scholarly journals Paper-Based Test for Rapid On-Site Screening of SARS-CoV-2 in Clinical Samples

Biosensors ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 488
Author(s):  
Wen Ren ◽  
Joseph Irudayaraj
Keyword(s):  
Nasal Swab ◽  
Lateral Flow ◽  
Detection Methods ◽  
Clinical Samples ◽  
Virus Particles ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Lateral Flow Strips ◽  
Magnetic Probes ◽  
Colorimetric Reaction

Detection methods for monitoring infectious pathogens has never been more important given the need to contain the spread of the COVID-19 pandemic. Herein we propose a highly sensitive magnetic-focus-enhanced lateral flow assay (mLFA) for the detection of SARS-CoV-2. The proposed mLFA is simple and requires only lateral flow strips and a reusable magnet to detect very low concentrations of the virus particles. The magnetic focus enhancement is achieved by focusing the SARS-CoV-2 conjugated magnetic probes in the sample placed in the lateral flow (LF) strips for improved capture efficiency, while horseradish peroxidase (HRP) was used to catalyze the colorimetric reaction for the amplification of the colorimetric signal. With the magnetic focus enhancement and HRP-based amplification, the mLFA could yield a highly sensitive technology for the recognition of SARS-CoV-2. The developed methods could detect as low as 400 PFU/mL of SARS-CoV-2 in PBS buffer based on the visible blue dots on the LF strips. The mLFA could recognize 1200 PFU/mL of SARS-CoV-2 in saliva samples. With clinical nasal swab samples, the proposed mLFA could achieve 66.7% sensitivity and 100% specificity.

scholarly journals Development of a highly sensitive magneto-enzyme lateral flow immunoassay for dengue NS1 detection

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7779 ◽  
Author(s):  
Tien V. Tran ◽  
Ba V. Nguyen ◽  
Thao T.P. Nguyen ◽  
Tung T. Tran ◽  
Khanh G. Pham ◽  
...  
Keyword(s):  
Test Performance ◽  
Limit Of Detection ◽  
Dengue Infection ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
The Novel ◽  
Structural Protein ◽  
Highly Sensitive

Background Dengue infection represents a global health issue of growing importance. Dengue non-structural protein 1 (NS1) plays a central role in the early detection of the disease. The most common method for NS1 detection is testing by lateral flow immunoassays (LFIAs) with varying sensitivity. In this study, we present a highly sensitive magneto-enzyme LFIA for prompt diagnosis of dengue. Methods We have demonstrated the development of a magneto-enzyme LFIA combining super-paramagnetic nanoparticles as labels and Biotin–Streptavidin signal amplification strategy to detect dengue NS1. Factors affecting the test performance including antibody pair, super-paramagnetic nanoparticle size, nitrocellulose membrane type, amounts of detection and capture antibodies, and amounts of Streptavidin-polyHRP were optimized. Analytical sensitivity and cross-reactivity were determined. Clinical performance of the novel assay was evaluated using a panel of 120 clinical sera. Results This newly developed assay could detect NS1 of all four serotypes of dengue virus (DENV). The limit of detection (LOD) was found to be as low as 0.25 ng ml−1 for DENV-1 and DENV-3, 0.1 ng ml−1 for DENV-2, and 1.0 ng ml−1 for DENV-4. The LOD for DENV-2 was a 50-fold improvement over the best values previously reported. There was an absence of cross-reactivity with Zika NS1, Hepatitis B virus, Hepatitis C virus, and Japanese encephalitis virus. The sensitivity and specificity of the novel assay were 100% when tested on clinical samples. Conclusions We have successfully developed a magneto-enzyme LFIA, allowing rapid and highly sensitive detection of dengue NS1, which is essential for proper management of patients infected with DENV.

Flow control for lateral flow strips with centrifugal microfluidics

Lab on a Chip ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 2718-2727 ◽  
Author(s):  
Daniel M. Kainz ◽  
Susanna M. Früh ◽  
Tobias Hutzenlaub ◽  
Roland Zengerle ◽  
Nils Paust
Keyword(s):  
Flow Control ◽  
Lateral Flow ◽  
Clinical Diagnostics ◽  
Centrifugal Microfluidics ◽  
Highly Sensitive ◽  
Lateral Flow Strips

Lateral flow strips (LFSs) are widely used for clinical diagnostics. The restricted flow control is one challenge to the development of quantitative and highly sensitive LFSs. Here, we present a flow control for LFSs using centrifugal microfluidics.

scholarly journals Highly Sensitive Chemiluminescence-Based Lateral Flow Immunoassay for Cardiac Troponin I Detection in Human Serum

