A microfluidic chip capable of generating and trapping emulsion droplets for digital loop-mediated isothermal amplification analysis

Lab on a Chip ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 296-303 ◽  
Author(s):  
Yu-Dong Ma ◽  
Kang Luo ◽  
Wen-Hsin Chang ◽  
Gwo-Bin Lee
Keyword(s):  
Nucleic Acids ◽  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Novel Device ◽  
Dna Molecule ◽  
Emulsion Droplets ◽  
Droplet Array ◽  
Single Dna Molecule

A microfluidic droplet array chip was designed to execute the digital LAMP. This novel device was capable of 1) creating emulsion droplets, 2) sorting them into a trapping array, and 3) executing LAMP for only 40 min. Nucleic acids could be accurately quantified and the limit of detection was only single DNA molecule.

scholarly journals Loop-mediated isothermal amplification of a single DNA molecule in polyacrylamide gel-based microchamber

2009 ◽  
Vol 11 (3) ◽  
pp. 711-711
Author(s):  
Liza Lam ◽  
Shouichi Sakakihara ◽  
Koji Ishizuka ◽  
Shoji Takeuchi ◽  
Hideyuki F. Arata ◽  
...  
Keyword(s):  
Polyacrylamide Gel ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Dna Molecule ◽  
Single Dna Molecule

scholarly journals Fast and Parallel Detection of Four Ebola Virus Species on a Microfluidic-Chip-Based Portable Reverse Transcription Loop-Mediated Isothermal Amplification System

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 777 ◽  
Author(s):  
Xue Lin ◽  
Xiangyu Jin ◽  
Bin Xu ◽  
Ruliang Wang ◽  
Rongxin Fu ◽  
...  
Keyword(s):  
Microfluidic Chip ◽  
Reverse Transcription ◽  
Ebola Virus ◽  
Limit Of Detection ◽  
Isothermal Amplification ◽  
Diagnostic Methods ◽  
Virus Species ◽  
Fluorescence Detector ◽  
Parallel Detection ◽  
Loop Mediated Isothermal Amplification

Considering the lack of official vaccines and medicines for Ebola virus infection, reliable diagnostic methods are necessary for the control of the outbreak and the spread of the disease. We developed a microfluidic-chip-based portable system for fast and parallel detection of four Ebola virus species. The system is based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) and consists of four specific LAMP primers, a disc microfluidic chip, and a portable real-time fluorescence detector. It could specifically and parallelly distinguish four species of the Ebola virus after only one sampling, including the Zaire Ebola virus, the Sudan Ebola virus, the Bundibugyo Ebola virus, and the Tai Forest Ebola virus, without cross-contamination. The limit of detection was as small as 10 copies per reaction, while the total consumption of sample and reagent was 0.94 μL per reaction. The final results could be obtained in 50 min after one addition of sample and reagent mixture. This approach provides simplicity, high sensitivity, and multi-target parallel detection at a low cost, which could enable convenient and effective on-site detections of the Ebola virus in the outdoors, remote areas, and modern hospitals.

Loop-mediated isothermal amplification of a single DNA molecule in polyacrylamide gel-based microchamber

2008 ◽  
Vol 10 (4) ◽  
pp. 539-546 ◽  
Author(s):  
Liza Lam ◽  
Shouichi Sakakihara ◽  
Koji Ishizuka ◽  
Shoji Takeuchi ◽  
Hideyuki F. Arata ◽  
...  
Keyword(s):  
Polyacrylamide Gel ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Dna Molecule ◽  
Single Dna Molecule

scholarly journals An LED-Driven AuNPs-PDMS Microfluidic Chip and Integrated Device for the Detection of Digital Loop-Mediated Isothermal DNA Amplification

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 177 ◽  
Author(s):  
Zengming Zhang ◽  
Shuhao Zhao ◽  
Fei Hu ◽  
Guangpu Yang ◽  
Juan Li ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Microfluidic Chip ◽  
Cross Flow ◽  
Flow Channel ◽  
Isothermal Amplification ◽  
Fluorescent Detection ◽  
Lamp Method ◽  
Biological Studies ◽  
Micro Cavity ◽  
Integrated Device

