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1.
Anal Chem ; 94(2): 1256-1263, 2022 01 18.
Article in English | MEDLINE | ID: covidwho-1604219

ABSTRACT

Continued advances in label-free electrical biosensors pave the way to simple, rapid, cost-effective, high-sensitivity, and quantitative biomarker testing at the point-of-care setting that would profoundly transform healthcare. However, implementation in routine diagnostics is faced with significant challenges associated with the inherent requirement for biofluid sample processing before and during testing. We present here a simple yet robust autonomous finger-prick blood sample processing platform integrated with nanoscale field-effect transistor biosensors and demonstrate the feasibility of measuring the SARS-CoV-2 nucleocapsid protein. The 3D-printed platform incorporates a high-yield blood-to-plasma separation module and a delay valve designed to terminate the assay at a specific time. The platform is driven by hydrostatic pressure to efficiently and automatically dispense plasma and washing/measurement buffer to the nanosensors. Our model study demonstrates the feasibility of detecting down to 1.4 pg/mL of the SARS-CoV-2 nucleocapsid protein within 25 min and with only minimal operator intervention.


Subject(s)
COVID-19 , Point-of-Care Systems , Biomarkers , Humans , Point-of-Care Testing , SARS-CoV-2
2.
Recenti Prog Med ; 112(12): 821-823, 2021 12.
Article in Italian | MEDLINE | ID: covidwho-1599874

ABSTRACT

Portable blood gas analyzers are intended for blood Point-of-care testing (POCT); they make it possible to perform the examination directly at the patient's bed. During the SARS-CoV-2 pandemic, this device proved useful in emergency medical service for the early assessment of respiratory distress, allowing the appropriate care level to be determined for each patient. 25 cases of covid-19 positive patients in the province of Arezzo were analyzed; POCT blood gas analysis made it possible to evaluate and treat at home about half of the patients (52%) and to admit the others directly to the most appropriate ward. However, some critical issues were found; the limited sample size suggest further research to assess the actual impact of this technology.


Subject(s)
COVID-19 , Emergency Medical Services , Blood Gas Analysis , Humans , Point-of-Care Systems , SARS-CoV-2
4.
Biosens Bioelectron ; 200: 113900, 2022 Mar 15.
Article in English | MEDLINE | ID: covidwho-1588212

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the major shortcoming of healthcare systems globally in their inability to diagnose the disease rapidly and accurately. At present, the molecular approaches for diagnosing COVID-19 primarily use reverse transcriptase polymerase chain reaction (RT-PCR) to create and amplify cDNA from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. Although molecular tests are reported to be specific, false negatives are quite common. Furthermore, literally all these tests require a step involving RNA isolation which does not make them point-of-care (POC) in the true sense. Here, we report a lateral flow strip-based RNA extraction and amplification-free nucleic acid test (NAT) for rapid diagnosis of positive COVID-19 cases at POC. The assay uses highly specific 6-carboxyfluorescein (6-FAM) and biotin labeled antisense oligonucleotides (ASOs) as probes those are designed to target N-gene sequence of SARS-CoV-2. Additionally, we utilized cysteamine capped gold-nanoparticles (Cyst-AuNPs) to augment the signal further for enhanced sensitivity. Without any large-stationary equipment and highly trained staffers, the entire sample-to-answer approach in our case would take less than 30 min from a patient swab sample collection to final diagnostic result. Moreover, when evaluated with 60 clinical samples and verified with an FDA-approved TaqPath RT-PCR kit for COVID-19 diagnosis, the assay obtained almost 99.99% accuracy and specificity. We anticipate that the newly established low-cost amplification-free detection of SARS-CoV-2 RNA will aid in the development of a platform technology for rapid and POC diagnosis of COVID-19 and other pathogens.


