß transport through the BBB and the effect of QKL injection in AD mice. The results showed that QKL could improve the cognitive dysfunction of AD mice, decrease the level of Aß and Aß transporter-RAGE, which was supported by the results of network pharmacology, molecular docking and molecular dynamics simulation. In conclusion, RAGE is a potential target for QKL's therapeutic effect on AD.
Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Modelos Animais de Doenças , Receptor para Produtos Finais de Glicação Avançada , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Animais , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Camundongos , Peptídeos beta-Amiloides/metabolismo , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Masculino , Simulação de Acoplamento Molecular , Camundongos Transgênicos , Simulação de Dinâmica Molecular , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismoRESUMO
Aiming for sustainable crop productivity under changing climate conditions, it is essential to develop handy models for in-situ monitoring of reactive oxygen species (ROS). Herein, this work reports a simple electrochemical sensing toward hydrogen peroxide (H2O2) for tracking crop growth status sensitized with electron-migration nanostructure. To be specific, Cu-based metal-organic frameworks (MOFs) with high HOMO energy level are designed for H2O2 reduction on account of Cu(I)/Cu(II) redox switchability. Importantly, the sensing performance is improved by electrochemically reduced graphene oxide (GO) with ready to use feature. To overcome the shortcomings of traditional liquid electrolytes, conductive hydrogel as semi-solid electrolyte exhibits the adhesive property to the cut plant petiole surface. Benefitting from the preferred composite models and conductive hydrogel, the electrochemical sensing toward H2O2 with high sensitivity and good anti-interference against the coexistent molecules, well qualified for acquiring plant growth status.
RESUMO
The combination of carbon dots (CDs) with covalent organic frameworks (COFs) was used to design an innovative sensor based on fluorescence resonance energy transfer (FRET) for the detection of Escherichia coli O157:H7 (E. coli O157:H7) in food samples. Carbon dots were used as fluorescence donors, covalent organic frameworks as fluorescence acceptors. The antibody (Ab) specific to E. coli O157:H7 was used to form a CD-Ab-COF immunosensor by linking CDs and COFs. The antibody was specifically bound with E. coli O157:H7, which caused the connection between CDs and COFs to be interrupted, and the carbon dots exhibited fluorescence restoration. The sensor exhibited a linear detection range spanning from 0 to 106 CFU/mL, with the limit of detection (LOD) of 7 CFU/mL. The analytical performance of the developed immunosensor was evaluated using spiked food samples with different concentrations of E. coli O157:H7, validating the capability of assessing risks in food testing.
Assuntos
Técnicas Biossensoriais , Escherichia coli O157 , Estruturas Metalorgânicas , Transferência Ressonante de Energia de Fluorescência , Carbono , Imunoensaio , AnticorposRESUMO
Accurate assessment of dough kneading is pivotal in pasta processing, where both under-kneading and over-kneading can detrimentally impact dough quality. This study proposes an innovative approach utilizing a cost-effective current sensor to ascertain the optimal kneading time for dough. Throughout the kneading process, the dough's tensile resistance gradually increases, reflecting the evolution of properties such as the gluten network. This leads to a discernible ascending phase in dough quality, evident through an increase in the load current of the mixing machine, succeeded by a subsequent decline beyond a certain threshold. The identification of this peak point enables the achievement of optimal dough consistency, thereby enhancing the overall quality of both the dough and subsequent pasta products. After the final product quality assessment, this novel method promises to be a valuable tool in optimizing pasta processing and ensuring consistent product quality.
RESUMO
Packaging plays an important role in protecting food from environmental impacts. However, traditional petroleum-based packaging has difficulty in meeting the antimicrobial and antioxidant requirements of prepared foods. This study introduced carbon dots (CDs), prepared by using carrot as a precursor, into corn starch (CS) to construct a bio-friendly composite film with high freshness retention properties. The scavenging of DPPH radicals reached 92.77 % at a CDs concentration of 512 µg/mL, and the antimicrobial activity of CS/5% CDs against Escherichia coli and Staphylococcus aureus was increased to 99.9 %. Notably, the homogeneous doping of CDs creates a dense surface and high carbon content inside the film, which promotes the elasticity and thermal stability of the composite film. Finally, we encapsulated deep-fried meatballs in CS-CDs films. The results showed that the CS-CDs films effectively protected the quality of deep-fried meatballs, and have excellent potential for application in food preservation.
