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1.
Revista Colombiana de Ciencias Quimico-Farmaceuticas(Colombia) ; 50(3):633-649, 2021.
Article in English, Portuguese, Spanish | EMBASE | ID: covidwho-20243809

ABSTRACT

Summary Introduction: The SARS-CoV-2 coronavirus, that causes the COVID-19 disease, has become a global public health problem that requires the implementation of rapid and sensitive diagnostic tests. Aim(s): To evaluate and compare the sensitivity of LAMP assay to a standard method and use RT-LAMP for the diagnosis of SARS-CoV-2 in clinical samples from Colombian patients. Method(s): A descriptive and cross-sectional study was conducted. A total of 25 nasopharyngeal swab samples including negative and positive samples for SARS-CoV-2 were analyzed, through the RT-LAMP method compared to the RT-qPCR assay. Result(s): LAMP method detected ~18 copies of the N gene, in 30 min, evidenced a detection limit similar to the standard method, in a shorter time and a concordance in RT-LAMP of 100% with the results. Conclusion(s): RT-LAMP is a sensitive, specific, and rapid method that can be used as a diagnostic aid of COVID-19 disease.Copyright © 2021. All Rights Reserved.

2.
HAYATI Journal of Biosciences ; 30(4):621-631, 2023.
Article in English | Scopus | ID: covidwho-20241710

ABSTRACT

Colorimetric RT-LAMP Assay is a diagnostic method that has attracted much attention because of its rapidity, simplicity, and accuracy compared to other disease diagnosis methods. Despite having many advantages, the RT-LAMP Colorimetric Assay has disadvantages, especially for kits that use phenol red as an indicator. The disadvantage derives from the input RNA/DNA samples containing high buffer levels, which causes no color change and false-negative results. This study aimed to develop and optimize the colorimetric RT-LAMP method on high-buffered SARS-CoV-2 RNA samples. We found that a temperature of 69°C for 50 minutes with the addition of post-treatment in the form of heating at 80°C for 10 minutes is an optimal condition for high-buffered SARS-CoV-2 samples. The condition proved effective in changing the result's color from red (negative) to yellow (positive). We also classified the analysis results based on the correlation between the Cycle threshold (Ct) value of SARS-CoV-2 viruses and the Optical Density (OD) value, which was quantified using a spectrophotometer at 415 nm (with a correlation value of-0.9084), where yellow color indicated Ct below 20, amber color indicated Ct between 20 and 30, orange color indicated Ct between 30 and 35, and red indicated Ct more than 35 (negative). In conclusion, this study successfully detects the SARS-CoV-2 virus in high-buffered samples using Phenol Red Colorimetric RT-LAMP Assay, with a sensitivity of 85% for Ct Cutoff 40. © 2023, Bogor Agricultural University. All rights reserved.

3.
J Clin Virol Plus ; 3(1): 100132, 2023 Feb.
Article in English | MEDLINE | ID: covidwho-20232657

ABSTRACT

The emergence of SARS-CoV-2 has caused worldwide pandemic of COVID-19. Infection is difficult to diagnose early as some patients remain asymptomatic and may carry this virus to other people. Currently, qRT-PCR is the widely accepted mode for detection. However, the need for sophisticated instrument and trained personnel may hinder its application, especially in remote and facility-lacking areas. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) may serve as a potential approach for detection of SARS-CoV-2 as the resources needed in its application is far less complex than those of qRT-PCR. Herein, we evaluated RT-LAMP based analytical method (COVIDNow), relative to qRT-PCR, in detecting SARS-CoV-2 by using 63 clinical respiratory samples. Based on our finding, COVIDNow exhibited sensitivity and specificity values of 87.5% and 80.6%, respectively. Taken together, RT-LAMP based detection of SARS-CoV-2 by utilizing COVIDNow might serves as a valuable diagnostic tool in the management of global COVID-19 pandemic condition.

