scholarly journals Padlock Probe Assay for Detection and Subtyping of Seasonal Influenza

2018 ◽  
Vol 64 (12) ◽  
pp. 1704-1712 ◽  
Author(s):  
Felix Neumann ◽  
Iván Hernández-Neuta ◽  
Malin Grabbe ◽  
Narayanan Madaboosi ◽  
Jan Albert ◽  
...  

Abstract BACKGROUND Influenza remains a constant threat worldwide, and WHO estimates that it affects 5% to 15% of the global population each season, with an associated 3 to 5 million severe cases and up to 500000 deaths. To limit the morbidity and the economic burden of influenza, improved diagnostic assays are needed. METHODS We developed a multiplexed assay for the detection and subtyping of seasonal influenza based on padlock probes and rolling circle amplification. The assay simultaneously targets all 8 genome segments of the 4 circulating influenza variants—A(H1N1), A(H3N2), B/Yamagata, and B/Victoria—and was combined with a prototype cartridge for inexpensive digital quantification. Characterized virus isolates and patient nasopharyngeal swabs were used for assay design and analytical validation. The diagnostic performance was assessed by blinded testing of 50 clinical samples analyzed in parallel with a commercial influenza assay, Simplexa™ Flu A/B & RSV Direct. RESULTS The assay had a detection limit of 18 viral RNA copies and achieved 100% analytical and clinical specificity for differential detection and subtyping of seasonal circulating influenza variants. The diagnostic sensitivity on the 50 clinical samples was 77.5% for detecting influenza and up to 73% for subtyping seasonal variants. CONCLUSIONS We have presented a proof-of-concept padlock probe assay combined with an inexpensive digital readout for the detection and subtyping of seasonal influenza strains A and B. The demonstrated high specificity and multiplexing capability, together with the digital quantification, established the assay as a promising diagnostic tool for seasonal influenza.

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
James H. Smith ◽  
Miao Cui ◽  
David Y. Zhang ◽  
Thomas P. Beals ◽  
Fei Ye

We evaluated single nucleotide polymorphism (SNP) detection via a target-capture, C-probe ligation, and RAM assay in a single-blind comparison to clinical samples that had been tested with FDA-cleared tests for up to 4 different vascular disease-related SNPs. In the RAM assay circulizable linear probes (C- or padlock probes) were annealed directly to genomic DNA, processed on a largely automated platform, and ligated C-probes were amplified by real-time RAM. After allele determinations were made with the experimental system, the sample genotypes were unblinded and the experimentally determined genotypes were found to be completely consistent with the FDA-cleared test results. The methods and results presented here show that a combination of C-probes, automated sample processing, and isothermal RAM provides a robust, and specific, nucleic acid detection platform that is compatible with automated DNA sample preparation and the throughput requirements of the clinical laboratory.


Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 222
Author(s):  
Chenxin Fang ◽  
Ping Ouyang ◽  
Yuxing Yang ◽  
Yang Qing ◽  
Jialun Han ◽  
...  

A microRNA (miRNA) detection platform composed of a rolling circle amplification (RCA) system and an allosteric deoxyribozyme system is proposed, which can detect miRNA-21 rapidly and efficiently. Padlock probe hybridization with the target miRNA is achieved through complementary base pairing and the padlock probe forms a closed circular template under the action of ligase; this circular template results in RCA. In the presence of DNA polymerase, RCA proceeds and a long chain with numerous repeating units is formed. In the presence of single-stranded DNA (H1 and H2), multi-component nucleic acid enzymes (MNAzymes) are formed that have the ability to cleave substrates. Finally, substrates containing fluorescent and quenching groups and magnesium ions are added to the system to activate the MNAzyme and the substrate cleavage reaction, thus achieving fluorescence intensity amplification. The RCA–MNAzyme system has dual signal amplification and presents a sensing platform that demonstrates broad prospects in the analysis and detection of nucleic acids.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Thanyarat Chaibun ◽  
Jiratchaya Puenpa ◽  
Tatchanun Ngamdee ◽  
Nimaradee Boonapatcharoen ◽  
Pornpat Athamanolap ◽  
...  

