Community Group Purchasing of Next-Day Delivery: Bridging the Last Mile Delivery for Urban Residents during COVID-19 in China (preprint)

The rapid development of new retail and the impact of COVID-19 have catalyzed the blowout growth of community group purchasing. The emergence of community group purchasing collection and delivery points (CGPCDPs) has become a new way to solve the "last mile" problem of new retail delivery. Based on the point of interest (POI) data of CGPCDPs of Nansha District, Guangzhou City, this study uses text analysis, spatial analysis, model analysis, and other methods to analyze the operation mode, spatial distribution, and influencing factors of CGPCDPs. The conclusions are as follows: CGPCDPs initiators are mainly shopkeepers. They depend mainly on wholesale and retail shops. Service targets are mainly urban and rural communities, followed by industrial areas. The distribution of CGPCDPs has apparent spatial differentiation. At the macro scale, it shows the characteristics of "central agglomeration and peripheral dispersion". It is distributed along the "northwest-southeast" direction and presents a "dual-core multi-center" pattern. At meso-micro scale, different built environments in developed areas of cities, villages in the city (ChengZhongCun) and rural areas show distinct distribution patterns. The MGWR regression model has a better fitting effect than OLS and GWR. The main influencing factors are population density, construction land, house price, supporting place, residence density, urban community, and road proximity.

Neutrophil Elastase Inhibitor (Sivelestat) in the Treatment of Acute Respiratory Distress Syndrome Induced by COVID- 19: A Multicenter Retrospective Cohort Study (preprint)

Background Recent studies suggest that neutrophil elastase inhibitor (Sivelestat) may improve pulmonary function and reduce mortality in patients with acute respiratory distress syndrome. We examined the association between receipt of sivelestat and improvement in oxygenation among patients with acute respiratory distress syndrome (ARDS) induced by COVID-19.Methods A large multicentre cohort study of patients with ARDS induced by COVID-19 who had been admitted to intensive care units (ICUs). We used propensity score matching to compare the outcomes of patients treated with sivelestat to those who were not. The differences in continuous outcomes were assessed with the Wilcoxon signed-rank test. Kaplan-Meier method was used to show the 28-day survival curves in the matched cohorts. A log-rank P-test stratified on the matched pairs was used to test the equality of the estimated survival curves. A Cox proportional hazards model that incorporated a robust sandwich-type variance estimator to account for the matched nature of the data was used to estimate hazard ratios (HR). All statistical analyses were performed with SPSS 26.0 and R 4.2.3. A two-sided p-value of < 0.05 was considered statistically significant.Results A total of 387 patients met inclusion criteria, including 259 patients (66.9%) who were treated with sivelestat. In 158 patients matched on the propensity for treatment, receipt of sivelestat was associated with improved oxygenation, decreased Murray lung injury score, increased non-mechanical ventilation time within 28 days, increased alive and ICU-free days within 28 days (HR, 1.85; 95% CI, 1.29 to 2.64; log-rank p < 0.001), shortened ICU stay and ultimately improved survival (HR, 2.78; 95% CI, 1.32 to 5.88; log-rank p = 0.0074).Conclusions Among patients with ARDS induce by COVID-19, sivelestat administration is associated with improved clinical outcomes.

SARS-CoV-2 NSP13 suppresses the Hippo pathway downstream effector YAP (preprint)

The Hippo pathway plays critical roles in tissue development, regeneration, and immune homeostasis. The widespread pandemic of Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has resulted in a global healthcare crisis and strained health resources. How SARS-CoV-2 affects Hippo signaling in host cells has remained poorly understood. Here, we report that SARS-CoV-2 infection in patient lung cells and cardiomyocytes derived from human induced pluripotent stem cells (iPS-CMs) suppressed YAP target gene expression, as evidenced by RNA sequencing data. Furthermore, in a screening of nonstructural proteins from SARS-CoV-2, nonstructural protein 13 (NSP13) significantly inhibited YAP transcriptional activity independent of the YAP upstream suppressor kinase Lats1/2. Consistent with this, NSP13 suppressed active YAP (YAP5SA) in vivo, whereby NSP13 expression reverted the phenotype of YAP5SA transgenic mice. From a mechanistic standpoint, NSP13 helicase activity was shown to be required for its suppression of YAP. Furthermore, through the interaction of NSP13 with TEAD4, which is the most common YAP-interacting transcription factor in the nucleus, NSP13 recruited endogenous YAP suppressors such as CCT3 and TTF2 to inactivate the YAP/TEAD4 complex. These findings reveal the function and mechanism of the SARS-CoV-2 helicase NSP13 in host cells and partially explain the toxic effect of SARS-CoV-2 in particular host tissue with high YAP activity.