4.
J Infect Public Health ; 16(7): 1081-1088, 2023 Jul.
Article in English | MEDLINE | ID: covidwho-2314012

ABSTRACT

BACKGROUND: COVID-19 has become a major public health problem after the outbreak caused by SARS-CoV-2 virus. Great efforts to contain COVID-19 transmission have been applied worldwide. In this context, accurate and fast diagnosis is essential. METHODS: In this prospective study, we evaluated the clinical performance of three different RNA-based molecular tests - RT-qPCR (Charité protocol), RT-qPCR (CDC (USA) protocol) and RT-LAMP - and one rapid test for detecting anti-SARS-CoV-2 IgM and IgG antibodies. RESULTS: Our results demonstrate that RT-qPCR using the CDC (USA) protocol is the most accurate diagnostic test among those evaluated, while oro-nasopharyngeal swabs are the most appropriate biological sample. RT-LAMP was the RNA-based molecular test with lowest sensitivity while the serological test presented the lowest sensitivity among all evaluated tests, indicating that the latter test is not a good predictor of disease in the first days after symptoms onset. Additionally, we observed higher viral load in individuals who reported more than 3 symptoms at the baseline. Nevertheless, viral load had not impacted the probability of testing positive for SARS-CoV-2. CONCLUSION: Our data indicates that RT-qPCR using the CDC (USA) protocol in oro-nasopharyngeal swabs samples should be the method of choice to diagnosis COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19 Testing , Prospective Studies , Brazil/epidemiology , Clinical Laboratory Techniques/methods , Health Personnel , RNA , Immunoglobulin G , Immunoglobulin M , Sensitivity and Specificity
5.
Cell Rep Med ; 4(5): 101037, 2023 05 16.
Article in English | MEDLINE | ID: covidwho-2317671

ABSTRACT

CRISPR-Cas-based diagnostics have the potential to elevate nucleic acid detection. CRISPR-Cas systems can be combined with a pre-amplification step in a one-pot reaction to simplify the workflow and reduce carryover contamination. Here, we report an engineered Cas12b with improved thermostability that falls within the optimal temperature range (60°C-65°C) of reverse transcription-loop-mediated isothermal amplification (RT-LAMP). Using de novo structural analyses, we introduce mutations to wild-type BrCas12b to tighten its hydrophobic cores, thereby enhancing thermostability. The one-pot detection assay utilizing the engineered BrCas12b, called SPLENDID (single-pot LAMP-mediated engineered BrCas12b for nucleic acid detection of infectious diseases), exhibits robust trans-cleavage activity up to 67°C in a one-pot setting. We validate SPLENDID clinically in 80 serum samples for hepatitis C virus (HCV) and 66 saliva samples for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high specificity and accuracy. We obtain results in as little as 20 min, and with the extraction process, the entire assay can be performed within an hour.


Subject(s)
COVID-19 , Nucleic Acids , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/genetics , Nucleic Acids/genetics , COVID-19 Testing , CRISPR-Cas Systems/genetics
6.
Quimica Nova ; 2023.
Article in English | Web of Science | ID: covidwho-2310978

ABSTRACT

3D PRINTING OF MAGNETIC SEPARATOR: AN AFFORDABLE APPROACH TO SAMPLE PREPARATION IN THE COVID-19 DIAGNOSIS. This report describes the fabrication of a low-cost magnetic separator holder combining 3D printing and compact neodymium blocks for allowing magnetic extraction and purification of RNA from samples collected by nasopharyngeal swab from patients infected by SARS-CoV-2. The device was designed to contain 24 entrances for plastic microtubes in an arrangement like a commercial device. The proof of concept of the proposed device was successfully demonstrated through the sample extraction and purification of swab samples collected from eight patients suspected of SARS-CoV-2 infection. The sample preparation protocol was performed using a commercial kit containing magnetic beads and different solutions. The performance of the printed device was compared to a commercial magnetic separator, usually employed in the golden standard techniques. The fabrication of the 3D printed magnetic separator was completed under optimized printing conditions within 6 h at cost of 4 USD per unit. The RNA extracted from samples using both devices was analyzed by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and the achieved results have indicated no statistical different at confidence level of 95%. Based on the achievements, the use of 3D printing and neodymium blocks have demonstrated an alternative route to be used in routing analysis associated to COVID-19 diagnosis.

