*2.1. Materials*

Nitrocellulose membranes on a polyester backing (UniSart Lateral Flow CN95 Backed, 20 μm nominal pore size) were purchased from Sartorius (Göttingen, Germany). Phosphatebuffered saline (PBS) and sodium chloride solution (NaCl, 1 M) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Deionized (DI) water was produced in our facilities (conductivity σ = 6.6 × 10−<sup>6</sup> S/m).
