Goat anti-mouse IgG, N-hydroxysuccinimide (NHS), 1-ethyl-3-[3-dimethylaminopropyl]–carbodiimide hydrochloride (EDC), 2-(N-morpholino)ethanesulfonic acid (MES), bovine serum albumin (BSA), phosphate-buffered saline (PBS), silver nitrate (AgNO3), hydroquinone (C6H4-1,4-(OH)2), gold(III) chloride hydrate (HAuCl4), and sodium citrate tribasic dihydrate (C6H5Na3O7·2H2O) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Sodium dodecyl sulfate (SDS) (C12H25NaO4S) was purchased from PanReac AppliChem (Barcelona, Spain).
HS-C2H4-CONH-PEG-C3H6-COOH, MW = 5000 g mol−1 (4900 Da), and CH3O-PEG-NH2, MW = 725–850 Da were purchased from RAPP POLYMER (Tuebingen, Germany). All the reagents were prepared using Milli-Q ultrapure water (resistivity 18.2 MΩ·cm at 25 °C), unless otherwise stated.
An IsoFlow reagent dispensing system (ImageneTechnology, USA) was used to dispense the detection lines (dispense rate 0.100μL mm−1) and the strips were cut with a guillotine Fellowes Gamma (Spain).
A portable strip reader ESE Quant LR3 lateral flow system (Qiagen Inc., Germany) was used to quantify the intensity of the test line by reflectance measurements.