scholarly journals PCORI Biweekly COVID-19 Scan: AI–Assisted Radiographic Image Assessment, Dual Point-of-Care Nucleic Acid Assays (October 15-28, 2020)

2020 ◽  
Keyword(s):  
Nucleic Acid ◽  
Point Of Care ◽  
Radiographic Image ◽  
Nucleic Acid Assays ◽  
Image Assessment

Gold-Aptamer-Nanoconstructs Engineered to Detect Conserved Enteroviral Nucleic Acid Sequences

2019 ◽  
Author(s):  
Veeren Chauhan ◽  
Mohamed M Elsutohy ◽  
C Patrick McClure ◽  
Will Irving ◽  
Neil Roddis ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
In Silico ◽  
Point Of Care ◽  
Lateral Flow ◽  
Nucleic Acid Sequence ◽  
In Silico Screening ◽  
Lateral Flow Assays ◽  
Life Threatening ◽  
Software And Hardware ◽  
Nucleic Acid Sequences

<p>Enteroviruses are a ubiquitous mammalian pathogen that can produce mild to life-threatening disease. Bearing this in mind, we have developed a rapid, accurate and economical point-of-care biosensor that can detect a nucleic acid sequences conserved amongst 96% of all known enteroviruses. The biosensor harnesses the physicochemical properties of gold nanoparticles and aptamers to provide colourimetric, spectroscopic and lateral flow-based identification of an exclusive enteroviral RNA sequence (23 bases), which was identified through in silico screening. Aptamers were designed to demonstrate specific complementarity towards the target enteroviral RNA to produce aggregated gold-aptamer nanoconstructs. Conserved target enteroviral nucleic acid sequence (≥ 1x10<sup>-7</sup> M, ≥1.4×10<sup>-14</sup> g/mL), initiates gold-aptamer-nanoconstructs disaggregation and a signal transduction mechanism, producing a colourimetric and spectroscopic blueshift (544 nm (purple) > 524 nm (red)). Furthermore, lateral-flow-assays that utilise gold-aptamer-nanoconstructs were unaffected by contaminating human genomic DNA, demonstrated rapid detection of conserved target enteroviral nucleic acid sequence (< 60 s) and could be interpreted with a bespoke software and hardware electronic interface. We anticipate our methodology will translate in-silico screening of nucleic acid databases to a tangible enteroviral desktop detector, which could be readily translated to related organisms. This will pave-the-way forward in the clinical evaluation of disease and complement existing strategies at overcoming antimicrobial resistance.</p>

scholarly journals A glucose meter interface for point-of-care gene circuit-based diagnostics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evan Amalfitano ◽  
Margot Karlikow ◽  
Masoud Norouzi ◽  
Katariina Jaenes ◽  
Seray Cicek ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Synthetic Biology ◽  
Molecular Diagnostics ◽  
Point Of Care ◽  
Low Cost ◽  
Gene Circuit ◽  
Reporter Systems ◽  
Glucose Meter ◽  
Pandemic Response ◽  
Glucose Output

AbstractRecent advances in cell-free synthetic biology have given rise to gene circuit-based sensors with the potential to provide decentralized and low-cost molecular diagnostics. However, it remains a challenge to deliver this sensing capacity into the hands of users in a practical manner. Here, we leverage the glucose meter, one of the most widely available point-of-care sensing devices, to serve as a universal reader for these decentralized diagnostics. We describe a molecular translator that can convert the activation of conventional gene circuit-based sensors into a glucose output that can be read by off-the-shelf glucose meters. We show the development of new glucogenic reporter systems, multiplexed reporter outputs and detection of nucleic acid targets down to the low attomolar range. Using this glucose-meter interface, we demonstrate the detection of a small-molecule analyte; sample-to-result diagnostics for typhoid, paratyphoid A/B; and show the potential for pandemic response with nucleic acid sensors for SARS-CoV-2.

scholarly journals Comparison of four commercial, automated antigen tests to detect SARS-CoV-2 variants of concern

2021 ◽  
Author(s):  
Andreas Osterman ◽  
Maximilian Iglhaut ◽  
Andreas Lehner ◽  
Patricia Späth ◽  
Marcel Stern ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Point Of Care ◽  
Study Cohort ◽  
Operating Characteristics ◽  
Testing Strategies ◽  
Level 3 ◽  
Amino Acid Mutations ◽  
Antigen Tests ◽  
Roche Diagnostics ◽  
Analytical Sensitivities

