Portable microfluidic impedance biosensor for SARS-CoV-2 detection.

Pandemics as the one we are currently facing, where fast-spreading viruses present a threat to humanity, call for simple and reliable methods to perform early diagnosis, enabling detection of very low pathogen loads even before symptoms start showing in the host. So far, standard polymerase chain reaction (PCR) is the most reliable method for doing so, but it is rather slow and needs specialized reagents and trained personnel to operate it. Additionally, it is expensive and not easily accessible. Therefore, developing miniaturized and portable sensors which perform early detection of pathogens with high reliability is necessary to not only prevent the spreading of the disease but also to monitor the effectiveness of the developed vaccines and the appearance of new pathogenic variants. Thus, in this work we develop a sensitive microfluidic impedance biosensor for the direct detection of SARS-CoV-2, towards a mobile point-of-care (POC) platform. The operational parameters are optimized with the aid of design-of-experiment (DoE), for an accurate detection of the viral antigens using electrochemical impedance spectroscopy (EIS). We perform the biodetection of buffer samples spiked with fM concentration levels and validate the biosensor in a clinical context of relevance by analyzing 15 real patient samples up to a Ct value (cycle threshold) of 27. Finally, we demonstrate the versatility of the developed platform using different settings, including a small portable potentiostat, using multiple channels for self-validation, as well as with single biosensors for a smartphone-based readout. This work contributes to the rapid and reliable diagnostics of COVID-19 and can be extended to other infectious diseases, allowing the monitoring of viral load in vaccinated and unvaccinated people to anticipate a potential relapse of the disease.

Multi-modal approach for COVID-19 detection using coughs and self-reported symptoms

COVID-19 (Coronavirus Disease of 2019) is one of the most challenging healthcare crises of the twenty-first century. The pandemic causes many negative impacts on all aspects of life and livelihoods. Although recent developments of relevant vaccines, such as Pfizer/BioNTechmRNA, AstraZeneca, or Moderna, the emergence of newvirus mutations and their fast infection rate yet pose significant threats to public health. In this context, early detection of the disease is an important factor to reduce its effect and quickly control the spread of pandemic. Nevertheless, many countries still rely on methods that are either expensive and time-consuming (i.e., Reverse-transcription polymerase chain reaction) or uncomfortable and difficult for self-testing (i.e., Rapid Antigen Test Nasal). Recently, deep learning methods have been proposed as a potential solution for COVID-19 analysis. However, previous works usually focus on a single symptom, which can omit critical information for disease diagnosis. Therefore, in this study, we propose a multi-modal method to detect COVID-19 using cough sounds and self-reported symptoms. The proposed method consists of five neural networks to deal with different input features, including CNN-biLSTM for MFCC features, EfficientNetV2 for Mel spectrogram images, MLP for self-reported symptoms, C-YAMNet for cough detection, and RNNoise for noise-canceling. Experimental results demonstrated that our method outperformed the other state-of-the-art methods with a high AUC, accuracy, and F1-score of 98.6%, 96.9%, and 96.9% on the testing set.

COVID-19 Detection via Fusion of Modulation Spectrum and Linear Prediction Speech Features

The coronavirus disease 2019 (COVID-19) pandemic has drastically impacted life around the globe. As life returns to pre-pandemic routines, COVID-19 testing has become a key component, assuring that travellers and citizens are free from the disease. Conventional tests can be expensive, time-consuming (results can take up to 48h), and require laboratory testing. Rapid antigen testing, in turn, can generate results within 15-30 minutes and can be done at home, but research shows they achieve very poor sensitivity rates. In this paper, we propose an alternative test based on speech signals recorded at home with a portable device. It has been well-documented that the virus affects many of the speech production systems (e.g., lungs, larynx, and articulators). As such, we propose the use of new modulation spectral features and linear prediction analysis to characterize these changes and design a two-stage COVID-19 prediction system by fusing the proposed features. Experiments with three COVID-19 speech datasets (CSS, DiCOVA2, and Cambridge subset) show that the two-stage feature fusion system outperforms the benchmark systems of CSS and Cambridge datasets while maintaining lower complexity compared to DL-based systems. Furthermore, the two-stage system demonstrates higher generalizability to unseen conditions in a cross-dataset testing evaluation scheme. The generalizability and interpretability of our proposed system demonstrate the potential for accessible, low-cost, at-home COVID-19 testing. IEEE

