Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 548
Filtrar
1.
Methods Mol Biol ; 2804: 195-206, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38753149

RESUMEN

Clinical diagnostics of infectious diseases via nucleic acid amplification tests (NAATs) depend on a separate step of isolation of nucleic acids from cells/viruses embedded in complex biological matrices. The most recent example has been reverse transcription polymerase chain reaction (RT-PCR) for amplification and detection of SARS-CoV-2 RNA for COVID-19 diagnostics. Kits for RNA extraction and purification are commercially available; however, their integration with amplification systems is generally lacking, resulting in two separate steps, i.e., sample preparation and amplification. This makes NAATs more time-consuming, requiring skilled personnel, and can increase the likelihood of contamination. Here, we describe a setup and methodology to perform the quick extraction and detection of nucleic acids in an integrated manner. In particular, we focus on the use of an immiscible filtration device for capture, isolation, concentration, amplification, and colorimetric detection of SARS-CoV-2 RNA.


Asunto(s)
COVID-19 , Filtración , Técnicas de Amplificación de Ácido Nucleico , ARN Viral , SARS-CoV-2 , ARN Viral/aislamiento & purificación , ARN Viral/análisis , ARN Viral/genética , Humanos , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , COVID-19/diagnóstico , COVID-19/virología , Filtración/instrumentación , Filtración/métodos , Prueba de Ácido Nucleico para COVID-19/métodos , Prueba de Ácido Nucleico para COVID-19/instrumentación , Colorimetría/métodos , Colorimetría/instrumentación
2.
Biosens Bioelectron ; 256: 116282, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38626615

RESUMEN

Helicobacter pylori (H. pylori) infection correlates closely with gastric diseases such as gastritis, ulcers, and cancer, influencing more than half of the world's population. Establishing a rapid, precise, and automated platform for H. pylori diagnosis is an urgent clinical need and would significantly benefit therapeutic intervention. Recombinase polymerase amplification (RPA)-CRISPR recently emerged as a promising molecular diagnostic assay due to its rapid detection capability, high specificity, and mild reaction conditions. In this work, we adapted the RPA-CRISPR assay on a digital microfluidics (DMF) system for automated H. pylori detection and genotyping. The system can achieve multi-target parallel detection of H. pylori nucleotide conservative genes (ureB) and virulence genes (cagA and vacA) across different samples within 30 min, exhibiting a detection limit of 10 copies/rxn and no false positives. We further conducted tests on 80 clinical saliva samples and compared the results with those derived from real-time quantitative polymerase chain reaction, demonstrating 100% diagnostic sensitivity and specificity for the RPA-CRISPR/DMF method. By automating the assay process on a single chip, the DMF system can significantly reduce the usage of reagents and samples, minimize the cross-contamination effect, and shorten the reaction time, with the additional benefit of losing the chance of experiment failure/inconsistency due to manual operations. The DMF system together with the RPA-CRISPR assay can be used for early detection and genotyping of H. pylori with high sensitivity and specificity, and has the potential to become a universal molecular diagnostic platform.


Asunto(s)
Técnicas Biosensibles , Técnicas de Genotipaje , Infecciones por Helicobacter , Helicobacter pylori , Helicobacter pylori/genética , Helicobacter pylori/aislamiento & purificación , Humanos , Infecciones por Helicobacter/diagnóstico , Infecciones por Helicobacter/microbiología , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Técnicas de Genotipaje/instrumentación , Técnicas de Genotipaje/métodos , Genotipo , Proteínas Bacterianas/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Microfluídica/métodos , Antígenos Bacterianos/genética , Antígenos Bacterianos/análisis , ADN Bacteriano/genética , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , Recombinasas/metabolismo
3.
J Agric Food Chem ; 72(19): 11195-11204, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38564697

RESUMEN

Genetically modified crops (GMCs) have been discussed due to unknown safety, and thus, it is imperative to develop an effective detection technology. CRISPR/Cas is deemed a burgeoning technology for nucleic acid detection. Herein, we developed a novel detection method for the first time, which combined thermostable Cas12b with loop-mediated isothermal amplification (LAMP), to detect genetically modified (GM) soybeans in a customized one-pot vessel. In our method, LAMP-specific primers were used to amplify the cauliflower mosaic virus 35S promoter (CaMV35S) of the GM soybean samples. The corresponding amplicons activated the trans-cleavage activity of Cas12b, which resulted in the change of fluorescence intensity. The proposed bioassay was capable of detecting synthetic plasmid DNA samples down to 10 copies/µL, and as few as 0.05% transgenic contents could be detected in less than 40 min. This work presented an original detection method for GMCs, which performed rapid, on-site, and deployable detection.