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2593 ◽  
Author(s):  
Gyeo-Re Han ◽  
Min-Gon Kim
Keyword(s):  
Cardiac Troponin ◽  
High Performance ◽  
Troponin I ◽  
Performance Testing ◽  
Lateral Flow ◽  
Cardiac Troponin I ◽  
World Health ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Highly Sensitive

Lateral flow assays (LFAs) have become the most common biosensing platforms for point-of-care testing due to their compliance with the ASSURED (affordable, sensitive, specific, user-friendly, rapid/robust, equipment-free, and deliverable to end-users) guidelines stipulated by the World Health Organization. However, the limited analytical sensitivity and low quantitative capability of conventional LFAs, which use gold nanoparticles (AuNPs) for colorimetric labeling, have prevented high-performance testing. Here, we report the development of a highly sensitive chemiluminescence (CL)-based LFA involving AuNPs conjugated with aldehyde-activated peroxidase and antibody molecules—i.e., AuNP-(ald)HRP-Ab—as a new conjugation scheme for high-performance testing in LFAs. When paired with the CL-based signal readout modality, the AuNP-(ald)HRP-Ab conjugate resulted in 110-fold enhanced sensitivity over the colorimetric response of a typical AuNP-Ab conjugate. To evaluate the performance of the CL-based LFA, we tested it with human cardiac troponin I (cTnI; a standard cardiac biomarker used to diagnose myocardial infarction) in standard and clinical serum samples. Testing the standard samples revealed a detection limit of 5.6 pg·mL−1 and acceptably reliable precision (with a coefficient of variation of 2.3%–8.4%), according to clinical guidelines. Moreover, testing the clinical samples revealed a high correlation (r = 0.97) with standard biochemical analyzers, demonstrating the potential clinical utility of the CL-based LFA for high-performance cTnI testing.

scholarly journals Evaluation of a fully automated high-throughput SARS-CoV-2 multiplex qPCR assay with build-in screening functionality for DelHV69/70- and N501Y variants such as B.1.1.7

2021 ◽  
Author(s):  
Dominik Nörz ◽  
Moritz Grunwald ◽  
Flaminia Olearo ◽  
Nicole Fischer ◽  
Martin Aepfelbacher ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Simultaneous Detection ◽  
Multiplex Assay ◽  
Detection Methods ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Pcr Assay ◽  
Multiplex Pcr Assay ◽  
Highly Sensitive

1AbstractBackgroundNew SARS-CoV-2 variants with increased transmissibility, like B.1.1.7 from England or B1.351 from South Africa, have caused considerable concern worldwide. In order to contain the spread of these lineages, it is of utmost importance to have rapid, sensitive and high-throughput detection methods at hand.MethodsAnalytical sensitivity was assessed for both wild-type SARS-CoV-2 and B.1.1.7 lineage by serial dilution. A total of 141 clinical samples were subjected to the test and results compared to a commercial manual typing-PCR assay and NGS.ResultsThe multiplex assay is highly sensitive for detection of SARS-CoV-2 RNA in clinical samples, with an LoD of 25.82 cp/ml (CI: 11.61 – 57.48). LoDs are slightly higher for the HV68/70 deletion (111.36 cp/ml; CI: 78.16 – 158.67) and the N501Y SNP (2548.04 cp/ml, CI: 1592.58 – 4076.73). A total of 141 clinical samples were tested with the assay, including 16 samples containing SARS-CoV-2 of the B.1.1.7 lineage. Three non-B.1.1.7 samples contained a HV69/70 deletion. All were correctly identified by the multiplex assay.ConclusionWe describe here a highly sensitive, fully automated multiplex PCR assay for the simultaneous detection of del-HV69/70 and N501Y that can distinguish between lineages B.1.1.7 and B1.351. The assay allows for high-throughput screening for relevant variants in clinical samples prior to sequencing.

scholarly journals Recent Trends in Rapid Environmental Monitoring of Pathogens and Toxicants: Potential of Nanoparticle-Based Biosensor and Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Preeyaporn Koedrith ◽  
Thalisa Thasiphu ◽  
Jong-Il Weon ◽  
Rattana Boonprasert ◽  
Kooranee Tuitemwong ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Environmental Samples ◽  
Socioeconomic Development ◽  
Detection Methods ◽  
Current State ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Highly Sensitive Detection ◽  
Parasitic Pathogens ◽  
Conventional Detection