Subject(s)
Biosensing Techniques , COVID-19 , Metal Nanoparticles , COVID-19 Testing , Gold , Humans , Nucleic Acid Amplification Techniques , Point-of-Care Systems , RNA, Viral/genetics , SARS-CoV-2 , Sensitivity and Specificity
5.
Med Intensiva (Engl Ed) ; 46(1): 42-45, 2022 01.
Article in English | MEDLINE | ID: covidwho-1587006
6.
Sci Rep ; 11(1): 24234, 2021 12 20.
Article in English | MEDLINE | ID: covidwho-1585791

ABSTRACT

The main strategy for response and control of COVID-19 demands the use of rapid, accurate diagnostic tests aimed at the first point of health care. During the emergency, an increase in asymptomatic and symptomatic cases results in a great demand for molecular tests, which is promoting the development and application of rapid diagnostic technologies. In this study, we describe the development and evaluation of RT-LAMP to detect SARS-CoV-2 based on three genes (ORF1ab, M and N genes) in monoplex and triplex format. RT-LAMP assays were compared with the gold standard method RT-qPCR. The triplex format (RdRp, M and N genes) allowed obtaining comparable results with de RT-qPCR (RdRp and E genes), presented a sensitivity of 98.9% and a specificity of 97.9%, opening the opportunity to apply this method to detect SARS-CoV-2 at primary health-care centers.


Subject(s)
Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , RNA, Viral/metabolism , SARS-CoV-2/isolation & purification , COVID-19/diagnosis , COVID-19/virology , COVID-19 Nucleic Acid Testing/methods , Coronavirus RNA-Dependent RNA Polymerase/genetics , Humans , Limit of Detection , Nasopharynx/virology , Nucleocapsid Proteins/genetics , Point-of-Care Systems , RNA, Viral/genetics , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Viral Matrix Proteins/genetics
7.
Adv Emerg Nurs J ; 43(4): 279-292, 2021.
Article in English | MEDLINE | ID: covidwho-1574416

ABSTRACT

Since the introduction of ultrasonography, clinicians have discovered different uses for embedding this technology in the clinical setting. The use of point-of-care ultrasonography has gained a lot of interest in the emergency department. It is a procedure that a clinician can rapidly utilize to triage, risk stratify, evaluate, and monitor the patient's condition. The COVID-19 pandemic has highlighted the significance and application of ultrasonography in identifying and managing patients presenting with lung pathology in the emergency setting.


Subject(s)
COVID-19 , Nurse Practitioners , Emergency Service, Hospital , Humans , Lung/diagnostic imaging , Pandemics , Point-of-Care Systems , SARS-CoV-2 , Ultrasonography
8.
Chem Soc Rev ; 51(1): 329-375, 2022 Jan 04.
Article in English | MEDLINE | ID: covidwho-1569286

ABSTRACT

This review article deals with the concepts, principles and applications of visible-light and near-infrared (NIR) fluorescence and surface-enhanced Raman scattering (SERS) in in vitro point-of-care testing (POCT) and in vivo bio-imaging. It has discussed how to utilize the biological transparency windows to improve the penetration depth and signal-to-noise ratio, and how to use surface plasmon resonance (SPR) to amplify fluorescence and SERS signals. This article has highlighted some plasmonic fluorescence and SERS probes. It has also reviewed the design strategies of fluorescent and SERS sensors in the detection of metal ions, small molecules, proteins and nucleic acids. Particularly, it has provided perspectives on the integration of fluorescent and SERS sensors into microfluidic chips as lab-on-chips to realize point-of-care testing. It has also discussed the design of active microfluidic devices and non-paper- or paper-based lateral flow assays for in vitro diagnostics. In addition, this article has discussed the strategies to design in vivo NIR fluorescence and SERS bio-imaging platforms for monitoring physiological processes and disease progression in live cells and tissues. Moreover, it has highlighted the applications of POCT and bio-imaging in testing toxins, heavy metals, illicit drugs, cancers, traumatic brain injuries, and infectious diseases such as COVID-19, influenza, HIV and sepsis.


Subject(s)
COVID-19 , Nucleic Acids , Humans , Point-of-Care Systems , SARS-CoV-2 , Spectrum Analysis, Raman
9.
Clin Transl Med ; 11(12): e668, 2021 12.
Article in English | MEDLINE | ID: covidwho-1568016

ABSTRACT

The level of postvaccine protection depends on two factors: antibodies and T-cell responses. While the first one is relatively easily measured, the measuring of the second one is a difficult problem. The recent studies indicate that the first one may be a good proxy for the protection, at least for SARS-CoV-2. The massive data currently gathered by both researcher and citizen scientists may be pivotal in confirming this observation, and the collective body of evidence is growing daily. This leads to an acceptance of IgG antibody levels as an accessible biomarker of individual's protection. With enormous and immediate need for assessing patient condition at the point of care, quantitative antibody analysis remains the most effective and efficient way to assess the protection against the disease. Let us not discount importance of reference points in the turmoil of current pandemics.


