“…1 chromatography paper is the most-used paper substrate for paper-based microfluidics, while nitrocellulose paper is more widely used for lateral flow immunoassays 63,64 for its better protein adsorption ability. 65,66 As an alternative, office paper, a substrate of commercial interest, is accessible but less attractive for technical paper, 67,68 because the high amount of calcium carbonate (CaCO 3 ) present may interfere with the pH. 69 Using Whatman No.…”