The sensitive quantification of low-abundance nucleic acids holds importance for a range of clinical applications and biological studies. In this study, we describe a facile microfluidic chip for absolute DNA quantifications based on the digital loop-mediated isothermal amplification (digital LAMP) method. This microfluidic chip integrates a cross-flow channel for droplet generation with a micro-cavity for droplet tiling. DNA templates in the LAMP reagent were divided into ~20,000 water-in-oil droplets at the cross-flow channel. The droplets were then tiled in the micro-cavity for isothermal amplification and fluorescent detection. Different from the existing polydimethylsiloxane (PDMS) microfluidic chips, this study incorporates gold nanoparticles (AuNPs) into PDMS substrate through silica coating and dodecanol modification. The digital LAMP chip prepared by AuNPs-PDMS combines the benefits of the microstructure manufacturing performance of PDMS with the light-to-heat conversion advantages of AuNPs. Upon illumination with a near infrared (NIR) LED, the droplets were stably and efficiently heated by the AuNPs in PDMS. We further introduce an integrated device with a NIR heating unit and a fluorescent detection unit. The system could detect HBV (hepatitis B virus)-DNA at a concentration of 1 × 101 to 1 × 104 copies/μL. The LED-driven digital LAMP chip and the integrated device; therefore, demonstrate high accuracy and excellent performance for the absolute quantification of low-abundance nucleic acids, showing the advantages of integration, miniaturization, cost, and power consumption.

scholarly journals SARS-CoV-2 Direct Detection Without RNA Isolation With Loop-Mediated Isothermal Amplification (LAMP) and CRISPR-Cas12

2021 ◽  
Vol 8 ◽  
Author(s):  
Alfredo Garcia-Venzor ◽  
Bertha Rueda-Zarazua ◽  
Eduardo Marquez-Garcia ◽  
Vilma Maldonado ◽  
Angelica Moncada-Morales ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Direct Detection ◽  
Direct Method ◽  
Rna Extraction ◽  
Rna Isolation ◽  
High Sensitivity ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification

As to date, more than 49 million confirmed cases of Coronavirus Disease 19 (COVID-19) have been reported worldwide. Current diagnostic protocols use qRT-PCR for viral RNA detection, which is expensive and requires sophisticated equipment, trained personnel and previous RNA extraction. For this reason, we need a faster, direct and more versatile detection method for better epidemiological management of the COVID-19 outbreak. In this work, we propose a direct method without RNA extraction, based on the Loop-mediated isothermal amplification (LAMP) and Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein (CRISPR-Cas12) technique that allows the fast detection of SARS-CoV-2 from patient samples with high sensitivity and specificity. We obtained a limit of detection of 16 copies/μL with high specificity and at an affordable cost. The diagnostic test readout can be done with a real-time PCR thermocycler or with the naked eye in a blue-light transilluminator. Our method has been evaluated on a small set of clinical samples with promising results.

scholarly journals Rapid detection of cytochrome cd1-containing nitrite reductase encoding gene nirS of denitrifying bacteria with loop-mediated isothermal amplification assay

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xuzhi Zhang ◽  
Qianqian Yang ◽  
Qingli Zhang ◽  
Xiaoyu Jiang ◽  
Xiaochun Wang ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Genomic Dna ◽  
Limit Of Detection ◽  
Lamp Assay ◽  
Denitrifying Bacteria ◽  
Isothermal Amplification ◽  
Target Sequence ◽  
Bacterial Cells ◽  
Loop Mediated Isothermal Amplification ◽  
Order Of Magnitude

Abstract The cytochrome cd1-containing nitrite reductase, nirS, plays an important role in biological denitrification. Consequently, investigating the presence and abundance of nirS is a commonly used approach to understand the distribution and potential activity of denitrifying bacteria, in addition to denitrifier communities. Herein, a rapid method for detecting nirS gene with loop-mediated isothermal amplification (LAMP) was developed, using Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1) as model microorganism to optimize the assay. The LAMP assay relied on a set of four primers that were designed to recognize six target sequence sites, resulting in high target specificity. The limit of detection for the LAMP assay under optimized conditions was 1.87 pg/reaction of genomic DNA, which was an order of magnitude lower than that required by conventional PCR assays. Moreover, it was validated that P. aeruginosa PAO1 cells as well as genomic DNA could be directly used as template. Only 1 h was needed from the addition of bacterial cells to the reaction to the verification of amplification success. The nirS gene of P. aeruginosa PAO1 in spiked seawater samples could be detected with both DNA-template based LAMP assay and cell-template based LAMP assay, demonstrating the practicality of in-field use.

