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1.
Cell Systems ; 2023.
Article in English | ScienceDirect | ID: covidwho-2165139

ABSTRACT

Summary The recognition of pathogen or cancer-specific epitopes by CD8+ T cells is crucial for the clearance of infections and the response to cancer immunotherapy. This process requires epitopes to be presented on class I human leukocyte antigen (HLA-I) molecules and recognized by the T-cell receptor (TCR). Machine learning models capturing these two aspects of immune recognition are key to improve epitope predictions. Here, we assembled a high-quality dataset of naturally presented HLA-I ligands and experimentally verified neo-epitopes. We then integrated these data in a refined computational framework to predict antigen presentation (MixMHCpred2.2) and TCR recognition (PRIME2.0). The depth of our training data and the algorithmic developments resulted in improved predictions of HLA-I ligands and neo-epitopes. Prospectively applying our tools to SARS-CoV-2 proteins revealed several epitopes. TCR sequencing identified a monoclonal response in effector/memory CD8+ T cells against one of these epitopes and cross-reactivity with the homologous peptides from other coronaviruses.

2.
Acta Biomaterialia ; 2022.
Article in English | ScienceDirect | ID: covidwho-2164932

ABSTRACT

Effective antigen delivery facilitates antiviral vaccine success defined by effective immune protective responses against viral exposures. To improve severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antigen delivery, a controlled biodegradable, stable, biocompatible, and nontoxic polymeric microsphere system was developed for chemically inactivated viral proteins. SARS-CoV-2 proteins encapsulated in polymeric microspheres induced robust antiviral immunity. The viral antigen-loaded microsphere system can preclude the need for repeat administrations, highlighting its potential as an effective vaccine. Statement of Significance Successful SARS-CoV-2 vaccines were developed and quickly approved by the US Food and Drug Administration (FDA). However, each of the vaccines requires boosting as new variants arise. We posit that injectable biodegradable polymers represent a means for the sustained release of emerging viral antigens. The approach offers a means to reduce immunization frequency by predicting viral genomic variability. This strategy could lead to longer-lasting antiviral protective immunity. The current proof-of-concept multipolymer study for SARS-CoV-2 achieve these metrics.

3.
Talanta ; 255:124200, 2023.
Article in English | ScienceDirect | ID: covidwho-2165885

ABSTRACT

Vaccination is an effective strategy to fight COVID-19. However, the effectiveness of the vaccine varies among different populations in varying immune effects. Neutralizing antibody (NAb) level is an important indicator to evaluate the protective effect of immune response after vaccination. Lateral flow immunoassay (LFIA) is a rapid, safe and sensitivity detection method, which has great potential in the detection of SARS-CoV-2 NAb. In this study, a fluorescent beads-based lateral flow immunoassay (FBs-LFIA) and a latex beads-based LFIA (LBs-LFIA) using double antigen sandwich (DAS) strategy were established to detect NAbs in the serum of vaccinated people. The limit of detection (LoD) of the FBs-LFIA was 1.13 ng mL− 1 and the LBs-LFIA was 7.11 ng mL− 1. The two LFIAs were no cross-reactive with sera infected by other pathogenic bacteria. Furthermore, the two LFIAs showed a good performance in testing clinical samples. The sensitivity of FBs-LFIA and LBs-LFIA were 97.44% (95%CI: 93.15%–99.18%) and 98.29% (95%CI: 95.84%–99.37%), and the specificity were 98.28% (95%CI: 95.37%–99.45%) and 97.70% (95%CI: 94.82%–99.06%) compared with the conventional virus neutralization test (cVNT), respectively. Notably, the LBs-LFIA was also suitable for whole blood sample, requiring only 3 μL of whole blood, which provided the possibility to detect NAbs at home. To sum up, the two LFIAs based on double antigen sandwich established by us can rapidly, safely, sensitively and accurately detect SARS-CoV-2 NAb in human serum.