Cities and epidemics: Reflection based on spatio-temporal spread and medical carrying capacity of early COVID-19 outbreak in China (preprint)

New and more dreadful viruses may emerge again in the future and cause a large demand for medical care. It is essential to explore different cities’ early spatio-temporal spread characteristics of the COVID-19 epidemic and the medical carrying capacity. This study examined the situation of six high-incidence Chinese cities using an integrated manual text and spatial analysis approach. Results show that the initial COVID-19 outbreak went through three phases: unknown-origin incubation, Wuhan-related outbreak, and local exposure outbreak. Cities with massive confirmed cases exhibited the multicore pattern, while those with fewer cases exhibited the single-core pattern. The cores were hierarchically located in the central built-up areas of cities’ economic, political, or transportation centers, and the radii of the cores shrank as the central built-up area’s level decreased, showing the hierarchical decay and the core-edge structure. That is, a decentralized built environment (non-clustered economies and populations) is less likely to create a large-scale epidemic cluster. Besides, the clusters of excellent hospital resources were consistent with those of COVID-19 outbreaks, but their carrying capacity still needs urgent improvement. And the essence of prevention and control is the governance of human activities and the management, allocation, and efficient use of limited resources about people, places, and materials leveraging IT and GIS, to confront the contradiction between supply and demand.

Photocatalytic Chemical Crosslinking for Profiling RNA–Protein Interactions in Living Cells

The dynamic interactions between RNAs and proteins play crucial roles in regulating diverse cellular processes. Proteome‐wide characterization of these interactions in their native cellular context remains desirable but challenging. Herein, we developed a photocatalytic crosslinking (PhotoCAX) strategy coupled with mass spectrometry (PhotoCAX‐MS) and RNA sequencing (PhotoCAX‐seq) for the study of the composition and dynamics of protein‐RNA interactions. By integrating the blue light‐triggered photocatalyst with a dual‐functional RNA–protein crosslinker (RP‐linker) and the phase separation‐based enrichment strategy, PhotoCAX‐MS revealed a total of 2044 RBPs in human HEK293 cells. We further employed PhotoCAX to investigate the dynamic change of RBPome in macrophage cells upon LPS‐stimulation, as well as the identification of RBPs interacting directly with the 5′ untranslated regions of SARS‐CoV‐2 RNA. [ FROM AUTHOR] Copyright of Angewandte Chemie International Edition is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

A multi-dimensional robust optimization approach for cold-chain emergency medical materials dispatch under COVID-19: A case study of Hubei Province

For the optimization problem of the cold-chain emergency materials (CEM) distribution routes with multi-demand centers and soft time windows and to solve dispatching materials to medical treatment institutions in various places of the disaster areas under COVID-19, a multi-dimensional robust optimization (MRO) model was proposed, which was solved by a hybrid algorithm combined Pareto genetic algorithm and the improved grey relative analysis (IGRA). The proposed model comprehensively takes into consideration of the cost factors of the cold-chain logistics and robustness of solution with the purpose of minimizing the costs and maximizing robustness. The availability of the proposed approach and hybrid algorithm were thoroughly discussed and qualified through a real-world numerical simulation test case, which was a previous risk area located at Hubei Province. Research results show an average-cost reduction of 4.51% and a robustness increment of 11.69% in addition to consider the urgencies of demand. Consequently, not only the costs can be slightly reduced and the robustness be heightened, but also the blindness of the distribution can be avoided effectively with the demand urgency being considered. Research result indicates that when combining with the specific process of supplies dispatching in the prevention and control, the proposed approach is in a far better agreement in practice, and it could meet the diverse requirements of the emergency scenarios flexibly.