Recent Developments and Opportunities in Fighting COVID-19

Background: COVID-19, a Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2), was first diagnosed in the patients from Wuhan, China, in December 2019. Within a cou-ple of months of infection, it was declared as pandemic by the World health organization. COVID-19 has become the most contagious infection with a serious threat to global health. In this review, we aimed to discuss the pathogenesis, diagnostics, current treatments and potential vaccines for COVID-19. Method(s): An extensive literature search was conducted using keywords "COVID-19";"Coron-avirus";"SARS-Cov-2";"SARS" in public domains of Google, Google scholar, PubMed, and Sci-enceDirect. Selected articles were used to construct this review. Result(s): SARS-Cov-2 uses the Spike (S) protein on its surface to recognize the receptor on an-giotensin-converting enzyme 2 (ACE2) and bind with 10-folds greater affinity than SARS-Cov-1. Molecular assays and immunoassays are the most frequently used tests, whereas computed tomog-raphy (CT) scans and artificial intelligence enabled diagnostic tools were also used in patients. In therapeutic treatment, few drugs were repurposed and about 23 therapeutic molecules, including the repurposed drugs are at different stages of the clinical trial. Similarly, the development of vaccines is also in the pipeline. Few countries have managed well to contain the spread by rapid testing and identifying the clusters. Conclusion(s): Till now, the acute complications and mortality of COVID-19 have been linked to pre-existing comorbid conditions or age. Besides the development of therapeutic strategies that include drugs and vaccine, the long term implication of COVID-19 infection in terms of the disor-der/disability in the cured/discharged patients is a new area to investigate.Copyright © 2021 Bentham Science Publishers.

Nanomaterial: A Sustainable Way to Fight Against COVID-19

Nanotechnology is a multidisciplinary field of science which deals with physics, chemistry, material science, and engineering sciences. The applications of Nanotechnology cover almost all the branches of science and technology. In late 2019, SARS-CoV-2 virus became the cause of infection for coronavirus infectious disease (COVID-19). The outbreak of 2019 coronavirus disease (COVID-19) be-comes a challenge for Hospitals and laboratories due to the large number of samples testing the presence of the causative pathogen. Many Scientists and researchers are devotedly working on finding out rapid immunodiagnostic methods to find positive cases. Nano based drugs offer a new therapeutic scheme against the wide range of bacterial pathogens. In this review article, the role of nanomaterial is focused on the fight against COVID-19.Copyright © 2021 Bentham Science Publishers.

Symptoms, Transmission, Prevention and Treatment of Pandemic Corona Virus: A Review

Coronaviruses belong to the largest group of viruses that elicit acute respiratory, enteric and systemic infections in an extensive range of hosts. A few coronaviruses from animals can progress into a new human coronavirus that can spread from person to person. On February 12, 2020, WHO officially termed the disease as Corona Virus Disease 2019 (COVID-19) and declared it a pandemic on March 11, 2020. COVID-19 is a newly emerging viral disease that has an effect on the lower respiratory tract and shows as pneumonia. Despite laborious efforts for worldwide lockdown and quarantine, the occurrence of COVID-19 continues to increase. Proper and well-designed strategies are needed to reduce social and economic consequences arisen due to this pandemic disease. Presently, there is no effective specific vaccine and anti-viral drug supported by great-level confirmation, but dexamethasone is approved in the UK for treatment of critically ill COVID-19 patients (patients on ventilators and patients requiring only oxygen) on June 16, 2020. Further research is required to clarify the factors that affect virus pathogene-sis and lethal infections.Copyright © 2021 Bentham Science Publishers.

Epidemiological Situation of Syphilis and Gonorrhea in Uzbekistan during the Covid-19 Pandemic

The research describes the epidemiological situation in Uzbekistan for sexually transmitted diseases (syphilis, gonorrhea) during the Covid-19 pandemic (2019-2021).Copyright © 2022 Wolters Kluwer Medknow Publications. All rights reserved.