5.
Journal of Clinical Virology Plus ; : 100133, 2022.
Article in English | ScienceDirect | ID: covidwho-2165517

ABSTRACT

Although real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) remains as a golden standard for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, it can not be easily expanded to large-scaled screening during outbreaks, and the positive results do not necessarily correlate with infectious status of the identified subjects. In this study, the performance of Vstrip® RV2 COVID-19 Antigen Rapid Test (RAT) and its correlation with virus infectivity was examined by virus culture using 163 sequential respiratory specimens collected from 26 SARS-CoV-2 infected patients. When the presence of cytopathic effects (CPE) in cell culture was used as a reference method for virus infectivity, the sensitivity, specificity and accuracy of Vstrip® RV2 COVID-19 Antigen Rapid Test was 96.43%, 89.63%, and 90.8%, respectively. The highest Ct value was 27.7 for RdRp gene and 25.79 for E gene within CPE-positive samples, and the highest Ct value was 31.9 for RdRp gene and 29.1 for E gene within RAT positive samples. When the Ct values of specimens were below 25, the CPE and RAT results had high degree of consistency. We concluded that the RAT could be a great alternative method for determining the infectious potential of individuals with high viral load.

6.
Journal of Colloid and Interface Science ; 634:963-971, 2023.
Article in English | ScienceDirect | ID: covidwho-2165506

ABSTRACT

Hypothesis Virus-like particles (VLPs) are promising scaffolds for developing mucosal vaccines. For their optimal performance, in addition to design parameters from an immunological perspective, biophysical properties may need to be considered. Experiments We investigated the mechanical properties of VLPs scaffolded on the coat protein of Acinetobacter phage AP205 using atomic force microscopy and small angle X-ray scattering. Findings Investigations showed that AP205 VLP is a tough nanoshell of stiffness 93 ± 23 pN/nm and elastic modulus 0.11 GPa. However, its mechanical properties are modulated by attaching muco-inert polyethylene glycol to 46 ± 10 pN/nm and 0.05 GPa. Addition of antigenic peptides derived from SARS-CoV2 spike protein by genetic fusion increased the stiffness to 146 ± 54 pN/nm although the elastic modulus remained unchanged. These results, which are interpreted in terms of shell thickness and coat protein net charge variations, demonstrate that surface conjugation can induce appreciable changes in the biophysical properties of VLP-scaffolded vaccines.

7.
Chembiochem ; 23(18): e202200303, 2022 09 16.
Article in English | MEDLINE | ID: covidwho-1958520

ABSTRACT

Antibodies recognize their cognate antigens with high affinity and specificity, but the prediction of binding sites on the antigen (epitope) corresponding to a specific antibody remains a challenging problem. To address this problem, we developed AbAdapt, a pipeline that integrates antibody and antigen structural modeling with rigid docking in order to derive antibody-antigen specific features for epitope prediction. In this study, we systematically assessed the impact of integrating the state-of-the-art protein modeling method AlphaFold with the AbAdapt pipeline. By incorporating more accurate antibody models, we observed improvement in docking, paratope prediction, and prediction of antibody-specific epitopes. We further applied AbAdapt-AF in an anti-receptor binding domain (RBD) antibody complex benchmark and found AbAdapt-AF outperformed three alternative docking methods. Also, AbAdapt-AF demonstrated higher epitope prediction accuracy than other tested epitope prediction tools in the anti-RBD antibody complex benchmark. We anticipate that AbAdapt-AF will facilitate prediction of antigen-antibody interactions in a wide range of applications.