7.
Malaysian Journal of Medicine and Health Sciences ; 18(2):286-292, 2023.
Article in English | Scopus | ID: covidwho-2301006

ABSTRACT

COVID-19 outbreak caused by the newly discovered SARS-CoV-2 has become a major public health threat around the world and has create a tremendous effect on the global economy. Hence, there is a high demand for rapid and accurate diagnosis to contain the spread of the disease. The Reverse-Transcription Polymerase Chain Reaction (RT-PCR), the current standard for diagnosis of COVID-19 however possesses certain drawbacks that limits its application to meet the high demand of the continually increasing COVID-19 cases. Conversely, Loop-Mediated Isothermal Amplification (LAMP) is another nucleic acid amplification method that shows a great potential as an alternative tool in rapid diagnosis of COVID-19 due to its simplicity and rapidity. This review summarized the recent published research articles related to the application and modification of RT-LAMP assay for the rapid detection of COVID-19 in comparison with other available diagnostic methods. © 2023 Authors. All rights reserved.

8.
Methods Mol Biol ; 2621: 307-323, 2023.
Article in English | MEDLINE | ID: covidwho-2297362

ABSTRACT

Zika virus (ZIKV) infection may cause serious birth defects and is a critical concern for women of child-bearing age in affected regions. A simple, portable, and easy-to-use ZIKV detection method would enable point-of-care testing, which may aid in prevention of the spread of the virus. Herein, we describe a reverse transcription isothermal loop-mediated amplification (RT-LAMP) method that detects the presence of ZIKV RNA in complex samples (e.g., blood, urine, and tap water). Phenol red is the colorimetric indicator of successful amplification. Color changes based on the amplified RT-LAMP product from the presence of viral target are monitored using a smartphone camera under ambient light conditions. A single viral RNA molecule per µL can be detected in as quickly as 15 min using this method with 100% sensitivity and 100% specificity in blood and tap water, while 100% sensitivity and 67% specificity in urine. This platform can also be used to identify other viruses including SARS-CoV-2 and improve the current state of field-based diagnostics.


Subject(s)
COVID-19 , Zika Virus Infection , Zika Virus , Female , Humans , Zika Virus/genetics , Microfluidics , Smartphone , Sensitivity and Specificity , SARS-CoV-2
9.
Diagnostics (Basel) ; 13(7)2023 Apr 06.
Article in English | MEDLINE | ID: covidwho-2302188

ABSTRACT

Quick and reliable mass testing of infected people is an effective tool for the contingency of SARS-CoV-2. During the COVID-19 pandemic, Point-of-Care (POC) tests using Loop-Mediated Isothermal Amplification (LAMP) arose as a useful diagnostic tool. LAMP tests are a robust and fast alternative to Polymerase Chain Reaction (PCR), and their isothermal property allows easy incorporation into POC platforms. The main drawback of using colorimetric LAMP is the reported short-term stability of the pre-mixed reagents, as well as the relatively high rate of false-positive results. Also, low-magnitude amplification can produce a subtle color change, making it difficult to discern a positive reaction. This paper presents Hilab Molecular, a portable device that uses the Internet of Things and Artificial Intelligence to pre-analyze colorimetric data. In addition, we established manufacturing procedures to increase the stability of colorimetric RT-LAMP tests. We show that ready-to-use reactions can be stored for up to 120 days at -20 °C. Furthermore, we validated both the Hilab Molecular device and the Hilab RT-LAMP test for SARS-CoV-2 using 581 patient samples without any purification steps. We achieved a sensitivity of 92.93% and specificity of 99.42% (samples with CT ≤ 30) when compared to RT-qPCR.

