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Background Several reports on epidemiological and clinical features of the 2019 coronavirus disease (COVID-19) have been published. However, mortality and morbidity analyses, important for better understanding the pathogenesis of this disease, are scarce. We examine the clinical and laboratory features of 14 patients who died of COVID-19. Methods The cohort consisted of 11 male and 3 female patients, with 9 patients aged 70 years or above, and nearly all had underlying diseases. Results Fever with bilateral pneumonia was the main manifestation. Most patients had consolidations combined with ground glass opacity (GGO) on chest computed tomography scan. Laboratory tests showed lymphocytopenia in 10 patients, high blood glucose in 11, GGT in 5 of the 14 patients, and high LDH in 5 of 6 patients tested. In addition, this cohort had high level of cytokines such as interleukin-6 in all 8 patients tested. Conclusions The clinical and laboratory parameters in the cohort of fatal cases may be incorporated into future clinical prognosis models and will be of help in understanding the pathogenesis of this disease. [ABSTRACT FROM AUTHOR]

The formulation of substrates with reliable quantitative detection and robust molecular anchoring is crucial for surface-enhanced Raman scattering (SERS) technique. In this context, an appealing hydrophilic-hydrophobic polymer strip with Raman internal standard (IS) was generated by in-situ growing hydrophilic non-metallic black phosphorus/metal-organic frameworks (BP/ZIF-67) onto special regions of hydrophobic polydimethylsiloxane (PDMS) matrix, which dramatically promoted the concentration of target molecules. Furthermore, a specific detection of coronavirus disease 2019 (SARS-CoV-2) N-protein with a limit of 6.4 × 10−6 mg/mL was facilitated, benefiting from the selective capture rendered by the mesoporous surface of ZIF-67 and the ultra-high enhancement effect arose from BP/ZIF-67 hybrid structure-triggered charge transfer resonance process. Moreover, the extent of quantification in the SERS assay was significantly remedied due to the IS strategy. Especially, the slight local surface plasmon resonance (LSPR) capability of BP could readily provoke additional electromagnetic field to complement its powerful chemical enhancement, which was significantly superior to other non-metallic substrates. Such an upgraded platform may deliver another prospering technology for dependable virus monitoring. [Display omitted] • SERS-active polymer strip with BP/ZIF-67 for straightforward virus detection. • Comprehensive explanation of chemical-electromagnetic synergistic enrichment mechanism. • Quantitative detection of SARS-CoV-2 with LOD of 6.4 × 10−6 mg/mL was achieved. [ABSTRACT FROM AUTHOR]

The Coronavirus disease 2019 (COVID-19) pandemic brings great challenges to the public health and social economics around the world. As the pandemic continues and the mass vaccination goes on, monitoring the antibodies is particularly important for the epidemiological survey and vaccine assessment. Here, we developed a luciferase immunoprecipitation assay combined with an automated platform to detect anti-Receptor Binding Domain (RBD) antibody, where protein A and protein G modified magnetic beads were used to capture antibodies in serum samples and SARS-CoV-2 RBD was fused with Gaussia luciferase to label the captured target antibodies. The whole detection procedure can be completed within 20 min. The developed assay has proven up to 32 times more sensitive than ELISA for the detection of RBD antibodies. Furthermore, the results of the antibody detection of sera from vaccination as well as convalescence displayed good performance. The automated platform may provide a powerful tool for the control of COVID-19 pandemic by vaccination and the research of SARS-CoV-2 seroconversion. [Display omitted] • Fast and sensitive detection of SARS-CoV-2 antibodies. • Luciferase immunoprecipitation system combined with automatic platform. • Detecting RBD specific antibodies which can predict the viral neutralizing capability. [ABSTRACT FROM AUTHOR]

A new antibody diagnostic assay with more rapid and robust properties is demanded to quantitatively evaluate anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity in a large population. Here, we developed a nanometer-scale fluorescent biosensor system consisting of CdSe-ZnS quantum dots (QDs) coupled with the highly sensitive B-cell epitopes of SARS-CoV-2 that could remarkably identify the corresponding antibody with a detection limit of 100 pM. Intriguingly, we found that fluorescence quenching of QDs was stimulated more obviously when coupled with peptides than the corresponding proteins, indicating that the energy transfer between QDs and peptides was more effective. Compared to the traditional enzyme-linked immunosorbent assay (ELISA), the B-cell-epitope-based QD-biosensor could robustly distinguish coronavirus disease 2019 (COVID-19) antibody-positive patients from uninfected individuals with a higher sensitivity (92.3–98.1% positive rates by QD-biosensor vs. 78.3–83.1% positive rates by ELISAs in 207 COVID-19 patients' sera) in a more rapid (5 min) and labor-saving manner. Taken together, the 'QD-peptides' biosensor provided a novel real-time, quantitative, and high-throughput method for clinical diagnosis and home-use tests. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a free radical playing an important pathophysiological role in cardiovascular and immune systems. Recent studies reported that NO levels were significantly lower in patients with COVID-19, which was suggested to be closely related to vascular dysfunction and immune inflammation among them. In this review, we examine the potential role of NO during SARS-CoV-2 infection from the perspective of the unique physical, chemical and biological properties and potential mechanisms of NO in COVID-19, as well as possible therapeutic strategies using inhaled NO. We also discuss the limits of NO treatment, and the future application of this approach in prevention and therapy of COVID-19. Image 1 • Decreased NO level and bioavailability has been observed in patients with COVID-19. • SARS-CoV-2 infection may cause NO dysfunction in cells and tissue via four pathways. • Inhaled NO might participate in multiple stages of COVID-19 prevention or therapy. [ABSTRACT FROM AUTHOR]