The Novel SARS-CoV-2: An Overview on its Detection, Prevention and Control

On 30 January 2020, the World Health Organization (WHO) characterized the novel severe acute respiratory syndrome Coronavirus 2 (SARSCoV- 2) outbreak as a Public Health Emergency of International Concern. Subsequently, on 11 March 2020, WHO declared the global spread of Coronavirus disease 2019 (COVID-19) as a pandemic triggered by this causative virus. This COVID-19 pandemic has impacted lives and livelihoods worldwide, resulting in unprecedented social disruption and economic losses. In order to design and develop effective diagnostics, vaccines and therapeutic interventions against SARS-CoV-2, it is imperative to understand the molecular and cellular mechanisms underpinning the complex interactions between this virus, its variants, and its infected hosts. This chapter provides an overview on the classification, genomic organization and evolution of SARS-CoV-2 (including the emergence of variants from Alpha to Omicron), and summarizes existing and emerging testing strategies. With unprecedented speed, an array of conventional and new COVID-19 vaccines has been developed, evaluated in clinical trials, and administered to billions worldwide. Current and novel antiviral drugs and immunomodulatory approaches are discussed for the therapeutic and prophylactic management of SARS-CoV-2 infections. Finally, much remains for humanity to discover and learn as the world must continue to adapt and live with endemic COVID-19 and SARSCoV- 2 evolution. © 2023 by World Scientific Publishing Co. Pte. Ltd.

COVID-19 diagnostics and early phase clinical trials: challenges and risk mitigation in the Omicron variants era

The evolution of the coronavirus disease 2019 (COVID-19) pandemic and widespread community of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variants continues to present new challenges for early phase clinical trials and COVID-19 diagnostic strategies. Many regulatory agencies, including the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) continue to provide updated guidance on the operations of clinical trials during the pandemic. However, guidance is limited with respect to medical and scientific specific issues, such as COVID-19 diagnostics. Here we discuss, the challenges for early phase studies associated with COVID-19 diagnostics in the Omicron era and potential risk mitigation strategies in the face of continued widespread community transmission. We note how careful consideration and planning can help mitigating the risk of COVID-19 impacting the medical and scientific validity and patient safety in clinical trials. Clinical study design should consider mitigation strategies at the patient, investigator, and clinical research organization (CRO)/Sponsor level following evaluation of the overall for their specific study/investigational product and patient overall wellbeing. Specific language regarding COVID-19-related policies and procedures should be included in the study protocol. Special considerations should be taken for novel immunotherapeutics which may require interruption in the event of a subject developing COVID-19 or for investigative products that may have hazardous interactions with commonly prescribed anti-COVID-19 therapies. Moving forward, its essential for trials to remain adaptable to evolving nature of the pandemic. © Journal of Laboratory and Precision Medicine. All rights reserved.

Multi-Modal Point-of-Care Diagnostics for COVID-19 Based on Acoustics and Symptoms.

BACKGROUND: The COVID-19 pandemic has highlighted the need to invent alternative respiratory health diagnosis methodologies which provide improvement with respect to time, cost, physical distancing and detection performance. In this context, identifying acoustic bio-markers of respiratory diseases has received renewed interest. OBJECTIVE: In this paper, we aim to design COVID-19 diagnostics based on analyzing the acoustics and symptoms data. Towards this, the data is composed of cough, breathing, and speech signals, and health symptoms record, collected using a web-application over a period of twenty months. METHODS: We investigate the use of time-frequency features for acoustic signals and binary features for encoding different health symptoms. We experiment with use of classifiers like logistic regression, support vector machines and long-short term memory (LSTM) network models on the acoustic data, while decision tree models are proposed for the symptoms data. RESULTS: We show that a multi-modal integration of inference from different acoustic signal categories and symptoms achieves an area-under-curve (AUC) of 96.3%, a statistically significant improvement when compared against any individual modality ([Formula: see text]). Experimentation with different feature representations suggests that the mel-spectrogram acoustic features performs relatively better across the three kinds of acoustic signals. Further, a score analysis with data recorded from newer SARS-CoV-2 variants highlights the generalization ability of the proposed diagnostic approach for COVID-19 detection. CONCLUSION: The proposed method shows a promising direction for COVID-19 detection using a multi-modal dataset, while generalizing to new COVID variants.

Genetically engineered pair of cells for serological testing and its application for SARS-CoV-2.

We have developed a serology test platform for identifying individuals with prior exposure to specific viral infections and provide data to help reduce public health risks. The serology test composed of a pair of cell lines engineered to express either a viral envelop protein (Target Cell) or a receptor to recognize the Fc region of an antibody (Reporter Cell), that is, Diagnostic-Cell-Complex (DxCell-Complex). The formation of an immune synapse, facilitated by the analyte antibody, resulted into a dual-reporter protein expression by the Reporter Cell. We validated it with human serum with confirmed history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. No signal amplification steps were necessary. The DxCell-Complex quantitatively detected the target-specific immunoglobulin G (IgG) within 1 h. Validation with clinical human serum containing SARS-CoV-2 IgG antibodies confirmed 97.04% sensitivity and 93.33% specificity. The platform can be redirected against other antibodies. Self-replication and activation-induced cell signaling, two attributes of the cell, will enable rapid and cost-effective manufacturing and its operation in healthcare facilities without requiring time-consuming signal amplification steps.

