Artificial saliva a7990

In this section, we introduce the materials, reagents, and facilities used in this work, as well as the hybrid biosensor fabrication and the biosensing system setup.
The 11-mercaptoundecanoic acid, 2-(N-morpholino) ethane sulfonic acid (MES), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) reagents were purchased from Macklin. N-hydroxy succinimide (NHS) and bovine serum albumin (BSA) were bought from Sigma. The capture monoclonal antibody (40150-D006), SARS-CoV-2 pseudovirus (PSV-001), and MERS-CoV spike protein (40071-V08B1) were purchased from Sino Biological (Beijing, China). The artificial saliva (A7990) was obtained from Solarbio Life Science (Beijing, China). The physical vapor deposition (PVD) (ZD-400 single chamber high vacuum resistive evaporator) was from Shenyang Kecheng Vacuum Tech Co. Ltd (Shenyang, China). The halogen light source, spectrometer (PG2000-Pro), and Y-shaped optic fibers were bought from Idea Optics (Shanghai, China). The robotic arm (Z-Arm 1632) was purchased from HITBOT (Shenzhen, China). The blade dicing machine (DS616) was bought from Shenyang Heyan Technology Co., Ltd. (Shenyang, China).

Artificial saliva (A7990) was purchased from Solarbio Life Science (Beijing, China). A freshly prepared, TE-buffered solution (10 mM Tri-HCl, 1 mM EDTA) was used throughout the study. A freshly prepared buffer B (4.5 g/L glucose, 0.1 g/L CaCl², 0.2 g/L KCl, 0.2 g/L KH₂PO⁴, 0.1 g/L MgCl² 6H₂O, 8 g/L NaCl, 2.1716 g/L Na₂HPO⁴) was used for diluting BSA. Alcohol (99% wt) was purchased from Jiushan Chemical Ltd. (Nanjing, China). Tween-20, BSA, and TCEP (C4706-10G) were purchased from Sigma-Aldrich, PDMS (DC184), and quartz glasses were purchased from Suzhou Research Materials Microtech Ltd. (Suzhou, China). Glycerol and aptamers (Table 1) for SARS-CoV-2 were purchased from Sangon Biotech (Shanghai, China); SARS-CoV-2 pseudovirus (PSV-001) was purchased from Sino Biological (Beijing, China).