Assuntos
Anti-Infecciosos , Quitosana , Embalagem de Alimentos/métodos , Zea mays , Amido/química , Quitosana/química , Antibacterianos/farmacologia , Antibacterianos/química , Anti-Infecciosos/químicaRESUMO
As a traditional Chinese dish cutting technology process, Gaidao artificially create cuts embedded in the food surface by cutting through it with knife, a process that currently plays an important role in the beef marinating process. And different Gaidao processes directly affect the beef marination flavour and marination efficiency. This study is the first to propose the use of Hyperspectral imaging technology (HSI) combined with finite element analysis to investigate the effect of Gaidao process on the quality of marinated beef. The study was carried out by collecting spectral information of beef marinated with different sucrose concentrations and combining various pre-processing methods and algorithms such as PLS, BiPLS, iPLS, and SiPLS to establish a quantitative model of sucrose concentration in beef, and finally optimizing parameters such as the length, position and number of Gaidao by Finite Element Analysis (FEA), which showed that when marinated with 1.0 mol/m³ sucrose solution, the concentration of sucrose in all tissues in the Gaidao steak reached 0.8 mol/m³ and above, which greatly improved the diffusion effect of the marinade. This work provides new ideas and methods to optimize the beef marinade Gaidao process, which has important practical value and research significance.
RESUMO
Advances in flexible SERS substrates has made it possible to approach the ultimate goal of rapid in-situ monitoring of fruit and vegetable safety, but its vulnerability under laser ablation results in low utilization. In order to solve this problem, a 3D framework of TiO2-doped PVDF\PVP polymer was utilized to self-assemble gold-silver core-shell nanorods (Au@Ag NRs) to prepare a flexible SERS substrate with good physical stability and self-cleaning properties. This substrate showed excellent detection limit and recyclability after the detection of three pesticide residues in apple peel. The LOD of methyl-parathion (MP) was as low as 0.037 ng/cm2, with an RSD of 5.61 % for 5 cycle-detection. The recoveries of two additional pesticides thiram (TMTD) and chlorpyrifos (CPF) were 86.32 %-112.47 %. We hoped that this research will contribute to providing a recyclable and facile method for in-situ analysis of fruit and vegetable surface residues and functional manufacture of flexible SERS substrates.
Assuntos
Malus , Nanopartículas Metálicas , Resíduos de Praguicidas , Praguicidas , Malus/química , Análise Espectral Raman/métodos , Nanopartículas Metálicas/química , Praguicidas/análise , Resíduos de Praguicidas/análise , Tiram/análise , Verduras/química , Ouro/químicaRESUMO
Herein, a bifunctional electrochemical biosensor based on the DNA tetrahedral scaffolds (TDNs) was proposed, OTA@TDNs and AFB1@TDNs were adopted for electrochemical signal output in response to OTA and AFB1 concentration, simultaneously. In order to increase the conductivity of the biosensor, highly porous gold (HPG) was loaded on electrode surface by pulse electrodeposition. Under optimal conditions, the PFc displayed a linear range with AFB1 concentration between 0.05 â¼ 360 ng·mL-1 with the LOD of 3.5 pg·mL-1. And the PMB selective and sensitive responses to OTA are achieved with a linear range of 0.05 â¼ 420 ng·mL-1 and a LOD of 2.4 pg·mL-1. This biosensor has high sensitivity, selectivity and stability for OTA and AFB1 detection in peanut samples. The approach streamlines the experimental procedure, leading to significantly improve the detection efficiency of mycotoxins. Collectively, this method suggest a novel approach for the detection and monitoring of OTA and AFB1 in food sample.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Ocratoxinas , Ocratoxinas/análise , Aflatoxina B1/análise , Contaminação de Alimentos/análise , DNA , Limite de Detecção , Técnicas EletroquímicasRESUMO
Diabetic cardiomyopathy is a chronic cardiovascular complication caused by diabetes that is characterized by changes in myocardial structure and function, ultimately leading to heart failure and even death. Mitochondria serve as the provider of energy to cardiomyocytes, and mitochondrial dysfunction plays a central role in the development of diabetic cardiomyopathy. In response to a series of pathological changes caused by mitochondrial dysfunction, the mitochondrial quality control system is activated. The mitochondrial quality control system (including mitochondrial biogenesis, fusion and fission, and mitophagy) is core to maintaining the normal structure of mitochondria and performing their normal physiological functions. However, mitochondrial quality control is abnormal in diabetic cardiomyopathy, resulting in insufficient mitochondrial fusion and excessive fission within the cardiomyocyte, and fragmented mitochondria are not phagocytosed in a timely manner, accumulating within the cardiomyocyte resulting in cardiomyocyte injury. Currently, there is no specific therapy or prevention for diabetic cardiomyopathy, and glycemic control remains the mainstay. In this review, we first elucidate the pathogenesis of diabetic cardiomyopathy and explore the link between pathological mitochondrial quality control and the development of diabetic cardiomyopathy. Then, we summarize how clinically used hypoglycemic agents (including sodium-glucose cotransport protein 2 inhibitions, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, metformin, and α-glucosidase inhibitors) exert cardioprotective effects to treat and prevent diabetic cardiomyopathy by targeting the mitochondrial quality control system. In addition, the mechanisms of complementary alternative therapies, such as active ingredients of traditional Chinese medicine, exercise, and lifestyle, targeting mitochondrial quality control for the treatment of diabetic cardiomyopathy are also added, which lays the foundation for the excavation of new diabetic cardioprotective drugs.