Subject(s)
Antibodies , Antigens , Antibody Specificity , Binding Sites, Antibody , Epitopes/chemistry
8.
Front Med (Lausanne) ; 9: 970423, 2022.
Article in English | MEDLINE | ID: covidwho-2163038

ABSTRACT

The multi-ligand receptor for advanced glycation end-products (RAGE) and its ligands are contributing factors in autoimmunity, cancers, and infectious disease. RAGE activation is increased in chronic kidney disease (CKD) and coronavirus disease 2019 (COVID-19). CKD may increase the risk of COVID-19 severity and may also develop in the form of long COVID. RAGE is expressed in essentially all kidney cell types. Increased production of RAGE isoforms and RAGE ligands during CKD and COVID-19 promotes RAGE activity. The downstream effects include cellular dysfunction, tissue injury, fibrosis, and inflammation, which in turn contribute to a decline in kidney function, hypertension, thrombotic disorders, and cognitive impairment. In this review, we discuss the forms and mechanisms of RAGE and RAGE ligands in the kidney and COVID-19. Because various small molecules antagonize RAGE activity in animal models, targeting RAGE, its co-receptors, or its ligands may offer novel therapeutic approaches to slowing or halting progressive kidney disease, for which current therapies are often inadequate.

9.
Front Immunol ; 13: 960985, 2022.
Article in English | MEDLINE | ID: covidwho-2154722

ABSTRACT

One of the primary tasks in vaccine design and development of immunotherapeutic drugs is to predict conformational B-cell epitopes corresponding to primary antibody binding sites within the antigen tertiary structure. To date, multiple approaches have been developed to address this issue. However, for a wide range of antigens their accuracy is limited. In this paper, we applied the transfer learning approach using pretrained deep learning models to develop a model that predicts conformational B-cell epitopes based on the primary antigen sequence and tertiary structure. A pretrained protein language model, ESM-1v, and an inverse folding model, ESM-IF1, were fine-tuned to quantitatively predict antibody-antigen interaction features and distinguish between epitope and non-epitope residues. The resulting model called SEMA demonstrated the best performance on an independent test set with ROC AUC of 0.76 compared to peer-reviewed tools. We show that SEMA can quantitatively rank the immunodominant regions within the SARS-CoV-2 RBD domain. SEMA is available at https://github.com/AIRI-Institute/SEMAi and the web-interface http://sema.airi.net.


Subject(s)
COVID-19 , Vaccines , Antigens , Epitopes, B-Lymphocyte , Humans , Immunodominant Epitopes , Machine Learning , SARS-CoV-2
10.
Transplant Cell Ther ; 2022 Oct 21.
Article in English | MEDLINE | ID: covidwho-2150218

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), disproportionately affects immunocompromised and elderly patients. Not only are hematopoietic cell transplantation (HCT) and chimeric antigen receptor (CAR) T-cell recipients at greater risk for severe COVID-19 and COVID-19-related complications, but they also may experience suboptimal immune responses to currently available COVID-19 vaccines. Optimizing the use, timing, and number of doses of the COVID-19 vaccines in these patients may provide better protection against SARS-CoV-2 infection and better outcomes after infection. To this end, current guidelines for COVID-19 vaccination in HCT and CAR T-cell recipients from the American Society of Transplantation and Cellular Therapy Transplant Infectious Disease Special Interest Group and the American Society of Hematology are provided in a frequently asked questions format.

11.
Indonesian Journal of Biotechnology ; 27(3):151-162, 2022.
Article in English | Scopus | ID: covidwho-2164486

ABSTRACT

More than 6,000,000 people have died due to the coronavirus (COVID-19) pandemic. This disease spread quickly due to its highly contagious nature. The SARS-CoV-2 virus that causes the disease can be transmitted through saliva droplets secreted by infected people at a distance of less than 1 m. As a result, saliva has been accepted as an alternative specimen for COVID-19 detection by the Centers for Disease Control and Prevention (CDC). Furthermore, WHO recommended the use of rapid antigen tests based on lateral flow immunoassay when reverse transcription-polymerase chain reaction (RT-PCR) is not available. We developed a saliva-based rapid antigen test by optimizing the antibody concentration and optimum pH for the conjugation of antibody and gold nanoparticles. We found that the best running buffer formulation consisted of 75 mM sodium phosphate buffer, 1% NaCl, 1% Triton X-100, 0.5% N-acetyl-L-cysteine, and 0.02% sodium azide. The addition of a mucolytic agent in the buffer can reduce the viscosity of saliva, thus improving sensitivity. The rapid test developed detected the lowest concentration of nucleocapsid protein at 0.1 μg/mL. Our study revealed 100% specificity against negative COVID-19 saliva and no cross-reaction with avian influenza virus hemagglutinin. © 2022 THE AUTHOR(S). This article is distributed under a Creative Commons Attribution-ShareAlike 4.0 International license.

