查找使用阿拉丁产品的科研文献

A “sense-and-treat” ELISA using zeolitic imidazolate framework-8 as carriers for dual-modal detection of carcinoembryonic antigen

Hongye Yan,Lei Jiao,Hengjia Wang,Weiqing Xu,Yu Wu,Wenling Gu,Dan Du,Yuehe Lin,Chengzhou Zhu

Enzyme-linked immunosorbent assay (ELISA) has been widely used in the area of biological analysis, while there are still some challenges getting in the way to ensure both excellent sensitivity and reliable accuracy. To overcome these obstacles, we simulated the “smart” sense-and-treat carriers in a drug delivery system to fabricate an improved ELISA, employing zeolitic imidazolate framework-8 (ZIF-8) as the carrier to deliver the tracer agent carbon dots (CDs) and the “drug” thymolphthalein (TP), which was referred to as a “sense-and-treat” ELISA. In the “sense” part, the strong fluorescence intensity of CDs could be observed directly to achieve the sensitive detection of the target. In the “treat” part, after stimulation of alkaline solution, TP was released from ZIF-8 carriers and generated a color change with an obvious absorption, which was beneficial for increasing the sensitivity of this ELISA due to the high loading of the TP. Finally, we took carcinoembryonic antigen (CEA) as a model and performed dual-modal detection using this improved “sense-and-treat” ELISA to accomplish quantitative determinations sensitively and accurately. In addition, the results indicated by the two parts kept good concordance, which could demonstrate the reliable accuracy of this ELISA.

Development of an ic-ELISA and immunochromatographic assay strip for the rapid detection of chloridazon in oranges and celery

Qing Zhang,Aihong Wu,Jinyan Li,Liqiang Liu,Hua Kuang,Chuanlai Xu,Lingling Guo

Chloridazon (CLZ) is a selective herbicide used in the control of annual broadleaf weeds. The misuse or abuse of CLZ may result in the accumulation of CLZ in crops and water, which can pose a risk to human health. In this study, a hapten of CLZ with three carbon spacer arms was designed and a highly sensitive and specific antibody against CLZ was prepared with a half-maximal inhibitory concentration of 0.630 ng mL−1 and a linear range of 0.181–2.195 ng mL−1.Based on this antibody, we developed an immunochromatographic assay (ICA) strip for the detection of CLZ in oranges and celery. Under optimized conditions, the visual limit of detection was 2 ng mL−1 and 10 ng mL−1 in oranges and celery, respectively, and the cut-off value was 50 ng mL−1. In CLZ-spiked samples and the recovery test, the results of the ICA strip were consistent with those of indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Therefore, the ICA strip developed in our study represents an efficient and reliable method for the rapid screening of CLZ in oranges and celery.

Competitive ELISA based on pH-responsive persistent luminescence nanoparticles for autofluorescence-free biosensor determination of ochratoxin A in cereals

Wang Yinghui,Yu Ling,Zhang Hui,Zhu Runzhi,Meng Zhe

An accurate and sensitive competitive enzyme-linked immunosorbent assay (ELISA) based on persistent luminescence nanoparticles Zn 2 GeO 4 :Mn 2+ , Eu 3+ (ZGME) was developed for detecting ochratoxin A (OTA), a powerfully toxic mycotoxin usually found in grains. As a signal output element of autofluorescence-free biosensors, ZGME can be integrated into ELISA with glucose oxidase (GOx)-binding OTA molecules due to its excellent pH-responsive persistent luminescence. In the absence of OTA, the OTA-GOx conjugate was captured by the anti-OTA monoclonal antibody (anti-OTA mAb) pre-coated on the 96-well plate. The results indicate a decrease in the pH value of the solution, which triggered the quenching of ZGME luminescence due to GOx-dependent gluconic acid production. The presence of OTA inhibited the binding of OTA-GOx on the plate, thus decreasing the production of gluconic acid and increasing the persistent luminous intensity of ZGME. Under the optimized concentrations of anti-OTA mAb and OTA-GOx, quantitative determination of OTA was achieved by plotting the increase or decrease in persistent luminescence intensity of ZGME at 535 nm. In this study, the linear range was from 0.1 μg L −1 to 63 μg L −1 , and the limit of detection (LOD) was as low as 0.045 μg L −1 . In five food samples (corn grit, brown rice, soybean, rice, and wheat), the results exhibited good stability and repeatability, with a recovery range from 81.3% to 94.4% and a relative standard deviation (RSD) of less than 4.2%. Hence, the established method provides a sensitive, accurate, and autofluorescence-free approach for the determination of OTA in different grain samples.