Assuntos
Diabetes Mellitus , Cardiomiopatias Diabéticas , Humanos , Cardiomiopatias Diabéticas/metabolismo , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Hipoglicemiantes/metabolismo , Mitocôndrias , Miocárdio/patologia , Miócitos Cardíacos , Diabetes Mellitus/tratamento farmacológicoRESUMO
BACKGROUND: Lentinan medicament from Lentinus edodes has been considered as natural medicinal products with minimal side effects for cancer therapy, but Lentinus edodes are easily polluted by nonbiodegradable heavy metals, especially silver ion (Ag+). Therefore, it is highly desirable to monitor Ag + pollution in Lentinus edodes considering their adverse impact on lentinan medicament. Electrochemical sensor isn't affected from the interference of matrix turbidity and color, and offers a powerful means for determination of variant analytes. As for electrochemical sensing toward Ag+, there is a great need to design efficient signal probes for specific recognition and signal generation. RESULTS: We present an appropriate electrochemical aptasensor for Ag + assay based on biomimetic catalysis of porphyrin-encapsulated MOF (PorMOF) and allosteric switch of C-rich DNA. Thanks to the excellent biocompatibility, PorMOFs as nanozyme are used to design signal probes by loading duplex-like DNA scaffold. Owing to the specific recognition of Ag+ toward cytosine (C) base-rich DNA, PorMOF at the distal end was close to the underlying electrode via C-Ag+-C formation, leading to an enhanced current of catalytic hydroxylamine oxidation for signal generation. Using the positive correlation between current response and Ag+ level, the electrochemical system provides a promising means for on-line monitoring of Ag+ in Lentinus edodes with recoveries from 92.8% to 106.4% and relative standard deviation from 3.98% to 8.24%, verifying the applicability of the electrochemical aptasensor toward Ag+ in Lentinus edodes. SIGNIFICANCE AND NOVELTY: With merits of portability, simple operation, and rapid response, the electrochemical pattern offers a useful solution for on-line monitoring of Ag+ in Lentinus edodes. By altering the DNA sequence, the proposed aptasensor provides a powerful way for monitoring other heavy metals, capable of protecting medicament production from heavy metal pollution.
Assuntos
Produtos Biológicos , Estruturas Metalorgânicas , Metais Pesados , Cogumelos Shiitake , Lentinano , PrataRESUMO
Herein, the cooperative catalysis effect between nanocomposite (AgPd NPs/POD-M/PEI-rGO) and horseradish peroxidase (HRP) was applied for the fast and sensitive detection of aflatoxin B1 (AFB1). Upon specific and competitive binding of HRP@DNA and AFB1 to cDNA, the working electrode presented different catalytic capacities for supporting electrolytes (TMB and H2O2). In the redox mechanism of TMB and H2O2, HRP and nanocomposite effectively catalyzed the oxidization of TMB to form the one-electron oxidation intermediate TMB+, and contributed the electrical signals and absorbance signals. Electrochemistry and colorimetric analyses were successfully realized for AFB1 detection with 0.2 pg/mL and 8 pg/mL of detection limits, respectively, which is much lower than that of traditional HPLC methods. Overall, this method had significant reliability and sensitivity, offering a promising potential for conveniently evaluating the quality of agri-products polluted with AFB1. Moreover, this approach provides a new idea for fast and accurate detection of mycotoxin.
Assuntos
Técnicas Biossensoriais , Peróxido de Hidrogênio , Reprodutibilidade dos Testes , Peroxidase do Rábano Silvestre , Catálise , Aflatoxina B1/análise , Limite de DetecçãoRESUMO
In this study, a novel strategy for accelerating the production of pumpable ice slurry (PIS) by using ozone micro-nano bubbles (O3-MNBs) was proposed. The effect of PIS containing sodium alginate (SA) and O3-MNBs on the preservation of small yellow croaker (Larimichthys polyactis) was investigated. The results indicate that using SA solution containing O3-MNBs instead of only SA solution resulted in quicker production of PIS by promoting ice nucleation and eliminating supercooling. The distribution and positive effect of O3-MNBs as a nucleation agent on freezing characteristics were discussed. Microbial concentrations, pH, total volatile basic nitrogen, and thiobarbituric acid reactive substance content were also examined. Storage in novel PIS (containing O3-MNBs) had higher performance than storage in flake ice or conventional PIS due to the strong bacteriostatic ability of O3. Therefore, O3-MNBs injection can be used as a novel method for PIS production and the preservation of fresh marine products.