Asunto(s)
Glycine max , Técnicas de Amplificación de Ácido Nucleico , Plantas Modificadas Genéticamente , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/química , Glycine max/genética , Glycine max/química , Bioensayo/métodos , Sistemas CRISPR-Cas , Caulimovirus/genética , Proteínas Bacterianas/genética
4.
Lab Chip ; 24(10): 2622-2632, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38644672

RESUMEN

Genetically modified (GM) food is still highly controversial nowadays. Due to the disparate policies and attitudes worldwide, demands for a rapid, cost-effective and user-friendly GM crop identification method are increasingly significant for import administration, market supervision, etc. However, as the most-recognized methods, nucleic acid-based identification approaches require bulky instruments, long turn-around times and trained personnel, which are only suitable in laboratories. To fulfil the urgent needs of on-site testing, we develop a point-of-care testing platform that is able to identify 12 types of GM crops in less than 40 minutes without using laboratory settings. Our system integrates sample pre-treatment modules in a microfluidic chip, performs DNA amplification via a battery-powered portable kit, and presents results via eye-recognized colorimetric change. A paraffin-based reflow method and a slip plate-based fluid switch are developed to encapsulate and release amplification primers in individual microwells on demand, thus enabling identification of varied targets simultaneously. Our system offers an efficient, affordable and convenient tool for GM crop identification, thus it will not only benefit customs and market administration bureaus, but also satisfy demands of numerous consumers.


Asunto(s)
Productos Agrícolas , Plantas Modificadas Genéticamente , Pruebas en el Punto de Atención , Plantas Modificadas Genéticamente/genética , Productos Agrícolas/genética , Dispositivos Laboratorio en un Chip , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas Analíticas Microfluídicas/instrumentación
5.
Lab Chip ; 24(9): 2485-2496, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38587207

RESUMEN

The COVID-19 pandemic greatly impacted the in vitro diagnostic market, leading to the development of new technologies such as point-of-care testing (POCT), multiplex testing, and digital health platforms. In this study, we present a self-contained microfluidic chip integrated with an internet-of-things (IoT)-based point-of-care (POC) device for rapid and sensitive diagnosis of respiratory viruses. Our platform enables sample-to-answer diagnostics within 70 min by automating RNA extraction, reverse transcription-loop-mediated isothermal amplification (RT-LAMP), and fluorescence detection. The microfluidic chip is designed to store all the necessary reagents for the entire diagnostic assay, including a lysis buffer, a washing buffer, an elution buffer, and a lyophilized RT-LAMP cocktail. It can perform nucleic acid extraction, aliquoting, and gene amplification in multiple reaction chambers without cross-contamination. The IoT-based POC device consists of a Raspberry Pi 4 for device control and data processing, a CMOS sensor for measuring fluorescence signals, a resistive heater panel for temperature control, and solenoid valves for controlling the movement of on-chip reagent solutions. The proposed device is portable and features a touchscreen for user control and result display. We evaluated the performance of the platform using 11 clinical respiratory virus samples, including 5 SARS-CoV-2 samples, 2 influenza A samples, and 4 influenza B samples. All tested clinical samples were accurately identified with high specificity and fidelity, demonstrating the ability to simultaneously detect multiple respiratory viruses. The combination of the integrated microfluidic chip with the POC device offers a simple, cost-effective, and scalable solution for rapid molecular diagnosis of respiratory viruses in resource-limited settings.


Asunto(s)
COVID-19 , Internet de las Cosas , Dispositivos Laboratorio en un Chip , Técnicas de Amplificación de Ácido Nucleico , SARS-CoV-2 , Humanos , COVID-19/diagnóstico , COVID-19/virología , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/genética , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Sistemas de Atención de Punto , Técnicas de Diagnóstico Molecular/instrumentación , Diseño de Equipo , Pruebas en el Punto de Atención , ARN Viral/análisis , ARN Viral/aislamiento & purificación , ARN Viral/genética , Infecciones del Sistema Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/virología
6.
Biosens Bioelectron ; 257: 116292, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38653014

