Performance and Application Evaluation of SARS-CoV-2 Antigen Assay

Research on coronavirus disease 2019 and the kidney: A bibliometric analysis

Background

In addition to damage to the lungs, coronavirus disease 2019 (COVID-19) can damage multiple organs, including the kidney. Our purpose was to analyze the research hotspots and trends in COVID-19 and kidney diseases using bibliometrics to help clarify the development direction of this field.

Methods

We selected and extracted all relevant publications related to COVID-19 and the kidney from the Web of Science from December 1, 2019, to July 24, 2022. VOSviewer, RStudio, CiteSpace, and other software were used to visualize keywords, publishing trends, authors and their countries, and institutions in this field and perform the statistical analysis.

Results

A total of 645 articles published in 220 journals were included in this study. The United States and China contributed the most publications and were most active in international cooperation. In addition to COVID-19 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), acute kidney injury (AKI), kidney transplant and mortality were the three keywords with the highest frequencies. In the initial stage of the COVID-19 outbreak, research focused on the clinical symptoms of COVID-19 and other macrocharacteristics, while in a later stage, the associations between SARS-CoV-2 infection and CKD and AKI, as well as the prognosis of patients with kidney disease or those who underwent kidney transplantation, gained more attention. The immune response and vaccines were also recent research hotspots.

Conclusions

This bibliometric analysis provides a comprehensive overview of research on COVID-19 and kidney disease, which has received continuous, global attention. AKI, CKD, kidney transplantation, immune response and vaccines are among the hotspots in this field.

An overview for monitoring and prediction of pathogenic microorganisms in the atmosphere

Corona virus disease 2019 (COVID-19) has exerted a profound adverse impact on human health. Studies have demonstrated that aerosol transmission is one of the major transmission routes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pathogenic microorganisms such as SARS-CoV-2 can survive in the air and cause widespread infection among people. Early monitoring of pathogenic microorganism transmission in the atmosphere and accurate epidemic prediction are the frontier guarantee for preventing large-scale epidemic outbreaks. Monitoring of pathogenic microorganisms in the air, especially in densely populated areas, may raise the possibility to detect viruses before people are widely infected and contain the epidemic at an earlier stage. The multi-scale coupled accurate epidemic prediction system can provide support for governments to analyze the epidemic situation, allocate health resources, and formulate epidemic response policies. This review first elaborates on the effects of the atmospheric environment on pathogenic microorganism transmission, which lays a theoretical foundation for the monitoring and prediction of epidemic development. Secondly, the monitoring technique development and the necessity of monitoring pathogenic microorganisms in the atmosphere are summarized and emphasized. Subsequently, this review introduces the major epidemic prediction methods and highlights the significance to realize a multi-scale coupled epidemic prediction system by strengthening the multidisciplinary cooperation of epidemiology, atmospheric sciences, environmental sciences, sociology, demography, etc. By summarizing the achievements and challenges in monitoring and prediction of pathogenic microorganism transmission in the atmosphere, this review proposes suggestions for epidemic response, namely, the establishment of an integrated monitoring and prediction platform for pathogenic microorganism transmission in the atmosphere.

Rapid assays of SARS-CoV-2 virus and noble biosensors by nanomaterials

The COVID-19 outbreak caused by SARS-CoV-2 in late 2019 has spread rapidly across the world to form a global epidemic of respiratory infectious diseases. Increased investigations on diagnostic tools are currently implemented to assist rapid identification of the virus because mass and rapid diagnosis might be the best way to prevent the outbreak of the virus. This critical review discusses the detection principles, fabrication techniques, and applications on the rapid detection of SARS-CoV-2 with three categories: rapid nuclear acid augmentation test, rapid immunoassay test and biosensors. Special efforts were put on enhancement of nanomaterials on biosensors for rapid, sensitive, and low-cost diagnostics of SARS-CoV-2 virus. Future developments are suggested regarding potential candidates in hospitals, clinics and laboratories for control and prevention of large-scale epidemic.