Broad ultra-potent neutralization of SARS-CoV-2 variants by monoclonal antibodies specific to the tip of RBD (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) continue to wreak havoc across the globe. Higher transmissibility and immunologic resistance of VOCs bring unprecedented challenges to epidemic extinguishment. Here we describe a monoclonal antibody, 2G1, that neutralizes all current VOCs and has surprising tolerance to mutations adjacent to or within its interaction epitope. Cryo-electron microscopy structure showed that 2G1 bound to the tip of receptor binding domain (RBD) of spike protein with small contact interface but strong hydrophobic effect, which resulted in nanomolar to sub-nanomolar affinities to spike proteins. The epitope of 2G1 on RBD partially overlaps with ACE2 interface, which gives 2G1 ability to block interaction between RBD and ACE2. The narrow binding epitope but high affinity bestow outstanding therapeutic efficacy upon 2G1 that neutralized VOCs with sub-nanomolar IC50 in vitro. In SARS-CoV-2 and Beta- and Delta-variant-challenged transgenic mice and rhesus macaque models, 2G1 protected animals from clinical illness and eliminated viral burden, without serious impact to animal safety. Mutagenesis experiments suggest that 2G1 could be potentially capable of dealing with emerging SARS-CoV-2 variants in future. This report characterized the therapeutic antibodies specific to the tip of spike against SARS-CoV-2 variants and highlights the potential clinical applications as well as for developing vaccine and cocktail therapy.

Coronavirus disease 2019 in pregnancy

Objectives: This study aimed to compare clinical courses and outcomes between pregnant and reproductive-aged non-pregnant women with COVID-19, and to assess the vertical transmission potential of COVID-19 in pregnancy.

Health-Seeking Behavior of Patients with Cardiovascular Diseases During COVID-19 Epidemic and Post-Epidemic Period in Shanghai, China (preprint)

Background: The COVID-19 pandemic has led to concerns around its subsequent impact on patients with non-COVID-19 diseases, and the health-seeking behavior of such patients must be investigated.Methods: Taking advantage of the remote ECG system covering 278 medical institutions throughout Shanghai, the numbers of hospital visits with ECG examinations during the lockdown (between January 23 and April 7, 2020), post-lockdown (between April 8 and December 31, 2020) and post-epidemic (between January 23 and April 7, 2021) periods were analyzed and compared against those during the same periods of the preceding years (2018 and 2019).Findings: Compared with those of the same period during pre-COVID years, the number of hospital visits decreased during the lockdown (a 38% reduction), followed by a rebound post-lockdown (a 17% increase) and a fall to the baseline level of the post-epidemic period. This decrease-rebound-fallback pattern was largely attributed to the dynamics of visits to community clinics rather than academic hospitals. The number of new COVID-19 cases or deaths announced on a given day correlated negatively with hospital visits during the same day and for the following 42 days, with the correlation at its most prominent at seven days. Hospital visit dynamics differed for various cardiovascular diseases. Whereas hospital visits for sinus bradycardia exhibited a typical decrease-rebound-fallback pattern, hospital visits for ST-segment elevated myocardial infarction did not fall during the lockdown period but did exhibit a subsequent increase during the post-lockdown period. By comparison, the volume for ventricular tachycardia remained constant throughout this entire period.Interpretation: The health-seeking behavior of patients with cardiovascular diseases exhibited a decrease-rebound-fallback pattern following the COVID-19 lockdowns. Hospital visits for diseases with more severe symptoms were less influenced by the lockdowns, showing a resilient demand for healthcare.Funding: Shanghai Hospital Development Center, National Natural Science Foundation of China, Shanghai Municipal Science and Technology Commission, and Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. Declaration of Interest: All authors declare no conflicts of interest.Ethical Approval: This study was approved by the ethics committee at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine.

The epidemic characteristics of COVID-19 in different regions of Guangxi

Objective: The epidemic of corona Virus disease 2019 (COVID- 19) in Guangxi Zhuang Autonnmous Region during January 23 and February 16, 2020 was evaluated to provide evidence for the prevention and control of the- COV1D-19 outbreak.

Text-based Analysis of the Geographic Spread of the COVID-19 Pandemic in China (preprint)

