Sars cov 2 spike s1 antibody

10,12-pentacosadiynoic acid (PCDA) was purchased from Sigma-Aldrich (St. Louis, MO, USA). 1,2-dimyristoyl-sn-glycerol-3-phosphocholine (DMPC) was purchased from Avanti Polar Lipids (Alabaster, AL, USA). PVDF transfer membranes (0.45 µm) were purchased from Thermo Fisher Scientific (Waltham, MA, USA). Artificial saliva with mucin (Pickering Laboratories) was purchased from Fisher Scientific (Waltham, MA, USA). SARS-CoV-2 Spike S1 Antibody, SARS-CoV-2 Spike S1-His Recombinant Protein, and MERS-CoV Spike S1 Protein were purchased from Sino Biological (Beijing, China). All other compounds were purchased from Sigma-Aldrich (St. Louis, MO, USA).

Primary antibody staining was performed at 4°C for 1 hour, cells were then washed in FACS buffer (1% BSA and 0.05% Sodium Azide in phosphate-buffered saline) and secondary antibody was added for 30 minutes at 4°C. Then, cells were washed in FACS buffer and fixed with 4% paraformaldehyde for 20 minutes followed by CytoFlex analysis. We used the following primary antibodies: Rabbit MAb SARS-CoV-2 Spike S1 Antibody (Cat#40150-R007-100, Sino Biological), Purified anti-DYKDDDDK Tag Antibody (Cat#637302, BioLegend), anti-ACE2 01 (generated by us). The following secondary antibodies were used: Alexa Fluor 647- conjugated Goat Anti-Rabbit IgG (Cat#111-606-144, Jackson ImmunoResearch Laboratories), Alexa Fluor 647-conjugated Donkey anti-human IgG (Cat#709-606-098, Jackson ImmunoResearch Laboratories), Alexa Fluor 647-conjugated Goat Anti-Mouse IgG (Cat#115-606-062, Jackson ImmunoResearch Laboratories). Data were analyzed using FCS Express 6/7.

Graphene dispersion (0.4 ml, 1 mg/ml) was spray-coated onto the interdigital gold electrode on a hot plate at 140°C. The sprayed graphene sample was treated with UV-ozone (UVO) cleaning in a Jelight 144AX-220 cleaner for 5 min and immersed in DI water for 12 hours to remove the sodium dodecyl benzene sulfonate surfactant. Next, 10 μl of PBA (5 mM in methanol) was linked to the graphene surface and rested in methanol atmosphere at room temperature for 3 hours. Following the sample washing with methanol and air dry, 5 μl of mixed solution of EDC [1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; 0.4 M] and NHS (N-hydroxysuccinimide; 0.1 M) in MES (0.025 M) was added on graphene surface and rested for 1 hour. After washing the sample by DI water, SARS-CoV-2 spike S1 antibody (5 μl, 250 μg/ml; Sino Biological, catalog no. 40150-R007) was added onto the graphene and rested for 4 hours. Finally, the sensor was blocked with 2% BSA in 1× phosphate-buffered saline (PBS) buffer for 1 hour. Through this process, this sensor was functionalized to enable the detection of SARS-CoV-2 virus.