Rhodamine b

HAuCl₄·3H₂O (99.9% pure), H₂PtCl₆·6H₂O (99% pure), L-(+)-ascorbic acid (99% pure), 3,3′-diaminobenzidine (99% pure), o-phenylenediamine (98% pure) and carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-yloxy (CTPO, 99% pure) were provided by Alfa Aesar. 5,5-Dimethyl-1-pyrroline N-oxide (DMPO, 98% pure) and 2,2,6,6-tetramethylpiperidine (TEMP, 99% pure) were acquired from Innochem. Rhodamine B and glucose oxidase (GOx) were supplied by Amresco. Reduced cytochrome C was purchased from Abcam (Shanghai, China). 2,2′-Azinobis (3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (99% pure) was bought from J&K Scientific Ltd. (Beijing, China). TMB (99% pure) was obtained from Acros. Trisodium citrate dihydrate (99% pure) was provided by Sinopharm Chemical Reagent Co., Ltd. (Beijing, China). PBS buffer (pH 7.2–7.4), α-amylase, lysozyme, and horseradish peroxidase (HRP) were provided by Solarbio Science & Technology Co., Ltd. (Beijing, China). Collagen was supplied by Yuanye Co., Ltd. (Shanghai, China). SARS-CoV-2 S1 recombinant protein (S1 protein), nucleocapsid protein (N protein) and anti-SARS-CoV-2 S1 antibody were acquired from Sangon Biotech Co., Ltd. (Shanghai, China).