scholarly journals Immobilized cellulose nanospheres in lateral flow immunoassay enable rapid nucleocapsid antigen-based diagnosis of SARS-CoV-2 from salivary samples

2021 ◽  
Author(s):  
Katariina Solin ◽  
Marco Beaumont ◽  
Maryam Borghei ◽  
Hannes Orelma ◽  
Pascal Mertens ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Low Cost ◽  
Surface Protein ◽  
Confocal Imaging ◽  
Diagnostic Systems ◽  
Viral Pathogens ◽  
Optical Signals ◽  
Antigen Tests ◽  
Antigen Testing ◽  
Oppositely Charged

Rapid and efficient diagnostic systems are essential in controlling the spread of viral pathogens and efficient patient management. The available technologies for low-cost viral antigen testing have several limitations, including lack of accuracy and sensitivity. Here, we develop sensitive antigen tests based on recently introduced, oppositely charged cellulose II nanoparticles (NPan and NPcat) that are effective in controlling surface protein interactions. Passivation against non-specific adsorption and augmented immobilization of sensing antibodies are achieved by adjusting the electrostatic charge of the nanoparticles. The interactions affecting the performance of the system are investigated by microgravimetry and confocal imaging. We further demonstrate SARS-CoV-2 nucleocapsid rapid sensing by saliva-wicking channels stencil-printed on flexible paper supports. Therein, NPcat inkjet printed on the channels elicit distinctive optical signals, visible after only a few minutes, allowing faster diagnosis compared to current microfluidic devices designed for saliva sampling.

scholarly journals Strategies for antigen testing: An alternative approach to widespread PCR testing

2021 ◽  
Author(s):  
Sanjay G. Reddy ◽  
Saumya Das
Keyword(s):  
Low Cost ◽  
Sequential Testing ◽  
Rapid Testing ◽  
Alternative Method ◽  
Alternative Approach ◽  
Wide Availability ◽  
Antigen Tests ◽  
Antigen Testing

ABSTRACTMultiple applications of low cost and rapid antigen tests for individuals, in parallel (at the same time) or at times sufficiently close to each other, when appropriately interpreted can considerably increase sensitivity of these tests, improving on their performance greatly. Under reasonable assumptions, this occurs when considering a positive to arise in a composite test if at least one of two underlying repeated tests are positive. Parallel Rapid Testing can potentially provide a form of testing that is accessible (combining wide availability and lack of expense) and quick. Moreover, it can provide a level of sensitivity that is comparable to seemingly more sophisticated but more expensive alternatives. In combination with sequential testing, this strategy offers an alternative method of testing that can be applied immediately and on a widespread basis.

scholarly journals Liquid Crystal Based Binding Assay for Detecting HIV-1 Surface Glycoprotein

2021 ◽  
Vol 9 ◽  
Author(s):  
Amna Didar Abbasi ◽  
Zakir Hussain ◽  
Usman Liaqat ◽  
Dooa Arif ◽  
Kun-Lin Yang
Keyword(s):  
Liquid Crystal ◽  
Early Stage ◽  
Low Cost ◽  
Surface Protein ◽  
High Specificity ◽  
Surface Glycoprotein ◽  
Optical Signals ◽  
Gp 120 ◽  
Binding Event ◽  
Hiv 1

Surface protein gp-120 of HIV-1 virus plays an important role in the infection of HIV-1, but detection of gp-120 during the early stage of infection is very difficult. Herein, we report a binding bioassay based on an RNA aptamer B40t77, which binds specifically to gp-120. The bioassay is built upon a hydrophobic glass slide with surface immobilized gp-120. When the glass surface is incubated in a solution containing B40t77, the aptamer is able to bind to gp-120 specifically and remove it from the surface after a short incubation time of 30 min. The result of the binding event can be amplified by using liquid crystal (LC) into optical signals in the final step. By using this bioassay, we are able to detect as low as 1 μg/ml of gp-120 with high specificity within 30 min. No response is obtained when gp-120 is replaced by other protein such as bovine serum albumin (BSA). This is the first qualitative bioassay which provides a simple way for the detection of gp-120 with the naked eye. The assay is robust, low-cost and does not require additional labeling. Thus, the bioassay is potentially useful for the early detection of HIV-1 in resources-limited regions.

scholarly journals Importance of Inoculum Size and Sampling Effect in Rapid Antigen Detection for Diagnosis of Streptococcus pyogenes Pharyngitis

2000 ◽  
Vol 38 (1) ◽  
pp. 279-281 ◽  
Author(s):  
Bradley Kurtz ◽  
Michael Kurtz ◽  
Martha Roe ◽  
James Todd
Keyword(s):  
Sample Size ◽  
Streptococcus Pyogenes ◽  
Disease Status ◽  
Inoculum Size ◽  
Antigen Detection ◽  
Detection Rates ◽  
Sample Distribution ◽  
Antigen Tests ◽  
The One ◽  
Antigen Testing

