Fluorescence recognition of double-stranded DNA based on the quenching of gold nanoparticles to a fluorophore labeled DNA probe

The Analyst ◽  
2016 ◽  
Vol 141 (20) ◽  
pp. 5829-5834 ◽  
Author(s):  
Xiangmin Miao ◽  
Zongbing Li ◽  
Liansheng Ling
Keyword(s):  
Gold Nanoparticles ◽  
Fluorescent Sensor ◽  
Dna Probe ◽  
Specific Recognition ◽  
Double Stranded Dna

This work described an ultrasensitive fluorescent sensor for sequence-specific recognition of dsDNA based on the quenching of gold nanoparticles (AuNPs) to a fluorophore labeled DNA probe.

Colorimetric multiplexed analysis of mercury and silver ions by using a unimolecular DNA probe and unmodified gold nanoparticles

2012 ◽  
Vol 4 (10) ◽  
pp. 3320 ◽  
Author(s):  
Zhihe Qing ◽  
Xiaoxiao He ◽  
Kemin Wang ◽  
Zhen Zou ◽  
Xue Yang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Silver Ions ◽  
Dna Probe ◽  
Multiplexed Analysis

A colorimetric method for the sequence-specific recognition of double-stranded DNA on the surface of a silver-coated glass slide

2018 ◽  
Vol 96 (5) ◽  
pp. 466-470
Author(s):  
Xiaoting Guo ◽  
Jing Wang ◽  
Zhifang Zhu ◽  
Manjun Zhang ◽  
Haigang Li ◽  
...  
Keyword(s):  
Colorimetric Method ◽  
Colour Change ◽  
Glass Slide ◽  
Coated Glass ◽  
Specific Recognition ◽  
Double Stranded Dna ◽  
Pcr Products ◽  
Polymerase Chain ◽  
Good Sequence ◽  
Coated Glass Slide

In this study, a colorimetric method for sequence-specific recognition of double-stranded DNA (dsDNA) was established on the surface of a silver-coated glass slide. Oligo-1 was assembled on the surface of a silver-coated glass slide through an Ag–S bond, and Oligo-2 as reporter was used to bind with streptavidin-horseradish peroxidase (SA–HRP). They could bind with target dsDNA that was composed of Oligo-3 and Oligo-4 on the surface of a silver-coated glass slide through triplex formation. The bound HRP could be moved into the solution by DNase I and catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). Therefore, the concentration of target dsDNA could be determined with the colour change of TMB. Under the optimum conditions, the absorbance was proportional to the concentration of target dsDNA over the range of 100 pmol/L to 2.0 nmol/L, with a detection limit of 13 pmol/L. In addition, this method showed good sequence selectivity, enabling it to be further developed for the detection of other polymerase chain reaction (PCR) products.

scholarly journals Single-molecule visualization of RecQ helicase reveals DNA melting, nucleation, and assembly are required for processive DNA unwinding

2015 ◽  
Vol 112 (50) ◽  
pp. E6852-E6861 ◽  
Author(s):  
Behzad Rad ◽  
Anthony L. Forget ◽  
Ronald J. Baskin ◽  
Stephen C. Kowalczykowski
Keyword(s):  
Single Molecule ◽  
Fluorescent Sensor ◽  
Holliday Junctions ◽  
Dna Unwinding ◽  
Recq Helicase ◽  
Dna Breaks ◽  
Dna Helicases ◽  
Double Stranded Dna ◽  
Functional Forms ◽  
And Migration

DNA helicases are motor proteins that unwind double-stranded DNA (dsDNA) to reveal single-stranded DNA (ssDNA) needed for many biological processes. The RecQ helicase is involved in repairing damage caused by DNA breaks and stalled replication forks via homologous recombination. Here, the helicase activity of RecQ was visualized on single molecules of DNA using a fluorescent sensor that directly detects ssDNA. By monitoring the formation and progression of individual unwinding forks, we observed that both the frequency of initiation and the rate of unwinding are highly dependent on RecQ concentration. We establish that unwinding forks can initiate internally by melting dsDNA and can proceed in both directions at up to 40–60 bp/s. The findings suggest that initiation requires a RecQ dimer, and that continued processive unwinding of several kilobases involves multiple monomers at the DNA unwinding fork. We propose a distinctive model wherein RecQ melts dsDNA internally to initiate unwinding and subsequently assembles at the fork into a distribution of multimeric species, each encompassing a broad distribution of rates, to unwind DNA. These studies define the species that promote resection of DNA, proofreading of homologous pairing, and migration of Holliday junctions, and they suggest that various functional forms of RecQ can be assembled that unwind at rates tailored to the diverse biological functions of RecQ helicase.

Fluorescence quenching biosensor for acrylamide detection in food products based on double-stranded DNA and gold nanoparticles

2018 ◽  
Vol 265 ◽  
pp. 339-345 ◽  
Author(s):  
Maryam Asnaashari ◽  
Reza Esmaeilzadeh Kenari ◽  
Reza Farahmandfar ◽  
Seyed Mohammad Taghdisi ◽  
Khalil Abnous
Keyword(s):  
Gold Nanoparticles ◽  
Fluorescence Quenching ◽  
Food Products ◽  
Double Stranded Dna
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