scholarly journals Simple and Label-Free Fluorescent Detection of Melamine Based on Melamine–Thymine Recognition

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2968 ◽  
Author(s):  
Hualin Yang ◽  
Jiujun Wang ◽  
Qinghua Wu ◽  
Yun Wang ◽  
Li Li ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Chain Structure ◽  
Sybr Green ◽  
Sybr Green I ◽  
Fluorescent Detection ◽  
Fluorescence Signal ◽  
Label Free ◽  
Protein Levels ◽  
Fluorescent Method ◽  
Milk Adulteration

In the past few years, melamine has been illegally added into dairy products to increase the apparent crude protein levels. If humans or animals drink the milk adulteration of melamine, it can form insoluble melamine–cyanurate crystals in their kidneys which causes kidney damage or even death. In the present work, we constructed a simple and label-free fluorescent method for melamine detection based on melamine-thymine recognition. SYBR Green I was utilized as a reporter for this method as it did not require any modification or expensive equipment. In the absence of melamine, polythymine DNA was digested by Exo I, which caused a decrease in the fluorescence signal. In the presence of melamine, the polythymine DNA was able to fold into a double chain structure, however this was done with the help of T-melamine-T mismatches to prevent degradation. Then, the SYBR Green I combined with the double-stranded DNA to result in an intense fluorescence signal. The limit of detection in this method was 1.58 μM, which satisfied the FDA standards. This method also had a good linear relationship within the range of 10–200 μM. In addition, this new method has a good selectivity to distinguish melamine from the component of milk. As a result, we developed a simple and highly selectivity method for melamine detection.

Improved Detection of Hg2+ in Aqueous Solution with High Sensitivity and Selectivity by Using Mercury-Specific DNA, Sybr Green I and Gold Nanoparticles

2011 ◽  
Vol 239-242 ◽  
pp. 934-939
Author(s):  
Hui Xu ◽  
Shuli Gao ◽  
Jian Nong Chen ◽  
Quan Wen Liu
Keyword(s):  
Gold Nanoparticles ◽  
High Sensitivity ◽  
Sybr Green ◽  
Sybr Green I ◽  
Fluorescence Signal ◽  
Potassium Ions ◽  
Label Free ◽  
Turn On ◽  
Sensitivity And Selectivity ◽  
Fluorescence Turn On

We report a label-free, fast, fluorescence turn on assay for Hg2+detecton by using mercury-specific DNA (MSD), Sybr Green I (SG) and gold nanoparticles (AuNPs). SG efficiently discriminates MSD and MSD/Hg2+complex. The addition of gold nanoparticle decreases the background fluorescence signal further for MSD. The fluorescence intensity of MSD/Hg2+complex keeps constant after addition of AuNPs. This property improves the signal-to-background ratio and decreases the detection limitation further. In addition, the method shows improved selectivity compared with that in the absence of AuNPs. This strategy could be applied to the detection of potassium ions and showed good generality.

Label-free fluorescence assay coupled exonuclease reaction and SYBR Green I for the detection of T4 polynucleotide kinase activity

2020 ◽  
Vol 12 (6) ◽  
pp. 807-812
Author(s):  
Xu Wu ◽  
Shuyi He ◽  
Julia Xiaojun Zhao
Keyword(s):  
Kinase Activity ◽  
Sybr Green ◽  
Fluorescence Assay ◽  
Sybr Green I ◽  
Label Free ◽  
Cleavage Reaction ◽  
Polynucleotide Kinase ◽  
T4 Polynucleotide Kinase

A sensitive label-free fluorescence assay for monitoring T4 polynucleotide kinase (T4 PNK) activity and inhibition was developed based on a coupled λ exonuclease cleavage reaction and SYBR Green I.

A universal and label-free aptasensor for fluorescent detection of ATP and thrombin based on SYBR Green Idye

2013 ◽  
Vol 42 ◽  
pp. 193-197 ◽  
Author(s):  
Ling Kong ◽  
Jin Xu ◽  
Yunying Xu ◽  
Yun Xiang ◽  
Ruo Yuan ◽  
...  
Keyword(s):  
Sybr Green ◽  
Fluorescent Detection ◽  
Label Free

scholarly journals Fluorescence Based on Surface Plasmon Coupled Emission for Ultrahigh Sensitivity Immunoassay of Cardiac Troponin I

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 448
Author(s):  
Vien Thi Tran ◽  
Heongkyu Ju
Keyword(s):  
Surface Plasmon ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Limit Of Detection ◽  
Delayed Diagnosis ◽  
Cardiac Troponin I ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Label Free ◽  
Ultrahigh Sensitivity

