Label-free and highly sensitive electrochemical detection of E. coli based on rolling circle amplifications coupled peroxidase-mimicking DNAzyme amplification

2016 ◽  
Vol 75 ◽  
pp. 315-319 ◽  
Author(s):  
Yuna Guo ◽  
Yu Wang ◽  
Su Liu ◽  
Jinghua Yu ◽  
Hongzhi Wang ◽  
...  
Keyword(s):  
Electrochemical Detection ◽  
Label Free ◽  
Rolling Circle ◽  
E Coli ◽  
Highly Sensitive

A functional oligonucleotide probe from an encapsulated silver nanocluster assembled by rolling circle amplification and its application in label-free sensors

RSC Advances ◽  
2016 ◽  
Vol 6 (92) ◽  
pp. 88967-88973 ◽  
Author(s):  
Yuna Guo ◽  
Yu Wang ◽  
Su Liu ◽  
Jinghua Yu ◽  
Qianqian Pei ◽  
...  
Keyword(s):  
Electrochemical Biosensor ◽  
Oligonucleotide Probe ◽  
Low Cost ◽  
Rolling Circle Amplification ◽  
Silver Nanoclusters ◽  
Label Free ◽  
Rolling Circle ◽  
Silver Nanocluster ◽  
E Coli ◽  
Highly Sensitive

A novel label-free, low cost electrochemical biosensor for highly sensitive and selective detection of E. coli has been developed based on rolling circle amplification coupled silver nanoclusters as effective electrochemical probe.

Target-responsive dumbbell probe-mediated rolling circle amplification strategy for highly sensitive Hg2+ detection

RSC Advances ◽  
2014 ◽  
Vol 4 (51) ◽  
pp. 27091-27097 ◽  
Author(s):  
Qingwang Xue ◽  
Yanqin Lv ◽  
Yuanfu Zhang ◽  
Shuling Xu ◽  
Qiaoli Yue ◽  
...  
Keyword(s):  
Rolling Circle Amplification ◽  
Selective Detection ◽  
Label Free ◽  
Rolling Circle ◽  
Fluorescent Sensing ◽  
Highly Sensitive ◽  
Mercuric Ions ◽  
Amplification Strategy

A novel label-free amplified fluorescent sensing scheme based on target-responsive dumbbell probe-mediated rolling circle amplification (D-RCA) has been developed for sensitive and selective detection of mercuric ions.

scholarly journals Electrochemical Detection of Waterborne Bacteria Using Bi-Functional Magnetic Nanoparticle Conjugates

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Dharanivasan Gunasekaran ◽  
Yoram Gerchman ◽  
Sefi Vernick
Keyword(s):  
Electrochemical Detection ◽  
Electrochemical Method ◽  
Magnetic Nanoparticle ◽  
Specific Binding ◽  
Dependent Manner ◽  
Igg Antibody ◽  
E Coli ◽  
Amine Functionalized ◽  
Highly Sensitive ◽  
Dose Dependent

Detection of microbial contamination in water is imperative to ensure water quality. We have developed an electrochemical method for the detection of E. coli using bi-functional magnetic nanoparticle (MNP) conjugates. The bi-functional MNP conjugates were prepared by terminal-specific conjugation of anti-E. coli IgG antibody and the electroactive marker ferrocene. The bi-functional MNP conjugate possesses both E. coli-specific binding and electroactive properties, which were studied in detail. The conjugation efficiency of ferrocene and IgG antibodies with amine-functionalized MNPs was investigated. Square-wave voltammetry enabled the detection of E. coli concentrations ranging from 101–107 cells/mL in a dose-dependent manner, as ferrocene-specific current signals were inversely dependent on E. coli concentrations, completely suppressed at concentrations higher than 107 cells/mL. The developed electrochemical method is highly sensitive (10 cells/mL) and, coupled to magnetic separation, provides specific signals within 1h. Overall, the bi-functional conjugates serve as ideal candidates for electrochemical detection of waterborne bacteria. This approach can be applied for the detection of other bacteria and viruses.

scholarly journals A Label-Free Fluorescent Sensor Based on the Formation of Poly(thymine)-Templated Copper Nanoparticles for the Sensitive and Selective Detection of MicroRNA from Cancer Cells

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 52
Author(s):  
Qian Ma ◽  
Zhiqiang Gao ◽  
Hiranya Dayal ◽  
Sam Fong Yau Li
Keyword(s):  
Cancer Cells ◽  
Copper Nanoparticles ◽  
Fluorescent Sensor ◽  
Rolling Circle Amplification ◽  
High Specificity ◽  
Excitation Wavelength ◽  
Selective Detection ◽  
Label Free ◽  
Rolling Circle ◽  
Highly Sensitive

In this work, a simple and label-free fluorescence “off” to “on” platform was designed for the sensitive and selective detection of microRNA (miRNA) in cancer cells. This method utilized a padlock DNA-based rolling circle amplification (P-RCA) to synthesize fluorescent poly(thymine) (PolyT) which acted as a template for the synthesis of copper nanoparticles (CuNPs) within 10 minutes under mild conditions. While the repeated PolyT sequence was used as the template for CuNP synthesis, other non-PolyT parts (single strand-DNAs without the capacity to act as the template for CuNP formation) served as “smart glues” or rigid linkers to build complex nanostructures. Under the excitation wavelength of 340 nm, the synthesized CuNPs emitted strong red fluorescence effectively at 620 nm. To demonstrate the use of this method as a universal biosensor platform, lethal-7a (let-7a) miRNA was chosen as the standard target. This sensor could achieve highly sensitive and selective detection of miRNA in the presence of other homologous analogues for the combination of P-RCA with the fluorescent copper nanoparticle. Overall, this novel label-free method holds great potential in the sensitive detection of miRNA with high specificity in real samples.

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