查找使用阿拉丁产品的科研文献

A ratiometric electrochemiluminescent/electrochemical strategy based on novel designed BPYHBF nanorod and Fc-MOF with tungsten for ultrasensitive AFB1 detection

Xiaoyi Lv,Xiaoyun Xu,Tian Miao,Xufeng Zang,Chao Geng,Yanping Li,Bo Cui,Yishan Fang

Fluorescent dyes have been considered as one of the most potential candidates for electrochemiluminescence (ECL) reagent due to the excellent photophysical and electrochemical characteristics in recent years. However, the severe self-absorption effect caused by narrow stokes shift inevitably limits its application for ECL. In this work, a new type of ECL emitter, 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene derivative, a BF2 complex of hydrazine-schiff base linked bispyrrole, namely BPYHBF, was prepared and employed as a probe to label the competitor of target in the immunosensor, which could emit powerful ECL signal with tri- n -propylamine. The structure and ECL property of BPYHBF were investigated. Additionally, multi-walled carbon nanotube/ferrocenecarboxaldehyde-metal organic framework (MWCNTs/Fc-MOF) as sensing substrate for Ab1 incubation was synthesized, where the large specific surface area and stable internal reference electrochemical signals improved the sensitivity and reliability of the sensor by self-correction. Herein, a novel ratiometric competitive immunosensor based on the ECLBPYHBF/DPVFc was prepared for ultrasensitive detection of aflatoxin B1 (AFB1). The ratio value is linear in the range from 10 fg/mL to 100 ng/mL, and the detection limit is 5.39 fg/mL. The prepared sensor exhibited excellent sensitivity, accuracy and reproducibility, and achieved satisfactory detection towards AFB1 in actual samples, this demonstrates a promising application in biomolecules detection.

Simultaneous detection of OTA and AFB1 in cereals based on bispecific monoclonal antibody using quantum dot nanobead lateral flow immunoassay

Mengyun Wu,Jun Xia,Tingting Liu,Guangjian Xue,Xuechen Fang,Weihua Lai,Juan Peng

Defective UIO66 metal–organic framework nanoparticles assisted by cascade isothermal amplification technology for the detection of aflatoxin B1

Yanyan Shao,Qian Tao,Luyao Shao,Jing Bi,Qian Wang,Zhigang Wang,Xuan Sun

Aflatoxin B1 (AFB1) exhibits significant toxicity and pose a serious threat to food safety, environmental hygiene, and public health even in trace amounts. Hence, the development of a rapid, accurate, and sensitive detection technology has become a pivotal aspect of ensuring control standards. In this study, we introduce the UIO66 and two defective dichloroacetic acid@UIO66 (DCA@UIO66, DU) metal–organic framework nanoparticles, named DU1 and DU2, characterized by different defect levels. It is noteworthy that DU1 exhibits superior DNA sensing capability compared to UIO66 and DU2. With a fluorescence quenching efficiency of 92.66 % and a recovery efficiency of 1256.75 %, DU1 demonstrates the substantial potential in the detection field. Furthermore, we employ cascade isothermal amplification to assist DU1–mediated fluorescence sensors in detecting AFB1. AFB1 is efficiently identified through an aptamer competition process facilitated by magnetic nanoparticles, which initiates the exponential amplification triggered rolling circle amplification reaction, and converts trace amounts of toxin signal into a large number of long single–stranded DNA molecules. Upon recognition of the amplification product by the fluorescent probe on DU1, a more stable double–stranded DNA is formed and leaves the surface of DU1, leading to a significant change in fluorescence intensity. This method exhibits acceptable sensitivity, with a detection limit of 0.09 pg mL −1 and a wide detection range spanning from 0.2 pg mL −1 to 20 pg mL −1 . Additionally, this assay exhibits satisfactory specificity and high accuracy in practical sample applications. Our proposed method offers a solid theoretical framework and technical backing, thereby facilitating the establishment of a new generation of mycotoxin detection standards.

Metagenomics analysis reveals flavors formation and AFB1 metabolic network of doubanjiang-meju microbiota in rotary drum fermenter of Unsteady Temperature Field

Hong Liu,Xiaoqing Mei,Xiaoqing Ye,Yuan Liu,Yuhui Zheng,Yu Chen,Ziqi Xiao,Yusheng Xu,Jing Ding,Ping Liu,Min Xu,Weifeng Sun,Wenwu Ding

The doubanjiang-meju was an important intermediate product for Pixian Douban (PXDB) production. In this study, the fermentation in rotary drum fermenter (FRDF) for doubanjiang-meju was studied by comparing with the fermentation in the fermenter of constant temperature (FFCT). Compared with the FFCT, the FRDF showed higher contents of organic acids and free amino acids, and lower content of aflatoxin B 1 (AFB 1 ). The largest quantity of detected volatiles was 87 in the FRDF but 78 in the FFCT. Six key aromas in the FRDF showed stronger odor activities than those in the FFCT, and one key aroma 2,6-dimethylpyrazine appeared only in the FRDF. The core microbes were the same in the two processes except that Tetragonococcus halophilus appeared only in the FRDF, but the microorganisms in the FRDF presented more effective for the flavor formations and the AFB 1 degradation. The results indicated the FRDF had the better performances than the FFCT.