Comparative study of Pd@Pt nanozyme improved colorimetric N-ELISA for the paper-output portable detection of Staphylococcus aureus

Xin Wang,Min Zhang,Xiaoxu Pang,Kunlun Huang,Zhiyi Yao,Xiaohong Mei,Nan Cheng

Staphylococcus aureus is a frequent pathogenic bacterium that has a significant detrimental influence on the health of the human body. Therefore, developing a practical and portable detection platform is critical to ensuring food safety. Nanozymes are a kind of engineered nanomaterials with superior enzyme-like activities, providing infinite possibilities for the development of highly sensitive analytical assays. In this study, mesoporous core−shell [email protected] ( [email protected] ) nanozymes were synthesized and then applied as a signal amplifier in Staphylococcus aureus colorimetric immunoassay . At the same time, a careful comparative study of the catalytic performance with natural horseradish peroxidase (HRP), [email protected] nanozymes and their complexes [email protected] (HRP coupling with [email protected] nanozymes) were firstly performed, as well as clever using a colorimeter to achieve portable signal output. [email protected] bioprobes enable remarkable peroxidase-like catalytic activity, resulting in the highest sensitivity with a limit of detection (LOD) improved from 1 × 10 5 to 1 × 10 3  CFU/mL. In all, this work conducted a valuable comparative study and presented an improved strategy for the portable detection of pathogenic bacteria, which was expected to be used in a wide range of applications in food safety regulation and biomedicals arenas.

Construction and characterization of a class-specific single-chain variable fragment against pyrethroid metabolites

Liu Yuan,Liu Dan,Shen Chen,Dong Sa,Hu Xiaodan,Lin Manman,Zhang Xiao,Xu Chongxin,Zhong Jianfeng,Xie Yajing,Zhang Cunzheng,Wang Donglan,Liu Xianjin

Abstract Pyrethroids are insecticides that are widely used in rural and urban areas worldwide. After entering the environment, pyrethroids are rapidly metabolized or degraded by various biological or abiotic methods. In this study, a single-chain variable fragment (scFv) which could simultaneously detect three pyrethroid metabolites was constructed based on a hybridoma raised against 3-phenoxybenzoic acid (3-PBA). By molecular docking, it showed that there were hydrogen bonds, hydrophobic interactions, CH-π interaction, and cation-π interaction between 3-PBA and its scFv. All the contact residues contributing to hydrogen bonds are located in VH-CDR2 or its neighboring region, and two of them were mutants of the closest germline sequence. Based on competitive ELISA, the half maximal inhibitory concentration (IC 50 ) of the scFv for 3-PBA, 3-phenoxybenzaldehyde (PBAld), and 3-phenoxybenzyl alcohol (PBAlc) were calculated to be 0.55, 0.59, and 0.63 μgmL −1 , respectively. The scFv also showed 23.91%, 13.41%, 1.15%, 1.00%, and 0.56% cross-reactivity with phenothrin, deltamethrin, fenvalerate, beta-cypermethrin, and fenpropathrin. The broad specificity of the scFv may be due to its hapten design. The scFv could be employed in class-specific immunoassays for pyrethroid metabolites with phenoxybenzyl (PB) group. It is also potentially used for characterizing degradation of pyrethroids or detecting PBAlc (PBAld) alone, and the detection results should be confirmed by other selective methods. Key points • A scFv which can simultaneously detect 3-PBA, PBAlc, and PBAld was constructed. • Antibody informatics and binding mode of the scFv were obtained. • The reason for its broad specificity was discussed. • It could be used to monitor single or multi-pyrethroid metabolites with PB group.

