ZnO Nanowire-Based Early Detection of SARS-CoV-2 Antibody Responses in Asymptomatic Patients with COVID-19 (Adv. Mater. Interfaces 14/2022)

ZnO Nanowire Microplate for COVID-19 Antibody Responses In article number 2102046, Jung Kim, Chang-Seop Lee, Hong Gi Kim, and co-workers report the development of ZnO nanowire-fabricated microplate by a modified hydrothermal synthesis method for early detection of SARS-CoV-2 antibody response in asymptomatic patients with COVID-19 as well as symptomatic patients.

ZnO Nanowire-Based Early Detection of SARS-CoV-2 Antibody Responses in Asymptomatic Patients with COVID-19.

A serological immunoassay based on enzyme-linked immunosorbent assay (ELISA) is a crucial tool for screening and identification of human SARS-CoV-2 seroconversion. Various immunoassays are developed to detect the spike 1 (S1) and nucleocapsid (NP) proteins of SARS-CoV-2; however, these serological tests have low sensitivity. Here, a novel microplate (MP) is developed on which a ZnO nanowire (NW) is fabricated by a modified hydrothermal synthesis method. This plate is coated with SARS-CoV-2 NP and used as a fluorescent immunoassay (FIA) to detect antibodies specific for SARS-CoV-2 NP. Compared with the bare MP, the ZnO-NW MP binds high levels (up to 5 µg mL-1) of SARS-CoV-2 NP tagged to histidine without any surface treatment. A novel serological assay based on the ZnO-NW MP is more sensitive than a commercial immunoassay, enabling early detection (within <5 days of a reverse transcription polymerase chain reaction-confirmed COVID-19 infection) of anti-SARS-CoV-2 NP IgG antibodies in asymptomatic patients with COVID-19. This is the first assay to detect early antibody responses to SARS-CoV-2 in asymptomatic patients. Therefore, this serological assay will facilitate accurate diagnosis of COVID-19, as well as estimation of COVID-19 prevalence and incidence.

Rapid Biosensor of SARS-CoV-2 Using Specific Monoclonal Antibodies Recognizing Conserved Nucleocapsid Protein Epitopes.

Coronavirus disease 2019 (COVID-19), the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is characterized by symptoms such as fever, fatigue, a sore throat, diarrhea, and coughing. Although various new vaccines against COVID-19 have been developed, early diagnostics, isolation, and prevention remain important due to virus mutations resulting in rapid and high disease transmission. Amino acid substitutions in the major diagnostic target antigens of SARS-CoV-2 may lower the sensitivity for the detection of SARS-CoV-2. For this reason, we developed specific monoclonal antibodies that bind to epitope peptides as antigens for the rapid detection of SARS-CoV-2 NP. The binding affinity between antigenic peptides and monoclonal antibodies was investigated, and a sandwich pair for capture and detection was employed to develop a rapid biosensor for SARS-CoV-2 NP. The rapid biosensor, based on a monoclonal antibody pair binding to conserved epitopes of SARS-CoV-2 NP, detected cultured virus samples of SARS-CoV-2 (1.4 × 103 TCID50/reaction) and recombinant NP (1 ng/mL). Laboratory confirmation of the rapid biosensor was performed with clinical specimens (n = 16) from COVID-19 patients and other pathogens. The rapid biosensor consisting of a monoclonal antibody pair (75E12 for capture and the 54G6/54G10 combination for detection) binding to conserved epitopes of SARS-CoV-2 NP could assist in the detection of SARS-CoV-2 NP under the circumstance of spreading SARS-CoV-2 variants.

Versatile role of ACE2-based biosensors for detection of SARS-CoV-2 variants and neutralizing antibodies.

