A rapid detection method is introduced for residual trace levels of triazophos in water and agricultural products using an immunoassay based on catalytic hairpin self-assembly (CHA). The gold nanoparticle (AuNPs) surface was modified with triazophos antibody and sulfhydryl bio-barcode, and an immune competition reaction system was established between triazophos and its ovalbumin-hapten (OVA-hapten). The bio-barcode served as a catalyst to continuously induce the CHA reaction to achieve the dual signal amplification. The method does not rely on the participation of enzymes, and the addition of fluorescent materials in the last step avoids interfering factors, such as a fluorescence burst. The emitted fluorescence was detected at 489/521 nm excitation/emission wavelengths. The detection range of the developed method was 0.01-50 ng/mL for triazophos, and the limit of detection (LOD) was 0.0048 ng/mL. The developed method correlates well with the results obtained by LC-MS/MS, with satisfactory recovery and sensitivity. In sum, the designed method is reliable and provides a new approach to detect pesticide residues rapidly and quantitatively.
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http://dx.doi.org/10.1007/s00604-022-05217-5 | DOI Listing |
Anal Chim Acta
February 2025
Key Laboratory of Luminescence Analysis and Molecular Sensing, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, PR China. Electronic address:
Background: β-lactoglobulin (β-Lg), a major allergen in dairy products, can trigger severe allergic reactions and even fatal outcomes in infants. In this work, we develop a new low background current redox recycling strategy by conjugating the electrochemical mediator to trimetallic hybrid nanoparticles (NPs)-dispersed graphene as the signal tag, which is coupled with DNAzyme amplifications to construct highly catalytic and ultrasensitive β-Lg aptasensor.
Results: Target β-Lg molecules bind aptamers in DNAzyme/aptamer duplexes to release active DNAzymes to initiate cyclic cleavage of hairpin substrates.
Anal Chim Acta
February 2025
College of Food Science and Technology, Henan Key Laboratory of Cereal and Oil Food Safety Inspection and Control, Henan University of Technology, Zhengzhou, 450001, China.
Background: Aflatoxin B1 (AFB1) is a secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus. This toxin is highly carcinogenic and toxic, posing a serious threat to human and animal health. AFB1 primarily enters the human body through contaminated food, particularly peanuts, corn, nuts, and wheat.
View Article and Find Full Text PDFSince microRNAs (miRNAs) serve as markers for early cancer diagnosis, it is crucial to develop a novel biosensor to detect miRNAs quickly, sensitively and selectively. Hence, we developed a fluorescence biosensor based on target miRNA-initiated rolling circle amplification (RCA) to generate RCA products with multiple tandem catalytic hairpin DNA templates that trigger primer exchange reactions (PER) which extend short single-strand DNA (ssDNA) primers into long ssDNA. Subsequently, the long ssDNA activates the -cleavage activity of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a system to cleave a fluorescent reporter chain, enabling ultrasensitive detection of miRNAs through the output fluorescence signal.
View Article and Find Full Text PDFAnal Chem
January 2025
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, People's Republic of China.
Precise identification and analysis of multiple protein biomarkers on the surface of breast cancer cell-derived extracellular vesicles (BC-EVs) are of great significance for noninvasive diagnosis of the breast cancer subtypes, but it remains a major challenge owing to their high heterogeneity and low abundance. Herein, we established a CRISPR-based homogeneous electrochemical strategy for near-zero background and ultrasensitive detection of BC-EVs. To realize the high-performance capture and isolation of BC-EVs, fluidity-enhanced magnetic nanoprobes were facilely prepared.
View Article and Find Full Text PDFTalanta
January 2025
School of Public Health, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250117, China; Institute of Brain Science and Brain-inspired Research, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, 250117, China. Electronic address:
The use of dynamic DNA logic circuits for disease diagnosis at the molecular level plays a considerable role in biomedical fields. Nevertheless, how to create programmable nanomachines based on molecular logical gates to accurately identify multiple biomarkers from tumor cells remains a pivotal challenge. Herein, we developed a DNA-based nanomachine for analyzing and imaging multiple microRNAs (miRNAs) in cancerous cells with a logical AND operation.
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