Advances in loop-mediated isothermal amplification: integrated with several point-of-care diagnostic methods

2014 ◽  
Vol 6 (19) ◽  
pp. 7585-7589 ◽  
Author(s):  
Pin Gong ◽  
Taotao Zhang ◽  
Fuxin Chen ◽  
Lan Wang ◽  
Sai Jin ◽  
...  

Recent outbreaks linked to pathogenic bacteria heighten the need to develop rapid, sensitive, portable and low-cost pathogen diagnostic systems.

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 461 ◽  
Author(s):  
Stefano Panno ◽  
Slavica Matić ◽  
Antonio Tiberini ◽  
Andrea Giovanni Caruso ◽  
Patrizia Bella ◽  
...  

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.


2020 ◽  
Vol 21 (21) ◽  
pp. 7981
Author(s):  
Catalina Avendaño ◽  
Manuel Alfonso Patarroyo

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas’ disease, cysticercosis/taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This technique’s advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the technique’s high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for others.


2020 ◽  
Author(s):  
Daniel Urrutia-Cabrera ◽  
Roxanne Hsiang-Chi Liou ◽  
Jianxiong Chan ◽  
Sandy Shen-Chi Hung ◽  
Alex W Hewitt ◽  
...  

AbstractThe COVID-19 pandemic caused by SARS-CoV-2 has infected millions worldwide and there is an urgent need to increase our diagnostic capacity to identify infected cases. Although RT-qPCR remains the gold standard for SARS-CoV-2 detection, this method requires specialised equipment in a diagnostic laboratory and has a long turn-around time to process the samples. To address this, several groups have recently reported development of loop-mediated isothermal amplification (LAMP) as a simple, low cost and rapid method for SARS-CoV-2 detection. Herein we present a comparative analysis of three LAMP-based assays that target different regions of the SARS-CoV-2: ORF1ab RdRP, ORF1ab nsp3 and Gene N. We perform a detailed assessment of their sensitivity, kinetics and false positive rates for SARS-CoV-2 diagnostics in LAMP or RT-LAMP reactions, using colorimetric or fluorescent detection. Our results independently validate that all three assays can detect SARS-CoV-2 in 30 minutes, with robust accuracy at detecting as little as 1000 RNA copies and the results can be visualised simply by color changes. We also note the shortcomings of these LAMP-based assays, including variable results with shorter reaction time or lower load of SARS-CoV-2, and false positive results in some experimental conditions. Overall for RT-LAMP detection, the ORF1ab RdRP and ORF1ab nsp3 assays have higher sensitivity and faster kinetics for detection, whereas the Gene N assay exhibits no false positives in 30 minutes reaction time. This study provides validation of the performance of LAMP-based assays for SARS-CoV-2 detection, which have important implications in development of point-of-care diagnostic for SARS-CoV-2.


2021 ◽  
Vol 15 (1) ◽  
pp. e0008996
Author(s):  
Thoko Flav Kapalamula ◽  
Jeewan Thapa ◽  
Mwangala Lonah Akapelwa ◽  
Kyoko Hayashida ◽  
Stephen V. Gordon ◽  
...  

Bovine tuberculosis (TB) caused by Mycobacterium bovis is a significant health threat to cattle and a zoonotic threat for humans in many developing countries. Rapid and accurate detection of M. bovis is fundamental for controlling the disease in animals and humans, and for the proper treatment of patients as one of the first-line anti-TB drug, pyrazinamide, is ineffective against M. bovis. Currently, there are no rapid, simplified and low-cost diagnostic methods that can be easily integrated for use in many developing countries. Here, we report the development of a loop-mediated isothermal amplification (LAMP) assay for specific identification of M. bovis by targeting the region of difference 4 (RD4), a 12.7 kb genomic region that is deleted solely in M. bovis. The assay's specificity was evaluated using 139 isolates comprising 65 M. bovis isolates, 40 M. tuberculosis isolates, seven M. tuberculosis complex reference strains, 22 non-tuberculous mycobacteria and five other bacteria. The established LAMP detected only M. bovis isolates as positive and no false positives were observed using the other mycobacteria and non-mycobacteria tested. Our LAMP assay detected as low as 10 copies of M. bovis genomic DNA within 40 minutes. The procedure of LAMP is simple with an incubation at a constant temperature. Results are observed with the naked eye by a color change, and there is no need for expensive equipment. The established LAMP can be used for the detection of M. bovis infections in cattle and humans in resource-limited areas.


Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1950
Author(s):  
Woong Sik Jang ◽  
Da Hye Lim ◽  
YoungLan Choe ◽  
Hyunseul Jee ◽  
Kyung Chul Moon ◽  
...  

Malaria, caused by the parasite Plasmodium and transmitted by mosquitoes, is an epidemic that mainly occurs in tropical and subtropical regions. As treatments differ across species of malarial parasites, there is a need to develop rapid diagnostic methods to differentiate malarial species. Herein, we developed a multiplex malaria Pan/Pf/Pv/actin beta loop-mediated isothermal amplification (LAMP) to diagnose Plasmodium spp., P. falciparum, and P. vivax, as well as the internal control (IC), within 40 min. The detection limits of the multiplex malaria Pan/Pf/Pv/IC LAMP were 1 × 102, 1 × 102, 1 × 102, and 1 × 103 copies/µL for four vectors, including the 18S rRNA gene (Plasmodium spp.), lactate dehydrogenase gene (P. falciparum), 16S rRNA gene (P. vivax), and human actin beta gene (IC), respectively. The performance of the LAMP assay was compared and evaluated by evaluating 208 clinical samples (118 positive and 90 negative samples) with the commercial RealStar® Malaria S&T PCR Kit 1.0. The developed multiplex malaria Pan/Pf/Pv/IC LAMP assay showed comparable sensitivity (100%) and specificity (100%) with the commercial RealStar® Malaria S&T PCR Kit 1.0 (100%). These results suggest that the multiplex malaria Pan/Pf/Pv/IC LAMP could be used as a point-of-care molecular diagnostic test for malaria.


Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Lindomar Pena

The recent outbreak of Zika virus (ZIKV) in the Americas and its devastating developmental and neurological manifestations has prompted the development of field-based diagnostics that are rapid, reliable, handheld, specific, sensitive, and inexpensive. The gold standard molecular method for lab-based diagnosis of ZIKV, from either patient samples or insect vectors, is reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The method, however, is costly and requires lab-based equipment and expertise, which severely limits its use as a point-of-care (POC) tool in resource-poor settings. Moreover, given the lack of antivirals or approved vaccines for ZIKV infection, a POC diagnostic test is urgently needed for the early detection of new outbreaks and to adequately manage patients. Loop-mediated isothermal amplification (LAMP) is a compelling alternative to RT-qPCR for ZIKV and other arboviruses. This low-cost molecular system can be freeze-dried for distribution and exhibits high specificity, sensitivity, and efficiency. A growing body of evidence suggests that LAMP assays can provide greater accessibility to much-needed diagnostics for ZIKV infections, especially in developing countries where the ZIKV is now endemic. This review summarizes the different LAMP methods that have been developed for the virus and summarizes their features, advantages, and limitations.


Biology ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 182 ◽  
Author(s):  
Robin Augustine ◽  
Anwarul Hasan ◽  
Suvarthi Das ◽  
Rashid Ahmed ◽  
Yasuyoshi Mori ◽  
...  