Since the beginning of the COVID-19 pandemic, accumulating mutations have led to marked changes in the genetic sequence of SARS-CoV-2. Of these, mutations in the spike (S) protein can alter the properties of the virus, particularly transmissibility and antigenicity. However, it is difficult to detect antigenic variants of the SARS-CoV-2 S protein by immunoassay. Here, we developed an ACE2-based biosensor designed to detect both SARS-CoV-2 S1 mutations and neutralizing antibodies. In "binding mode", the biosensor works by detecting binding of the S protein to an immobilized ACE2 receptor. The ACE2-based biosensor was able to detect S1 proteins of the alpha (500 pg/mL) and beta variants (10 ng/mL), as well as wild-type S1 (10 ng/mL), of SARS-CoV-2. The biosensor distinguished wild-type SARS-CoV-2 S1 from the S1 alpha and beta variants via color differences. In addition, a slight modification to the protocol enabled the ACE2-based biosensor to operate in "blocking mode" to detect neutralizing antibodies in serum samples from COVID-19 patients. Therefore, the ACE2-based biosensor is a versatile test for detecting wild-type S1, S1 mutants, and neutralizing antibodies against SARS-CoV-2. This approach to targeting both the mechanism by which SARS-CoV-2 enters host cells and the subsequent adaptive immune response will facilitate the development of various biosensors against SARS-CoV-2.

Metabolically unhealthy individuals, either with obesity or not, have a higher risk of critical coronavirus disease 2019 outcomes than metabolically healthy individuals without obesity.

BACKGROUND: This study aimed to determine the relative and independent contributions of impaired metabolic health and obesity to critical coronavirus disease 2019 (COVID-19). METHODS: We analyzed 4069 COVID-19 patients between January and June 2020 in South Korea, classified into four groups according to metabolic health status and body mass index (BMI): metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUO). The primary outcome was a composite of intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), extracorporeal membrane oxygenation (ECMO), and death. Multivariable Cox proportional hazard regression models were used to estimate the hazard ratio (HR) for the outcome. RESULTS: The incidence rate (per 100 person-months) of critical COVID-19 was the lowest in the MHNW group (0.90), followed by the MHO (1.64), MUNW (3.37), and MUO (3.37) groups. Compared with MHNW, a significantly increased risk of critical COVID-19 was observed in MUNW (HR, 1.41; 95% CI, 1.01-1.98) and MUO (HR, 1.77; 95% CI, 1.39-2.44) but not in MHO (HR, 1.48; 95% CI, 0.98-2.23). The risk of ICU admission or IMV/ECMO was increased only in MUO; however, the risk of death was significantly higher in MUNW and MUO. The risk of critical COVID-19 increased insignificantly by 2% per 1 kg/m2 BMI increase but significantly by 13% per 1 metabolically unhealthy component increase, even after mutually adjusting for BMI and metabolic health status. CONCLUSIONS: Metabolic health is more important to COVID-19 outcomes than obesity itself, suggesting that metabolic health status should be considered for a precise and tailored management of COVID-19 patients.

High-volume sampler for size-selective sampling of bioaerosols including viruses.

Owing to the recent global spread of the new coronavirus SARS-CoV-2, the development of technology to effectively detect viruses in crowded public places is urgently needed. In this study, a three-stage high-volume bioaerosol sampler was developed for the size-selective sampling of bioaerosols through the suction of air at a high flow rate of 1000 L/min. In stage 1, an omnidirectional inlet cyclone separator that can draw air from all directions was applied to collect bioaerosols larger than 10 µm in the collection fluid. In stage 2, an axial flow cyclone separator was used to collect bioaerosols sized between 2.5 and 10 µm in the collection fluid. In stage 3, bioaerosols smaller than 2.5 µm were collected on a filter and extracted in a solution through an elution process using a sodium phosphate buffer. To simulate the suspension of bioparticles including viruses that are attached to other particles in the atmosphere, the aerosol samples were prepared by coagulating aerosolized bacteriophages with Arizona test dust. Then, the coagulated particles were collected for 30 min using the developed bioaerosol sampler, and the samples collected in each stage were analyzed via polymerase chain reaction (PCR) method. The PCR analysis results confirmed that the high-volume bioaerosol sampler enables size-selective bioaerosol sampling even at a high airflow rate of 1000 L/min. The developed high-volume bioaerosol sampler will be useful in detecting viruses through PCR analysis because it can collect bioaerosols within a specific size range.

