Fig. 4. (A) photographic images of the fiberglass microfluidic paper-based calorimetric sensor for evaluation of capillary: AuNPs–CysA and colored TMB solution and AuNPs–CysA (zone 1–1 and 2–1), AuNFs pH = 6.15 and colored TMB solution and AuNFs pH = 6.15 (zone 1–2 and 2–2), AuNFs pH = 4.91 and colored TMB solution and AuNFs pH = 4.91 (zone 1–3 and 2–3), GNSs and colored TMB solution and GNSs (zone 1–4 and 2–4). (B) Colorimetric detection of UA by capillary method under UV light.