A paper based microfluidic device for easy detection of uric acid using positively charged gold nanoparticles

A paper based microfluidic device is fabricated that can rapidly detect very low concentrations of uric acid (UA) using 3,5,3', 5'-tetramethyl benzidine (TMB), H2O2 and positively charged gold nanoparticles ((+) AuNPs). In the presence of (+) AuNPs, H2O2 reacts with TMB to produce a bluish-green colour which becomes colourless on reaction with UA. This colorimetric method can detect as low as 8.1 ppm of UA within <20 minutes on white filter paper. This technique provides an alternative way for UA detection.