12.
Pediatrics ; 150, 2022.
Article in English | ProQuest Central | ID: covidwho-2162658

ABSTRACT

PURPOSE OF THE STUDY: T cell lymphopenia is prevalent in severe coronavirus disease 2019 (COVID-19). This study evaluated associations with homeostatic and functional T cell responses in COVID-19 with the goal of identifying immunologic features of severe disease. STUDY POPULATION: Patients aged 18 years and older with symptomatic, real time-quantitative polymerase chain reaction confirmed SARS-CoV-2 (mild, n = 54;severe, n = 49) were recruited at 4 hospitals in the Canton of Zurich, Switzerland from April 2 to August 19, 2020, and a group of healthy controls recruited for comparison (n = 27). A subset (mild, n = 28;severe, n = 38, healthy, n = 22) had comprehensive T cell characterization. METHODS: In this prospective, observational, cross-sectional study, symptomatic participants with mild and severe COVID-19 and healthy controls were sampled at a single time point. Phenotypic and functional characteristics of T cells were evaluated using 40-parameter mass cytometry, flow cytometry, targeted proteomics, and functional assays. RESULTS: Compared with mild disease, severe COVID-19 was associated with T cell lymphopenia and redistribution of T cell populations, including loss of naïve and memory CD4+ and CD8+ T cells, skewing toward CD4+ T follicular helper cells and cytotoxic CD4+ T cells, and expansion of activated and exhausted T cells. Individuals with severe disease and T cell lymphopenia had signs of tissue migration, extensive T cell apoptosis, and impaired T cell responses to common viral antigens. Patients with severe disease also showed elevated interleukin-7 and increased T cell proliferation. Those sampled longest after symptom onset had higher T cell counts and improved antiviral T cell responses. CONCLUSIONS: Severe COVID-19 is characterized by extensive T cell dysfunction. Reduced naïve T cells and virus-specific memory T cell numbers are associated with severe disease and impaired T cell responses to viral antigens, particularly early in the disease. Increased T follicular helper cells may contribute to a robust antibody response often observed in COVID-19. T cell apoptosis is associated with lymphopenia and homeostatic T cell proliferation and T cell recovery in the later stages of disease.

13.
Journal for ImmunoTherapy of Cancer ; 10(Supplement 2):A961, 2022.
Article in English | EMBASE | ID: covidwho-2161952

ABSTRACT

Background The adaptive immune system identifies foreign antigens based on a series of highly specific interactions involving multiple immune cell types. Identifying the exact mechanisms of said interactions can be difficult to achieve using bulk sequencing methods due to poor resolution. Single cell sequencing offers the ability to match a specific antigen to an immune cell receptor sequence at the cellular level. Methods We used Barcode Enabled Antigen Mapping (BEAM) and Single Cell Immune Profiling technology to profile hundreds of thousands of human peripheral blood mononuclear cells (PBMCs) from a donor following their recovery from COVID-19. These cells were screened for potential binding interactions with multiple antigens from SARS-CoV-2 and other viral pathogens. Sequencing data were also generated for gene expression and paired sequences for both BCRs and TCRs. Results The combination of these two techniques allowed us to identify a number of antigen-specific clonotypes of T cells and B cells. The high throughput of the experiment allowed us to gain understanding on a global scale of the state of the immune system following recovery from a COVID-19 infection, as well as to identify potentially rare clonotypes that may not have been discerned from a smaller sample size. Conclusions This experiment demonstrates the ability of BEAM to both profile the entire immune system at the cellular level at a given point in time as well as distinguish specific antigen-receptor interactions with the same resolution. Insights provided by similar experiments could be invaluable in the creation of precision cell therapies for use in cancer treatment, as well as the development of vaccines and analysis of allergic and autoimmune responses.