RESUMO
Patients with sick sinus syndrome (SSS) experience a decrease in health-related quality of life (HRQoL), but there is currently no scale available to measure their unpleasant symptoms. The Short Form 36 Health Survey (SF-36) is a commonly used scale to assess HRQoL. In this study, we aimed to evaluate the reliability, validity, and sensitivity of SF-36 in patients with SSS. The sample included 199 eligible participants. We estimated the reliability through test-retest reliability, internal consistency, and split-half reliability. To examine the validity of the questionnaire, confirmatory factor analysis, convergent validity, and discriminant validity were conducted. Sensitivity was determined by the differences in age (cutoff 65 years) and New York Heart Association class. The intraclass correlational coefficients scores showed high test-retest reliability (intraclass correlational coefficients > 0.7). The overall Cronbach α was 0.87 (8 scales range: 0.85-0.87), showing good internal consistency reliability. The split-half reliability coefficient of the SF-36 is 0.814, indicating good reliability. Factor analysis showed that SF-36 subscales could be drawn into 6 components that explain 61% of the total variance. Results of model fit indicate comparative fit index = 0.9, incremental fit index = 0.92, Turker-Lewis index = 0.90, approximate root mean square error = 0.07, and normalized root mean square residual = 0.06. Convergent validity and discriminative validity showed adequate results. Comparison of different ages and New York Heart Association class groups showed statistical significance on most SF-36 subscales. We confirmed the SF-36 as a valid instrument for evaluating HRQoL patients with SSS. The reliability, validity, and sensitivity of SF-36 are acceptable for patients with SSS.
Assuntos
Qualidade de Vida , Síndrome do Nó Sinusal , Humanos , Idoso , Reprodutibilidade dos Testes , Síndrome do Nó Sinusal/diagnóstico , Psicometria/métodos , Inquéritos e Questionários , Inquéritos EpidemiológicosRESUMO
The goal of food safety supervision is to directly identify the pesticide residues on the surface of fruits and vegetables. This study proposed to develop a facile, non-destructive, and sensitive method based on surface-enhanced Raman scattering (SERS) to detect non-systemic pesticides on the surface of fruits and vegetables. The composite material was prepared by loading CTAB guided Au@Ag NRs with positive charge onto filter paper which was modified with PDADMAC(+) and PSS(-) using electrostatic adsorption. Au@Ag NRs with bimetallic synergies were effectively adsorbed in the fiber grid to generate 3D SERS hotspots within a few microns of depth. The results showed that the 3D composite flexible substrate had a high SERS activity, great repeatability, and sensitivity when the method was utilized to detect 4-MBA, methyl-parathion, thiram and chlorpyrifos. Three kinds of non-systemic pesticides on the peel could be detected directly and quickly owing to the arbitrary bending of the substrate, demonstrating the efficiency of the SERS "paste-reading" method. The acquired findings demonstrated that PDADMAC/PSS/Au@Ag NRs composite filter paper had the potential to provide rapid feedback for in-situ analysis of pesticide residues on the surface of fruit and vegetable.
Assuntos
Nanopartículas Metálicas , Resíduos de Praguicidas , Praguicidas , Praguicidas/análise , Frutas/química , Resíduos de Praguicidas/análise , Verduras/química , Nanopartículas Metálicas/química , Ouro/química , Análise Espectral Raman/métodosRESUMO
A novel ratiometric sensor using an electrochemically active metal-organic framework of Mo@MOF-808 and NH2-UiO-66 as response signals was developed to detect tetracycline (TET) in ultratrace quantities. To achieve the dual-response strategy, Mo@MOF-808, with a reduction peak at -1.06 V, and NH2-UiO-66, with an oxidation peak at 0.724 V, were used as signal probes directly. Concretely, Mo@MOF-808, single-stranded DNA (ssDNA), and complex system (Apt@NH2-UiO-66) of aptamer (Apt) and NH2-UiO-66 were sequentially immobilized on the electrode. With the addition of TET, Apt was hybridized with TET and Apt@NH2-UiO-66 was detached from the electrode, resulting in an increase in the current at -1.06 V and a decrease in the current at 0.724 V. Through this strategy, the sensor achieved a wide linear range (0.1-10000 nM) and a low limit of detection (0.009792 nM) for TET. Moreover, the ratiometric sensor exhibited better sensitivity, reproducibility, and stability than a single-signal sensor. Furthermore, the constructed sensor was successfully applied to detect TET in milk samples, suggesting excellent application prospects.