Cell-Based Platform for Antigen Testing and Its Application for SARS-CoV-2 Infection.

We have engineered a cell that can be used for diagnosing active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Isolation of individuals with active infections offers an effective solution for mitigating pandemics. However, the implementation of this practice requires robust infrastructure for rapid and intuitive testing, which is currently missing in our communities. To address this need, we engineered a fast-growing cell line into a cell-based antigen test platform for emerging viruses, i.e., DxCell, that can be rapidly deployed in decentralized health care facilities for continuous testing. The technology was characterized using cells engineered to present spike glycoprotein of SARS-CoV-2 (SARS-CoV-2-Sgp-cells) and Calu-3 host cells infected with competent SARS-CoV-2. Preclinical validation was conducted by directly incubating the DxCell with oropharyngeal swabs from mice infected with SARS-CoV-2. No sample preparation steps are necessary. The DxCell quantitatively detected the SARS-CoV-2-Sgp-cells within 1 h (P < 0.02). Reporter signal was proportional to the number of SARS-CoV-2-Sgp-cells, which represents the infection burden. The SARS-CoV-2 DxCell antigen test was benchmarked against quantitative PCR (qPCR) test and accurately differentiated between infected (n = 8) and control samples (n = 3) (P < 0.05). To demonstrate the broad applicability of the platform, we successfully redirected its specificity and tested its sensing function with cells engineered to present antigens from other viruses. In conclusion, we have developed an antigen test platform that capitalizes on the two innate functions of the cell, self-replication and activation-induced cell signaling. These provide the DxCell key advantages over existing technologies, e.g., label-free testing without sample processing, and will facilitate its implementation in decentralized health care facilities. IMPORTANCE Pandemic mitigation requires continuous testing of symptomatic or asymptomatic individuals with rapid turnaround time, and lack of this capability in our community has prolonged pandemic duration leading to obliteration of world economies. The DxCell platform is a cell-based self-replicative antigen test that detects molecular signatures of the target pathogen and can be distributed in small quantities to testing facilities for expansion on site to the desired volume. In this work, we directed this platform to target SARS-CoV-2. Unlike the PCR detection of viral mRNA that requires trained personnel, the DxCell does not require any sample preparation or signal amplification step and introduces an opportunity for a decentralized testing network.

COVID-19: Clinical laboratory diagnosis and monitoring of novel coronavirus infected patients using molecular, serological and biochemical markers: A review.

COVID-19, a novel coronavirus disease, has provoked a variety of health and safety concerns, and socioeconomic challenges around the globe. The laboratory diagnosis of SARS-CoV-2 was quickly established utilizing nucleic acid amplification techniques (NAAT) after the disease causing virus has been identified, and its genetic sequence has been determined. In addition to NAAT, serological tests based on antibodies testing against SARS-CoV-2 were introduced for diagnostic and epidemiologic studies. Other biochemical investigations include monitoring of peripheral blood cells count, platelets/lymphocyte ratio, coagulation profile, cardiac, and inflammatory markers such as cytokines storm are also crucial in combating COVID-19 pandemic. Further, accurate and reliable laboratory results for SARS-CoV-2 play very important role in the initiation of early treatment and timely management of COVID-19 patients, provide support in clinical decision-making process to control infection, and detection of asymptomatic cases. The Task Force on Coronavirus-19 constituted by International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has recognized informational framework for epidemiology, pathogenesis, and recommended the PCR-based analysis, serological and biochemical assays for analysis, monitoring, and management of disease. This literature review provides an overview of the currently used diagnostic techniques in clinical laboratories for the diagnosis, treatment monitoring, and management of COVID-19 patients. We concluded that each assays differ in their performance characteristics and the utilization of multiple techniques is necessary for the accurate diagnosis and management of SARS-CoV-2 infection.