14.
Journal for ImmunoTherapy of Cancer ; 10(Supplement 2):A338, 2022.
Article in English | EMBASE | ID: covidwho-2161945

ABSTRACT

Background We are developing MiNK-413;a novel allogeneic CAR-iNKT product targeting BCMA and secreting soluble IL-15 for treatment of relapsed/refractory Multiple Myeloma (rrMM). Chimeric Antigen Receptor (CAR)-T cell therapy has revolutionized treatment of rrMM with two autologous products already approved by the FDA. However, current treatments come with significant toxicity, cost, and logistical challenge and many patients relapse, with 60% of relapsed patients still expressing BCMA. To address these, we propose the use of invariant Natural Killer T (iNKT) cells as a platform for BCMA-targeted allogenic cell therapy for rrMM. iNKT cells have potent immunostimulatory activity and intrinsic CD1d-and NK receptor ligand targeted cytotoxicity, and do not cause Graft versus Host Disease due to their invariant T cell receptor. In our native iNKT cell (agenT-797) clinical trials for COVID, solid tumors and Multiple Myeloma we observe excellent tolerability to up to 1 billion cell dosing with minimal treatment-related adverse events, absence of signs of CRS or peripheral neuropathy, and early signs of biological activity. AgenT-797 is administered without prior lymphodepletion, which is an approach we intend to pursue with MiNK-413. Methods Our proprietary CARDISTM platform consists of highly diverse (>1010) scFv library screening followed by library-based direct functional selection in CAR format using mammalian display. Candidates can be further optimized using affinity tuning to ensure optimal and highly selective on-target/ on-tumor activity. We developed a manufacturing approach to engineer and specifically expand CAR and soluble IL-15-expressing allogeneic iNKT cells. Lead candidates are assessed in vitro and in vivo for cytotoxicity, cytokine secretion, exhaustion, tumor homing and persistence. Results Discovery using our CARDISTM platform generated a fully human, potent, and specific anti-BCMA CAR which forms the basis for MiNK-413. Xenograft in vivo studies demonstrate effective bone marrow homing, and potent cytotoxic activity, with soluble IL-15 prolonging persistence. In vitro data show potent immunomodulatory activity and lack of exhaustion against BCMA+ human hematologic tumor cell lines in vitro and in vivo. Conclusions Combination of our proprietary CARDISTM and iNKT platforms enabled rapid discovery and development of MiNK-413, a next generation armored allogeneic BCMA-targeting CAR therapies. MiNK-413 is eligible to target a broader rrMM patient population due to intrinsic iNKT cell properties such as effective bone-marrow homing, high BCMA specific activity augmented by natural CD1d and NK receptorligand mediated activity. We believe MiNK-413 will provide additional benefits to rrMM patients beyond currently available treatments.

15.
Zeitschrift fur Gastroenterologie ; 60(11):1610-1611, 2022.
Article in German | EMBASE | ID: covidwho-2160379
16.
Medical Hypotheses ; : 111001, 2022.
Article in English | ScienceDirect | ID: covidwho-2159554

ABSTRACT

Immune system battles with deadly pathogens that mostly deteriorate health and cause morbidity and mortality. Antibodies are considered great players in the elimination of pathogens and hence, provide a shield against the future onset of various diseases. The immune complex, also known as an antigen-antibody (Ag-Ab) complex, exhibits the immunomodulatory potential leading to enhanced vaccine efficacy. A deeper understanding of Fc receptors (FcRs) and the interaction of the Fc part of an antibody with the different immune cells lead to in-depth knowledge of using this strategy for the development of immune complex vaccines. The concept of the Ag-Ab complex has been used in the prevention and therapy of various viral and bacterial diseases. Ag-Ab complex is gaining attention in COVID-19 vaccine development too, due to their greater immunoregulatory potential. The present literature highlights the importance of the Ag-Ab complex, the role of Fc receptors in immunomodulation, and their success as vaccines in viral and bacterial diseases of human and animal origin. Moreover, potential areas and lapses are explored to make better use of this prospect as a vaccine candidate. Studies revealed that the immunogenic and immunomodulatory potential of Ag-Ab complex can lead to greater protection. However, there is a dire need of establishing a link between laboratory and clinical findings to make it effective and safe tool for in vivo treatments.