RESUMEN

We report the development and initial validation of a paper-based nucleic acid testing platform that integrates Loop-mediated isothermal amplification (LAMP) with clustered regularly interspaced short palindromic repeats (CRISPR) technology, referred to as PLACID (Paper-based LAMP-CRISPR Integrated Diagnostics). LAMP eliminates the need for thermal cycling, resulting in simplified instrumentation, and the CRISPR-associated protein (Cas 12a) system eliminates false positive signals from LAMP products, resulting in highly selective and sensitive assays. We optimized the assay to perform both amplification and detection entirely on paper, eliminating the need for complex fluid handling steps and lateral flow assay transfers. Additionally, we engineered a smartphone-operated system that includes a low-powered, non-contact IR heating chamber to actuate paper-based LAMP and CRISPR reactions and enable the detection of fluorescent signals from the paper. The platform demonstrates high specificity and sensitivity in detecting nucleic acid targets with a limit of detection of 50 copies/µL. We integrate an equipment-free sample preparation separation technology designed to streamline the preparation of crude samples prior to nucleic acid testing. The practical utility of our platform is demonstrated by the successful detection of spiked SARS-CoV-2 RNA fragments in saliva, E. Coli in soil, and pathogenic E. Coli in clinically fecal samples of infected patients. Furthermore, we demonstrate that the paper-based LAMP CRISPR chips employed in our assays possess a shelf life of several weeks, establishing them as viable candidates for on-site diagnostics.


Asunto(s)
Técnicas Biosensibles , COVID-19 , Sistemas CRISPR-Cas , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Papel , SARS-CoV-2 , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Humanos , Técnicas Biosensibles/métodos , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , COVID-19/diagnóstico , COVID-19/virología , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Diagnóstico Molecular/instrumentación , Sistemas CRISPR-Cas/genética , Límite de Detección , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Diseño de Equipo , Prueba de Ácido Nucleico para COVID-19/métodos , Prueba de Ácido Nucleico para COVID-19/instrumentación , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Proteínas Asociadas a CRISPR/genética , Teléfono Inteligente
7.
Biosens Bioelectron ; 257: 116325, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38669843

RESUMEN

In dairy industry, expensive yak's milk, camel's milk, and other specialty dairy products are often adulterated with low-cost cow's milk, goat's milk and so on. Currently, the detection of specialty dairy products typically requires laboratory settings and relies on skilled operators. Therefore, there is an urgent need to develop a multi-detection technology and on-site rapid detection technique to enhance the efficiency and accuracy of the detection of specialty dairy products. In this study, we introduced a fully integrated and portable microfluidic detection platform called Sector Self-Driving Microfluidics (SDM), designed to simultaneously detect eight common species-specific components in milk. SDM integrated nucleic acid extraction, purification, loop-mediated isothermal amplification (LAMP), and lateral flow strip (LFS) detection functions into a closed microfluidic system, enabling contamination-free visual detection. The SDM platform used a constant-temperature heating plate, powered by a mobile battery, eliminated the need for additional power support. The SDM platform achieved nucleic acid enrichment and transfer through magnetic force and liquid flow driven by capillary forces, operating without external pumps. The standalone SDM platform could detect dairy components with as low as 1% content within 1 h. Validation with 35 commercially available samples demonstrated 100% specificity and accuracy compared to the gold standard real-time PCR. The SDM platform provided the dairy industry with an efficient, convenient, and accurate detection tool, enabling rapid on-site testing at production facilities or sales points. This facilitated real-time monitoring of quality issues during the production process, quickly identifying potential risks and preventing substandard products from entering the market.


Asunto(s)
Técnicas Biosensibles , Leche , Técnicas de Amplificación de Ácido Nucleico , Animales , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Leche/química , Bovinos , Contaminación de Alimentos/análisis , Dispositivos Laboratorio en un Chip , Diseño de Equipo , Técnicas Analíticas Microfluídicas/instrumentación , Productos Lácteos/análisis , Técnicas de Diagnóstico Molecular
8.
Biosensors (Basel) ; 12(9)2022 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-36140111