Background: The COVID-19 pandemic spread rapidly due to the mass migration during the Spring Festival in China, bringing a significant public health challenge. This study aims to explore the pattern of COVID-19 diffusion related to the Spring festival and provide some suggestions on controlling the epidemic.Methods: We included 10316 cases from provincial or city Health Commission websites outside Hubei in China from December 30, 2019 to February 27, 2020. Data on the gender, age, occupation, inflow and outflow places were extracted from confirmed cases' detailed records. Results: The number of confirmed cases who worked in commercial service was the largest, accounting for nearly 55%, followed by sales service (22%) and transport service (13.6%). "Wuhan", "close contact", "quarantine" (15.31) and "fever" (13.43) were the highest-linked centers within the text analysis. Most of the infected are relatives of confirmed cases and people mainly choose the self-driving transportation mode to go to hospitals. The clinical symptoms' expression varies among different age groups. Over time, infected areas and generations have experienced transitions from the nonlocal first to the local third group, and from more males infected to females. The source of the epidemic spreads to the south, then to the north, and finally evolves to the southeast, and the spread direction is from south to north afterward to west, over time. Wuhan and Shenzhen had the biggest influence on the flow as essential points of the flow network. The principal path often originated in Hubei or provincial capital cities and flowed to those cities which are densely populated and economically developed. “Returning home to visit relatives”, “migrant workers returning home” and “returning home after traveling” are the chief migration reasons. Compared with the long-term flows, short-term paths are of shorter distance. About half of confirmed cases migrated with their families. Finally, the flows are always opposite to the gradient mobility pattern of China's labor.Conclusion: Based on the background of the reunion tradition in the Spring Festival, the diffusion of COVID-19 outside Hubei in China presented a pattern tied to person migration to return home. At the macroscopic scale, the pattern shows a linear relocation diffusion from vertical to horizontal. On the microscopic scale, radiation contact diffusion with transit from the nonlocal first to the local third group and male-dominated cases in the early stage to mostly female cases in the later stage were the apparent trend.

Association Between an Increase in Blood Urea Nitrogen at 24 Hours and Worse Outcomes in COVID-19 Pneumonia (preprint)

Background and objectives: The dynamic change of blood urea nitrogen (BUN) have been proved to be related to the worse outcomes in various diseases such as pulmonary embolism, acute pancreatitis and acute nonvariceal upper GI bleeding. In the present study, we aimed to identify the association between blood urea nitrogen (BUN) change and clinical outcomes in patients presenting with COVID-19 pneumonia.Methods: This is a retrospective study conducted in the Huoshenshan hospital. Patients with laboratory-confirmed COVID-19 from Feb 5th to March 5th in 2020 who had BUN level tested on admission and on the second day consecutively were included. Patients were stratified into two groups according to the BUN change (increase vs. no increase) during the first 24 hours. The primary outcome was in-hospital mortality. Moreover, other clinical outcomes were also compared. The potential risk factors of in-hospital mortality were analyzed. Results: There were 266 patients included in the study. The mean change in BUN at 24 hours was 1.0 mg/dL, with 206 patients (77.4%) experiencing no increase in BUN and 60 patients (22.6%) experiencing an increase in BUN. In-hospital mortality was significantly higher in the BUN increase group compared to no increase group (30.0% vs. 5.8%, P<0.001). BUN increase group also had higher requirement for ICU admission, use of invasive mechanical ventilation and incidence of AKI (all P<0.001). After adjusted for related factors, the BUN increase was independently associated with the mortality with an odds ratio of 7.427[95% CI 2.370-23.279]. In the multivariable and survival analysis, BUN increase was also found to be associated with survival regardless of the admission BUN.Conclusions: In patients with COVID-19, BUN increase at 24 hours was an independent predictor for a composite clinical outcome and in-hospital mortality. The association of BUN increase with worse outcomes further emphasizes the importance of monitoring BUN change and kidney function in the course of COVID-19.

Characteristics of myocardial injury in severe and critical coronavirus disease 2019 patients and its effect on prognosis