A semi-quantitative upconversion nanoparticle-based immunochromatographic assay for SARS-CoV-2 antigen detection

The unprecedented public health and economic impact of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been met with an equally unprecedented scientific response. Sensitive point-of-care methods to detect SARS-CoV-2 antigens in clinical specimens are urgently required for the rapid screening of individuals with viral infection. Here, we developed an upconversion nanoparticle-based lateral flow immunochromatographic assay (UCNP-LFIA) for the high-sensitivity detection of SARS-CoV-2 nucleocapsid (N) protein. A pair of rabbit SARS-CoV-2 N-specific monoclonal antibodies was conjugated to UCNPs, and the prepared UCNPs were then deposited into the LFIA test strips for detecting and capturing the N protein. Under the test conditions, the limit of detection (LOD) of UCNP-LFIA for the N protein was 3.59 pg/mL, with a linear range of 0.01-100 ng/mL. Compared with that of the current colloidal gold-based LFIA strips, the LOD of the UCNP-LFIA-based method was increased by 100-fold. The antigen recovery rate of the developed method in the simulated pharyngeal swab samples ranged from 91.1 to 117.3%. Furthermore, compared with the reverse transcription-polymerase chain reaction, the developed UCNP-LFIA method showed a sensitivity of 94.73% for 19 patients with COVID-19. Thus, the newly established platform could serve as a promising and convenient fluorescent immunological sensing approach for the efficient screening and diagnosis of COVID-19.

Immunochromatographic enhancement strategy for SARS-CoV-2 detection based on nanotechnology

The global outbreak of coronavirus disease 2019 (COVID-19) has been catastrophic to both human health and social development. Therefore, developing highly reliable and sensitive point-of-care testing (POCT) for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a priority. Among all available POCTs, the lateral flow immunoassay (LFIA, also known as immunochromatography) has proved to be effective due to its accuracy, portability, convenience, and speed. In areas with a scarcity of laboratory resources and medical personnel, the LFIA provides an affordable option for the diagnosis of COVID-19. This review offers a comprehensive overview of methods for improving the sensitivity of SARS-CoV-2 detection using immunochromatography based on nanotechnology, sorted according to the different detection targets (antigens, antibodies, and nucleic acids). It also looks into the performance and properties of the various sensitivity enhancement strategies, before delving into the remaining challenges in COVID-19 diagnosis through LFIA. Ultimately, it seeks to provide helpful guidance in selecting an appropriate strategy for SARS-CoV-2 immunochromatographic detection based on nanotechnology.

Recent Advances in DNA Nanotechnology-Enabled Biosensors for Virus Detection

Virus-related infectious diseases are serious threats to humans, which makes virus detection of great importance. Traditional virus-detection methods usually suffer from low sensitivity and specificity, are time-consuming, have a high cost, etc. Recently, DNA biosensors based on DNA nanotechnology have shown great potential in virus detection. DNA nanotechnology, specifically DNA tiles and DNA aptamers, has achieved atomic precision in nanostructure construction. Exploiting the programmable nature of DNA nanostructures, researchers have developed DNA nanobiosensors that outperform traditional virus-detection methods. This paper reviews the history of DNA tiles and DNA aptamers, and it briefly describes the Baltimore classification of virology. Moreover, the advance of virus detection by using DNA nanobiosensors is discussed in detail and compared with traditional virus-detection methods. Finally, challenges faced by DNA nanobiosensors in virus detection are summarized, and a perspective on the future development of DNA nanobiosensors in virus detection is also provided.

Epidemiology and SARS-CoV-2 Infection Patterns among Youth Followed at a Large Los Angeles Health Network during 2020-2022: Clinical Presentation, Prevalent Strains, and Correlates of Disease Severity

BACKGROUND

Outcomes of SARS CoV-2 infection in infants, children and young adults are reported less frequently than in older populations. The evolution of SARS-CoV-2 cases in LA County youths followed at a large health network in southern California over two years was evaluated.

METHODS

A prospective cohort study of patients aged 0-24 years diagnosed with COVID-19 was conducted. Demographics, age distribution, disease severity, circulating variants of concern (VOCs), and immunization rates were compared between first and second pandemic years. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) of factors associated with severe/critical COVID-19.

RESULTS

In total, 61,208 patients 0-24 years of age were tested for SARS-CoV-2 by polymerase chain reaction (PCR); 5263 positive patients (8.6%) with available data were identified between March 2020 and March 2022. In Year 1, 5.8% (1622/28,088) of youths tested positive, compared to 11% (3641/33,120) in Year 2 (p < 0.001). Most youths had mild/asymptomatic illness over two years. SARS-CoV-2 positivity was >12% across all age groups in the second half of Year 2, when Omicron prevailed. Pulmonary disease was associated with higher risk of severe COVID-19 in both years (OR: 2.4, 95% CI: 1.4-4.3, p = 0.002, Year 1; OR: 11.3, 95% CI: 4.3-29.6, Year 2, p < 0.001). Receipt of at least one COVID-19 vaccine dose was protective against severe COVID-19 (OR: 0.3, 95% CI: 0.11-0.80, p < 0.05).