Subject(s)
Antibodies, Viral/chemistry , Antibodies/chemistry , Biomarkers/metabolism , COVID-19/blood , COVID-19/immunology , Antibody Specificity , Humans , Immune System , Immunity , Immunoglobulin G/metabolism , Intensive Care Units , Pandemics , Point-of-Care Systems , SARS-CoV-2 , Serologic Tests/methods , Serologic Tests/standards , Vaccines
10.
Biosens Bioelectron ; 199: 113866, 2022 Mar 01.
Article in English | MEDLINE | ID: covidwho-1560591

ABSTRACT

The outbreak of COVID-19 pandemics highlighted the need of sensitive, selective, and easy-to-handle biosensing devices. In the contemporary scenario, point-of-care devices for mass testing and infection mapping within a population have proven themselves as of primordial importance. Here, we introduce a graphene-based Electrical-Electrochemical Vertical Device (EEVD) point-of-care biosensor, strategically engineered for serologic COVID-19 diagnosis. EEVD uses serologic IgG quantifications on SARS-CoV-2 Receptor Binding Domain (RBD) bioconjugate immobilized onto device surface. EEVD combines graphene basal plane with high charge carrier mobility, high conductivity, low intrinsic resistance, and interfacial sensitivity to capacitance alterations. EEVD application was carried out in real human serum samples. Since EEVD is a miniaturized device, it requires just 40 µL of sample for a point-of-care COVID-19 infections detection. When compared to serologic assays such ELISA and other immunochromatographic methods, EEVD presents some advantages such as time of analyses (15 min), sample preparation, and a LOD of 1.0 pg mL-1. We glimpse that EEVD meets the principles of robustness and accuracy, desirable analytic parameters for assays destined to pandemics control strategies.


Subject(s)
Biosensing Techniques , COVID-19 , Graphite , Antibodies, Viral , COVID-19 Testing , Humans , Point-of-Care Systems , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests
12.
J Mater Chem B ; 9(42): 8851-8861, 2021 11 03.
Article in English | MEDLINE | ID: covidwho-1526111

ABSTRACT

Nanomaterial-based optical techniques for biomarker detection have garnered tremendous attention from the nanofabrication community due to their high precision and enhanced limit of detection (LoD) features. These nanomaterials are highly responsive to local refractive index (RI) fluctuations, and their RI unit sensitivity can be tuned by varying the chemical composition, geometry, and dimensions of the utilized nanostructures. To improve the sensitivity and LoD values of these nanomaterials, it is common to increase both dimensions and aspect ratios of the fabricated nanostructures. However, limited by the complexity, prolonged duration, and elevated costs of the available nanofabrication techniques, mass production of these nanostructures remains challenging. To address not only high accuracy, but also speed and production effectiveness in these nanostructures' fabrication, our work reports, for the first time, a fast, high-throughput, and cost-effective nanofabrication protocol for routine manufacturing of polymer-based nanostructures with high sensitivity and calculated LoD in the pM range by utilizing anodized aluminum oxide (AAO) membranes as templates. Specifically, our developed platform consists of arrays of nearly uniform polystyrene nanopillars with an average diameter of ∼185 nm and aspect ratio of ∼11. We demonstrate that these nanostructures can be produced at a high speed and a notably low price, and that they can be efficiently applied for biosensing purposes after being coated with aluminum-doped silver (Ag/Al) thin films. Our platform successfully detected very low concentrations of human C-reactive protein (hCRP) and SARS-CoV-2 spike protein biomarkers in human plasma samples with LoDs of 11 and 5 pM, respectively. These results open new opportunities for day-to-day fabrication of high aspect ratio arrays of nanopillars that can be used as a base for nanoplasmonic sensors with competitive LoD values. This, in turn, contributes to the development of point-of-care devices and further improvement of the existing nanofabrication techniques, thereby enriching the fields of pharmacology, clinical analysis, and diagnostics.