AbstractA versatile portfolio of diagnostic tests is essential for the containment of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Besides nucleic acid-based test systems and point-of-care (POCT) antigen (Ag) tests, quantitative, laboratory-based nucleocapsid Ag tests for SARS-CoV-2 have recently been launched. Here, we evaluated four commercial Ag tests on automated platforms and one POCT to detect SARS-CoV-2. We evaluated PCR-positive (n = 107) and PCR-negative (n = 303) respiratory swabs from asymptomatic and symptomatic patients at the end of the second pandemic wave in Germany (February–March 2021) as well as clinical isolates EU1 (B.1.117), variant of concern (VOC) Alpha (B.1.1.7) or Beta (B.1.351), which had been expanded in a biosafety level 3 laboratory. The specificities of automated SARS-CoV-2 Ag tests ranged between 97.0 and 99.7% (Lumipulse G SARS-CoV-2 Ag (Fujirebio): 97.03%, Elecsys SARS-CoV-2 Ag (Roche Diagnostics): 97.69%; LIAISON® SARS-CoV-2 Ag (Diasorin) and SARS-CoV-2 Ag ELISA (Euroimmun): 99.67%). In this study cohort of hospitalized patients, the clinical sensitivities of tests were low, ranging from 17.76 to 52.34%, and analytical sensitivities ranged from 420,000 to 25,000,000 Geq/ml. In comparison, the detection limit of the Roche Rapid Ag Test (RAT) was 9,300,000 Geq/ml, detecting 23.58% of respiratory samples. Receiver-operating-characteristics (ROCs) and Youden’s index analyses were performed to further characterize the assays’ overall performance and determine optimal assay cutoffs for sensitivity and specificity. VOCs carrying up to four amino acid mutations in nucleocapsid were detected by all five assays with characteristics comparable to non-VOCs. In summary, automated, quantitative SARS-CoV-2 Ag tests show variable performance and are not necessarily superior to a standard POCT. The efficacy of any alternative testing strategies to complement nucleic acid-based assays must be carefully evaluated by independent laboratories prior to widespread implementation.

scholarly journals Diagnosis of SARS-Cov-2 Infection by RT-PCR Using Specimens Other Than Naso- and Oropharyngeal Swabs: A Systematic Review and Meta-Analysis

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 363
Author(s):  
Vânia M. Moreira ◽  
Paulo Mascarenhas ◽  
Vanessa Machado ◽  
João Botelho ◽  
José João Mendes ◽  
...  
Keyword(s):  
Systematic Review ◽  
Clinical Performance ◽  
Point Of Care ◽  
Meta Analysis ◽  
High Sensitivity ◽  
Nasopharyngeal Swab ◽  
Sample Collection ◽  
Rt Pcr ◽  
Oropharyngeal Swab ◽  
Nucleic Acid Assays

The rapid and accurate testing of SARS-CoV-2 infection is still crucial to mitigate, and eventually halt, the spread of this disease. Currently, nasopharyngeal swab (NPS) and oropharyngeal swab (OPS) are the recommended standard sampling techniques, yet, these have some limitations such as the complexity of collection. Hence, several other types of specimens that are easier to obtain are being tested as alternatives to nasal/throat swabs in nucleic acid assays for SARS-CoV-2 detection. This study aims to critically appraise and compare the clinical performance of RT-PCR tests using oral saliva, deep-throat saliva/posterior oropharyngeal saliva (DTS/POS), sputum, urine, feces, and tears/conjunctival swab (CS) against standard specimens (NPS, OPS, or a combination of both). In this systematic review and meta-analysis, five databases (PubMed, Scopus, Web of Science, ClinicalTrial.gov and NIPH Clinical Trial) were searched up to the 30th of December, 2020. Case-control and cohort studies on the detection of SARS-CoV-2 were included. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2). We identified 1560 entries, 33 of which (1.1%) met all required criteria and were included for the quantitative data analysis. Saliva presented the higher accuracy, 92.1% (95% CI: 70.0–98.3), with an estimated sensitivity of 83.9% (95% CI: 77.4–88.8) and specificity of 96.4% (95% CI: 89.5–98.8). DTS/POS samples had an overall accuracy of 79.7% (95% CI: 43.3–95.3), with an estimated sensitivity of 90.1% (95% CI: 83.3–96.9) and specificity of 63.1% (95% CI: 36.8–89.3). The remaining index specimens could not be adequately assessed given the lack of studies available. Our meta-analysis shows that saliva samples from the oral region provide a high sensitivity and specificity; therefore, these appear to be the best candidates for alternative specimens to NPS/OPS in SARS-CoV-2 detection, with suitable protocols for swab-free sample collection to be determined and validated in the future. The distinction between oral and extra-oral salivary samples will be crucial, since DTS/POS samples may induce a higher rate of false positives. Urine, feces, tears/CS and sputum seem unreliable for diagnosis. Saliva testing may increase testing capacity, ultimately promoting the implementation of truly deployable COVID-19 tests, which could either work at the point-of-care (e.g. hospitals, clinics) or at outbreak control spots (e.g., schools, airports, and nursing homes).