10.
ACS Sens ; 8(5): 1960-1970, 2023 05 26.
Article in English | MEDLINE | ID: covidwho-2306620

ABSTRACT

Rapid and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the most effective measures to control the coronavirus disease 2019 (COVID-19) pandemic. However, there is still lack of an ideal detection platform capable of high sample throughput, portability, and multiplicity. Herein, by combining Hive-Chip (capillary microarray) and reverse transcriptional loop-mediated isothermal amplification (RT-LAMP), we developed an iPad-controlled, high-throughput (48 samples at one run), portable (smaller than a backpack), multiplex (monitoring 8 gene fragments in one reaction), and real-time detection platform for SARS-CoV-2 detection. This platform is composed of a portable Hive-Chip device (HiCube; 32.7 × 29.7 × 20 cm, 5 kg), custom-designed software, and optimized Hive-Chips. RT-LAMP primers targeting seven SARS-CoV-2 genes (S, E, M, N, ORF1ab, ORF3a, and ORF7a) and one positive control (human RNase P) were designed and prefixed in the Hive-Chip. On-chip RT-LAMP showed that the limit of detection (LOD) of SARS-CoV-2 synthetic RNAs is 1 copy/µL, and there is no cross-reaction among different target genes. The platform was validated by 100 clinical samples of SARS-CoV-2, and the results were highly consistent with those of the traditional real-time PCR assay. In addition, on-chip detection of 6 other respiratory pathogens showed no cross-reactivity. Overall, our platform has great potential for fast, accurate, and on-site detection of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19 Testing , Limit of Detection , RNA, Viral/genetics , RNA, Viral/analysis
11.
Iranian Journal of Science and Technology ; 47(2):359-367, 2023.
Article in English | ProQuest Central | ID: covidwho-2283671

ABSTRACT

The pandemic of severe acute respiratory syndrome 2 (SARS-CoV-2) revealed the necessity of diagnosis of the infected people to prevent the prevalence infection cycle. Many commercial pathogen diagnosis methods are based on the detection of genomic materials. Isothermal amplification methods such as loop-mediated-isothermal amplification (LAMP) are the method of choice in these cases. Reverse transcription steps are efficiently coupled to LAMP for the detection of pathogens with genomic RNAs such as SARS-CoV-2. Many detection systems for LAMP include fluorescent readout systems. Although such systems result in desirable limits of detection, the need for special instrumentation is the main dispute of such systems to become real point of care assays. In contrast, colorimetric detection methods would reduce costs and improve the applicability of the system. In this study one-step reverse transcription-LAMP reaction was established that enables visual detection of the SARS-CoV-2 genome. Nasopharyngeal RNA samples were first validated by reverse transcription quantitative polymerase chain reaction and then subjected to RT-LAMP. To lower the cost associated with the readout system equipment, malachite green (MG) was used. The color change of MG to blue allowed visual detection of the virus. Firstly, experiments were set up as two-step RT-LAMP reaction to identify the best primer sets. In addition, MG concentration was optimized with the significant colorimetric signal for the positive samples. Next, a one-step colorimetric method was developed for the detection of SARS-CoV-2 based on MG color shift in 2 h.

12.
Biomedical Signal Processing and Control ; 83 (no pagination), 2023.
Article in English | EMBASE | ID: covidwho-2282952

ABSTRACT

Pandemics such as COVID-19 have exposed global inequalities in essential health care. Here, we proposed a novel analytics of nucleic acid amplification tests (NAATs) by combining paper microfluidics with deep learning and cloud computing. Real-time amplifications of synthesized SARS-CoV-2 RNA templates were performed in paper devices. Information pertained to on-chip reactions in time-series format were transmitted to cloud server on which deep learning (DL) models were preloaded for data analysis. DL models enable prediction of NAAT results using partly gathered real-time fluorescence data. Using information provided by the G-channel, accurate prediction can be made as early as 9 min, a 78% reduction from the conventional 40 min mark. Reaction dynamics hidden in amplification curves were effectively leveraged. Positive and negative samples can be unbiasedly and automatically distinguished. Practical utility of the approach was validated by cross-platform study using clinical datasets. Predicted clinical accuracy, sensitivity and specificity were 98.6%, 97.6% and 99.1%. Not only the approach reduced the need for the use of bulky apparatus, but also provided intelligent, distributable and robotic insights for NAAT analysis. It set a novel paradigm for analyzing NAATs, and can be combined with the most cutting-edge technologies in fields of biosensor, artificial intelligence and cloud computing to facilitate fundamental and clinical research.Copyright © 2023 Elsevier Ltd

