scholarly journals Optical Temperature Control Unit and Convolutional Neural Network for Colorimetric Detection of Loop-Mediated Isothermal Amplification on a Lab-On-A-Disc Platform

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3207 ◽  
Author(s):  
Da Ye Seul Lim ◽  
Moo-Jung Seo ◽  
Jae Chern Yoo
Keyword(s):  
High Efficiency ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Control Unit ◽  
Dna Amplification ◽  
Heating System ◽  
Isothermal Amplification ◽  
Physical Contact ◽  
Loop Mediated Isothermal Amplification ◽  
Polymeric Substrates

Lab-on-a-disc (LOD) has emerged as a promising candidate for a point-of-care testing (POCT) device because it can effectively integrate complex fluid manipulation steps using multiple layers of polymeric substrates. However, it is still highly challenging to design and fabricate temperature measurement and heating system in non-contact with the surface of LOD, which is a prerequisite to successful realization of DNA amplification especially with a rotatable disc. This study presents a Lab-on-a-disc (LOD)-based automatic loop-mediated isothermal amplification (LAMP) system, where a thermochromic coating (<~420 µm) was used to distantly measure the chamber’s temperature and a micro graphite film was integrated into the chamber to remotely absorb laser beam with super high efficiency. We used a deep learning network to more consistently analyze the product of LAMP than we could with the naked eye. Consequently, both temperature heating and measurement were carried out without a physical contact with the surface of LOD. The experimental results show that the proposed approach, which no previous work has attempted, was highly effective in realizing LAMP in LOD.

scholarly journals Essential properties and pitfalls of colorimetric Reverse Transcription Loop-mediated Isothermal Amplification as a point-of-care test for SARS-CoV-2 diagnosis

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Bruna de Oliveira Coelho ◽  
Heloisa Bruna Soligo Sanchuki ◽  
Dalila Luciola Zanette ◽  
Jeanine Marie Nardin ◽  
Hugo Manuel Paz Morales ◽  
...  
Keyword(s):  
Viral Load ◽  
Internal Control ◽  
Reverse Transcription ◽  
Color Change ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
False Negative ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification

Abstract Background SARS-CoV-2 Reverse Transcription Loop-mediated Isothermal Amplification (RT-LAMP) colorimetric detection is a sensitive and specific point-of-care molecular biology technique used to detect the virus in only 30 min. In this manuscript we have described a few nuances of the technique still not properly described in the literature: the presence of three colors clusters; the correlation of the viral load with the color change; and the importance of using an internal control to avoid false-negative results. Methods To achieve these findings, we performed colorimetric RT-LAMP assays of 466 SARS-CoV-2 RT-qPCR validated clinical samples, with color quantification measured at 434 nm and 560 nm. Results First we determinate a sensitivity of 93.8% and specificity of 90.4%. In addition to the pink (negative) and yellow (positive) produced colors, we report for the first time the presence of an orange color cluster that may lead to wrong diagnosis. We also demonstrated using RT-qPCR and RT-LAMP that low viral loads are related to Ct values > 30, resulting in orange colors. We also demonstrated that the diagnosis of COVID-19 by colorimetric RT-LAMP is efficient until the fifth symptoms day when the viral load is still relatively high. Conclusion This study reports properties and indications for colorimetric RT-LAMP as point-of-care for SARS-CoV-2 diagnostic, reducing false results, interpretations and optimizing molecular diagnostics tests application.

scholarly journals Specific and sensitive, ready-to-use universal fungi detection by visual color using ITS1 loop-mediated isothermal amplification combined hydroxynaphthol blue

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11082
Author(s):  
Ilada Choopara ◽  
Yothin Teethaisong ◽  
Narong Arunrut ◽  
Sudaluck Thunyaharn ◽  
Wansika Kiatpathomchai ◽  
...  
Keyword(s):  
Point Of Care ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Fungal Species ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Fungal Isolates ◽  
Simple Detection ◽  
Hydroxynaphthol Blue ◽  
Life Threatening

Being ubiquitous, fungi are common opportunistic pathogens to humans that can lead to invasive and life-threatening infections in immunocompromised individuals. Eukaryote-resembling cell membrane and filamentous branches make the fungal diagnosis difficult. This study therefore developed a ready-to-use ITS1 loop-mediated isothermal amplification combined with hydroxynaphthol blue (LAMP-HNB) for rapid, sensitive and specific colorimetric detection of universal fungi in all phyla. The ITS1 LAMP-HNB could identify every evolutionary phylum of fungi according to sequence analyses. We tested a total of 30 clinically relevant fungal isolates (representing three major human pathogenic phyla of fungi, namely Zygomycota, Ascomycota and Basidiomycota) and 21 non-fungal isolates, and the ITS1 LAMP-HNB properly identified all isolates, with a detection limit of as low as 4.6 ag (9.6 copies), which was identical to ITS1 and 18S rDNA PCR. The assays were also validated on the feasibility of point-of-care diagnostic with real food (dry peanuts, chili and garlics) and blood samples. Furthermore, the shelf life of our ready-to-use ITS1 LAMP activity (≥50%) was more than 40 days at 30 °C with 3–5% polyvinyl alcohol or glycerol additive. The results supported the ready-to-use ITS1 LAMP-HNB for simple detection of fungi contamination with high sensitivity in local and resource-constrained areas to prevent opportunistic fungal species infections.