2021 Clinical Practice Guidelines for Diabetes Mellitus of the Korean Diabetes Association.

The Committee of Clinical Practice Guidelines of the Korean Diabetes Association (KDA) updated the previous clinical practice guidelines for Korean adults with diabetes and prediabetes and published the seventh edition in May 2021. We performed a comprehensive systematic review of recent clinical trials and evidence that could be applicable in real-world practice and suitable for the Korean population. The guideline is provided for all healthcare providers including physicians, diabetes experts, and certified diabetes educators across the country who manage patients with diabetes or the individuals at the risk of developing diabetes mellitus. The recommendations for screening diabetes and glucose-lowering agents have been revised and updated. New sections for continuous glucose monitoring, insulin pump use, and non-alcoholic fatty liver disease in patients with diabetes mellitus have been added. The KDA recommends active vaccination for coronavirus disease 2019 in patients with diabetes during the pandemic. An abridgement that contains practical information for patient education and systematic management in the clinic was published separately.

Use of Renin-Angiotensin-Aldosterone System Inhibitors and Severe COVID-19 Outcomes in Patients with Hypertension: A Nationwide Cohort Study.

BACKGROUND: Angiotensin-converting enzyme 2 facilitates the entry of severe acute respiratory syndrome coronavirus 2 into the human body. We investigated the association of renin-angiotensin-aldosterone system (RAAS) inhibitor use with severe coronavirus disease 2019 (COVID-19) outcomes in hypertensive patients. METHODS: We identified hypertensive patients with confirmed COVID-19 from the Korean Health Insurance Review and Assessment Service from inception to May 15, 2020. The primary outcome was the composite of intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), continuous renal replacement therapy (CRRT), extracorporeal membrane oxygenation (ECMO), and death from COVID-19. The individual components were evaluated as secondary outcomes. RESULTS: Of 1,374 hypertensive patients with COVID-19, 1,076 (78.3%) and 298 (21.7%) were users and never-users of RAAS inhibitors, respectively. The RAAS inhibitor users were not associated with the risk of the primary outcome (adjusted odds ratio [aOR], 0.72; 95% confidence interval [CI], 0.46 to 1.10). The risk of ICU admission was significantly lower in the users than the never-users (aOR, 0.44; 95% CI, 0.24 to 0.84). The RAAS inhibitors were beneficial only in ICU admissions that did not require IMV (aOR, 0.28; 95% CI, 0.14 to 0.58). The risk of death from COVID-19 was comparable between the groups (aOR, 1.09; 95% CI, 0.64 to 1.85). We could not evaluate the risks of CRRT and ECMO owing to the small number of events. CONCLUSION: RAAS inhibitor use was not associated with the composite of severe outcomes in the hypertensive patients with COVID-19 but significantly lowered the risk of ICU admission, particularly in patients who did not require IMV.

A novel rapid detection for SARS-CoV-2 spike 1 antigens using human angiotensin converting enzyme 2 (ACE2).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), a newly emerging human infectious disease. Because no specific antiviral drugs or vaccines are available to treat COVID-19, early diagnostics, isolation, and prevention are crucial for containing the outbreak. Molecular diagnostics using reverse transcription polymerase chain reaction (RT-PCR) are the current gold standard for detection. However, viral RNAs are much less stable during transport and storage than proteins such as antigens and antibodies. Consequently, false-negative RT-PCR results can occur due to inadequate collection of clinical specimens or poor handling of a specimen during testing. Although antigen immunoassays are stable diagnostics for detection of past infection, infection progress, and transmission dynamics, no matched antibody pair for immunoassay of SARS-CoV-2 antigens has yet been reported. In this study, we designed and developed a novel rapid detection method for SARS-CoV-2 spike 1 (S1) protein using the SARS-CoV-2 receptor ACE2, which can form matched pairs with commercially available antibodies. ACE2 and S1-mAb were paired with each other for capture and detection in a lateral flow immunoassay (LFIA) that did not cross-react with SARS-CoV Spike 1 or MERS-CoV Spike 1 protein. The SARS-CoV-2 S1 (<5 ng of recombinant proteins/reaction) was detected by the ACE2-based LFIA. The limit of detection of our ACE2-LFIA was 1.86 × 105 copies/mL in the clinical specimen of COVID-19 Patients without no cross-reactivity for nasal swabs from healthy subjects. This is the first study to detect SARS-CoV-2 S1 antigen using an LFIA with matched pair consisting of ACE2 and antibody. Our findings will be helpful to detect the S1 antigen of SARS-CoV-2 from COVID-19 patients.