RESUMEN

Foodborne pathogenic bacteria have become a worldwide threat to human health, and rapid and sensitive bacterial detection methods are urgently needed. In this study, a facile microfluidic chip was developed and combined with recombinase-aided amplification (RAA) for rapid and sensitive detection of Salmonella typhimurium using a non-contact eddy heater for dynamic lysis of bacterial cells and a 3D-printed fan-shaped active mixer for continuous-flow mixing. First, the bacterial sample was injected into the chip to flow through the spiral channel coiling around an iron rod under an alternating electromagnetic field, resulting in the dynamic lysis of bacterial cells by this non-contact eddy heater to release their nucleic acids. After cooling to ~75 °C, these nucleic acids were continuous-flow mixed with magnetic silica beads using the fan-shaped mixer and captured in the separation chamber using a magnet. Finally, the captured nucleic acids were eluted by the eluent from the beads to flow into the detection chamber, followed by RAA detection of nucleic acids to determine the bacterial amount. Under the optimal conditions, this microfluidic chip was able to quantitatively detect Salmonella typhimurium from 1.1 × 102 to 1.1 × 105 CFU/mL in 40 min with a detection limit of 89 CFU/mL and might be prospective to offer a simple, low-cost, fast and specific bacterial detection technique for ensuring food safety.


Asunto(s)
Microfluídica , Técnicas de Amplificación de Ácido Nucleico , Recombinasas , Salmonella typhimurium , Hierro , Microfluídica/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Ácidos Nucleicos , Estudios Prospectivos , Salmonella typhimurium/aislamiento & purificación , Dióxido de Silicio
9.
Sci Rep ; 12(1): 4132, 2022 03 08.
Artículo en Inglés | MEDLINE | ID: mdl-35260715

RESUMEN

This paper presents a deep learning-driven portable, accurate, low-cost, and easy-to-use device to perform Reverse-Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) to facilitate rapid detection of COVID-19. The 3D-printed device-powered using only a 5 Volt AC-DC adapter-can perform 16 simultaneous RT-LAMP reactions and can be used multiple times. Moreover, the experimental protocol is devised to obviate the need for separate, expensive equipment for RNA extraction in addition to eliminating sample evaporation. The entire process from sample preparation to the qualitative assessment of the LAMP amplification takes only 45 min (10 min for pre-heating and 35 min for RT-LAMP reactions). The completion of the amplification reaction yields a fuchsia color for the negative samples and either a yellow or orange color for the positive samples, based on a pH indicator dye. The device is coupled with a novel deep learning system that automatically analyzes the amplification results and pays attention to the pH indicator dye to screen the COVID-19 subjects. The proposed device has been rigorously tested on 250 RT-LAMP clinical samples, where it achieved an overall specificity and sensitivity of 0.9666 and 0.9722, respectively with a recall of 0.9892 for Ct < 30. Also, the proposed system can be widely used as an accurate, sensitive, rapid, and portable tool to detect COVID-19 in settings where access to a lab is difficult, or the results are urgently required.


Asunto(s)
COVID-19/diagnóstico , Aprendizaje Profundo , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , SARS-CoV-2/genética , Área Bajo la Curva , Prueba de COVID-19 , Colorantes/química , Humanos , Técnicas de Diagnóstico Molecular/instrumentación , Nasofaringe/virología , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Sistemas de Atención de Punto , Impresión Tridimensional , ARN Viral/análisis , ARN Viral/metabolismo , Curva ROC , SARS-CoV-2/aislamiento & purificación , Sensibilidad y Especificidad
10.
Biomed Environ Sci ; 35(2): 133-140, 2022 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-35197178

RESUMEN

OBJECTIVE: To establish a sensitive, simple and rapid detection method for African swine fever virus (ASFV) B646L gene. METHODS: A recombinase-aided amplification-lateral flow dipstick (RAA-LFD) assay was developed in this study. Recombinase-aided amplification (RAA) is used to amplify template DNA, and lateral flow dipstick (LFD) is used to interpret the results after the amplification is completed. The lower limits of detection and specificity of the RAA assay were verified using recombinant plasmid and pathogenic nucleic acid. In addition, 30 clinical samples were tested to evaluate the performance of the RAA assay. RESULTS: The RAA-LFD assay was completed within 15 min at 37 °C, including 10 min for nucleic acid amplification and 5 minutes for LFD reading results. The detection limit of this assay was found to be 200 copies per reaction. And there was no cross-reactivity with other swine viruses. CONCLUSION: A highly sensitive, specific, and simple RAA-LFD method was developed for the rapid detection of the ASFV.