17.
Kathmandu University Medical Journal ; 20(79):207-211, 2022.
Article in English | EMBASE | ID: covidwho-2156617

ABSTRACT

Background The Coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) has spread worldwide since its first recorded case in the city of Wuhan, China, in December 2019. SARS-CoV-2 infection causes asymptomatic to sever pneumonia. Severe cases may develop acute respiratory disease symdrome (ARDS), with an average mortality rate of 6.9%. Real Time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) assay is the current reference standard laboratory method for the diagnosis of SARS-CoV-2 infection. However, it takes around 6-8 hours to get the result and is time consuming. Therefore, rapid and accurate tests for SARS-CoV-2 screening are essential to expedite disease prevention and control. Lateral flow immunoassay using monoclonal anti SARS-CoV-2 antibodies which target for SARS-CoV-2 antigen can be complimentary screening test if their accuracy were comparable to that of the real time reverse transcription-polymerase chain reaction (RT-PCR) assay. Objective To find the sensitivity and specificity of a rapid antigentest kit in comparison to reverse transcription-polymerase chain reaction (RT-PCR). Method A cross-sectional hospital based study was carried out at Shree Birendra Army Hospital, Kathmandu for a period of four months. Result Our finding shows sensitivity and specificity of rapid diagnostic tests (RDT) Ag kit as 60.6% and 96.4% respectively. Positive and negative predictive value was 83.7% and 89.0%. Likewise, positive and negative likelihood ratio was 17.0 and 0.4. The overall accuracy of the antigen kit was 88.1% in comparison to reverse transcription-polymerase chain reaction (RT-PCR) as the gold standard. Conclusion Our study concluded the use of rapid antigen kit is mainly useful for screening purposes. Copyright © 2022, Kathmandu University. All rights reserved.

18.
International Journal of Pharmaceutical Sciences and Research ; 13(12):5050-5056, 2022.
Article in English | EMBASE | ID: covidwho-2155832

ABSTRACT

Background: Severe Acute Respiratory Syndrome Corona Virus Disease 2019 (COVID-19) is responsible for the COVID-19 pandemic causing respiratory illness worldwide. Hence there is an urgent need for simple, rapid, and accurate tests for diagnosis. Performance characteristic of Rapid Antigen detection test for identifying sensitivity and specificity with gold standard Real-Time Polymerase Chain Reaction and correlate the significance of non-specific parameters like CRP(C- Reactive Protein), IL-6(Interleukin-6), Procalcitonin for diagnosis of COVID-19. Method(s): The Rapid Antigen Detection test was compared with Real-Time Polymerase Chain Reaction to detect SARS CoV-2 in respiratory specimens. 100 respiratory samples (mainly nasopharyngeal and throat swab) and for CRP, IL6, and Procalcitonin serum samples were obtained from COVID-19 suspected cases, mostly in-patients at Saveetha Medical College from April 2021- to September 2021. Result(s): Out of 100 samples, 67% were positive, 33% were negative for SARS-CoV2 RNA by RT-PCR assay. When compared with Rapid Antigen Test, the RT-PCR test showed 83.8% sensitivity and 59.3% specificity, while non-specific parameters correlation in diagnosis of COVID-19 showed CRP insignificant, IL-6 and Procalcitonin significant. Conclusion(s): RT-PCR is considered the standard gold method for diagnosing COVID-19. On comparing RT-PCR with other non-specific tests like CRP, Procalcitonin, IL-6 showed Procalcitonin and IL-6 can be considered non-specific tests for diagnosing COVID-19. Copyright © 2022 are reserved by International Journal of Pharmaceutical Sciences and Research. This Journal licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

