Preparation and Evaluation of FICT Assay

To evaluate the performance of FICT assay, colloidal gold nanoparticles conjugated to Ab was prepared as previously described^{50 (link)}. After 0.02% chloroauric acid (HAuCl4·4H₂O) (Sigma-Aldrich) was brought to a boil, 0.2% sodium citrate was added with constant stirring. After the mixture changed to a wine-reddish color, the solution was boiled for additional 5 min and then stirring for 10 min without boiling. Next, 1 mg of the mAb (2F4) was conjugated with the prepared colloidal gold particles (100 mL). The mAb-gold conjugate was precipitated by centrifugation (27,237 × g) and resuspended in PBS containing 0.1% of BSA to an optical density at 450 nm (OD₄₅₀) of 10. The TL of the strip was prepared by dispensing a desired volume of 2.5 mg/mL mouse mAb (6D7) and 0.5 mg/ml IgG mouse on the CL. Same lysis buffer was used for RDT. A commercial influenza virus A/B RDT (Standard Diagnostics, Yongin, South Korea) was used for comparison. Samples were applied following the manufacturer’s instructions.