LAUSR

This paper describes enzyme‐linked immunosorbent assays (ELISAs) utilizing microfluidic thread/paper‐based analytical devices (μTPAD), microfluidic fabric‐based analytical devices (μFAD), and microfluidic thread‐based analytical devices (μTAD). Here, the quantitative detection of biotinylated goat anti‐mouse IgG (system one) and rabbit IgG (system two) antibodies via colorimetric analysis is detailed. In both systems, antibody is spotted on the detection site and subjected to a series of washes, addition of streptavidin‐alkaline phosphatase (Strep‐ALP) (system 1) or alkaline phosphatase (ALP)‐conjugated secondary antibody (system 2), and colorimetric substrate. The devices are scanned and analyzed yielding a correlation between inverse yellow (or purple) intensity. For system one, a linear range of detection at low concentrations of streptavidin‐alkaline phosphatase (Strep‐ALP) was observed befire the enzyme reached a Vmax. At higher concentrations of Strep‐ALP, saturation is achieved for both the μTPAD and μFAD devices. For system two, the IC50 values obtained for the non‐trifurcated and trifurcated μTADs were determined to be 180.2 fmol/zone and 133.8 fmol/zone, respectively. The IC50 value was demonstrated to be 1034 fmol/zone and 208.6 fmol/zone for the μTPADs and μFADs, respectively. For all devices the lowest concentration of Strep‐ALP or rabbit IgG used in the assay was 3.75 × 10−4 mg/mL and 0.7 fmol/zone, respectively. The development of this technology should further facilitate the use of these platforms for ELISA to detect and quantitate antibodies.