19.
Clin Chem Lab Med ; 2022.
Article in English | PubMed | ID: covidwho-2154344

ABSTRACT

OBJECTIVES: Various comorbidities associated with COVID-19 add up in severity of the disease and obviously prolonged the time for viral clearance. This study investigated a novel ultrasensitive MAGLUMI(®) SARS-CoV-2 Ag chemiluminescent immunoassay assay (MAG-CLIA) for diagnosis and monitoring the infectivity of COVID-19 patients with comorbid conditions during the pandemic of 2022 Shanghai. METHODS: Analytical performances of the MAG-CLIA were evaluated, including precision, limit of quantitation, linearity and specificity. Nasopharyngeal specimens from 232 hospitalized patients who were SARS-CoV-2 RT-qPCR positive and from 477 healthy donors were included. The longitudinal studies were performed by monitoring antigen concentrations alongside with RT-qPCR results in 14 COVID-19 comorbid participants for up to 22 days. The critical antigen concentration in determining virus infectivity was evaluated at the reference cycle threshold (Ct) of 35. RESULTS: COVID-19 patients were well-identified using an optimal threshold of 0.64 ng/L antigen concentration, with sensitivity and specificity of 95.7% (95% CI: 92.2-97.9%) and 98.3% (95% CI: 96.7-99.3%), respectively, while the Wondfo LFT exhibited those of 34.9% (95% CI: 28.8-41.4%) and 100% (95% CI: 99.23-100%), respectively. The sensitivity of MAG-CLIA remained 91.46% (95% CI: 83.14-95.8%) for the samples with Ct values between 35 and 40. Close dynamic consistence was observed between MAG-CLIA and viral load time series in the longitudinal studies. The critical value of 8.82 ng/L antigen showed adequate sensitivity and specificity in evaluating the infectivity of hospitalized convalescent patients with comorbidities. CONCLUSIONS: The MAG-CLIA SARS-CoV-2 Ag detection is an effective and alternative approach for rapid diagnosis and enables us to evaluate the infectivity of hospitalized convalescent patients with comorbidities.

20.
Materials Advances ; 2023.
Article in English | Web of Science | ID: covidwho-2151150

ABSTRACT

During the COVID'19 outbreak, biosensing devices won increasing relevance, demonstrating their potential in the medical diagnostic field. Hence, the present review reports on the main advances in 2D-ZnO nanostructure-based biosensors. So far, bulk ZnO has shown potential for biosensing, optical, and power electronic applications, mainly based on its wide band gap. In the post graphene era, its 2-D allotropes like ZnO sheets and ZnO nanoribbons have outperformed the bulk ZnO structures for specific applications. ZnO demonstrates various stable and feasible morphologies: nanotubes, nanowires, nanorods, nanosheets, nanoparticles, and nanobelts. As a matrix layer in biosensing applications, ZnO strongly binds to biomolecules due to its high isoelectric point (IEP) and shows a strong sensitivity due to the high surface-to-volume ratio. Further, ZnO nanostructures used as a matrix layer play an important role in inhibiting specific biological interactions and hence improve the sensitivity of sensing devices. Further, bioselective layers are typically immobilized onto ZnO either by direct adsorption or by covalent binding. ZnO based biosensors are categorized into optical, piezoelectric, and electrochemical biosensors, among others, based on their biosensing mechanism. In particular, electrochemical sensors produce signals via an electrical pathway for detecting and monitoring the target molecules. Optical sensors produce signals based on luminescence or reflectance, among others. Piezoelectric biosensors produce signals by mass loading of the piezoelectric material. ZnO-based FET biosensors are also reported, showing sensing application by the change in the channel's conductance. Further, recent literature on the detection of COVID-19 using ZnO nanostructures is presented.

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