13.
ASME 2022 International Mechanical Engineering Congress and Exposition, IMECE 2022 ; 4, 2022.
Article in English | Scopus | ID: covidwho-2249068

ABSTRACT

We report a point-of-care (POC) device for simultaneous detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A viruses. The device carries out sample preparation using ball-based valves for sequential delivery of reagents. A microfluidic paper-based analytical device (µPAD) in the detection unit enables RNA isolation and enrichment, followed by reverse transcription loop-mediated isothermal amplification (RT-LAMP) and colorimetric detection. The device integrates all the necessary steps for the sample preparation, including virus lysis, RNA enrichment and purification of two virus samples. The device enabled simultaneous detection of SARS-CoV-2 and Influenza A N1H1 viruses in 50 min., with limit of detection of 2 and 6 genome equivalents (GEs), respectively. The device was also capable of detecting environmental sample of the two viruses. Copyright © 2022 by ASME.

14.
Biosensors (Basel) ; 12(1)2021 Dec 26.
Article in English | MEDLINE | ID: covidwho-2287828

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus has led to a global pandemic with a high spread rate and pathogenicity. Thus, with limited testing solutions, it is imperative to develop early-stage diagnostics for rapid and accurate detection of SARS-CoV-2 to contain the rapid transmission of the ongoing COVID-19 pandemic. In this regard, there remains little knowledge about the integration of the CRISPR collateral cleavage mechanism in the lateral flow assay and fluorophotometer. In the current study, we demonstrate a CRISPR/Cas12a-based collateral cleavage method for COVID-19 diagnosis using the Cas12a/crRNA complex for target recognition, reverse transcription loop-mediated isothermal amplification (RT-LAMP) for sensitivity enhancement, and a novel DNA capture probe-based lateral flow strip (LFS) or real-time fluorescence detector as the parallel system readout facility, termed CRICOLAP. Our novel approach uses a customized reporter that hybridizes an optimized complementary capture probe fixed at the test line for naked-eye result readout. The CRICOLAP system achieved ultra-sensitivity of 1 copy/µL in ~32 min by portable real-time fluorescence detection and ~60 min by LFS. Furthermore, CRICOLAP validation using 60 clinical nasopharyngeal samples previously verified with a commercial RT-PCR kit showed 97.5% and 100% sensitivity for S and N genes, respectively, and 100% specificity for both genes of SARS-CoV-2. CRICOLAP advances the CRISPR/Cas12a collateral cleavage result readout in the lateral flow assay and fluorophotometer, and it can be an alternative method for the decentralized field-deployable diagnosis of COVID-19 in remote and limited-resource locations.


Subject(s)
COVID-19 Testing , COVID-19 , CRISPR-Cas Systems , COVID-19/diagnosis , Humans , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , RNA, Viral , SARS-CoV-2 , Sensitivity and Specificity
15.
Biosensors (Basel) ; 13(3)2023 Mar 13.
Article in English | MEDLINE | ID: covidwho-2288300

ABSTRACT

The COVID-19 pandemic has caused an unprecedented health and economic crisis, highlighting the importance of developing new molecular tools to monitor and detect SARS-CoV-2. Hence, this study proposed to employ the carrageenan extracted from Gigartina skottsbergii algae as a probe for SARS-CoV-2 virus binding capacity and potential use in molecular methods. G. skottsbergii specimens were collected in the Chilean subantarctic ecoregion, and the carrageenan was extracted -using a modified version of Webber's method-, characterized, and quantified. After 24 h of incubation with an inactivated viral suspension, the carrageenan's capacity to bind SARS-CoV-2 was tested. The probe-bound viral RNA was quantified using the reverse transcription and reverse transcription loop-mediated isothermal amplification (RT-LAMP) methods. Our findings showed that carrageenan extraction from seaweed has a similar spectrum to commercial carrageenan, achieving an excellent proportion of binding to SARS-CoV-2, with a yield of 8.3%. Viral RNA was also detected in the RT-LAMP assay. This study shows, for the first time, the binding capacity of carrageenan extracted from G. skottsbergii, which proved to be a low-cost and highly efficient method of binding to SARS-CoV-2 viral particles.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , Carrageenan/chemistry , Molecular Probes , Pandemics , Molecular Diagnostic Techniques/methods , RNA, Viral/genetics , Nucleic Acid Amplification Techniques/methods , Sensitivity and Specificity
16.
Biomed Pharmacother ; 153: 113538, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-2259011