Objective To analyze the characteristics and related risk factors of myocardial injury in severe and critical coronavirus disease 2019 (COVID-19) patients and their relationship with the prognosis. Methods The clinical data of severe and critical COVID-19 patients treated in General Hospital of Central Theater Command of PLA from Jan. 2020 to Mar. 2020 were collected. The patients were divided into non-myocardial injury group and myocardial injury group. The baseline data, clinical characteristics, auxiliary examination, treatment and prognosis were compared between the two groups, and the risk factors of myocardial injury and the effect on the prognosis of the severe and critical COVID-19 patients were analyzed. Results A total of 56 patients were included, with 22 in the non-myocardial injury group and 34 in the myocardial injury group. Patients were mostly male in both groups, and there was no significant difference in gender composition between the two groups (P>0.05). Compared with the non-myocardial injury group, the age of onset was significantly higher in the myocardial injury group (78.5[ 70.8, 89.0] years vs 56.5[ 50.3, 68.3] years, P<0.01), and the proportions of patients over 65 years old and combined with coronary heart disease were significantly greater (85.3%[ 29/34] vs 31.8%[ 7/22] and 38.2% [13/34] vs 9.1%[ 2/22], both P<0.05). In terms of symptoms, fever (87.5%, 49/56), cough (64.3%, 36/56) and fatigue (46.4%, 26/56) were the most common ones, and there were no significant differences between the two groups (all P>0.05). For the CT findings of the lungs, the proportion of patients having patch-like/plaque-like shadows and ground-glass opacities was significantly greater in the non-myocardial injury group versus the myocardial injury group (72.7%[ 16/22] vs 38.2%[ 13/34], χ2=6.364, P<0.05), and other signs were not significantly different between the two groups (P>0.05). Compared with the non-myocardial injury group, the levels of N-terminal pro-B-type natriuretic peptide, D-dimer, procalcitonin and IL-6 were significantly higher in the myocardial injury group (4 939.5[ 1 817.0, 9 450.3] pg/mL vs 612.5[ 301.0, 1 029.5] pg/mL, 4 386.5 [2 309.5, 9 635.3] ng/mL vs 850.5 [343.5, 2 333.8] ng/mL, 0.46 [0.23, 3.79] ng/mL vs 0.18 [0.13, 0.39] ng/mL, and 138.6 [41.9, 464.8] pg/mL vs 65.1[ 34.7, 99.3] pg/mL, respectively), and the differences were significant (all P<0.01). Multivariate logistic regression analysis showed that age≥65 years old (odds ratio[ OR] =18.62, 95% confidence interval[ CI] 1.61-215.96, P<0.05) and D-dimer level≥3 000 ng/mL (OR=15.48, 95% CI 1.45-164.77, P<0.05) were the independent risk factors for myocardial injury in severe and critical COVID-19 patients. There were no significant differences in the use of antiviral drugs, antibacterial drugs, or glucocorticoids between the two groups (all P>0.05). The mortality rate was significantly higher in the myocardial injury than that in the non-myocardial injury group (58.8% [20/34] vs 9.1% [2/22], P<0.01). Patients who received tracheal intubation, extracorporeal membrane oxygenation, continuous renal replacement therapy (CRRT) and other invasive life support measures were all in the myocardial injury group. Conclusion Older age, male gender, coronary heart disease and (or) cardiac insufficiency, and elevated D-dimer, procalcitonin and IL-6 are the risk factors of myocardial injury in severe and critical COVID-19 patients. Myocardial injury can aggravate the condition and some patients need invasive circulating breathing support, with poor prognosis and high mortality. Therefore, the above indicators need to be observed more closely and dynamically and active treatment should be given according to related factors.

Network pharmacologic molecular mechanism of Shenmai Injection in treatment of COVID-19 combined with coronary heart disease

Objective: To analyze the molecular interaction network pathway of Shenmai Injection in the treatment of COVID-19 with coronary heart disease by using network pharmacology. Methods: Using the TCMSP and ETCM to retrieve the chemical constituents of Ginseng Radix et Rhizoma Rubra and Ophiopogonis Radix in Shenmai Injection. The target of the compound was predicted through the SwissTargetPrediction database. The target of COVID-19 with coronary heart disease was screened through the NCBI database and the GeneCards database, and the targets of compound and disease were mapped to obtain the target of the compound for treating the disease. FunRich software and DAVID database were used to perform GO function enrichment analysis and KEGG pathway enrichment analysis, and Excel software and Tableau software to draw bar charts and bubble charts for visualization. Finally, Cytoscape 3.7.1 software was used to build compound-target-pathway network. Glide was used to dock the components of Shenmai Injection with 3CL hydrolase (Mpro). Results: The results showed that ophiopogonin D', ophiopogonin D, ginsenoside Rg 2, methyl ophiopogonanone A, ophiogenin-3-O-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranoside, ginsenoside Rb 2, ginsenoside R 0, ophiopogon A, sanchinoside Rd, ophiopogonanone E, and ginsenoside Re showed higher degrees in the analysis and stronger binding with 3CL hydrolase. Those compounds were the main effective components in the treatment of COVID-19 combined with coronary heart disease, involving 77 targets such as IL6, GAPDH, ALB, TNF, MAPK1, MAPK3, TP53, EGFR, CASP3, and CXCL8. KEGG pathway enrichment analysis revealed that there were 124 (P < 0.05) signaling pathways involving HIF-1 signaling pathway, TNF signaling pathway, sphingolipid signaling pathway, Toll-like receptor signaling pathway, neurotrophin signaling pathway, VEGF signaling pathway, apoptosis, Ras signaling pathway, PI3K-Akt signaling pathway, and prolactin signaling pathway. The results of molecular docking showed that the affinity between the 17 components of Shenmai Injection and the 3CL hydrolase of SARS-CoV-2 was less than -25 kJ/mol. Conclusion: Shenmai Injection can achieve simultaneous intervention of COVID-19 and coronary heart disease by inhibiting cytokine storms, maintaining cardiac function homeostasis, regulating immunity, and antivirals. It presents the network regulation mechanism of mutual influence and complex correlation. This study can provide a scientific basis for the treatment of Shenmai Injection in critically ill patients with COVID-19.

