Phosphate buffered saline solution

(3-Aminopropyl)triethoxysilane (APTES, 99%) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd (Shanghai, China). N-Hydroxysuccinimide (NHS), H₂O₂ (30%), KOH, and glutaraldehyde (GA, 25%) was purchased from Sinopharm Chemical Reagent Co., Ltd. H₂SO₄ was purchased from Yantai Far East Fine Chemical Co., Ltd (Yantai, China). Phosphate-buffered saline (PBS) solution was purchased from Cytiva. Bovine serum albumin labelled with fluorescein isothiocyanate (BSA-FITC) was purchased from Dalian Meilun Biotechnology Co., Ltd. Glass capillary (0.5 mm in diameter, 8 cm in length) was purchased from the Instrument Plant of West China Medical University (Chengdu, China). Mouse anti-SARS-CoV-2 NP monoclonal antibody-1 (Capture antibody), mouse anti-SARS-CoV-2 NP monoclonal antibody-2 (detection antibody), and recombinant human SARS-CoV-2 NP protein (N-protein) was purchased from Nanjing Baikang Biotechnology Co., Ltd (Nanjing, China). Green fluorescent microspheres was purchased from Huge Biotechnology Co., Ltd (Shanghai, China). MES, Free acid, HEPES was purchased from Coolaber. EDC•HCL was purchased from Solarbio Life Science Co., Ltd (Beijing, China). Green fluorescence microspheres (100 nm) were purchased from Huge Biotechnology. Bovine serum albumin was purchased from Sigma-Aldrich (St. Louis, MO, USA).