Journal: Nature Biomedical Engineering

Article Title: A lab-on-a-chip for the concurrent electrochemical detection of SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies in saliva and plasma

doi: 10.1038/s41551-022-00919-w

Figure Lengend Snippet: ROC curve analysis for electrochemical assays

Article Snippet: A volume of 100 μl of 1 μg ml −1 antigens S1 (SinoBiological, 40591-V08H), N (RayBiotech, 130−10760) and S1-RBD (The Native Antigen Company, REC31849) were prepared in a 10 mM PBS buffer at pH 7.4, added to Nunc MaxiSorp ELISA plates (BioLegend, 423501) and immobilized on the plates by overnight incubation at 4 °C.

Techniques:

Journal: Nature Biomedical Engineering

Article Title: A lab-on-a-chip for the concurrent electrochemical detection of SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies in saliva and plasma

doi: 10.1038/s41551-022-00919-w

Figure Lengend Snippet: a , Schematic illustrating the multiplexed EC serological assay to assess host antibody responses on electrodes functionalized with SARS-CoV-2 antigens. Host antibodies bind to the SARS-CoV-2 antigens immobilized on the chips. Subsequently, biotinylated anti-human IgG secondary antibodies bind, followed by polystreptavidin-HRP binding and TMB precipitation on the chips. b – e , Typical cyclic voltammograms for the four different electrodes that target host antibodies against S1 subunit ( b ), S1-RBD ( c ), N ( d ), and BSA negative control ( e ). f , ROC curves generated from the patient sample data obtained for the IgG EC serology assay.

Article Snippet: A volume of 100 μl of 1 μg ml −1 antigens S1 (SinoBiological, 40591-V08H), N (RayBiotech, 130−10760) and S1-RBD (The Native Antigen Company, REC31849) were prepared in a 10 mM PBS buffer at pH 7.4, added to Nunc MaxiSorp ELISA plates (BioLegend, 423501) and immobilized on the plates by overnight incubation at 4 °C.

Techniques: Serologic Assay, Binding Assay, Negative Control, Generated

Journal: Nature Biomedical Engineering

Article Title: A lab-on-a-chip for the concurrent electrochemical detection of SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies in saliva and plasma

doi: 10.1038/s41551-022-00919-w

Figure Lengend Snippet: a , Schematic of the multiplexed chip surface conjugated with SARS-CoV-2 antigens: S1, S1-RBD and N, as well as PNA for the detection of SARS-CoV-2 viral RNA on the LOC microfluidic system. b – e , Current (A) EC readout from the LOC microfluidic chip for a triplicate of clinical samples containing different host antibody and viral RNA combinations: b , Clinical samples negative for both serology and viral RNA. c , Clinical samples with negative host antibody levels but are positive for viral RNA. d , Clinical samples that contain host antibodies against SARS-CoV-2 but are negative for viral RNA. e , Clinical samples positive for both host antibodies and viral RNA. Clinical RNA samples showed clear signal difference between positive and negative clinical samples (Student’s t -test, P = 0.0002) and the clinical IgG showed clear signal difference for all three antigen tests (Student’s t -test for S1 and S1-RBD, P < 0.0001 and for N, P = 0.0004, datapoints represent independent replicates, black lines represent the median value).

Article Snippet: A volume of 100 μl of 1 μg ml −1 antigens S1 (SinoBiological, 40591-V08H), N (RayBiotech, 130−10760) and S1-RBD (The Native Antigen Company, REC31849) were prepared in a 10 mM PBS buffer at pH 7.4, added to Nunc MaxiSorp ELISA plates (BioLegend, 423501) and immobilized on the plates by overnight incubation at 4 °C.

Techniques:

Journal: PLoS ONE

Article Title: Epigallocatechin gallate (EGCG) attenuates severe acute respiratory coronavirus disease 2 (SARS-CoV-2) infection by blocking the interaction of SARS-CoV-2 spike protein receptor-binding domain to human angiotensin-converting enzyme 2

doi: 10.1371/journal.pone.0271112

Figure Lengend Snippet: (A) Schematic of the ELISA-based screening of phytochemical inhibitory activity on ACE2 and SARS-CoV-2 spike RBD binding. Upper scheme: When the compound does not block the ACE2 and spike RBD binding. Lower scheme: When the compound blocks the ACE2 and spike RBD binding. (B) ELISA results of phytochemical inhibition of the ACE2 and spike RBD binding. Low-intensity HRP signals indicate that the compound successfully blocked the ACE2 and spike RBD binding. Values are presented as the mean ± SD. Asterisks indicate the significant difference compared with the DMSO-treated control (** p < 0.01, * p < 0.05). (C) ELISA results of serially diluted EGCG (3.125–100 μM) inhibition of ACE2 and spike RBD binding b. IC50 was calculated using the IC50 calculator ( https://www.aatbio.com/tools/ic50-calculator ).