The epidemiologic and clinical characteristics of heart transplant (HTx) recipients during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic remains unclear. We studied the characteristics of HTx recipients from December 20, 2019, to February 25, 2020, in an effort to understand their risk and outcomes. All accessible HTx recipients were included in this single-center retrospective study. We collected information on the recipients using a web-based questionnaire as well as the hospital database. We followed 87 HTx recipients (72.4% were men, and the average age was 51 years). A total of 79 recipients resided in Hubei, and 57 recipients had a Wuhan-related history of travel or contact. Most took precautionary measures while in contact with suspicious crowds, and 96.6% of the families and communities undertook prevention and quarantine procedures. Four upper airway infections were reported, and 3 of them tested negative for SARS-CoV-2 (the fourth recovered and was not tested). All cases were mild and successfully recovered after proper treatment. Laboratory results of 47 HTx cases within the last 2 months were extracted. Of these, 21.3% of recipients had pre-existing lymphopenia, and 87.2% of recipients had a therapeutic concentration of tacrolimus (5–12 ng/ml). Liver and kidney insufficiency was seen in 5 and 6 recipients, respectively. HTx recipients who practiced appropriate prevention measures had a low rate of infection with SARS-CoV-2 and transition to the associated disease COVID-19. These early data will require confirmation as the pandemic establishes around the world. [ABSTRACT FROM AUTHOR]

Rapid and reliable detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody can provide immunological evidence in addition to nucleic acid test for the early diagnosis and on-site screening of coronavirus disease 2019 (COVID-19). All-solid-state biosensor capable of rapid, quantitative SARS-CoV-2 antibody testing is still lacking. Herein, we propose an electronic labelling strategy of protein molecules and demonstrate SARS-CoV-2 protein biosensor employing colloidal quantum dots (CQDs)-modified electrode. The feature current peak corresponding to the specific binding reaction of SARS-CoV-2 antigen and antibody proteins was observed for the first time. The unique charging and discharging effect depending on the alternating voltage applied was ascribed to the quantum confinement, Coulomb blockade and quantum tunneling effects of quantum dots. CQDs-modified electrode could recognize the specific binding reaction between antigen and antibody and then transduce it into significant electrical current. In the case of serum specimens from COVID-19 patient samples, the all-solid-state protein biosensor provides quantitative analysis of SARS-CoV-2 antibody with correlation coefficient of 93.8% compared to enzyme-linked immunosorbent assay (ELISA) results. It discriminates patient and normal samples with accuracy of about 90%. The results could be read within 1 min by handheld testing system prototype. The sensitive and specific protein biosensor combines the advantages of rapidity, accuracy, and convenience, facilitating the implement of low-cost, high-throughput immunological diagnostic technique for clinical lab, point-of-care testing (POCT) as well as home-use test. [Display omitted] • The facile electronic labelling method through one-step ligand exchange treatment without organic cross-linkers was proposed. • All-solid-state SARS-CoV-2 protein biosensor employing CQDs-modified electrode was demonstrated. • The detailed model for the signal transduction mechanism based on the quantum effect of CQDs was elucidated. • The patient and normal samples could be discriminated with an accuracy of about 90%. The results could be read within 1 min by the handheld testing system prototype. [ABSTRACT FROM AUTHOR]

A new SARS-CoV-2 variant B.1.1.529 was named by the WHO as Omicron and classified as a Variant of Concern (VOC) on 26 November 2021. Because this variant has more than 50 mutations, including 30 mutations on the spike, it has generated a lot of concerns on the potential impacts of the VOC on COVID-19. Here through ELISA assays using the recombinant RBD proteins with sequences the same to that of SARS-CoV-2 WIV04 (lineage B.1), the Delta variant and the Omicron variant as the coating antigens, the binding capabilities between the RBDs and the antibodies in COVID-19 convalescent sera and vaccine sera after two doses of the inactivated vaccine produced by Sinopharm WIBP are compared with each other. The results showed that the Omicron variant may evade antibodies induced by the ancestral strain and by the inactivated vaccine, with significant reduction in the binding capability of its RBD much greater than that of the Delta variant. [ABSTRACT FROM AUTHOR]

The spike protein of SARS-CoV-2 has been undergoing mutations and is highly glycosylated. It is critically important to investigate the biological significance of these mutations. Here, we investigated 80 variants and 26 glycosylation site modifications for the infectivity and reactivity to a panel of neutralizing antibodies and sera from convalescent patients. D614G, along with several variants containing both D614G and another amino acid change, were significantly more infectious. Most variants with amino acid change at receptor binding domain were less infectious, but variants including A475V, L452R, V483A, and F490L became resistant to some neutralizing antibodies. Moreover, the majority of glycosylation deletions were less infectious, whereas deletion of both N331 and N343 glycosylation drastically reduced infectivity, revealing the importance of glycosylation for viral infectivity. Interestingly, N234Q was markedly resistant to neutralizing antibodies, whereas N165Q became more sensitive. These findings could be of value in the development of vaccine and therapeutic antibodies. • Over 100 mutations were selected for analyses on their infectivity and antigenicity • The dominant D614G itself and combined with other mutations are more infectious • Ablation of both N331 and N343 glycosylation at RBD drastically reduced infectivity • Ten mutations such as N234Q, L452R, A475V, and V483A was markedly resistant to some mAbs Eighty natural variants and 26 glycosylation spike mutants of SARS-CoV-2 were analyzed in terms of infectivity and antigenicity using high throughput pseudovirus assay in conjunction with neutralizing antibodies. [ABSTRACT FROM AUTHOR]