Spatiotemporal evolution and diffusion pattern of the COVID-19 epidemic in Hainan Province, China (preprint)

Within one month after the first case occurred in Hainan Province, the number of confirmed cases increased to 168, and there was no increase in nearly three months. As the southernmost province and a famous tourist destination, its frequent economic exchanges and high-intensity movements may affect the spread of epidemic. Therefore, it is of great theoretical and practical significance to examine the spatiotemporal evolution and diffusion pattern of the COVID-19 epidemic in Hainan Province.

A Single-Center Retrospective and Descriptive Study of Hepatobiliary and Pancreatic Surgical Oncology during the COVID-19 Epidemic (preprint)

Objective: In the battle against COVID-19, most medical resources in China have been directed to infected patients in Wuhan. Thus, patients with hepatobiliary pancreatic tumors who are not suffering from COVID-19 are often not given timely and effective anti-cancer treatments. In this study, we aimed to describe clinical characteristics, treatment, and outcomes of patients with hepatobiliary and pancreatic oncology from our department, which retained normal working during the COVID-19 epidemic. We also sought to formulate a set of standardized hospitalization and treatment processes.Methods: A retrospective and descriptive study was conducted involving patients hospitalized from February 1, 2020, to February 29, 2020 (Return to work after the Spring Festival), at our Department of Hepatobiliary and Pancreatic Surgical Oncology. Results: The study included 92 patients from 12 provinces in the north of China who underwent surgical resection at our Department of Hepatobiliary and Pancreatic Surgical Oncology during the COVID-19 epidemic. Robotic surgery was performed on 82% (75/92) of patients, while the rest underwent laparoscopic (2/92) and open surgery (15/92). Eighty-six patients had malignant tumor, and six had emergency benign diseases. Only five patients had severe pancreatic fistula, and three had biliary fistula after operation. Conclusions: The standardized hospitalization and treatment processes described in this study could prevent cross-infection of patients and still ensure timely treatment of patients with hepatobiliary and pancreatic cancers. These study findings will guide the management of surgical oncology departments and treatment of patients with hepatobiliary and pancreatic oncology during serious epidemics.

Rapid Detection of Anti-SARS-CoV-2 IgM and IgG Using a Selenium Nanoparticle-based Lateral Flow Immunoassay (preprint)

Background: Coronavirus disease 2019 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 is highly transmissible. Early and rapid testing is necessary to effectively prevent and control the outbreak. Detection of SARS-CoV-2 antibodies with lateral flow immunoassay can achieve this goal. Antibody detection is especially effective for the detection of asymptomatic infection.Methods: In this study, SARS-CoV-2 nucleoprotein was expressed by E. coli and purified by affinity chromatography. We used the highly stable and sensitive selenium nanoparticle as the labeling probe coupled with the SARS-CoV-2 nucleoprotein to prepare a new SARS-CoV-2 antibody (IgM and IgG) detection kit. The sensitivity and specificity of the kit were verified by plasma of COVID-19 patients and health persons. Separate detection of IgM and IgG, such as in this assay, was performed in order to reduce mutual interference and improve the accuracy of the test results.Results: The SARS-CoV-2 nucleoprotein was purified on a nickel column, and the final purity was greater than 90%. The sensitivity of the kit was 94.74% and the specificity was 95.12% by 41 negative plasma samples and 19 positive plasma samples detection.Conclusions: The assay kit does not require any special device for reading the results and the readout is a simple color change that can be evaluated with the naked eye. This kit is suitable for rapid and real-time detection of the SARS-CoV-2 antibody.