A Turn-On Ratiometric Fluorescence Probe Based on Dye@MOFs for Visual Detection of AFB1 with Paper Sensor Assisted by Smartphone

Li Zhangmin,Li Zuopeng,Li Qianyi,Wang Min,Miao Chang-qing,Liu Yajia,Zhang Sanbing

Aflatoxin B 1 (AFB 1 ) is a potent carcinogen which threatens human health, therefore, rapid and efficient detection of AFB 1 is highly needed. Herein, a novel turn-on ratiometric fluorescent nanoprobe (RhB@NH 2 -MIL-53(Al)) was fabricated via a facial grinding for sensing AFB 1 . With increasing AFB 1 concentration, the fluorescence of Al-MOFs was enhanced due to molecular clamp action and electron transport, while the fluorescence of RhB remained almost unchanged, thus obtaining limit of detection (LOD) of 4.16 nM in the range of 0.005–2.56 µM. The sensor demonstrated excellent anti-interference capabilities and gave reasonable results when used to measure AFB 1 in grains. In addition, a paper-based portable sensor for AFB 1 detection was developed with a LOD of 29.89 nM in the range of 0.04–12.8 µM, while the colour changes from light pink to blue upon UV light exposure, making it a straightforward and effective technique for the on-site determination of AFB 1 . Graphical

Effect of food matrices on AFB1 recovery by lateral flow immunoassay with deep eutectic solvents as a green alternative to conventional extraction

Chen Mengtian,Yuan Mengdi,Bu Tong,Wang Yang,Huang Xianqing,Song Lianjun,Zhang Pingan,Mao Yexuan,Zhang Xiya

D ifferent samples may cause various types of matrix interference in lateral flow immunoassay (LFA), while deep eutectic solvents (DESs) as emerging green solvents can be synthesized to adapt to different extraction processes by adjusting the composition of hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs). Initially, 30 types of food samples were selected to explore the total dilution factors (tDFs) and limit of detection (LODs) on AFB 1 detection by acetonitrile/water extraction. The matrix effect may be induced by some food matrices with high-fat content, including pumpkin seed kernel, almond, pecan, black sesame seed, walnut, and pine nut (tDFs exceeding 70-fold). DES-5 composed of Bet and EG with a molar ratio of 1:3, and a water content of 5% was selected as the optimal extraction solvent, which possessed a strong binding energy with AFB 1 (− 147.35 kJ/mol) but weak interaction with four main fatty acids (− 67.28 kJ/mol to − 74.20 kJ/mol). The DES-based LFA demonstrated that the LODs of pumpkin seed kernel, almond, pecan, black sesame seed, walnut, and pine nut were 0.74 μg/kg, 1.18 μg/kg, 1.01 μg/kg. 0.68 μg/kg, 0.98 μg/kg, and 1.21 μg/kg with recoveries of 79.39% ~ 94.21%, which was about 50% lower than that by acetonitrile/water extraction. According to the results of Soxhlet extraction, 73.46% ~ 85.91% of the total fat content of six food samples with high-fat content was transferred to the upper layer, and the fat content of detection phases (1.16 ~ 3.71 mg/g) by DES extraction (2 mL) was much lower than that of detection phases (4.76 ~ 6.35 mg/g) by acetonitrile/water extraction (2 mL). These results demonstrate that DESs as promising green extraction solvents can weaken the fat-induced matrix effect to achieve accurate detection of AFB 1 , which may provide a new strategy for reducing the interference of other compounds in the use of  LFA. Graphical abstract

On-Site AFB1 detection in food via dual-equipped NH2-ZIF-8@Cu2+ and core-shell UCNPs embedded in SA-PAM hydrogel

