*4.1. Reagents and Materials*

ZEN, its analogs, and common mycotoxin standards were purchased from Pribolab Pte. Ltd. (Biopolis, Singapore). The BSA and GAM-IgG were supplied by Sigma-Aldrich (St. Louis, MO, USA). The trisodium citrate, HAuCl4, and K2CO<sup>3</sup> were bought from Aladdin (Shanghai, China). The NC membranes were from Millipore (Bedford, MA, USA). The absorbent pad, sample pad, polyvinyl chloride (PVC) sheet, and glass-fiber conjugate pad were provided by Jiening Bio. Tech. Co., Ltd. (Shanghai, China). The ZEN antigen (ZEN-BSA) and McAb against ZEN (ZEN-McAb) were supplied by Biosco Biological Tech. Co., Ltd. (Dalian, China). The other reagents were all of analytical grade.

The XYZ3030 dispense platform (Kinbio Tech. Co., Ltd., Shanghai, China) and the HGS201 automatic programmable cutter (Hangzhou Autokun Tech. Co., Ltd., Hangzhou, China) were used in the preparation of the ICA strips. The Tecnai 12 transmission electron microscope (Philips, Eindhoven, Netherlands) was used to scan the diameter and shape of the nanoparticles. The Milli-Q purification system (Millipore, Bedford, MA, USA) was used for preparing the purified water. The TG16-WS high-speed centrifuge was used for centrifuging (Cence Co., Changsha, China). The vortex mixer was provided by North TZ-Biotech Develop. Co., Ltd. (Beijing, China). The results of the ICA for detecting ZEN were confirmed with an Agilent 1200-6460 LC-MS/MS equipped with electrospray ionization (Agilent, Wilmington, DE, USA). The results of the ICA were digitized on an HG-1721 strip reader (Vict Tech. Co., Ltd., Suzhou, China).
