3.1. Materials

Sample pad, conjugate pad, Hi-Flow 120 NC membrane, and adsorption pad were purchased from Millipore (Darmstadt, Germany). Gold nanoparticles (AuNPs) 40 nm was purchased from Arista Biologicals Inc. (Pennsylvania, USA). Biotinylated anti-interleukin-6 antibodies, primary anti-interleukin-6 antibodies, and recombinant human IL-6 were purchased from BioLegend Inc. (California, USA). Streptavidin was purchased from Thermo Fisher Scientific (Massachusetts, USA). Potassium carbonate (K₂CO₃), tris-(hydroxymethyl) aminomethane, bovine serum albumin (BSA), Tween 20, and polyethylene glycol (M.W. ~8000) (PEG) were purchased from Sigma Aldrich (Missouri, USA).