Asunto(s)
Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/radioterapia , Fiebre Porcina Africana/virología , Técnicas de Amplificación de Ácido Nucleico/métodos , Fiebre Porcina Africana/diagnóstico , Virus de la Fiebre Porcina Africana/clasificación , Virus de la Fiebre Porcina Africana/aislamiento & purificación , Animales , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Recombinasas/química , Sensibilidad y Especificidad , Porcinos , Proteínas Virales/genética
11.
Biosensors (Basel) ; 12(2)2022 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-35200333

RESUMEN

Pathogen detection by nucleic acid amplification proved its significance during the current coronavirus disease 2019 (COVID-19) pandemic. The emergence of recombinase polymerase amplification (RPA) has enabled nucleic acid amplification in limited-resource conditions owing to the low operating temperatures around the human body. In this study, we fabricated a wearable RPA microdevice using poly(dimethylsiloxane) (PDMS), which can form soft-but tight-contact with human skin without external support during the body-heat-based reaction process. In particular, the curing agent ratio of PDMS was tuned to improve the flexibility and adhesion of the device for better contact with human skin, as well as to temporally bond the microdevice without requiring further surface modification steps. For PDMS characterization, water contact angle measurements and tests for flexibility, stretchability, bond strength, comfortability, and bendability were conducted to confirm the surface properties of the different mixing ratios of PDMS. By using human body heat, the wearable RPA microdevices were successfully applied to amplify 210 bp from Escherichia coli O157:H7 (E. coli O157:H7) and 203 bp from the DNA plasmid SARS-CoV-2 within 23 min. The limit of detection (LOD) was approximately 500 pg/reaction for genomic DNA template (E. coli O157:H7), and 600 fg/reaction for plasmid DNA template (SARS-CoV-2), based on gel electrophoresis. The wearable RPA microdevice could have a high impact on DNA amplification in instrument-free and resource-limited settings.


Asunto(s)
Temperatura Corporal , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Ácidos Nucleicos , Dispositivos Electrónicos Vestibles , COVID-19/diagnóstico , ADN , Escherichia coli O157 , Humanos , Técnicas de Amplificación de Ácido Nucleico/métodos , Ácidos Nucleicos/aislamiento & purificación , Recombinasas/química , Recombinasas/genética , SARS-CoV-2/genética , Sensibilidad y Especificidad
12.
PLoS One ; 17(1): e0259886, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35081119

RESUMEN

COVID-19 has exposed stark inequalities between resource-rich and resource-poor countries. International UN- and WHO-led efforts, such as COVAX, have provided SARS-CoV-2 vaccines but half of African countries have less than 2% vaccinated in their population, and only 15 have reached 10% by October 2021, further disadvantaging local economic recovery. Key for this implementation and preventing further mutation and spread is the frequency of voluntary [asymptomatic] testing. It is limited by expensive PCR and LAMP tests, uncomfortable probes deep in the throat or nose, and the availability of hardware to administer in remote locations. There is an urgent need for an inexpensive "end-to-end" system to deliver sensitive and reliable, non-invasive tests in resource-poor and field-test conditions. We introduce a non-invasive saliva-based LAMP colorimetric test kit and a $51 lab-in-a-backpack system that detects as few as 4 viral RNA copies per µL. It consists of eight chemicals, a thermometer, a thermos bottle, two micropipettes and a 1000-4000 rcf electronically operated centrifuge made from recycled computer hard drives (CentriDrive). The centrifuge includes a 3D-printed rotor and a 12 V rechargeable Li-ion battery, and its 12 V standard also allows wiring directly to automobile batteries, to enable field-use of this and other tests in low infrastructure settings. The test takes 90 minutes to process 6 samples and has reagent costs of $3.5 per sample. The non-invasive nature of saliva testing would allow higher penetration of testing and wider adoption of the test across cultures and settings (including refugee camps and disaster zones). The attached graphical procedure would make the test suitable for self-testing at home, performing it in the field, or in mobile testing centers by minimally trained staff.


Asunto(s)
COVID-19/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , ARN Viral/análisis , COVID-19/virología , Prueba de Ácido Nucleico para COVID-19/economía , Prueba de Ácido Nucleico para COVID-19/métodos , Colorimetría , Humanos , Técnicas de Diagnóstico Molecular/economía , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/economía , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Sistemas de Atención de Punto , ARN Viral/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Saliva/virología
13.
PLoS Negl Trop Dis ; 16(1): e0010180, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-35089927