Huanhuan Li,Yu Wu,Xorlali Nunekpeku,Yuhan Yang,Jingsa Zhao,Wei Sheng,Yuexia Wang

The increasing presence of Aflatoxin B 1 (AFB 1 ) residues in food continues to raise significant public health concerns. Herein, we designed an upconversion-based sensor integrated into an alginate-polyacrylamide (SA-PAM) hydrogel for on-site AFB 1 detection in food. First, core-shell upconversion nanoparticles (CSUCNPs) with enhanced fluorescence were modified with complementary DNA (cDNA), forming signal probes known as CSUCNPs-cDNA. Simultaneously, NH 2 -ZIF-8@Cu 2+ with a high surface area and specific affinity for aptamer was synthesized using a one-pot method. This was then modified with an AFB 1 -specific aptamer, forming the capture probe Apt-ZIF-8@Cu 2+ . Using base pairing, CSUCNPs-cDNA and Apt-ZIF-8@Cu 2+ were hybridized into sensing probes (CSUCNPs-ZIF-8@Cu 2+ ), which were embedded into SA-PAM hydrogels as stable sensor carrier. Furthermore, the SA-PAM hydrogel showed a reduced swelling ratio of 1.68–1.80 in water and phosphate buffer solution(s) (PBS), which improves stability. In the presence of AFB 1 , the aptamer selectively binds the AFB 1 , increasing electrostatic repulsion between CSUCNPs-cDNA and Apt-ZIF-8@Cu 2+ . This disrupts Förster resonance energy transfer (FRET), resulting in a pronounced “signal-on” fluorescence. This sensor achieves AFB 1 diffusion through the SA-PAM hydrogel, FRET disruption and upconversion signal stabilization within 18 min, faster than traditional methods. Under optimized conditions, the sensor exhibited a clear linear correlation between fluorescence intensity and the logarithm of AFB 1 concentration ranging from 0.1 to 100 µg/kg ( R ² = 0.994), with a detection limit as low as 0.08 µg/kg. Besides, its performance was further validated through tests on spiked wheat, corn, peanut, and water, demonstrating high accuracy and reproducibility with relative standard deviation (RSD) below 3.63 % and recoveries of 85.88–98.04 %.

Characterization of a Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) and its application in the AFB1 degradation of contaminated rice in situ

Yang Peizhou,Xiao Wei,Lu Shuhua,Jiang Shuying,Jiang Suwei,Chen Jianchao,Wu Wenjing,Zheng Zhi,Jiang Shaotong

Aflatoxin B1 (AFB1) contaminates rice during harvest or storage and causes a considerable risk to human and animal health. In this study, Trametes versicolor AFB1–degrading enzyme (TV–AFB1D) gene recombinantly expressed in engineered E. coli BL21 (DE3) and Saccharomyces cerevisiae. The TV–AFB1D enzymatic characteristics and AFB1 degradation efficiency in contaminated rice were investigated. Results showed that the size of recombinant TV-AFB1D expressing in E. coli BL21 (DE3) and S. cerevisiae was appropriately 77 KDa. The kinetic equation of TV-AFB1D was y = 0.01671x + 1.80756 (R2 = 0.994, Km = 9.24 mM, and Vmax = 553.23 mM/min). The Kcat and Kcat/Km values of TV-AFB1D were 0.07392 (s−1) and 8 M−1 s−1, respectively. The AFB1 concentration of contaminated rice decreased from 100 μg/ml to 32.6 μg/ml after treatment at 32°C for 5 h under the catabolism of TV-AFB1D. S. cerevisiae engineered strains carrying aldehyde oxidase 1 (AOX1) and Cauliflower mosaic virus 35 S (CaMV 35 S) promoters caused the residual AFB1 contents, respectively, decreased to 3.4 and 2.9 μg/g from the initial AFB1 content of 7.4 μg/g after 24 h of fermentation using AFB1-contaminated rice as substrate. The AFB1 degradation rates of S. cerevisiae engineered strains carrying AOX1 and CaMV promoters were 54 and 61%, respectively. Engineered S. cerevisiae strains integrated with TV-AFB1D expression cassettes were developed to simultaneously degrade AFB1 and produce ethanol using AFB1-contaminated rice as substrate. Thus, TV-AFB1D has significant application potential in the AFB1 decomposition from contaminated agricultural products.

Dual aptamer-regulated activation of CRISPR-Cas12a assisted self-enhanced electrochemiluminescence sensor for AFB1 detection based on ultrafine Au NCs-anchored g-C3N4

Xiaobo Zhang,Zekun Long,Wei Wang,Yafeng Jiang,Qiuyue Zheng,Jijuan Cao

Aflatoxin B1 (AFB1), the most toxic mycotoxin among aflatoxin family, which presents a risk to food safety and human health at a trace level. Herein, the self-enhanced electrochemiluminescence (ECL) emitters of Au nanoclusters-anchored g-C 3 N 4 nanosheet (Au NCs@g-C 3 N 4 ) were synthesized, in which the Au NCs as a co-reaction accelerator enhanced the ECL stability and intensity. Integrating with CRISPR/Cas12a system, the Au NCs@g-C 3 N 4 behaved as sensing substrate to construct a “off-on” switch-type ECL sensor for AFB1 detection based on ECL resonance energy transfer (ECL-RET). The presence of targets AFB1 can specifically bind its aptamer to trigger the release of the activator. Using dual aptamer-regulated activation of CRISPR-Cas12a, AFB1 can be quantified via the ECL sensor, displaying a wide detection range from 0.2 pg/mL-100 ng/mL and a detection limit of 0.08 pg/mL. Furthermore, good practicability was verified in real samples assay, providing an efficient tool for the early warning of AFB1 pollution.