scholarly journals Nitrocellulose-bound achromopeptidase for point-of-care nucleic acid tests

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Georgios Chondrogiannis ◽  
Shirin Khaliliazar ◽  
Anna Toldrà ◽  
Pedro Réu ◽  
Mahiar M. Hamedi
Keyword(s):  
Nucleic Acid ◽  
Sample Preparation ◽  
Point Of Care ◽  
Dna Amplification ◽  
Recombinase Polymerase Amplification ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Enzymatic Function ◽  
Modern Biotechnology ◽  
Nucleic Acid Tests

AbstractEnzymes are the cornerstone of modern biotechnology. Achromopeptidase (ACP) is a well-known enzyme that hydrolyzes a number of proteins, notably proteins on the surface of Gram-positive bacteria. It is therefore used for sample preparation in nucleic acid tests. However, ACP inhibits DNA amplification which makes its integration difficult. Heat is commonly used to inactivate ACP, but it can be challenging to integrate heating into point-of-care devices. Here, we use recombinase polymerase amplification (RPA) together with ACP, and show that when ACP is immobilized on nitrocellulose paper, it retains its enzymatic function and can easily and rapidly be activated using agitation. The nitrocellulose-bound ACP does, however, not leak into the solution, preventing the need for deactivation through heat or by other means. Nitrocellulose-bound ACP thus opens new possibilities for paper-based Point-of-Care (POC) devices.

Silver nanocluster-lightened hybridization chain reaction

RSC Advances ◽  
2016 ◽  
Vol 6 (62) ◽  
pp. 57502-57506 ◽  
Author(s):  
Lin Liu ◽  
Qing Li ◽  
Li-Juan Tang ◽  
Ru-Qin Yu ◽  
Jian-Hui Jiang
Keyword(s):  
Nucleic Acid ◽  
Silver Nanoclusters ◽  
Hybridization Chain Reaction ◽  
Label Free ◽  
Chain Reaction ◽  
Silver Nanocluster ◽  
Turn On ◽  
Nucleic Acid Assays

A hybridization chain reaction (HCR) lightened by DNA-stabilized silver nanoclusters (AgNCs) as a label-free and turn on fluorescence platform for nucleic acid assays.

Terminal Phosphate-Labeled Nucleotides with Improved Substrate Properties for Homogeneous Nucleic Acid Assays

2005 ◽  
Vol 127 (8) ◽  
pp. 2394-2395 ◽  
Author(s):  
Anup Sood ◽  
Shiv Kumar ◽  
Satyam Nampalli ◽  
John R. Nelson ◽  
John Macklin ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Substrate Properties ◽  
Nucleic Acid Assays

Achieving room temperature DNA amplification by dialling in destabilization

2015 ◽  
Vol 51 (44) ◽  
pp. 9101-9104 ◽  
Author(s):  
B. Safeenaz Alladin-Mustan ◽  
Catherine J. Mitran ◽  
Julianne M. Gibbs-Davis
Keyword(s):  
Nucleic Acid ◽  
Room Temperature ◽  
Point Of Care ◽  
Dna Amplification ◽  
Heating Element ◽  
Nucleic Acid Sequences

The ability to amplify nucleic acid sequences at room temperature without the need for any heating element has been achieved, which has promise in bio-diagnostics employed at the point of care.

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