scholarly journals Rapid and Extraction-Free Detection of SARS-CoV-2 from Saliva by Colorimetric Reverse-Transcription Loop-Mediated Isothermal Amplification

2020 ◽  
Author(s):  
Matthew A Lalli ◽  
Joshua S Langmade ◽  
Xuhua Chen ◽  
Catrina C Fronick ◽  
Christopher S Sawyer ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Viral Detection ◽  
Loop Mediated Isothermal Amplification

Abstract Background Rapid, reliable, and widespread testing is required to curtail the ongoing COVID-19 pandemic. Current gold-standard nucleic acid tests are hampered by supply shortages in critical reagents including nasal swabs, RNA extraction kits, personal protective equipment, instrumentation, and labor. Methods To overcome these challenges, we developed a rapid colorimetric assay using reverse-transcription loop-mediated isothermal amplification (RT-LAMP) optimized on human saliva samples without an RNA purification step. We describe the optimization of saliva pretreatment protocols to enable analytically sensitive viral detection by RT-LAMP. We optimized the RT-LAMP reaction conditions and implemented high-throughput unbiased methods for assay interpretation. We tested whether saliva pretreatment could also enable viral detection by conventional reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Finally, we validated these assays on clinical samples. Results The optimized saliva pretreatment protocol enabled analytically sensitive extraction-free detection of SARS-CoV-2 from saliva by colorimetric RT-LAMP or RT-qPCR. In simulated samples, the optimized RT-LAMP assay had a limit of detection of 59 (95% confidence interval: 44–104) particle copies per reaction. We highlighted the flexibility of LAMP assay implementation using 3 readouts: naked-eye colorimetry, spectrophotometry, and real-time fluorescence. In a set of 30 clinical saliva samples, colorimetric RT-LAMP and RT-qPCR assays performed directly on pretreated saliva samples without RNA extraction had accuracies greater than 90%. Conclusions Rapid and extraction-free detection of SARS-CoV-2 from saliva by colorimetric RT-LAMP is a simple, sensitive, and cost-effective approach with broad potential to expand diagnostic testing for the virus causing COVID-19.

scholarly journals q-LAMP Assays for the Detection of Botryosphaeria dothidea Causing Chinese Hickory Canker in Trunk, Water, and Air Samples

Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3142-3149
Author(s):  
Q. W. Wang ◽  
C. Q. Zhang
Keyword(s):  
Limit Of Detection ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Botryosphaeria Dothidea ◽  
Canker Disease ◽  
Air Samples ◽  
Loop Mediated Isothermal Amplification ◽  
Optimum Reaction ◽  
Epidemiological Characteristics ◽  
Trunk Canker

Trunk canker disease caused by Botryosphaeria dothidea with a prolonged latent infection phase poses a serious threat to Chinese hickory production. To further understand the epidemiological characteristics and develop reasonable management techniques, a quantitative loop-mediated isothermal amplification (q-LAMP) assay was developed to quantitatively monitor B. dothidea in hickory plants, water, and air samples. Specific primers were designed based on the different sites of the β-tubulin sequence between B. dothidea and other fungi commonly found on Chinese hickory. At the optimum reaction temperature of 65.9°C, this loop-mediated isothermal amplification (LAMP) assay can specifically distinguish B. dothidea from other tested fungi. The limit of detection of LAMP assays for B. dothidea was 0.001 ng/µl of pure genomic DNA and 10 spores per 1 ml of water. The q-LAMP assay enables rapid detection of B. dothidea within 60 min in hickory trunk, water in hickory forests, and spores captured on tapes. These results provide a powerful and convenient tool for monitoring B. dothidea, which could be applied widely in epidemiology, forecast, and management of tree canker disease.

Point-of-Care Multiplexed Assays of Nucleic Acids Using Microcapillary-based Loop-Mediated Isothermal Amplification

2014 ◽  
Vol 86 (14) ◽  
pp. 7057-7062 ◽  
Author(s):  
Yi Zhang ◽  
Lu Zhang ◽  
Jiashu Sun ◽  
Yulei Liu ◽  
Xingjie Ma ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Point Of Care ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification
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