Structure-Switching Electrochemical Aptasensor for Single-Step and Specific Detection of Trace Mercury in Dairy Products

2018 ◽  
Vol 66 (38) ◽  
pp. 10106-10112 ◽  
Author(s):  
Xinai Zhang ◽  
Chenyong Huang ◽  
Yanjuan Jiang ◽  
Yuxiang Jiang ◽  
Jianzhong Shen ◽  
...  
Keyword(s):  
Dairy Products ◽  
Single Step ◽  
Electrochemical Aptasensor ◽  
Specific Detection ◽  
Structure Switching

Structure-switching aptamer sensors for the specific detection of piperaquine and mefloquine

2021 ◽  
Vol 13 (585) ◽  
pp. eabe1535
Author(s):  
Erin S. Coonahan ◽  
Kyung-Ae Yang ◽  
Stevan Pecic ◽  
Maarten De Vos ◽  
Thomas E. Wellems ◽  
...  
Keyword(s):  
Drug Use ◽  
Antimalarial Drug ◽  
Dissociation Constants ◽  
Fluorescent Sensors ◽  
Specific Detection ◽  
Standard Drug ◽  
Sensing Platforms ◽  
Current Spread ◽  
Structure Switching ◽  
Exponential Enrichment

Tracking antimalarial drug use and efficacy is essential for monitoring the current spread of antimalarial drug resistance. However, available methods for determining tablet quality and patient drug use are often inaccessible, requiring well-equipped laboratories capable of performing liquid chromatography–mass spectrometry (LC-MS). Here, we report the development of aptamer-based fluorescent sensors for the rapid, specific detection of the antimalarial compounds piperaquine and mefloquine—two slow-clearing partner drugs in current first-line artemisinin-based combination therapies (ACTs). Highly selective DNA aptamers were identified that bind piperaquine and mefloquine with dissociation constants (Kd’s) measured in the low nanomolar range via two independent methods. The aptamers were isolated from a library of single-stranded DNA molecules using a capture–systematic evolution of ligands by exponential enrichment (SELEX) technique and then adapted into structure-switching aptamer fluorescent sensors. Sensor performance was optimized for the detection of drug from human serum and crushed tablets, resulting in two sensing platforms. The patient sample platform was validated against an LC-MS standard drug detection method in samples from healthy volunteers and patients with malaria. This assay provides a rapid and inexpensive method for tracking antimalarial drug use and quality for the containment and study of parasite resistance, a major priority for malaria elimination campaigns. This sensor platform allows for flexibility of sample matrix and can be easily adapted to detect other small-molecule drugs.

scholarly journals Aptamer-Based Fluorescence Quenching Approach for Detection of Aflatoxin M1 in Milk

2021 ◽  
Vol 9 ◽  
Author(s):  
Qinqin Qiao ◽  
Xiaodong Guo ◽  
Fang Wen ◽  
Lu Chen ◽  
Qingbiao Xu ◽  
...  
Keyword(s):  
Dairy Products ◽  
Limit Of Detection ◽  
Aflatoxin M1 ◽  
Fluorescence Signal ◽  
Simple Method ◽  
Global Concern ◽  
Structure Switching ◽  
Optimized Conditions ◽  
Milk And Dairy Products

Aflatoxin M1 (AFM1), one of the most toxic mycotoxins, is a feed and food contaminant of global concern. In this study, we developed a fast and simple method for detection of AFM1 based on a structure-switching signaling aptamer. This aptasensor is based on the change in fluorescence signal due to formation of an AFM1/aptamer complex. To generate the aptasensor, the specific aptamer was modified with FAM (carboxyfluorescein), and their complementary DNAs (cDNA) were modified with a carboxytetramethylrhodamine (TAMRA) quenching group. In the absence of AFM1, the aptamers were hybridized with cDNA, resulting in quenching of the aptamer fluorescence due to the proximity of the aptamer’s fluorophore to the quenching group on the cDNA. On the other hand, in the presence of AFM1, a structural switch in the aptamer was induced by formation of an AFM1/aptamer complex. Changes in the structure of the aptamer led to the release of the cDNA, causing the generation of a fluorescence signal. Thus, AFM1 concentrations could be quantitatively monitored based on the changes in fluorescences. Under optimized conditions, this assay exhibited a linear response to AFM1 in the range of 1–100 ng/mL and a limit of detection of 0.5 ng/mL was calculated. This proposed aptasensor was applied to milk samples spiked with a dilution series of AFM1, yielding satisfactory recoveries from 93.4 to 101.3%. These results demonstrated that this detection technique could be useful for high-throughput and quantitative determination of mycotoxin levels in milk and dairy products.

A novel electrochemical aptasensor based on MWCNTs–BMIMPF6 and amino functionalized graphene nanocomposite films for determination of kanamycin

2015 ◽  
Vol 7 (13) ◽  
pp. 5419-5427 ◽  
Author(s):  
Xiaoli Qin ◽  
Wenjuan Guo ◽  
Huijing Yu ◽  
Juan Zhao ◽  
Meishan Pei
Keyword(s):  
Nanocomposite Films ◽  
Functionalized Graphene ◽  
Electrochemical Aptasensor ◽  
Specific Detection ◽  
Graphene Nanocomposite ◽  
Cost Efficient

A simple and cost-efficient electrochemical aptasensor for sensitive and specific detection of kanamycin was reported.

A simple competitive enzyme-linked immunosorbent assay for the specific detection of the multiphosphorylated 1–25 β-casein fragment

2013 ◽  
Vol 80 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Akinori Kume ◽  
Akina Sasayama ◽  
Tetsuo Kaneko ◽  
Junichi Kurisaki ◽  
Munehiro Oda
Keyword(s):  
Mass Spectrometry ◽  
Immunosorbent Assay ◽  
Dairy Products ◽  
Sample Pretreatment ◽  
Competitive Elisa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Detection ◽  
Phosphorylated Form ◽  
Casein Phosphopeptides ◽  
Casein Phosphopeptide

A specific and simple competitive enzyme-linked immunosorbent assay (ELISA) was developed to determine bovine β-casein phosphopeptides (β-CPP) in casein phosphopeptides (CPP) or CPP complexes such as casein phosphopeptide amorphous calcium phosphate complexes added into dairy products. The method combines sample pretreatment designed for CPP enrichment and anti-β-CPP(f(1–25)) monoclonal antibody 1A5 (mAb 1A5). The mAb 1A5 bound specifically to the tryptic phosphopeptides from β-casein but not from αs1- or αs2-casein. Reactivity was also influenced by the extent of the phosphorylated form of serine residues. Based on the sequence-specific recognition and contribution of phosphorylated serine residues, the epitope of mAb 1A5 was found to reside within the cluster motif Ser(P)-Ser(P)-Ser(P)-Glu-Glu and the surrounding residues in β-CPP. The competitive ELISA developed here can be used as an alternative to specialised and expensive techniques such as mass spectrometry. In particular, it is suitable for the measurement of CPP or CPP complexes in dairy products, which contain closely related endogenous molecular species.

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