AbstractCoronavirus disease 2019 (COVID-19) is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnosis of COVID-19 depends on quantitative reverse transcription PCR (qRT-PCR), which is time-consuming and requires expensive instrumentation. Here, we report an ultrasensitive electrochemical biosensor based on isothermal rolling circle amplification (RCA) for rapid detection of SARS-CoV-2. The assay involves the hybridization of the RCA amplicons with probes that were functionalized with redox active labels that are detectable by an electrochemical biosensor. The one-step sandwich hybridization assay could detect as low as 1 copy/μL of N and S genes, in less than 2 h. Sensor evaluation with 106 clinical samples, including 41 SARS-CoV-2 positive and 9 samples positive for other respiratory viruses, gave a 100% concordance result with qRT-PCR, with complete correlation between the biosensor current signals and quantitation cycle (Cq) values. In summary, this biosensor could be used as an on-site, real-time diagnostic test for COVID-19.


Author(s):  
Alexandros Sountoulidis ◽  
Andreas Liontos ◽  
Hong Phuong Nguyen ◽  
Alexandra B. Firsova ◽  
Athanasios Fysikopoulos ◽  
...  

AbstractChanges in cell identities and positions underlie tissue development and disease progression. Although, single-cell mRNA sequencing (scRNA-Seq) methods rapidly generate extensive lists of cell-states, spatially resolved single-cell mapping presents a challenging task. We developed SCRINSHOT (Single Cell Resolution INSitu Hybridization On Tissues), a sensitive, multiplex RNA mapping approach. Direct hybridization of padlock probes on mRNA is followed by circularization with SplintR ligase and rolling circle amplification (RCA) of the hybridized padlock probes. Sequential detection of RCA-products using fluorophore-labeled oligonucleotides profiles thousands of cells in tissue sections. We evaluated SCRINSHOT specificity and sensitivity on murine and human organs. SCRINSHOT quantification of marker gene expression shows high correlation with published scRNA-Seq data over a broad range of gene expression levels. We demonstrate the utility of SCRISHOT by mapping the locations of abundant and rare cell types along the murine airways. The amenability, multiplexity and quantitative qualities of SCRINSHOT facilitate single cell mRNA profiling of cell-state alterations in tissues under a variety of native and experimental conditions.


PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000675
Author(s):  
Alexandros Sountoulidis ◽  
Andreas Liontos ◽  
Hong Phuong Nguyen ◽  
Alexandra B. Firsova ◽  
Athanasios Fysikopoulos ◽  
...  

Changes in cell identities and positions underlie tissue development and disease progression. Although single-cell mRNA sequencing (scRNA-Seq) methods rapidly generate extensive lists of cell states, spatially resolved single-cell mapping presents a challenging task. We developed SCRINSHOT (Single-Cell Resolution IN Situ Hybridization On Tissues), a sensitive, multiplex RNA mapping approach. Direct hybridization of padlock probes on mRNA is followed by circularization with SplintR ligase and rolling circle amplification (RCA) of the hybridized padlock probes. Sequential detection of RCA-products using fluorophore-labeled oligonucleotides profiles thousands of cells in tissue sections. We evaluated SCRINSHOT specificity and sensitivity on murine and human organs. SCRINSHOT quantification of marker gene expression shows high correlation with published scRNA-Seq data over a broad range of gene expression levels. We demonstrate the utility of SCRINSHOT by mapping the locations of abundant and rare cell types along the murine airways. The amenability, multiplexity, and quantitative qualities of SCRINSHOT facilitate single-cell mRNA profiling of cell-state alterations in tissues under a variety of native and experimental conditions.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hongke Qu ◽  
Chunmei Fan ◽  
Mingjian Chen ◽  
Xiangyan Zhang ◽  
Qijia Yan ◽  
...  

AbstractThe cyclic signal amplification technology has been widely applied for the ultrasensitive detection of many important biomolecules, such as nucleic acids, proteins, enzymes, adenosine triphosphate (ATP), metal ions, exosome, etc. Due to their low content in the complex biological samples, traditional detection methods are insufficient to satisfy the requirements for monitoring those biomolecules. Therefore, effective and sensitive biosensors based on cyclic signal amplification technology are of great significance for the quick and simple diagnosis and treatment of diseases. Fluorescent biosensor based on cyclic signal amplification technology has become a research hotspot due to its simple operation, low cost, short time, high sensitivity and high specificity. This paper introduces several cyclic amplification methods, such as rolling circle amplification (RCA), strand displacement reactions (SDR) and enzyme-assisted amplification (EAA), and summarizes the research progress of using this technology in the detection of different biomolecules in recent years, in order to provide help for the research of more efficient and sensitive detection methods. Graphical Abstract


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