Development of crosslinker-free antibody–enzyme conjugates for immunoassays in pesticide residue detection

Jiayi Chen,Qiyi He,Junkang Pan,El-Sayed A. El-Sheikh,Rubing Zou,Yirong Guo,Bruce D. Hammock,Li Li,Dongyang Li

Immunoassays are biochemical analytical techniques based on the specific binding between antigens and antibodies. Due to their high sensitivity, rapid analysis, high throughput, cost-effectiveness, and broad applicability, immunoassays have been widely utilized across various fields. Antibody–enzyme conjugates are essential components for signal generation in immunoassays, with crosslinking chemical (crosslinker)-based methods traditionally employed for their production. However, these methods often involve hazardous reagents and complex procedures, highlighting the need for more eco-friendly alternatives. In this study, we developed a universal, crosslinker-free approach for preparing antibody–enzyme conjugates. This method eliminates the use of chemical reagents such as glutaraldehyde or periodate, as well as the intricate conjugation and purification steps typically required. Instead, gold nanoparticles (AuNPs) were employed as a versatile nanomaterial to passively adsorb horseradish peroxidase (HRP) and antibodies through a simple procedure completed within 60 minutes. The resulting conjugates were characterized using UV-vis spectroscopy, transmission electron microscopy (TEM), and zeta potential analysis. Using acetamiprid (ACE), a widely-used pesticide, as the target model, an enzyme-linked immunosorbent assay (ELISA) was developed based on the AuNP-mediated conjugates. The assay demonstrated performance comparable to that of traditional crosslinker-based methods, with an IC50 of 0.49 ng mL−1 and a limit of detection (LOD) of 0.11 ng mL−1. Recovery rates for ACE in spiked fruit samples were consistent with those obtained using liquid chromatography-mass spectrometry (LC-MS). The proposed method not only provides a reliable alternative for HRP and antibody conjugation but also advances green analytical chemistry by minimizing the use of hazardous chemicals, reducing derivative waste, and improving energy efficiency.

Quantitative Determination of Acetamiprid in Pollen Based on a Sensitive Enzyme-Linked Immunosorbent Assay

Qingkui Fang,Quan Zu,Xiude Hua,Pei Lv,Wanwen Lin,Dahe Zhou,Zihan Xu,Jiarui Fan,Xiaohan Li,Haiqun Cao

A sensitive biotinylated indirect competitive enzyme-linked immunosorbent assay (Bic-ELISA) was developed to detect acetamiprid pesticides in pollen, based on the heterogeneous coating antigen and biotinylated anti-acetamiprid monoclonal antibody. Under optimized experimental conditions, the detection limit for the Bic-ELISA was 0.17 ng/mL and the linear range was 0.25–25 ng/mL. The cross-reactivities could be regarded as negligible for the biotinylated antibodies with their analogues except for thiacloprid (1.66%). Analyte recoveries for extracts of spiked pollen (camellia pollen, lotus pollen, rape pollen) ranged from 81.1% to 108.0%, with intra-day relative standard deviations (RSDs) of 4.8% to 10.9%, and the average reproducibility was 85.4% to 110.9% with inter-assay and inter-assay RSDs of 6.1% to 11.7%. The results of Bic-ELISA methods for the Taobao’s website samples were largely consistent with HPLC-MS/MS. Therefore, the established Bic-ELISA methods would be conducive to the monitoring of acetamiprid in pollen.Keywords:pollen;acetamiprid;pesticide;heterogeneous coating antigen;biotinylated mAb;Bic-ELISA

Investigation of diethylstilbestrol residue level in human urine samples by a specific monoclonal antibody

Zhang Dai,Zhou Lifang,Lei Yajing,Zhou Zhan,Zhou Jie,Chen Shuqing

Diethylstilbestrol (DES) is used as a kind of animal feed additive and affects people’s health through the food chain. The purpose of this study is to detect the residue level of DES in 576 human urine samples directly. DES-BSA was used to immunize Balb/c mice. The monoclonal antibody was produced by hybridoma that was screened through cell fusion techniques. Finally, we developed the indirect competitive ELISA method to analyze 576 human urine samples from Zhejiang Province, China. The IC 50 of this method was 3.33 ng/mL. The LOD and LOQ were 0.16 and 0.54 ng/mL. Linear range of the standard curve was from LOD to 12.50 ng/mL. There was no cross-reactivity with two kinds of estrogens and two structural analogs with DES. Five hundred seventy-six urine samples were analyzed by the indirect competitive ELISA method, and the detection rate was 98.78%. The mean concentration and geometric mean were 4.70 and 3.50 ng/mL. The indirect competitive ELISA method based on monoclonal antibody was sensitive and reliable for the detection of DES in human urine samples. The results warned us to pay more attention to human health and food safety.