DETECTION METHODS FOR RESULTS OF A LOOP-MEDIATED ISOTHERMAL AMPLIFICATION OF DNA

2020 ◽  
Vol 65 (1) ◽  
pp. 67-72
Author(s):  
Olga A. Petrusha ◽  
E. B. Faizuloev
Keyword(s):  
Gold Nanoparticles ◽  
Real Time ◽  
Fluorescence Detection ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Lamp Reaction ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Advantages And Disadvantages ◽  
Point Of Care Diagnostics

The loop mediated isothermal amplification (LAMP) was developed by T. Notomi et al. in 2000. It has become one of the most promising methods for point-of-care diagnostics due to its accuracy, sensitivity and ease of execution. In this review, various methods for detecting the results of the LAMP reaction are considered; their advantages and disadvantages are revealed. Methods for detecting LAMP results can be divided into indirect and direct. Indirect methods aimed at detecting changes in the chemical composition of the reaction mixture include real-time turbidimetry, fluorescence detection with calcein, colorimetric detection with hydroxynaphthol blue, and detection using modified gold nanoparticles. Direct methods based on the detection of accumulation amplicons during the reaction include fluorimetric detection with intercalating dyes, resonance fluorescence energy transfer, enzyme immunoassay, immunochromatography, using cationic polymers and gold nanoparticles. The development in the field of point-of-care diagnostics is characterized by a pronounced tendency to miniaturization, the LAMP reaction on microchips and microfluidic devices with an electrochemical or optical detection method. The most promising for the diagnosis of infectious diseases are turbidimetry methods and the use of intercalating dyes. The development of portable domestic instruments for detecting of LAMP results based on real-time fluorescence detection or turbidimetry will contribute to the widespread introduction of the method into clinical laboratory diagnostic practice. A literature research was conducted in the Pubmed ncbi based on keywords.

Loop-mediated Isothermal Amplification for Rapid Detection of Mating Types of Villosiclava virens

Plant Disease ◽  
2021 ◽  
Author(s):  
Xiayan Pan ◽  
Xiao Wang ◽  
Junjie Yu ◽  
Mina Yu ◽  
Huijuan Cao ◽  
...  
Keyword(s):  
Mating Type ◽  
Genomic Dna ◽  
High Efficiency ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Villosiclava Virens ◽  
False Smut ◽  
Mating Type Genes ◽  
Polymerase Chain

Rice false smut (RFS), caused by Villosiclava virens, is an important fungal disease in panicle of rice. V. virens is a heterothallic ascomycete that controlled by two opposite idiomorphs, MAT1-1 and MAT1-2. Previous study showed sexual reproduction of V. virens plays an important role in the epidemic of RFS. In this study, we have developed a loop-mediated isothermal amplification (LAMP) assay to detect mating type of V. virens easily and rapidly by using specific primers designed on the mating type genes MAT1-1-2 and MAT1-2-1, respectively. The LAMP assay required only a water/dry bath and could recognize the mating type of V. virens in just 45 min. The LAMP assay was so sensitive that could detect small amounts of V. virens genomic DNA (as low as 2.0 pg of MAT1-1, and 200.0 pg of MAT1-2), which was 10-fold more sensitive than polymerase chain reaction (PCR). In addition, the application of mating type using LAMP assay was demonstrated feasibly by assessing the genomic DNA of V. virens isolated from rice fields. The high efficiency and specificity of this LAMP assay suggested it can be used as a rapid testing tool in mating type recognition of V. virens isolates in the field.

scholarly journals Colorimetric Detection of Dengue by Single Tube Reverse-Transcription-Loop-Mediated Isothermal Amplification

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0138694 ◽  
Author(s):  
Yee-Ling Lau ◽  
Meng-Yee Lai ◽  
Boon-Teong Teoh ◽  
Juraina Abd-Jamil ◽  
Jefree Johari ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Colorimetric Detection ◽  
Isothermal Amplification ◽  
Single Tube ◽  
Loop Mediated Isothermal Amplification

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

scholarly journals Loop Mediated Isothermal Amplification: Principles and Applications in Plant Virology

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 461 ◽  
Author(s):  
Stefano Panno ◽  
Slavica Matić ◽  
Antonio Tiberini ◽  
Andrea Giovanni Caruso ◽  
Patrizia Bella ◽  
...  
Keyword(s):  
Plant Protection ◽  
Point Of Care ◽  
Low Cost ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
Plant Virology ◽  
Food Industries ◽  
Loop Mediated Isothermal Amplification ◽  
Application Fields ◽  
Agriculture And Food

In the last decades, the evolution of molecular diagnosis methods has generated different advanced tools, like loop-mediated isothermal amplification (LAMP). Currently, it is a well-established technique, applied in different fields, such as the medicine, agriculture, and food industries, owing to its simplicity, specificity, rapidity, and low-cost efforts. LAMP is a nucleic acid amplification under isothermal conditions, which is highly compatible with point-of-care (POC) analysis and has the potential to improve the diagnosis in plant protection. The great advantages of LAMP have led to several upgrades in order to implement the technique. In this review, the authors provide an overview reporting in detail the different LAMP steps, focusing on designing and main characteristics of the primer set, different methods of result visualization, evolution and different application fields, reporting in detail LAMP application in plant virology, and the main advantages of the use of this technique.

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