Of global concern, environmental pollution adversely affects human health and socioeconomic development. The presence of environmental contaminants, especially bacterial, viral, and parasitic pathogens and their toxins as well as chemical substances, poses serious public health concerns. Nanoparticle-based biosensors are considered as potential tools for rapid, specific, and highly sensitive detection of the analyte of interest (both biotic and abiotic contaminants). In particular, there are several limitations of conventional detection methods for water-borne pathogens due to low concentrations and interference with various enzymatic inhibitors in the environmental samples. The increase of cells to detection levels requires long incubation time. This review describes current state of biosensor nanotechnology, the advantage over conventional detection methods, and the challenges due to testing of environmental samples. The major approach is to use nanoparticles as signal reporter to increase output rather than spending time to increase cell concentrations. Trends in future development of novel detection devices and their advantages over other environmental monitoring methodologies are also discussed.

scholarly journals Duplex On-Site Detection of Vibrio cholerae and Vibrio vulnificus by Recombinase Polymerase Amplification and Three-Segment Lateral Flow Strips

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 151
Author(s):  
Pei Wang ◽  
Lei Liao ◽  
Chao Ma ◽  
Xue Zhang ◽  
Junwei Yu ◽  
...  
Keyword(s):  
Food Safety ◽  
Vibrio Cholerae ◽  
Bacterial Infections ◽  
Vibrio Vulnificus ◽  
Simultaneous Detection ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Detection Methods ◽  
Global Ocean ◽  
Clinical Samples

Vibrio cholerae and Vibrio vulnificus are two most reported foodborne Vibrio pathogens related to seafood. Due to global ocean warming and an increase in seafood consumption worldwide, foodborne illnesses related to infection of these two bacteria are growing, leading to food safety issues and economic consequences. Molecular detection methods targeting species-specific genes are effective tools in the fight against bacterial infections for food safety. In this study, a duplex detection biosensor based on isothermal recombinase polymerase amplification (RPA) and a three-segment lateral flow strip (LFS) has been established. The biosensor used lolB gene of Vibrio cholerae and empV gene of Vibrio vulnificus as the detection markers based on previous reports. A duplex RPA reaction for both targets were constructed, and two chemical labels, FITC and DIG, of the amplification products were carefully tested for effective and accurate visualization on the strip. The biosensor demonstrated good specificity and achieved a sensitivity of 101 copies per reaction or one colony forming unit (CFU)/10 g of spiked food for both bacteria. Validation with clinical samples showed results consistent with that of real-time polymerase chain reaction. The detection process was simple and fast with a 30-min reaction at 37 °C and visualization on the strip within 5 min. With little dependence on laboratory settings, this biosensor was suitable for on-site detection, and the duplex system enabled simultaneous detection of the two important foodborne bacteria. Moreover, the principle can be extended to healthcare and food safety applications for other pathogens.

Specific and sensitive detection of BRAF and KRAS mutations in clinical samples.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10587-10587
Author(s):  
Vanessa Kelchner ◽  
Sergey Chupreta ◽  
Anjali Mishra ◽  
Ron Beaubien ◽  
Laurie Kurihara ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Genomic Dna ◽  
Sanger Sequencing ◽  
Lung Tumor ◽  
Detection Methods ◽  
Clinical Samples ◽  
Published Data ◽  
Wild Type ◽  
Highly Sensitive ◽  
Mutant Braf

10587 Background: The development of highly sensitive and specific genotyping assays that are suitable for clinical research and molecular diagnostics opens new opportunities for the detection, assessment, and research of cancer. Swift Biosciences has developed myT Primer qPCR technology which has unique structural and thermodynamic properties that enables highly sensitive mismatch discrimination. The myT Primer reagents can detect 1% mutant BRAF or KRAS present in a background of 103 wild-type genomic DNA copies with no background signal from wild-type. A separate ultrasensitive BRAF format has been developed which enables the detection of a single mutant BRAF copy in > 104 wild-type genomic DNA copies, representing 0.01% detection. Methods: To evaluate the performance on clinical samples, DNA was prepared from 26 melanoma, 40 colorectal, and 49 lung tumor fresh frozen and FFPE samples, and their corresponding normal adjacent samples. qPCR was performed using standard cycling conditions in single tube format with allele-specific myT primers to assess two BRAF alleles or seven KRAS alleles. Performance of the assay was evaluated on the ABI 7500, CFX96, and Roche LightCycler. A subset of samples were selected for validation by Sanger sequencing. Results: Mutations of BRAF in melanoma, colorectal, and lung tumors were observed to be 46%, 5%, and 2%, in concordance with published data for the frequency of BRAF mutations. Mutations of KRAS in colorectal cancer were observed to be in 17/40, or 42% of samples, consistent with published reports of KRAS in colorectal cancer. 34% of lung cancer samples had a KRAS mutation, also consistent with available statistics. Mutation status was confirmed with Sanger sequencing in the subset of selected samples. Conclusions: The extreme selectivity of the myT BRAF Primers makes them well suited for genotyping of conventional FFPE and frozen tissue samples, whereas the ultrasensitive format is ideal for use with difficult samples such as needle biopsies, CTCs, and serum. The extreme selectivity of these primers results in a definitive Yes/No answer and eliminates the need to use a delta Ct method.