CONCLUSIONS

Despite different VOCs and higher rates of test positivity in Year 2 compared to Year 1, most youths with COVID-19 had asymptomatic/mild disease. Underlying pulmonary conditions increased the risk of severe COVID-19, while vaccination was highly protective against severe disease in youths.

Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies

The COVID-19 pandemic has posed enormous challenges for existing diagnostic tools to detect and monitor pathogens. Therefore, there is a need to develop point-of-care (POC) devices to perform fast, accurate, and accessible diagnostic methods to detect infections and monitor immune responses. Devices most amenable to miniaturization and suitable for POC applications are biosensors based on electrochemical detection. We have developed an impedimetric immunosensor based on an interdigitated microelectrode array (IMA) to detect and monitor SARS-CoV-2 antibodies in human serum. Conjugation chemistry was applied to functionalize and covalently immobilize the spike protein (S-protein) of SARS-CoV-2 on the surface of the IMA to serve as the recognition layer and specifically bind anti-spike antibodies. Antibodies bound to the S-proteins in the recognition layer result in an increase in capacitance and a consequent change in the impedance of the system. The impedimetric immunosensor is label-free and uses non-Faradaic impedance with low nonperturbing AC voltage for detection. The sensitivity of a capacitive immunosensor can be enhanced by simply tuning the ionic strength of the sample solution. The device exhibits an LOD of 0.4 BAU/ml, as determined from the standard curve using WHO IS for anti-SARS-CoV-2 immunoglobulins; this LOD is similar to the corresponding LODs reported for all validated and established commercial assays, which range from 0.41 to 4.81 BAU/ml. The proof-of-concept biosensor has been demonstrated to detect anti-spike antibodies in sera from patients infected with COVID-19 within 1 h. Photolithographically microfabricated interdigitated microelectrode array sensor chips & label-free impedimetric detection of COVID-19 antibody.

Promising instrument-free detections of various analytes using smartphones with Spotxel® Reader

In consideration of the problems related to food safety, environmental pollution, and the spread of infected diseases nowadays, we urgently need testing methods that can be easily performed by common people. Smartphone-based detections are promising for general applications. However, some of these analytical strategies require a combination of accessories and instruments, such as portable electrochemical workstations, mini multi-mode microplate readers, and complex temperature control devices, etc., which are small but still expensive. Herein, we comprehensively introduce a free app (Spotxel^® Reader) that can provide accurate data analysis for microplate or parallel-format test sensors without an instrument. By simulating the optical signal of the test samples through a smartphone, the sensing results can be obtained for free. We discuss the detection strategies involved in the reported smartphone-based analyses using Spotxel^® Reader. Prospects for the development of this free app for future detection applications are presented. This review aims to popularize free analysis software, so that ordinary people may realize convenient tests.

Visual Detection of COVID-19 from Materials Aspect

ABSTRACT

In the recent COVID-19 pandemic, World Health Organization emphasized that early detection is an effective strategy to reduce the spread of SARS-CoV-2 viruses. Several diagnostic methods, such as reverse transcription-polymerase chain reaction (RT-PCR) and lateral flow immunoassay (LFIA), have been applied based on the mechanism of specific recognition and binding of the probes to viruses or viral antigens. Although the remarkable progress, these methods still suffer from inadequate cellular materials or errors in the detection and sampling procedure of nasopharyngeal/oropharyngeal swab collection. Therefore, developing accurate, ultrafast, and visualized detection calls for more advanced materials and technology urgently to fight against the epidemic. In this review, we first summarize the current methodologies for SARS-CoV-2 diagnosis. Then, recent representative examples are introduced based on various output signals (e.g., colorimetric, fluorometric, electronic, acoustic). Finally, we discuss the limitations of the methods and provide our perspectives on priorities for future test development.

Accurate Interpretation of SARS-CoV-2 Antigen Detection by Immunochromatography

SARS-CoV-2 is a serious infectious respiratory virus that can cause lung, heart, kidney, and liver damage and even cause death. Early diagnosis of SARS-CoV-2 infection is vital for epidemic prevention and control. At present, the gold standard of COVID-19 diagnosis is nucleic acid detection of SARS-CoV-2. However, the nucleic acid detection of SARS-CoV-2 requires high site requirements and technology requirements, and the detection is time-consuming and cannot fully meet clinical needs. Although SARS-CoV-2 antigen test results cannot be directly used to diagnose COVID-19, positive results can be used for the early triage and rapid management of suspected populations. However, due to the limitations of the methodology itself, the SARS-CoV-2 antigen test is prone to produce false-positive and false-negative results in the process of detection. It is urgent to develop a batch of SARS-CoV-2 antigen reagents based on new detection technology and detection principles to overcome the defects of existing technologies.