RESUMEN

Enterotoxigenic E. coli (ETEC) and Shigella spp (Shigella) are complex pathogens. The diagnostic assays currently used to detect these pathogens are elaborate or complicated, which make them difficult to apply in resource poor settings where these diseases are endemic. The culture methods used to detect Shigella are not sensitive, and the methods used to detect ETEC are only available in a few research labs. To address this gap, we developed a rapid and simple diagnostic assay-"Rapid LAMP based Diagnostic Test (RLDT)." The six minutes sample preparation method directly from the fecal samples with lyophilized reaction strips and using established Loop-mediated Isothermal Amplification (LAMP) platform, ETEC [heat labile toxin (LT) and heat stable toxins (STh, and STp) genes] and Shigella (ipaH gene) detection was made simple, rapid (<50 minutes), and inexpensive. This assay is cold chain and electricity free. Moreover, RLDT requires minimal equipment. To avoid any end user's bias, a battery-operated, handheld reader was used to read the RLDT results. The results can be read as positive/negative or as real time amplification depending on the end user's need. The performance specifications of the RLDT assay, including analytical sensitivity and specificity, were evaluated using fecal samples spiked with ETEC and Shigella strains. The limit of detection was ~105 CFU/gm of stool for LT, STh, and STp and ~104 CFU/gm of stool for the ipaH gene, which corresponds to about 23 CFU and 1 CFU respectively for ETEC and Shigella per 25uL reaction within 40 minutes. The RLDT assay from stool collection to result is simple, and rapid and at the same time sufficiently sensitive. RLDT has the potential to be applied in resource poor endemic settings for the rapid diagnosis of ETEC and Shigella.


Asunto(s)
Disentería Bacilar/diagnóstico , Infecciones por Escherichia coli/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , ADN Bacteriano/análisis , Disentería Bacilar/microbiología , Escherichia coli Enterotoxigénica/genética , Escherichia coli Enterotoxigénica/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Humanos , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Shigella/genética , Shigella/aislamiento & purificación
14.
Bioprocess Biosyst Eng ; 45(3): 503-514, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35031864

RESUMEN

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had severe consequences for health and the global economy. To control the transmission, there is an urgent demand for early diagnosis and treatment in the general population. In the present study, an automatic system for SARS-CoV-2 diagnosis is designed and built to deliver high specification, high sensitivity, and high throughput with minimal workforce involvement. The system, set up with cross-priming amplification (CPA) rather than conventional reverse transcription-polymerase chain reaction (RT-PCR), was evaluated using more than 1000 real-world samples for direct comparison. This fully automated robotic system performed SARS-CoV-2 nucleic acid-based diagnosis with 192 samples in under 180 min at 100 copies per reaction in a "specimen in data out" manner. This throughput translates to a daily screening capacity of 800-1000 in an assembly-line manner with limited workforce involvement. The sensitivity of this device could be further improved using a CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-based assay, which opens the door to mixed samples, potentially include SARS-CoV-2 variants screening in extensively scaled testing for fighting COVID-19.


Asunto(s)
Prueba de Ácido Nucleico para COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2 , Algoritmos , Ingeniería Biomédica/instrumentación , Ingeniería Biomédica/métodos , Ingeniería Biomédica/estadística & datos numéricos , COVID-19/epidemiología , COVID-19/virología , Prueba de Ácido Nucleico para COVID-19/instrumentación , Prueba de Ácido Nucleico para COVID-19/estadística & datos numéricos , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Diseño de Equipo , Ensayos Analíticos de Alto Rendimiento/instrumentación , Ensayos Analíticos de Alto Rendimiento/métodos , Ensayos Analíticos de Alto Rendimiento/estadística & datos numéricos , Humanos , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas de Amplificación de Ácido Nucleico/estadística & datos numéricos , Pandemias , Robótica/instrumentación , Robótica/métodos , Robótica/estadística & datos numéricos , SARS-CoV-2/genética , Sensibilidad y Especificidad , Análisis de Sistemas
15.
Mol Biotechnol ; 64(4): 339-354, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34655396

RESUMEN

The outbreak of COVID-19 pandemic and its consequences have inflicted a substantial damage on the world. In this study, it was attempted to review the recent coronaviruses appeared among the human being and their epidemic/pandemic spread throughout the world. Currently, there is an inevitable need for the establishment of a quick and easily available biosensor for tracing COVID-19 in all countries. It has been known that the incubation time of COVID-19 lasts about 14 days and 25% of the infected individuals are asymptomatic. To improve the ability to determine SARS-CoV-2 precisely and reduce the risk of eliciting false-negative results produced by mutating nature of coronaviruses, many researchers have established a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay using mismatch-tolerant molecular beacons as multiplex real-time RT-PCR to distinguish between pathogenic and non-pathogenic strains of coronaviruses. The possible mechanisms and pathways for the detection of coronaviruses by biosensors have been reviewed in this study.


