Visual detection of Zika virus by isothermal nucleic acid amplification combined with a lateral-flow device

2019 ◽  
Vol 11 (13) ◽  
pp. 1795-1801 ◽  
Author(s):  
Xuemei Lin ◽  
Maoyong Wu ◽  
Wenbiao Wang ◽  
Yuhang Gao ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Zika Virus ◽  
Visual Detection ◽  
Lateral Flow ◽  
Nucleic Acid Amplification ◽  
Lateral Flow Device ◽  
Isothermal Nucleic Acid Amplification ◽  
The Past ◽  
Flow Device ◽  
Significant Attention

The Zika virus (ZIKV) did not receive significant attention in the past until the ZIKV outbreak occurred a few years ago.

scholarly journals High-Surety Isothermal Amplification and Detection of SARS-CoV-2

mSphere ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Sanchita Bhadra ◽  
Timothy E. Riedel ◽  
Simren Lakhotia ◽  
Nicholas D. Tran ◽  
Andrew D. Ellington
Keyword(s):  
Nucleic Acid ◽  
False Negative ◽  
Lateral Flow ◽  
Isothermal Amplification ◽  
Boolean Logic ◽  
Nucleic Acid Amplification ◽  
Rapid Diagnostics ◽  
One Pot ◽  
Loop Mediated Isothermal Amplification ◽  
Isothermal Nucleic Acid Amplification

ABSTRACT Isothermal nucleic acid amplification tests (iNATs), such as loop-mediated isothermal amplification (LAMP), are good alternatives to PCR-based amplification assays, especially for point-of-care and low-resource use, in part because they can be carried out with relatively simple instrumentation. However, iNATs can often generate spurious amplicons, especially in the absence of target sequences, resulting in false-positive results. This is especially true if signals are based on non-sequence-specific probes, such as intercalating dyes or pH changes. In addition, pathogens often prove to be moving, evolving targets and can accumulate mutations that will lead to inefficient primer binding and thus false-negative results. Multiplex assays targeting different regions of the analyte and logical signal readout using sequence-specific probes can help to reduce both false negatives and false positives. Here, we describe rapid conversion of three previously described SARS-CoV-2 LAMP assays that relied on a non-sequence-specific readout into individual and multiplex one-pot assays that can be visually read using sequence-specific oligonucleotide strand exchange (OSD) probes. We describe both fluorescence-based and Boolean logic-gated colorimetric lateral flow readout methods and demonstrate detection of SARS-CoV-2 virions in crude human saliva. IMPORTANCE One of the key approaches to treatment and control of infectious diseases, such as COVID-19, is accurate and rapid diagnostics that is widely deployable in a timely and scalable manner. To achieve this, it is essential to go beyond the traditional gold standard of quantitative PCR (qPCR) that is often faced with difficulties in scaling due to the complexity of infrastructure and human resource requirements. Isothermal nucleic acid amplification methods, such as loop-mediated isothermal amplification (LAMP), have been long pursued as ideal, low-tech alternatives for rapid, portable testing. However, isothermal approaches often suffer from false signals due to employment of nonspecific readout methods. We describe general principles for rapidly converting nonspecifically read LAMP assays into assays that are read in a sequence-specific manner by using oligonucleotide strand displacement (OSD) probes. We also demonstrate that inclusion of OSD probes in LAMP assays maintains the simplicity of one-pot assays and a visual yes/no readout by using fluorescence or colorimetric lateral-flow dipsticks while providing accurate sequence-specific readout and the ability to logically query multiplex amplicons for redundancy or copresence. These principles not only yielded high-surety isothermal assays for SARS-CoV-2 but might also aid in the design of more sophisticated molecular assays for other analytes.

scholarly journals Simultaneous Detection of Nucleic Acid and Protein Using Gold Nanoparticles and Lateral Flow Device

2014 ◽  
Vol 30 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Xun MAO ◽  
Anant GURUNG ◽  
Hui XU ◽  
Meenu BALODA ◽  
Yuqing HE ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Nucleic Acid ◽  
Simultaneous Detection ◽  
Lateral Flow ◽  
Lateral Flow Device ◽  
Flow Device

Evaluation of rapid test kits for quantification of HT-2 and T-2 toxins in naturally contaminated oats

2013 ◽  
Vol 6 (1) ◽  
pp. 31-41 ◽  
Author(s):  
H.U. Aamot ◽  
I.S. Hofgaard ◽  
G. Brodal ◽  
O. Elen ◽  
B. Holen ◽  
...  
Keyword(s):  
Concentration Ratio ◽  
Rapid Test ◽  
Reference Method ◽  
Lateral Flow ◽  
Cross Reaction ◽  
Cross Reactions ◽  
Lateral Flow Device ◽  
Simultaneous Testing ◽  
Flow Device ◽  
Mycotoxin Analysis

The aim of this study was to evaluate the performance and usefulness of three rapid test kits for analysis of HT-2 and T-2 toxins (HT-2 and T-2), two of the most potent trichothecenes commonly found in European oats. Concentrations of these two toxins combined (HT-2+T-2) were analysed in naturally contaminated oat samples (n=68) using the following test kits: Ridascreen® FAST T-2 Toxin (‘Fast ELISA’), DRAFT Ridascreen® HT-2/T-2 (‘Standard ELISA’, not commercially available), and the lateral flow device ROSA® HT-2-T-2 (‘Rosa LFD’). Mycotoxin analysis by LC-MS/MS was used as a reference method. Rosa LFD offered the best reliability, achieving detection that was stable across toxin levels, whereas detection by both ELISA kits differed significantly among toxin levels (P<0.01). The kits were also evaluated regarding agreement with the reference method (measured as Cohen's kappa) at a HT-2+T-2 concentration of 1000 μg/kg in naturally contaminated oats. Agreement was greatest for Rosa LFD (89.2%), intermediate for Standard ELISA (66.8%), and lowest for Fast ELISA (62.2%). Rosa LFD showed cross-reaction of 100% with both T-2 and HT-2. For the ELISA kits, cross-reactions were 100% with T-2 but below 100% with HT-2. Therefore, to estimate the sum of HT-2 and T-2 in an oat sample, it was necessary to re-calculate the data from both ELISA kits according to the known cross-reaction of each kit with HT-2 and the concentration ratio of HT-2 to T-2 in Norwegian oats. Rosa LFD had the highest correlation with LC-MS/MS (R2=0.94), and the corresponding R2 values for Fast and Standard ELISA were 0.61 and 0.83, respectively. Rosa LFD was well suited for on-site detection. Standard ELISA allows simultaneous testing of several samples that are useful for centralised laboratories.

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