Subject(s)
Aluminum Oxide/chemistry , Biomarkers/blood , High-Throughput Screening Assays/methods , Nanostructures/chemistry , Silver/chemistry , Biosensing Techniques , C-Reactive Protein/analysis , COVID-19/diagnosis , COVID-19/virology , Dimethylpolysiloxanes/chemistry , Humans , Limit of Detection , Point-of-Care Systems , Polystyrenes/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/blood
13.
J Clin Microbiol ; 59(12): e0118621, 2021 11 18.
Article in English | MEDLINE | ID: covidwho-1522902

ABSTRACT

Serologic point-of-care tests to detect antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are an important tool in the COVID-19 pandemic. The majority of current point-of-care antibody tests developed for SARS-CoV-2 rely on lateral flow assays, but these do not offer quantitative information. To address this, we developed a novel antibody test leveraging hemagglutination, employing a dry card format currently used for typing ABO blood groups. Two hundred COVID-19 patient and 200 control plasma samples were reconstituted with O-negative red blood cells (RBCs) to form whole blood and added to dried viral-antibody fusion protein, followed by a stirring step and a tilting step, 3-min incubation, and a second tilting step. The sensitivities of the hemagglutination test, Euroimmun IgG enzyme-linked immunosorbent assay (ELISA), and receptor binding domain (RBD)-based CoronaChek lateral flow assay were 87.0%, 86.5%, and 84.5%, respectively, using samples obtained from recovered COVID-19 individuals. Testing prepandemic samples, the hemagglutination test had a specificity of 95.5%, compared to 97.3% and 98.9% for the ELISA and CoronaChek, respectively. A distribution of agglutination strengths was observed in COVID-19 convalescent-phase plasma samples, with the highest agglutination score (4) exhibiting significantly higher neutralizing antibody titers than weak positives (2) (P < 0.0001). Strong agglutinations were observed within 1 min of testing, and this shorter assay time also increased specificity to 98.5%. In conclusion, we developed a novel rapid, point-of-care RBC agglutination test for the detection of SARS-CoV-2 antibodies that can yield semiquantitative information on neutralizing antibody titer in patients. The 5-min test may find use in determination of serostatus prior to vaccination, postvaccination surveillance, and travel screening.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Enzyme-Linked Immunosorbent Assay , Hemagglutination , Hemagglutination Tests , Humans , Pandemics , Point-of-Care Systems , Sensitivity and Specificity
14.
Clin Med (Lond) ; 21(3): e263-e268, 2021 05.
Article in English | MEDLINE | ID: covidwho-1518788

ABSTRACT

BACKGROUND: A qualitative fit test using bitter-tasting aerosols is the commonest way to determine filtering face-piece (FFP) mask leakage. This taste test is subjective and biased by placebo. We propose a cheap, quantitative modification of the taste test by measuring the amount of fluorescein stained filter paper behind the mask using image analysis. METHODS: A bitter-tasting fluorescein solution was aerosolised during mask fit tests, with filter paper placed on masks' inner surfaces. Participants reported whether they could taste bitterness to determine taste test 'pass' or 'fail' results. Filter paper photographs were digitally analysed to quantify total fluorescence (TF). RESULTS: Fifty-six healthcare professionals were fit tested; 32 (57%) 'passed' the taste test. TF between the taste test 'pass' and 'fail' groups was significantly different (p<0.001). A cut-off (TF = 5.0 × 106 units) was determined at precision (78%) and recall (84%), resulting in 5/56 participants (9%) reclassified from 'pass' to 'fail' by the fluorescein test. Seven out of 56 (12%) reclassified from 'fail' to 'pass'. CONCLUSION: Fluorescein is detectable and sensitive at identifying FFP mask leaks. These low-cost adaptations can enhance exiting fit testing to determine 'pass' and 'fail' groups, protecting those who 'passed' the taste test but have high fluorescein leak, and reassuring those who 'failed' the taste test despite having little fluorescein leak.


Subject(s)
Occupational Exposure , Respiratory Protective Devices , Cost-Benefit Analysis , Fluorescein , Humans , Point-of-Care Systems
16.
Biosensors (Basel) ; 11(11)2021 Oct 26.
Article in English | MEDLINE | ID: covidwho-1518595

ABSTRACT

Infectious agents, especially bacteria and viruses, account for a vast number of hospitalisations and mortality worldwide. Providing effective and timely diagnostics for the multiplicity of infectious diseases is challenging. Conventional diagnostic solutions, although technologically advanced, are highly complex and often inaccessible in resource-limited settings. An alternative strategy involves convenient rapid diagnostics which can be easily administered at the point-of-care (POC) and at low cost without sacrificing reliability. Biosensors and other rapid POC diagnostic tools which require biorecognition elements to precisely identify the causative pathogen are being developed. The effectiveness of these devices is highly dependent on their biorecognition capabilities. Naturally occurring biorecognition elements include antibodies, bacteriophages and enzymes. Recently, modified molecules such as DNAzymes, peptide nucleic acids and molecules which suffer a selective screening like aptamers and peptides are gaining interest for their biorecognition capabilities and other advantages over purely natural ones, such as robustness and lower production costs. Antimicrobials with a broad-spectrum activity against pathogens, such as antibiotics, are also used in dual diagnostic and therapeutic strategies. Other successful pathogen identification strategies use chemical ligands, molecularly imprinted polymers and Clustered Regularly Interspaced Short Palindromic Repeats-associated nuclease. Herein, the latest developments regarding biorecognition elements and strategies to use them in the design of new biosensors for pathogens detection are reviewed.