Asunto(s)
Prueba de COVID-19/métodos , Técnicas Biosensibles/métodos , Prueba de COVID-19/instrumentación , Sistemas CRISPR-Cas , Técnicas Electroquímicas , Ensayo de Inmunoadsorción Enzimática , Técnica del Anticuerpo Fluorescente/métodos , Humanos , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Diagnóstico Molecular/métodos , Pruebas de Neutralización , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa/instrumentación , Reacción en Cadena de la Polimerasa/métodos , SARS-CoV-2/patogenicidad , Resonancia por Plasmón de Superficie
16.
Adv Sci (Weinh) ; 9(4): e2104084, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34913619

RESUMEN

Herein, a programmable dual-catalyst hairpin assembly (DCHA) for realizing the synchronous recycle of two catalysts is developed, displaying high reaction rate and outstanding conversion efficiency beyond traditional nucleic acid signal amplifications (NASA). Once catalyst I interacts with the catalyst II, the DCHA can be triggered to realize the simultaneous recycle of catalysts I and II to keep the highly concentrated intermediate product duplex I-II instead of the steadily decreased one in typical NASA, which can accomplish in about only 16 min and achieves the outstanding conversion efficiency up to 4.54 × 108 , easily conquering the main predicaments of NASA: time-consuming and low-efficiency. As a proof of the concept, the proposed DCHA as a high-speed and hyper-efficiency DNA signal magnifier is successfully applied in the rapid and ultrasensitive detection of miRNA-21 in cancer cell lysates, which exploits the new generation of universal strategy for the applications in biosensing assay, clinic diagnose, and DNA nanobiotechnology.


Asunto(s)
Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/instrumentación , Técnicas Electroquímicas/métodos , MicroARNs/análisis , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Técnicas de Amplificación de Ácido Nucleico/métodos , Células HeLa , Humanos , Límite de Detección , Células MCF-7 , MicroARNs/genética
17.
Vet Res ; 52(1): 126, 2021 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-34600578

RESUMEN

This work modifies a loop-mediated isothermal amplification (LAMP) assay to detect the bovine respiratory disease (BRD) bacterial pathogens Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni in a colorimetric format on a farm. BRD causes a significant health and economic burden worldwide that partially stems from the challenges involved in determining the pathogens causing the disease. Methods such as polymerase chain reaction (PCR) have the potential to identify the causative pathogens but require lab equipment and extensive sample processing making the process lengthy and expensive. To combat this limitation, LAMP allows accurate pathogen detection in unprocessed samples by the naked eye allowing for potentially faster and more precise diagnostics on the farm. The assay developed here offers 66.7-100% analytical sensitivity, and 100% analytical specificity (using contrived samples) while providing 60-100% concordance with PCR results when tested on five steers in a feedlot. The use of a consumer-grade water bath enabled on-farm execution by collecting a nasal swab from cattle and provided a colorimetric result within 60 min. Such an assay holds the potential to provide rapid pen-side diagnostics to cattle producers and veterinarians.


Asunto(s)
Enfermedades de los Bovinos/diagnóstico , Colorimetría/veterinaria , Pruebas Diagnósticas de Rutina/veterinaria , Técnicas de Diagnóstico Molecular/veterinaria , Técnicas de Amplificación de Ácido Nucleico/veterinaria , Infecciones por Pasteurellaceae/veterinaria , Pasteurellaceae/aislamiento & purificación , Animales , Bovinos , Enfermedades de los Bovinos/microbiología , Colorimetría/instrumentación , Pruebas Diagnósticas de Rutina/instrumentación , Mannheimia haemolytica/aislamiento & purificación , Técnicas de Diagnóstico Molecular/instrumentación , Nariz/microbiología , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Infecciones por Pasteurella/diagnóstico , Infecciones por Pasteurella/microbiología , Infecciones por Pasteurella/veterinaria , Pasteurella multocida/aislamiento & purificación , Infecciones por Pasteurellaceae/diagnóstico , Infecciones por Pasteurellaceae/microbiología
18.
Biosensors (Basel) ; 11(10)2021 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-34677325