ABSTRACT

The World Health Organizations declaration of the COVID-19 pandemic was a milestone for the scientific community. The high transmission rate and the huge number of deaths, along with the lack of knowledge about the virus and the evolution of the disease, stimulated a relentless search for diagnostic tests, treatments, and vaccines. The main challenges were the differential diagnosis of COVID-19 and the development of specific, rapid, and sensitive tests that could reach all people. RT-PCR remains the gold standard for diagnosing COVID-19. However, new methods, such as other molecular techniques and immunoassays emerged. Also, the need for accessible tests with quick results boosted the development of point of care tests (POCT) that are fast, and automated, with high precision and accuracy. This assay reduces the dependence on laboratory conditions and mass testing of the population, dispersing the pressure regarding screening and detection. This review summarizes the advances in the diagnostic field since the pandemic started, emphasizing various laboratory techniques for detecting COVID-19. We reviewed the main existing diagnostic methods, as well as POCT under development, starting with RT-PCR detection, but also exploring other nucleic acid techniques, such as digital PCR, loop-mediated isothermal amplification-based assay (RT-LAMP), clustered regularly interspaced short palindromic repeats (CRISPR), and next-generation sequencing (NGS), and immunoassay tests, and nanoparticle-based biosensors, developed as portable instruments for the rapid standard diagnosis of COVID-19.


Subject(s)
COVID-19 , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques/methods , Humans , Molecular Diagnostic Techniques/methods , Pandemics , Point-of-Care Testing , RNA, Viral , SARS-CoV-2/genetics , Sensitivity and Specificity
17.
J Environ Chem Eng ; 10(3): 107488, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-2277654

ABSTRACT

The current pandemic COVID-19 caused by the coronavirus SARS-CoV-2, has generated different economic, social and public health problems. Moreover, wastewater-based epidemiology could be a predictor of the virus rate of spread to alert on new outbreaks. To assist in epidemiological surveillance, this work introduces a simple, low-cost and affordable electrochemical sensor to specifically detect N and ORF1ab genes of the SARS-CoV-2 genome. The proposed sensor works based on screen-printed electrodes acting as a disposable test strip, where the reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction takes place. Electrochemical detection relies upon methylene blue as a redox intercalator probe, to provide a diffusion-controlled current encoding the presence and concentration of RT-LAMP products, namely amplicons or double-stranded DNA. We test the performance of the sensor by testing real wastewater samples using end-point and time course measurements. Results show the ability of the electrochemical test strip to specifically detect and quantify RT-LAMP amplicons below to ~ 2.5 × 10-6 ng/µL exhibiting high reproducibility. In this sense, our RT-LAMP electrochemical sensor is an attractive, efficient and powerful tool for rapid and reliable wastewater-based epidemiology studies.