FUSION OF MODULATION SPECTRAL AND SPECTRAL FEATURES WITH SYMPTOM METADATA FOR IMPROVED SPEECH-BASED COVID-19 DETECTION

Existing speech-based coronavirus disease 2019 (COVID-19) detection systems provide poor interpretability and limited robustness to unseen data conditions. In this paper, we propose a system to overcome these limitations. In particular, we propose to fuse two different feature modalities with patient metadata in order to capture different properties of the disease. The first feature set is based on modulation spectral properties of speech. The second comprises spectral shape/descriptor features recently used for COVID-19 detection. Lastly, we fuse patient metadata in order to improve robustness and interpretability. Experiments are performed on the 2021 INTERSPEECH COVID Speech Sub-Challenge dataset with several different data partitioning paradigms. Results show the importance of the modulation spectral features. Metadata, in turn, did not perform very well when used alone but provided invaluable insights when fused with the other features. Overall, a system relying on the fusion of all three modalities showed to be robust to unseen conditions and to rely on interpretable features. The simplicity of the model suggests that it can be deployed in portable devices, hence providing accessible COVID-19 diagnostics worldwide. © 2022 IEEE

Possibilities of Differential Diagnosis of Atopic Dermatitis and Rash in COVID-19 Using Telemedicine Technologies

Currently, the relevance of remote express diagnostics of various diseases is beyond doubt. The active spread of various types of epidemics and pandemics necessitates the improvement of various types of express diagnostics. The authors conduct research in the field of remote visual diagnostics using modern methods of processing telemedicine video information. This paper discusses the possibility of improving the quality of visualization of diagnostic signs using the digital dermatoscopy method for express diagnostics of skin rashes in COVID-19 in comparison with the manifestations of atopic dermatitis. The prospect of this work is the study of illumination conditions during registration and selection of skin areas for the analysis of diagnostic images. © 2021 IEEE.

Healthy humans can be a source of antibodies countering COVID-19.

Here, we describe the isolation of 18 unique anti SARS-CoV-2 human single-chain antibodies from an antibody library derived from healthy donors. The selection used a combination of phage and yeast display technologies and included counter-selection strategies meant to direct the selection of the receptor-binding motif (RBM) of SARS-CoV-2 spike protein's receptor binding domain (RBD2). Selected antibodies were characterized in various formats including IgG, using flow cytometry, ELISA, high throughput SPR, and fluorescence microscopy. We report antibodies' RBD2 recognition specificity, binding affinity, and epitope diversity, as well as ability to block RBD2 binding to the human receptor angiotensin-converting enzyme 2 (ACE2) and to neutralize authentic SARS-CoV-2 virus infection in vitro. We present evidence supporting that: 1) most of our antibodies (16 out of 18) selectively recognize RBD2; 2) the best performing 8 antibodies target eight different epitopes of RBD2; 3) one of the pairs tested in sandwich assays detects RBD2 with sub-picomolar sensitivity; and 4) two antibody pairs inhibit SARS-CoV-2 infection at low nanomolar half neutralization titers. Based on these results, we conclude that our antibodies have high potential for therapeutic and diagnostic applications. Importantly, our results indicate that readily available non immune (naïve) antibody libraries obtained from healthy donors can be used to select high-quality monoclonal antibodies, bypassing the need for blood of infected patients, and offering a widely accessible and low-cost alternative to more sophisticated and expensive antibody selection approaches (e.g. single B cell analysis and natural evolution in humanized mice).

A Rapid, Highly Sensitive and Open-Access SARS-CoV-2 Detection Assay for Laboratory and Home Testing.

RT-qPCR-based diagnostic tests play important roles in combating virus-caused pandemics such as Covid-19. However, their dependence on sophisticated equipment and the associated costs often limits their widespread use. Loop-mediated isothermal amplification after reverse transcription (RT-LAMP) is an alternative nucleic acid detection method that overcomes these limitations. Here, we present a rapid, robust, and sensitive RT-LAMP-based SARS-CoV-2 detection assay. Our 40-min procedure bypasses the RNA isolation step, is insensitive to carryover contamination, and uses a colorimetric readout that enables robust SARS-CoV-2 detection from various sample types. Based on this assay, we have increased sensitivity and scalability by adding a nucleic acid enrichment step (Bead-LAMP), developed a version for home testing (HomeDip-LAMP), and identified open-source RT-LAMP enzymes that can be produced in any molecular biology laboratory. On a dedicated website, rtlamp.org (DOI: 10.5281/zenodo.6033689), we provide detailed protocols and videos. Our optimized, general-purpose RT-LAMP assay is an important step toward population-scale SARS-CoV-2 testing.