RESUMEN

The COVID-19 pandemic has changed people's lives and has brought society to a sudden standstill, with lockdowns and social distancing as the preferred preventative measures. To lift these measurements and reduce society's burden, developing an easy-to-use, rapid, and portable system to detect SARS-CoV-2 is mandatory. To this end, we developed a portable and semi-automated device for SARS-CoV-2 detection based on reverse transcription loop-mediated isothermal amplification followed by a CRISPR/Cas12a reaction. The device contains a heater element mounted on a printed circuit board, a cooler fan, a proportional integral derivative controller to control the temperature, and designated areas for 0.2 mL Eppendorf® PCR tubes. Our system has a limit of detection of 35 copies of the virus per microliter, which is significant and has the capability of being used in crisis centers, mobile laboratories, remote locations, or airports to diagnose individuals infected with SARS-CoV-2. We believe the current methodology that we have implemented in this article is beneficial for the early screening of infectious diseases, in which fast screening with high accuracy is necessary.


Asunto(s)
COVID-19/diagnóstico , Sistemas CRISPR-Cas/genética , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , SARS-CoV-2/genética , COVID-19/virología , Prueba de COVID-19/instrumentación , Prueba de COVID-19/métodos , Humanos , Límite de Detección , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Sistemas de Atención de Punto , ARN Viral/análisis , ARN Viral/metabolismo , SARS-CoV-2/aislamiento & purificación
19.
Biosensors (Basel) ; 11(10)2021 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-34677342

RESUMEN

Loop-mediated isothermal amplification (LAMP) has been recently studied as an alternative method for cost-effective diagnostics in the context of the current COVID-19 pandemic. Recent reports document that LAMP-based diagnostic methods have a comparable sensitivity and specificity to that of RT-qPCR. We report the use of a portable Arduino-based LAMP-based amplification system assisted by pH microelectrodes for the accurate and reliable diagnosis of SARS-CoV-2 during the first 3 min of the amplification reaction. We show that this simple system enables a straightforward discrimination between samples containing or not containing artificial SARS-CoV-2 genetic material in the range of 10 to 10,000 copies per 50 µL of reaction mix. We also spiked saliva samples with SARS-CoV-2 synthetic material and corroborated that the LAMP reaction can be successfully monitored in real time using microelectrodes in saliva samples as well. These results may have profound implications for the design of real-time and portable quantitative systems for the reliable detection of viral pathogens including SARS-CoV-2.


Asunto(s)
COVID-19/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , SARS-CoV-2/genética , COVID-19/virología , Proteínas de la Nucleocápside de Coronavirus/genética , Humanos , Microelectrodos , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Fosfoproteínas/genética , Sistemas de Atención de Punto , ARN Viral/análisis , ARN Viral/metabolismo , Tiempo de Reacción , SARS-CoV-2/aislamiento & purificación , Saliva/virología
20.
J Biosci ; 462021.
Artículo en Inglés | MEDLINE | ID: mdl-34635627

RESUMEN

L. donovani is an intracellular protozoan parasite, that causes visceral leishmaniasis (VL), and consequently, post-kala azar dermal leishmaniasis (PKDL). Diagnosis and treatment of leishmaniasis is crucial for decreasing its transmission. Various diagnostic techniques like microscopy, enzyme-linked immunosorbent assays (ELISA) and PCR-based methods are used to detect leishmaniasis infection. More recently, loop-mediated isothermal amplification (LAMP) assay has emerged as an ideal diagnostic measure for leishmaniasis, primarily due to its accuracy, speed and simplicity. However, point-of-care diagnosis is still not been tested with the LAMP assay. We have developed a portable LAMP device for the monitoring of Leishmania infection. The LAMP assay performed using our device can detect and amplify as little as 100 femtograms of L. donovani DNA. In a preliminary study, we have shown that the device can also amplify L. donovani DNA present in VL and PKDL patient samples with high sensitivity (100%), specificity (98%) and accuracy (99%), and can be used both for diagnostic and prognostic analysis. To our knowledge, this is the first report to describe the development and application of a portable LAMP device which has the potential to evolve as a point-of-care diagnostic and prognostic tool for Leishmania infections in future.


Asunto(s)
Leishmaniasis/diagnóstico , Leishmaniasis/parasitología , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Estudios de Casos y Controles , ADN Protozoario/genética , Diseño de Equipo , Fluorescencia , Humanos , Leishmania donovani/genética , Lepra/parasitología , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Carga de Parásitos , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y Especificidad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...