Development of an immunochromatographic test strip and ic-ELISA for tetrabromobisphenol: a detection in lake water and rice pudding samples

Li Yu,Liqiang Liu,Shanshan Song,Hua Kuang,Chuanlai Xu

Natural deep eutectic solvent-based QuEChERS followed by magnetic beads ELISA for the analysis of ochratoxin A in cereal samples

Luyao Zhao,Jin Liu,Bing Bai,Yongpeng An,Yukun Yang,Xiaowen Wang,Xu Jing

Herein, we established a green, rapid, and sensitive method to analyze ochratoxin A (OTA) in cereals based on modified QuEChERS and enzyme-linked immunosorbent assay (ELISA). Lignocellulose is a renewable material mainly consisting of cellulose, hemicellulose, and lignin. In the modified QuEChERS, a natural deep eutectic solvent synthesized from glucose and levulinic acid derived from cellulose and hemicellulose was used as an extraction solvent to replace traditional organic solvents. Furthermore, modified lignin was used as an adsorbent to purify the extraction solution. In the magnetic bead-based ELISA, the effervescent reaction accelerated the immune competition. Additionally, magnetic beads were used to shorten the incubation and washing time, whereas gold nanoparticles were used to amplify the optical signal. This method has been successfully applied to the analysis of OTA in cereal samples. The limits of detection were 0.68–0.83 μg kg −1 . This pretreatment and detection strategy has potential application in analyzing mycotoxins.

A one-pot purification-free strategy for biotinylated antibody preparation enables sensitive ELISA detection of cardiac troponin I-C complex

Gao Hongfan,Zhang Shujing,Li Xin

Biotinylated antibodies are widely used in ELISA. However, their preparation typically requires labor-intensive purification steps to remove the excess biotinylating reagent. Here, we present a novel one-pot, purification-free strategy for preparing biotinylated antibodies, enabling a robust sandwich ELISA platform for the detection of the cardiac troponin I-C complex, a key biomarker for acute myocardial infarction. By introducing glycine (Gly) as a quenching agent to inactivate the residual biotinylating reagent (NHS-biotin esters) during the labeling process, our method eliminates the need for post-labeling purification while effectively reducing nonspecific background. Systematic optimization of labeling conditions yielded an assay with a detection limit of 1.08 pM and a broad linear quantification range from 3.6 pM to 1 nM ( R 2  = 0.99). The platform demonstrated high specificity, with recovery rates ranging from 91.5 to 101.8% and intra-assay variation below 2.9%. Furthermore, successful validation in a serum amyloid A detection model confirmed the generalizability of the Gly-mediated background suppression strategy. This cost-effective, streamlined ELISA workflow offers a powerful tool for rapid and reliable clinical diagnostics, with potential for broad application in biomarker detection. Graphical abstract This schematic contrasts the conventional and novel one-pot strategies for antibody biotinylation in ELISA. The traditional method requires a cumbersome purification step to remove excess biotin-NHS reagent after labeling. In contrast, our one-pot approach introduces a key innovation: an in-solution quenching reaction. The addition of a small molecule (e.g., glycine) efficiently inactivates residual biotin esters, allowing the biotinylated antibody to be used directly in subsequent steps, thereby streamlining the workflow.

Development of sensitive and rapid immunoassays for Moniliformin (MON) detection based on nanomaterials labeled monoclonal antibodies

Lakshani Madushika,Yongming Huang,Menghan Sun,Yuxuan Liu,Linfang Lu,Xiaoli Li,Na Li,Kang Jiang,Sumei Ling,Shihua Wang

Moniliformin (MON) is a toxic secondary metabolite from Fusarium species. The natural contamination of MON in cereals and cereal by-products, poses a risk of exposure to MON. However, so far, no immunoassay method has been reported to detect MON in field samples. In this study, anti-MON monoclonal antibody (mAb) with high affinity (1 × 10 8 ) and isotype of IgG1 was subjected to establish indirect competitive ELISA (ic-ELISA) and immunochromatographic test strips (ICTS). The optimized ic-ELISA resulted in the lowest detection limit (LOD) of 1.55 μg/mL. The LOD value for gold nanoparticles (AuNP) -based test strip was 0.83 μg/mL. The multi branched gold nano-flower particles (AuNFs) reported higher sensitivity with LOD of 0.38 μg/mL. Moreover, the developed test strips exhibited a high specificity without cross-reactivity to related competitive toxins. In conclusion, immunoassay methods were successfully developed to detect MON in field samples with a short detection time to ensure food security.