This work demonstrates the quantitative assay of cardiac Troponin I (cTnI), one of the key biomarkers for acute cardiovascular diseases (the leading cause of death worldwide) using the fluorescence-based sandwich immune reaction. Surface plasmon coupled emission (SPCE) produced by non-radiative coupling of dye molecules with surface plasmons being excitable via the reverse Kretschmann format is exploited for fluorescence-based sandwich immunoassay for quantitative detection of cTnI. The SPCE fluorescence chip utilizes the gold (2 nm)-silver (50 nm) bimetallic thin film, with which molecules of the dye Alexa 488 (conjugated with detection antibodies) make a near field coupling with the plasmonic film for SPCE. The experimental results find that the SPCE greatly improves the sensitivity via enhancing the fluorescence signal (up to 50-fold) while suppressing the photo-bleaching, permitting markedly enhanced signal-to-noise ratio. The limit of detection of 21.2 ag mL−1 (atto-gram mL−1) is obtained, the lowest ever reported to date amid those achieved by optical technologies such as luminescence and label-free optical sensing techniques. The features discovered such as ultrahigh sensitivity may prompt the presented technologies to be applied for early diagnosis of cTnI in blood, particularly for emergency medical centers overloaded with patients with acute myocardial infarction who would suffer from time-delayed diagnosis due to insufficient assay device sensitivity.

An enzyme-free and label-free assay for copper(ii) ion detection based on self-assembled DNA concatamers and Sybr Green I

The Analyst ◽  
2013 ◽  
Vol 138 (17) ◽  
pp. 4737 ◽  
Author(s):  
Chenchen Ge ◽  
Junhua Chen ◽  
Wei Wu ◽  
Zhiyuan Fang ◽  
Lingbo Chen ◽  
...  
Keyword(s):  
Sybr Green ◽  
Sybr Green I ◽  
Label Free ◽  
Ion Detection ◽  
Self Assembled

Fluorescent detection of silver(I) and cysteine using SYBR Green I and a silver(I)-specific oligonucleotide

2012 ◽  
Vol 177 (1-2) ◽  
pp. 137-144 ◽  
Author(s):  
Wendan Pu ◽  
Huawen Zhao ◽  
Chengzhi Huang ◽  
Liping Wu ◽  
Dan Xua
Keyword(s):  
Sybr Green ◽  
Sybr Green I ◽  
Fluorescent Detection

scholarly journals Aptamer Conformation Switching-Induced Two-Stage Amplification for Fluorescent Detection of Proteins

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 77 ◽  
Author(s):  
Qiao Yu ◽  
Fenfen Zhai ◽  
Hong Zhou ◽  
Zonghua Wang
Keyword(s):  
Molecular Beacon ◽  
Limit Of Detection ◽  
Low Cost ◽  
Dna Aptamer ◽  
Fluorescent Detection ◽  
Fluorescence Signal ◽  
Sensing Platform ◽  
Low Concentrations ◽  
Diagnostic Applications ◽  
Recycling Amplification

Basing on the conformation change of aptamer caused by proteins, a simple and sensitive protein fluorescent assay strategy is proposed, which is assisted by the isothermal amplification reaction of polymerase and nicking endonuclease. In the presence of platelet-derived growth factor (PDGF-BB), the natural conformation of a DNA aptamer would change into a Y-shaped complex, which could hybridize with a molecular beacon (MB) and form a DNA duplex, leading to the open state of the MB and generating a fluorescence signal. Subsequently, with further assistance of isothermal recycling amplification strategies, the designed aptamer sensing platform showed an increment of fluorescence. As a benefit of this amplified strategy, the limit of detection (LOD) was lowered to 0.74 ng/mL, which is much lower than previous reports. This strategy not only offers a new simple, specific, and efficient platform to quantify the target protein in low concentrations, but also shows a powerful approach without multiple washing steps, as well as a precious implementation that has the potential to be integrated into portable, low-cost, and simplified devices for diagnostic applications.

A label-free signal amplification assay for DNA detection based on exonuclease III and nucleic acid dye SYBR Green I

Talanta ◽  
2013 ◽  
Vol 114 ◽  
pp. 49-53 ◽  
Author(s):  
Aihua Zheng ◽  
Ming Luo ◽  
Dongshan Xiang ◽  
Xia Xiang ◽  
Xinghu Ji ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Signal Amplification ◽  
Dna Detection ◽  
Sybr Green ◽  
Sybr Green I ◽  
Label Free ◽  
Acid Dye ◽  
Exonuclease Iii ◽  
Amplification Assay
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