The rampant spread of COVID-19 and the worldwide prevalence of infected cases demand a rapid, simple, and cost-effective Point of Care Test (PoCT) for the accurate diagnosis of this pandemic. The most common molecular tests approved by regulatory bodies across the world for COVID-19 diagnosis are based on Polymerase Chain Reaction (PCR). While PCR-based tests are highly sensitive, specific, and remarkably reliable, they have many limitations ranging from the requirement of sophisticated laboratories, need of skilled personnel, use of complex protocol, long wait times for results, and an overall high cost per test. These limitations have inspired researchers to search for alternative diagnostic methods that are fast, economical, and executable in low-resource laboratory settings. The discovery of Loop-mediated isothermal Amplification (LAMP) has provided a reliable substitute platform for the accurate detection of low copy number nucleic acids in the diagnosis of several viral diseases, including epidemics like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). At present, a cocktail of LAMP assay reagents along with reverse transcriptase enzyme (Reverse Transcription LAMP, RT-LAMP) can be a robust solution for the rapid and cost-effective diagnosis for COVID-19, particularly in developing, and low-income countries. In summary, the development of RT-LAMP based diagnostic tools in a paper/strip format or the integration of this method into a microfluidic platform such as a Lab-on-a-chip may revolutionize the concept of PoCT for COVID-19 diagnosis. This review discusses the principle, technology and past research underpinning the success for using this method for diagnosing MERS and SARS, in addition to ongoing research, and the prominent prospect of RT-LAMP in the context of COVID-19 diagnosis.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xu Chen ◽  
Qingxue Zhou ◽  
Xueli Wu ◽  
Shuoshi Wang ◽  
Rui Liu ◽  
...  

Neisseriagonorrhoeae is a host-adapted human pathogen that causes sexually transmitted gonorrhea and remains to be a serious global public health challenge, especially in low- and middle-income regions. It is vital to devise a reliable, simple, cost-saving, and easy-to-use assay for detecting the N. gonorrhoeae agent. In the current study, we firstly report a novel approach, loop-mediated isothermal amplification linked with a polymer nanoparticle–based biosensor (LAMP-PNB), that was used for identifying N. gonorrhoeae in clinical samples. The results showed that the LAMP primers based on the orf1 gene were valid for development of the N. gonorrhoeae-LAMP-PNB assay. The detection system with optimal conditions could be performed at a fixed temperature of 64°C for 40 min. The whole process, including genomic DNA preparation (approximately 10 min), LAMP reaction (40 min), and PNB reporting (approximately 2 min), could be accomplished within 60 min. The limit of detection (LoD) of the N. gonorrhoeae-LAMP-PNB assay was 50 copies per test. The specificity of the current assay was 100%, and no cross-reactions to non–N. gonorrhoeae isolates were observed. These results confirmed that the N. gonorrhoeae-LAMP-PNB technique is a reliable, specific, sensitive, rapid, low-cost, and easy-to-use method for detecting gonococci isolates. More importantly, this assay has great potential to develop a point-of-care (POC) testing method in clinical practice, especially in resource-constrained regions.


2021 ◽  
Vol 10 (3) ◽  
pp. 511
Author(s):  
Juan García-Bernalt Diego ◽  
Pedro Fernández-Soto ◽  
Begoña Febrer-Sendra ◽  
Beatriz Crego-Vicente ◽  
Antonio Muro

Human schistosomiasis is one of the most important parasitic diseases, causing around 250 million cases (mostly in Africa) and 280,000–500,000 deaths every year. Due to the limited resources and the far-removed nature of many endemic areas, the implementation of new, sensitive and specific diagnostic tools has had little success. This is particularly true for PCR-based molecular methods that require expensive equipment and trained personnel to be executed. Loop-mediated isothermal amplification (LAMP) along with other isothermal techniques appeared in the early 21st century as an alternative to those methods, overcoming some of the aforementioned limitations and achieving a more inexpensive diagnostic. However, to this date, neither LAMP nor any other isothermal technique have signified a meaningful change in the way schistosomiasis diagnosis is routinely performed. Here, we present the recent developments in LAMP-based schistosomiasis diagnosis. We expose the main advantages and disadvantages of LAMP technology over PCR and other classical diagnostic methods focusing in various research approaches on intermediate hosts, animal models and patients. We also examine its potential clinical application in post-therapy monitoring, as well as its usefulness as a point-of-care test.


2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Bruna de Oliveira Coelho ◽  
Heloisa Bruna Soligo Sanchuki ◽  
Dalila Luciola Zanette ◽  
Jeanine Marie Nardin ◽  
Hugo Manuel Paz Morales ◽  
...  

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.


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