ABSTRACT Current recommendations suggest that negative rapid Streptococcus pyogenes antigen tests be backed up with a culture, reflecting evidence that culture may have a higher sensitivity and also that testing of a second swab may yield a different (i.e., a positive) result because of variation in sample size or distribution. If the latter is common, the sensitivities of current antigen detection tests might be improved by simply increasing the amount of sample tested. The present study assessed the effect of antigen testing of two swabs extracted together compared to independent testing of each swab extracted separately for children with clinical pharyngitis. S. pyogenes grew from one or both swabs for 198 (37%) of 537 children. The combined culture was significantly ( P < 0.05) more sensitive than culture of either swab alone. Compared to combined culture, antigen testing of two swabs extracted and tested together was significantly more sensitive than two single swab extractions (94.1 versus 80%; P = 0.03); however, the specificity was decreased (81.5 versus 89.8 to 92.7%; P < 0.05). This study suggests that sample size and/or uneven sample distribution may have influenced the apparent sensitivities of prior studies that compared antigen tests to a single plate culture. A strategy, such as the one used in the present study, that increases the sample size available for antigen testing (i.e., extraction of samples from both swabs) may improve detection rates to a level that will better approximate true disease status and obviate the need for backup cultures if specificity can be improved.

scholarly journals Assessment of SARS-CoV-2 rapid antigen tests

2021 ◽  
Vol 45 (3) ◽  
pp. 143-148
Author(s):  
Mustafa Özcürümez ◽  
Antonios Katsounas ◽  
Stefan Holdenrieder ◽  
Alexander von Meyer ◽  
Harald Renz ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Sources Of Information ◽  
Package Inserts ◽  
Evaluation Of Performance ◽  
Specificity And Sensitivity ◽  
Performance Specifications ◽  
Antigen Tests ◽  
Minimum Criteria ◽  
Almost All

Abstract Objectives Point-of-care antigen tests (PoC-AgTs) for the rapid detection of SARS-CoV-2 infection enable screening of additional populations with less effort, independent of laboratories and at a low cost. PoC-AgTs have therefore been included in national testing strategies with additional quality requirements to address limitations in specificity and sensitivity. Information given in the package inserts of the test providers should enable the user to evaluate the performance of a PoC-AgT in advance. The quality of this information has been independently assessed since the Corona Test Ordinance came into force in Germany in October 2020. Methods The completeness of analytical and diagnostic performance specifications was assessed for all package inserts publicly available via the Paul Ehrlich Institute (PEI). It was ascertained whether the minimum criteria, recommendations, and extended criteria of the PEI were comprehensibly fulfilled. The number of tests removed from the list by March 2021 was determined. Results By the closing date of the survey (17.11.2020), the PEI had listed 165 PoC-AgTs that formally fulfilled the minimum criteria and were thus reimbursed. A total of 78 identical systems were identified. Almost all providers were found to have gaps in the information on the validation results of their tests, meaning that an evaluation of performance is only possible to a limited extent. Until March 2021, 25 non-identical PoC-AgTs have been removed from the list. Conclusions Many PoC-AgTs could not be comprehensively evaluated based on the information provided by the provider. Users are therefore dependent on provider-independent sources of information.

COVID-19 CORONAVIRUS SCREENING ANALYSIS NEURAL NETWORK TECHNOLOGY

2021 ◽  
Vol 2 (64) ◽  
pp. 53-57
Author(s):  
S. Aloshyn ◽  
I. Khomenko ◽  
N. Fursova
Keyword(s):  
Neural Networks ◽  
Pattern Recognition ◽  
Artificial Neural Networks ◽  
Low Cost ◽  
Signs And Symptoms ◽  
Multidimensional Space ◽  
Diagnostic Systems ◽  
Coronavirus Infection ◽  
Artificial Neural ◽  
High Degree

Low-cost, reliable and quick screening diagnosis of coronavirus can be implemented on the basis of intelligent technologies for analyzing a set of signs and symptoms with solving the problem of pattern recognition in the basis of artificial neural networks. The high degree of coronavirus infection diagnostic procedure uncertainty, the vector dimension of input factor-symptoms, fuzzy conditioning and poor formalizability of the subject condition connection with these symptoms require appropriate analytical tools. An analysis of the problem and possible solutions allows justifying the feasibilit y of implementing screening diagnostics as a solution to the problem of nonlinear optimization in a multidimensional space of high-dimensional factors and states. Artificial neural networks with compulsory training on a representative sample were chosen as a tool for implementing the project. The proposed technology brings diagnostics of coronavirus infection closer to full automation, robotization and intellectualization of complex monitoring (diagnostic) systems as the most promising technology for pattern recognition in systems with a high degree of entropy and allows you to solve the problem at the lowest cost and required performance indicators.