Article Snippet: We examined the inhibitory effects of SARS-CoV-2 RBD and ACE2 binding by ELISAs using the Spike S1 RBD (SARS-CoV-2): ACE2 Inhibitor Screening Assay Kit (BPS Bioscience, #79931, San Diego, CA, USA) following the manufacturer’s instructions; we tested all compounds at 100 or 20 μM, and we briefly incubated SARS-CoV-2 spike RBD-Fc (50 ng) overnight for 12 h into a nickel-coated 96-well plate.

Techniques: Enzyme-linked Immunosorbent Assay, Activity Assay, Binding Assay, Blocking Assay, Inhibition

Journal: PLoS ONE

Article Title: Epigallocatechin gallate (EGCG) attenuates severe acute respiratory coronavirus disease 2 (SARS-CoV-2) infection by blocking the interaction of SARS-CoV-2 spike protein receptor-binding domain to human angiotensin-converting enzyme 2

doi: 10.1371/journal.pone.0271112

Figure Lengend Snippet: ( A ) Interacting residues determined within a 5-Å region at the interface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain (RBD) and human ACE2 from their crystal structure (6M17). ( B & C ) Molecular docking of human ACE2 and EGCG. ( B ) Three-dimensional representation of EGCG binding with the human ACE2 peptidase domain (left) and magnified image (right). ( C ) Two-dimensional interaction analysis of ACE2 and EGCG, highlighting the ACE2 residues that interact with EGCG and the types and lengths of their bonds. Residues are color coded according to the type of interaction: dark green, conventional hydrogen bonds; light green, van der Waals forces; dark pink, Pi–Pi stacked interactions; and light pink, Pi–alkyl interactions.

Article Snippet: We examined the inhibitory effects of SARS-CoV-2 RBD and ACE2 binding by ELISAs using the Spike S1 RBD (SARS-CoV-2): ACE2 Inhibitor Screening Assay Kit (BPS Bioscience, #79931, San Diego, CA, USA) following the manufacturer’s instructions; we tested all compounds at 100 or 20 μM, and we briefly incubated SARS-CoV-2 spike RBD-Fc (50 ng) overnight for 12 h into a nickel-coated 96-well plate.

Techniques: Binding Assay

Journal: PLoS ONE

Article Title: Epigallocatechin gallate (EGCG) attenuates severe acute respiratory coronavirus disease 2 (SARS-CoV-2) infection by blocking the interaction of SARS-CoV-2 spike protein receptor-binding domain to human angiotensin-converting enzyme 2

doi: 10.1371/journal.pone.0271112

Figure Lengend Snippet: ( A ) Images of 293FT and Caco-2 cells grown on 100-mm plates taken under a phase-contrast microscope. Scale bar: 100 μm. ( B ) Cropped image of western blot performed with ACE2 and Glyceraldehyde 3-phosphate dehydrogenase antibodies. ( C ) Outline of the experimental procedure. Caco-2 cells were treated with or without EGCG for 2 h. After treatment, the cells were washed with PBS thrice, and fresh medium was added. After 22 h of incubation, cell growth was determined. ( D ) Effects of EGCG on Caco-2 cell growth. Cell growth was assessed by the cell proliferation assay and expressed as a percentage of dimethyl sulfoxide (DMSO)-treated control cells. Asterisks indicate the significant difference compared with the DMSO-treated control (** p < 0.01).

Article Snippet: We examined the inhibitory effects of SARS-CoV-2 RBD and ACE2 binding by ELISAs using the Spike S1 RBD (SARS-CoV-2): ACE2 Inhibitor Screening Assay Kit (BPS Bioscience, #79931, San Diego, CA, USA) following the manufacturer’s instructions; we tested all compounds at 100 or 20 μM, and we briefly incubated SARS-CoV-2 spike RBD-Fc (50 ng) overnight for 12 h into a nickel-coated 96-well plate.

Techniques: Microscopy, Western Blot, Incubation, Proliferation Assay