Horseradish peroxidase hrp

Chloroauric acid (HAuCl₄⋅3H₂O), chloroplatinic acid (H₂PtCl₆⋅6H₂O), trisodium citrate, and bovine serum albumin (BSA) were purchased from Sigma-Aldrich (St. Louis, MI, United States). Tween-20, horseradish peroxidase (HRP), hydrogen peroxide (30% H₂O₂), and tetramethylbenzidine (TMB) were purchased from Macklin (Shanghai, China). The magnetic beads (MBs), with a diameter of 5 μm, were purchased from Beaverbio (Suzhou, China). The reference standard of SARS-CoV-2 NP antigen was purchased from Bioeast Biotech (Hangzhou, China). The NP (SARS-CoV-2) Detection ELISA Kit was purchased from Biodragon Immunotechnologies (Beijing, China).

4,4-bipyridine, iodomethane, 3-bromo-1-propanamine hydrobromide, bromoacetic acid, carboxymethylcellulose sodium salt (CMC, 1200 cps), Polyethyleneimine (PEI, M_n = 10 K), Hyaluronic acid (HA, M_n = 100 K), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC·HCl), N-hydroxysulfosuccinimide sodium salt (sulfo-NHS), MES (2-morpholinoethanesulfonic acid) buffer (0.2 M, pH = 5.5), 1-adamantanamine hydrochloride (AdH), ferric chloride (FeCl₃), potassium thiocyanate (KSCN), cobaltous chloride (CoCl₂·6H₂O), 2-methylimidazole (2-MI), Zinc Nitrate (Zn(NO₃)₂·6H₂O), horseradish peroxidase (HRP), glucose oxidase (GOD) and o-phenylenediamine (OPDA) were purchased from Macklin. l-lactic acid (LLA), 4-Phenylazophenol, 2-Hydroxynaphthalene, 1-Pyrenol, Poly-l lactic acid (PLLA, M_n = 3.0 K), and Stannous octoate were purchased from J&K. The above reagents were used as received unless otherwise noted. All anhydrous solvents (toluene, dichloromethane (DCM), acetonitrile (MeCN), tetrahydrofuran (THF), N, N-dimethylformamide (DMF), and ethanol) were purchased commercially and used without further purification.