Multi-Modal Diagnostics for Vehicle Fault Detection

2001 ◽  
Author(s):  
Matthew L. Schwall ◽  
J. Christian Gerdes
Keyword(s):  
Bayesian Network ◽  
Low Cost ◽  
Diagnostic System ◽  
Cost Models ◽  
Diagnostic Systems ◽  
Computationally Efficient ◽  
Analytical Redundancy ◽  
Hardware Costs ◽  
And Function ◽  
Viable Model

Abstract On-board vehicle diagnostic systems must have low development and hardware costs in order to be viable. Model-based methods have shown promise since they use analytical redundancy to reduce costly physical redundancy. However, these methods must also be computationally efficient and function accurately even with simple, low-cost models. The approach presented in this paper uses multiple simple models to analyze dissimilar observable modes of a system. Residuals generated using the models are related and interpreted in a Bayesian network to determine fault probabilities and yield a diagnosis. The technique is demonstrated with a diagnostic system for automobile handling.

scholarly journals Low-cost and efficient confocal imaging method for arabidopsis flower

2020 ◽  
Vol 466 (1-2) ◽  
pp. 73-76
Author(s):  
Jiarong Wei ◽  
Yuqing Qi ◽  
Mengna Li ◽  
Ruoxuan Li ◽  
Meng Yan ◽  
...  
Keyword(s):  
Low Cost ◽  
Confocal Imaging ◽  
Imaging Method

Confocal Fluorescence Microscopy with CCD Sensors Speed by Parallelization, Low Cost by Using More Electronics

2000 ◽  
Vol 6 (S2) ◽  
pp. 814-815
Author(s):  
Rudolf E. Großkopf
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Confocal Imaging ◽  
The Novel ◽  
Optical Scanning ◽  
Semiconductor Chip ◽  
Confocal Fluorescence ◽  
Mechanical Scanning ◽  
Low Costs ◽  
Novel Concept

CCD sensors are able to image a few megapixels within one frame. The image is scanned electronically within the semiconductor chip (instead of mechanical-optical scanning with moving mirrors, Nipkow discs or acousto-optical devices). Through parallelization. the novel concept yields speed at an unprecedented degree for confocal imaging Routine applications requiring high speed and low costs will profit from this principle. Thus, confocal imaging technology will take the same path television technology has taken—from mechanical scanning to the broadest possible application of electronicsIn order to go this way, a pinhole matrix is used on the illumination side. It has as many pinholes and the same pitch as the pitch and number of pixels of the CCD (Figure 1). In front of the receiver, a second pinhole matrix with the same pitch and number of pinholes is used All pinholes of both matrices and the pixels of the CCD are in confocal position.

scholarly journals The Minor Matrix Protein VP24 from Ebola Virus Lacks Direct Lipid-Binding Properties

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 869
Author(s):  
Yuan Su ◽  
Robert V. Stahelin
Keyword(s):  
Protein Interactions ◽  
Matrix Protein ◽  
Ebola Virus ◽  
Cellular Membrane ◽  
Lipid Binding ◽  
Confocal Imaging ◽  
Host Cells ◽  
Binding Ability ◽  
Matrix Layer

Viral protein 24 (VP24) from Ebola virus (EBOV) was first recognized as a minor matrix protein that associates with cellular membranes. However, more recent studies shed light on its roles in inhibiting viral genome transcription and replication, facilitating nucleocapsid assembly and transport, and interfering with immune responses in host cells through downregulation of interferon (IFN)-activated genes. Thus, whether VP24 is a peripheral protein with lipid-binding ability for matrix layer recruitment has not been explored. Here, we examined the lipid-binding ability of VP24 with a number of lipid-binding assays. The results indicated that VP24 lacked the ability to associate with lipids tested regardless of VP24 posttranslational modifications. We further demonstrate that the presence of the EBOV major matrix protein VP40 did not promote VP24 membrane association in vitro or in cells. Further, no protein–protein interactions between VP24 and VP40 were detected by co-immunoprecipitation. Confocal imaging and cellular membrane fractionation analyses in human cells suggested VP24 did not specifically localize at the plasma membrane inner leaflet. Overall, we provide evidence that EBOV VP24 is not a lipid-binding protein and its presence in the viral matrix layer is likely not dependent on direct lipid interactions.

scholarly journals Optical Fiber Force Myography Sensor for Identification of Hand Postures

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Eric Fujiwara ◽  
Carlos Kenichi Suzuki
Keyword(s):  
Optical Fiber ◽  
Wrist Joint ◽  
Low Cost ◽  
Neural Network Classifier ◽  
Optical Signals ◽  
Computer Interfaces ◽  
Human Computer Interfaces ◽  
Average Accuracy ◽  
Artificial Neural Network Classifier ◽  
Force Myography

A low-cost optical fiber force myography sensor for noninvasive hand posture identification is proposed. The transducers are comprised of 10 mm periodicity silica multimode fiber microbending devices mounted in PVC plates, providing 0.05 N−1 sensitivity over ~20 N range. Next, the transducers were attached to the user forearm by means of straps in order to monitor the posterior proximal radial, the anterior medial ulnar, and the posterior distal radial muscles, and the acquired FMG optical signals were correlated to the performed gestures using a 5 hidden layers, 20-neuron artificial neural network classifier with backpropagation architecture, followed by a competitive layer. The overall results for 9 postures and 6 subjects indicated a 98.4% sensitivity and 99.7% average accuracy, being comparable to the electromyographic approaches. Moreover, in contrast to the current setups, the proposed methodology allows the identification of poses characterized by different configurations of fingers and wrist joint displacements with the utilization of only 3 transducers and a simple interrogation scheme, being suitable to further applications in human-computer interfaces.

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