18.
EMBO Rep ; 24(5): e57162, 2023 05 04.
Article in English | MEDLINE | ID: covidwho-2269718

ABSTRACT

Throughout the SARS-CoV-2 pandemic, limited diagnostic capacities prevented sentinel testing, demonstrating the need for novel testing infrastructures. Here, we describe the setup of a cost-effective platform that can be employed in a high-throughput manner, which allows surveillance testing as an acute pandemic control and preparedness tool, exemplified by SARS-CoV-2 diagnostics in an academic environment. The strategy involves self-sampling based on gargling saline, pseudonymized sample handling, automated RNA extraction, and viral RNA detection using a semiquantitative multiplexed colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay with an analytical sensitivity comparable with RT-qPCR. We provide standard operating procedures and an integrated software solution for all workflows, including sample logistics, analysis by colorimetry or sequencing, and communication of results. We evaluated factors affecting the viral load and the stability of gargling samples as well as the diagnostic sensitivity of the RT-LAMP assay. In parallel, we estimated the economic costs of setting up and running the test station. We performed > 35,000 tests, with an average turnover time of < 6 h from sample arrival to result announcement. Altogether, our work provides a blueprint for fast, sensitive, scalable, cost- and labor-efficient RT-LAMP diagnostics, which is independent of potentially limiting clinical diagnostics supply chains.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Testing , Clinical Laboratory Techniques/methods , Pandemics/prevention & control , Sensitivity and Specificity , RNA, Viral/genetics
19.
Methods Mol Biol ; 2610: 109-127, 2023.
Article in English | MEDLINE | ID: covidwho-2245117

ABSTRACT

Influenza A virus H1N1, a respiratory virus transmitted via droplets and responsible for the global pandemic in 2009, belongs to the Orthomyxoviridae family, a single-negative-stranded RNA. It possesses glycoprotein spikes neuraminidase (NA), hemagglutinin (HA), and a matrix protein named M2. The Covid-19 pandemic affected the world population belongs to the respiratory virus category is currently mutating, this can also be observed in the case of H1N1 influenza A virus. Mutations in H1N1 can enhance the viral capacity which can lead to another pandemic. This virus affects children below 5 years, pregnant women, old age people, and immunocompromised individuals due to its high viral capacity. Its early detection is necessary for the patient's recovery time. In this book chapter, we mainly focus on the detection methods for H1N1, from traditional ones to the most advance including biosensors, RT-LAMP, multi-fluorescent PCR.


Subject(s)
COVID-19 , Influenza A Virus, H1N1 Subtype , Influenza A virus , Influenza, Human , Pregnancy , Child , Humans , Female , Influenza A Virus, H1N1 Subtype/genetics , Pandemics , Sensitivity and Specificity , COVID-19/epidemiology , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A virus/genetics , Neuraminidase/genetics , RNA, Viral/genetics
20.
Talanta ; 253:N.PAG-N.PAG, 2023.
Article in English | Academic Search Complete | ID: covidwho-2227425

ABSTRACT

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has proven the need for developing reliable and affordable technologies to detect pathogens. Particularly, the detecting the genome in wastewater could be an indicator of the transmission rate to alert on new outbreaks. However, wastewater-based epidemiology remains a technological challenge to develop affordable technologies for sensing pathogens. In this work, we introduce a label-free and portable field-effect transistor (FET)-based sensor to detect N and ORF1ab genes of the SARS-CoV-2 genome. Our sensor integrates the reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction as a cost-effective molecular detection exhibiting high specificity. The detection relies upon pH changes, due to the RT-LAMP reaction products, which are detected through a simple, but effective, extended-gate FET sensor (EGFET). We evaluate the proposed device by measuring real wastewater samples to detect the presence of SARS-CoV-2 genome, achieving a limit of detection of 0.31 × 10−3 ng/ μ L for end-point measurement. Moreover, we find the ability of the sensor to perform real-time-like analysis, showing that the RT-LAMP reaction provides a good response after 15 min for concentrations as low as 0.37 ng/ μ L. Hence, we show that our EGFET sensor offers a powerful tool to detect the presence of the SARS-CoV-2 genome with a naked-eye method, in a straightforward way than the conventional molecular methods for wastewater analysis. [Display omitted] • Label-free extended-gate field-effect transistor sensor for detect SARS-CoV-2 genome. • Portable and reliable sensing based on isothermal amplification reaction. • Detection and quantification of nucleic-acids in real wastewater samples. • End-pint and time course detection of RT-LAMP products. • The wastewater-based epidemiology can use this method in limited-resource conditions. [ FROM AUTHOR]

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