Development of a new antibody with high organic solvent tolerance for the detection of AFB1 in plant oils and monitoring UV decontamination processes

Jie Zhang,Yalin Zhou,Jian Yuan,Guanglei Li,Peng Li,Wenjing Yan,Changrui Xing

Aflatoxin B 1 (AFB 1 ) contamination in plant oils poses a serious threat to food safety. Monitoring AFB 1 decontamination, such as by ultraviolet (UV) irradiation, is challenging due to matrix complexity and the lack of robust tools. This study developed a novel monoclonal antibody with exceptional organic solvent tolerance up to 60 % methanol, enabling a one-step direct competitive ELISA (dc-ELISA). This tolerance minimized sample preparation, allowing for direct AFB 1 quantification in diverse plant oil matrices with satisfactory recovery rates (73.7–128.9 %). The dc-ELISA was innovatively applied to monitor UV-induced AFB 1 degradation kinetics, showing a high correlation with HPLC and HPLC-MS/MS methods in acetonitrile and was effectively extended to track decontamination in peanut oil. Mechanistic studies via UPLC-Q/TOF-MS identified key degradation pathways involving demethylation, oxidation, hydrolysis, and loss of CO. Electrostatic potential (ESP) analysis revealed these structural modifications altered the electronic profiles of the degradation products, resulting in low cross-reactivity and fundamentally validating the assay's reliability for process monitoring. This work provides a practical, cost-effective, and reliable tool for both the detection and degradation monitoring of AFB 1 , establishing a promising on-site solution for comprehensive food safety control.

Aptamer truncation strategy assisted by molecular docking and sensitive detection of T-2 toxin using SYBR Green I as a signal amplifier

Pengfei Ma,Hua Ye,Hualin Guo,Xiaoyuan Ma,Lin Yue,Zhouping Wang

Herein, for the first time, a novel truncation strategy for aptamers’ sequences based on molecular docking was reported for the first time. T-2 toxin and AFB 1 aptamers were employed as models and fluorescence polarization was used to measure the affinity of aptamers. The T-2 toxin aptamer (T40) with 40 bases and the AFB 1 aptamer with 32 bases were successfully obtained with increased affinities compared with original aptamers. Meanwhile, circular dichroism, FAM-BHQ1 dual labeled T40, enzyme digestion, and molecular dynamics simulation were performed to investigate the binding mechanism between aptamer T40 and T-2 toxin. Finally, based on MnO 2 nanosheet and the fluorescence amplification effect of SYBR Green I, simplified and rapid fluorescence detection of T-2 toxin was achieved with a detection range of 0.03 nM to 30 nM, indicating the great potential of aptamer in practical detection applications.

An Enhanced Ratiometric Fluorescence Immunosensor for Rapid Detection of AFB1 Based on the Dual-Enzyme Synergistic Co-Catalytic Effect of Natural Enzymes and Nanozymes

Yinnan Jing,Jiamin Wang,Xuan Liu,Shurong Li,Qinkai Yang,Mengnan Wang,Xueyi Fan,Guangsheng Ge,Kai Zheng,Jianlong Wang,Xiaoqian Tang,Qi Zhang,Yanru Wang

Aflatoxin B1 (AFB1) is considered a critical analyte in food safety testing due to its widespread contamination and high toxicity. In this study, a ratiometric fluorescent immunosensor with synergistic catalysis by natural enzymes and nanozymes (N-N-RF-immunosensor) was constructed for the rapid detection of AFB1. Copper oxide and zeolitic imidazolate framework composite nanomaterials (CuO/ZIF-8 NCM) with peroxidase and oxidase activities were prepared. A ratiometric fluorescence signal was generated through the synergistic cocatalytic effect of the CuO/ZIF-8 NCM and alkaline phosphatase, in response to the competition interaction between the anti-idiotypic nanobody-alkaline phosphatase fusion protein (Nb2-5-AP) and AFB1. The assay could detect aflatoxins within 140 min, exhibiting a half maximal inhibitory concentration (IC50) of 0.032 ng/mL, a limit of detection (LOD) of 2.4 pg/mL, and a linear range of 0.0024–1.043 ng/mL. Compared with the traditional enzyme-linked immunosorbent assay (ELISA), the sensitivity was enhanced 25-fold, while the detection parameter was shortened by 1/3. Furthermore, the immunosensor was successfully applied in the actual samples, with recoveries ranging from 81 to 127%. The N-N-RF-immunosensor shows great potential for rapid and sensitive detection of aflatoxins.