Subject(s)
Bacteria , Biosensing Techniques , Point-of-Care Systems , Viruses , Reproducibility of Results
17.
Lab Chip ; 21(23): 4517-4548, 2021 11 25.
Article in English | MEDLINE | ID: covidwho-1517643

ABSTRACT

In this review, we provide an overview of developments in point-of-care (POC) diagnostics during the COVID-19 pandemic. We review these advances within the framework of a holistic POC ecosystem, focusing on points of interest - both technological and non-technological - to POC researchers and test developers. Technologically, we review design choices in assay chemistry, microfluidics, and instrumentation towards nucleic acid and protein detection for severe acute respiratory coronavirus 2 (SARS-CoV-2), and away from the lab bench, developments that supported the unprecedented rapid development, scale up, and deployment of POC devices. We describe common features in the POC technologies that obtained Emergency Use Authorization (EUA) for nucleic acid, antigen, and antibody tests, and how these tests fit into four distinct POC use cases. We conclude with implications for future pandemics, infectious disease monitoring, and digital health.


Subject(s)
COVID-19 , Pandemics , Ecosystem , Humans , Point-of-Care Systems , SARS-CoV-2
18.
ACS Sens ; 6(11): 4176-4184, 2021 11 26.
Article in English | MEDLINE | ID: covidwho-1517597

ABSTRACT

Early and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses at the point-of-care is crucial for reducing disease transmission during the current pandemic and future flu seasons. To prepare for potential cocirculation of these two viruses, we report a valve-enabled, paper-based sample preparation device integrated with isothermal amplification for their simultaneous detection. The device incorporates (1) virus lysis and RNA enrichment, enabled by ball-based valves for sequential delivery of reagents with no pipet requirement, (2) reverse transcription loop-mediated isothermal amplification, carried out in a coffee mug, and (3) colorimetric detection. We have used the device for simultaneously detecting inactivated SARS-CoV-2 and influenza A H1N1 viruses in 50 min, with limits of detection at 2 and 6 genome equivalents, respectively. The device was further demonstrated to detect both viruses in environmental samples.


Subject(s)
COVID-19 , Influenza A Virus, H1N1 Subtype , Humans , Influenza A Virus, H1N1 Subtype/genetics , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Point-of-Care Systems , RNA, Viral/genetics , SARS-CoV-2
20.
PLoS One ; 16(11): e0258819, 2021.
Article in English | MEDLINE | ID: covidwho-1511819

ABSTRACT

Inexpensive, simple, rapid diagnostics are necessary for efficient detection, treatment, and mitigation of COVID-19. Assays for SARS-CoV2 using reverse transcription polymerase chain reaction (RT-PCR) offer good sensitivity and excellent specificity, but are expensive, slowed by transport to centralized testing laboratories, and often unavailable. Antigen-based assays are inexpensive and can be rapidly mass-produced and deployed at point-of-care, with lateral flow assays (LFAs) being the most common format. While various manufacturers have produced commercially available SARS-Cov2 antigen LFAs, access to validated tests remains difficult or cost prohibitive in low-and middle-income countries. Herein, we present a visually read open-access LFA (OA-LFA) using commercially-available antibodies and materials for the detection of SARS-CoV-2. The LFA yielded a Limit of Detection (LOD) of 4 TCID50/swab of gamma irradiated SARS-CoV-2 virus, meeting the acceptable analytical sensitivity outlined by in World Health Organization target product profile. The open-source architecture presented in this manuscript provides a template for manufacturers around the globe to rapidly design a SARS-CoV2 antigen test.


Subject(s)
Antigens, Viral/immunology , COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , COVID-19/virology , Humans , Limit of Detection , Point-of-Care Systems , RNA, Viral/immunology , Sensitivity and Specificity
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