ASSESSMENT of SEROLOGICAL TESTS for ANTIBODIES to DIFFERENT ANTIGENS of the SARS-CoV-2 VIRUS: COMPARISON of SIX IMMUNOASSAYS

The new coronavirus SARS-CoV-2 has become a global challenge to medicine and, in particular, laboratory diagnostics. The study of the antibodies' level to SARS-CoV-2 can be used as a confirmation test in the diagnosis of a disease, but it becomes of paramount importance in assessing population immunity resulting from a disease or vaccination, as well as in selection of convalescent plasma donors. The kits developed in our country and abroad for detecting antibodies to the SARS-CoV-2 virus differ both in the methods of testing and in the used coronavirus antigens to which the antibodies are directed. The aim of this study was to compare the diagnostic sensitivity and specificity of five kits for the detection of IgG antibodies to the SARS-CoV-2 virus, based on different diagnostic methods. Serum samples from 137 COVID-19 convalescents and 166 donors of blood and its components were examined. The control group consisted of 50 blood sera collected at the beginning of 2019 and 19 sera collected in 2018 (before the advent of the SARS-CoV-2 virus) and stored at -70 °C. Testing was carried out in analytical systems: rapid test “COVID-19 IgM/IgG Rapid Test (Colloidal Gold)” (China), on an automatic immunochemical analyzer Abbott Architect™ i2000 and kit “SARS-CoV-2-IgG” (Abbot, Chicago, IL USA), by the chemiluminescence method using an automatic analyzer of the CL series and kits of the “Mindray” company (China) “SARS-CoV-2 IgM” and “SARS-CoV-2 IgG” and by the enzyme immunoassay method on the kits of the companies “Diagnostic Systems” Ltd (Russia, Nizhny Novgorod) “DS-IFA-ANTI-SARS-CoV-2-G”, “Xema” Ltd (Federal State Budgetary Institution “National Medical Research Center of Hematology” of the Ministry of Health of Russia) “SARS-CoV-2-IgG-IFA” and “Vector-Best” CJSC (Russia, Novosibirsk)” SARS-COV-2-IgM-IFA-BEST” and “SARS-COV-2-IgG-IFABEST”. When comparing the results of testing 137 plasma samples on the Vector-Best and Mindray kits for IgG antibodies, 127 samples were positive, 7 samples were negative on both kits, the discrepancy was 2.2%. In the study of IgM antibodies, 32.1% were positive, and 52.6% were negative in both kits. The discrepancy rate was 15.3%. Out of 166 samples, 1 serum (0.6%) was negative in 5 kits. On the Mindray kit, IgG antibodies to the antigens of the SARS-CoV-2 virus were detected in 165 samples (99.4%), on Vector-Best - in 164 sera (98.8%), on Diagnostic systems - in 151 (90.96%), on Xema - in 154 (92.8%), and on Abbott - in 155 samples (93.4%). At the same time, 135 (81.33%) samples were positive in all kits, while 30 samples had discordant results (18.07%), and in 9 sera, specific IgG was not detected in 2 or more kits. ROC analysis revealed a high diagnostic value of all tested kits (AUC from 0.908 to 0.998), which indicates a high quality of the separation model of positive and negative samples (p < 0.001). With the cut-off set by the manufacturers, the sensitivity and specificity ranged from 82.8% and 93.3% for the Diagnostic Systems kit to 99.4% and 95.8% for the Vector-Best kit. The calculated correlation coefficients were higher between kits with a similar composition of the antigen used in the kits;therefore, it is better to monitor the dynamics of antibodies by diagnostic kits from the same manufacturer. © 2021 Russian Association of Allergologists and Clinical Immunologists, St. Petersburg Regional Branch (SPb RAACI). All rights reserved.

Handheld Microfluidic Filtration Platform Enables Rapid, Low-Cost, and Robust Self-Testing of SARS-CoV-2 Virus (Small 52/2021)

COVID-19 Diagnostics In article number 2104009, Jiang Xu, Yan Zhang, Taotao Lao, and co-workers present a handheld microfluidic filtration platform that enables rapid, low-cost and robust self-testing of the SARS-CoV-2 virus. The cover design emphasizes its important advantages: (1) Equipment-free handheld injection, represented by the hands manipulation;(2) Visible and easy readout: a Taichi diagram is used to distinguish the negative/positive results, which is in line with the meaning of Taichi (Yin/Yang) in traditional Chinese culture. The Taichi eyes are filled with illustrational structures of negative/positive nanocomplexes;(3) Reusable chips: the flow arrows at both inlet and outlet indicate that the chip can be repeatedly cleaned and injected.