scholarly journals Prevalence of metallo-β-lactamase genes among Pseudomonas aeruginosa isolated from various clinical samples in China

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Wang ◽  
Xiaoya Wang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Susceptibility ◽  
Ethylenediaminetetraacetic Acid ◽  
Carbapenem Resistance ◽  
Opportunistic Pathogen ◽  
Detection Methods ◽  
Clinical Samples ◽  
Routine Practice ◽  
Carbapenem Resistant ◽  
High Prevalence

AbstractBackgroundPseudomonas aeruginosa is an opportunistic pathogen which is associated with nosocomial infections and causes various diseases including urinary tract infection, pneumonia, soft-tissue infection and sepsis. The emergence of P. aeruginosa-acquired metallo-β-lactamase (MBL) is most worrisome and poses a serious threat during treatment and infection control. The objective of this study was to identify antibiotic susceptibility, phenotypic detection of MBL production and to determine the prevalence of MBL genes in carbapenem-resistant P. aeruginosa isolated from different clinical samples.MethodsA total of 329 non-duplicate P. aeruginosa isolated from various clinical samples from two hospitals in China between September 2017 and March 2019 were included in this study. Phenotypic detection of MBL was performed by the combined detection method using imipenem and imipenem-ethylenediaminetetraacetic acid (EDTA) discs. MBL-encoding genes including blaVIM-1, blaVIM-2, blaIMP-1, blaIMP-2, blaSPM-1, blaSIM, blaNDM-1 and blaGIM were detected by polymerase chain reaction (PCR).ResultsOf the 329 P. aeruginosa, majority of the isolates were resistant to imipenem (77.5%) followed by meropenem (64.7%). Of the 270 P. aeruginosa isolates tested, 149 (55.2%) isolates were found to be positive for MBL detection. Of the different samples, 57.8% (n = 26) of P. aeruginosa isolated from blood were found to be positive for MBL production. Of the various MBL genes, blaIMP-1 (28.2%) was the most predominant gene detected followed by blaVIM-2 (18.8%), blaVIM-1 (16.1%), blaNDM-1 (9.4%), blaIMP-2 (6.7%), blaSIM (6.0%), blaSPM-1 (4.0%) and blaGIM (1.3%) genes.ConclusionsThe high resistance of P. aeruginosa toward imipenem and meropenem and the high prevalence of blaIMP-1 and blaVIM-2 set the alarm on the increasing, perhaps the increased, carbapenem resistance. In addition to routine antibiotic susceptibility testings, our results emphasize the importance of both the phenotypic and genotypic MBL detection methods in routine practice for early detection of carbapenem resistance and to prevent further dissemination of this resistant pathogen.

scholarly journals Recent Advancements in Enzyme-Based Lateral Flow Immunoassays

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3358
Author(s):  
Donato Calabria ◽  
Maria Maddalena Calabretta ◽  
Martina Zangheri ◽  
Elisa Marchegiani ◽  
Ilaria Trozzi ◽  
...  
Keyword(s):  
Lateral Flow ◽  
Qualitative Information ◽  
Eye Color ◽  
Commercial Success ◽  
Color Changes ◽  
Naked Eye ◽  
Future Developments ◽  
Highly Sensitive ◽  
Critical Overview ◽  
Detection Technologies

Paper-based lateral-flow immunoassays (LFIAs) have achieved considerable commercial success and their impact in diagnostics is continuously growing. LFIA results are often obtained by visualizing by the naked eye color changes in given areas, providing a qualitative information about the presence/absence of the target analyte in the sample. However, this platform has the potential to provide ultrasensitive quantitative analysis for several applications. Indeed, LFIA is based on well-established immunological techniques, which have known in the last year great advances due to the combination of highly sensitive tracers, innovative signal amplification strategies and last-generation instrumental detectors. All these available progresses can be applied also to the LFIA platform by adapting them to a portable and miniaturized format. This possibility opens countless strategies for definitively turning the LFIA technique into an ultrasensitive quantitative method. Among the different proposals for achieving this goal, the use of enzyme-based immunoassay is very well known and widespread for routine analysis and it can represent a valid approach for improving LFIA performances. Several examples have been recently reported in literature exploiting enzymes properties and features for obtaining significative advances in this field. In this review, we aim to provide a critical overview of the recent progresses in highly sensitive LFIA detection technologies, involving the exploitation of enzyme-based amplification strategies. The features and applications of the technologies, along with future developments and challenges, are also discussed.

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