Electrochemical detection of uric acid in undiluted human saliva using uricase paper integrated electrodes.

In this study, we introduce a uricase-immobilized paper (UOx--paper) integrated electrochemical sensor for detection of uric acid (UA) in saliva. The UOx was immobilized on the detection zone in the wax-patterned paper substrate. This UOx-paper was integrated with a Prussian blue--modified, screen-printed carbon electrode after electropolymerization of o-phenylenediamine to construct an electrochemical cell for small-volume (20 μL) of samples.

Rapid and simple colorimetric detection of hydrogen sulfide using an etching-resistant effect on silver nanoprisms.

A fast and sensitive colorimetric paper sensor has been developed using silver nanoprisms (Ag NPRs) with an edge length of ~50 nm for the detection of free HS gas. We prepared two types of Ag NPRs-coated HS sensing papers: a multi-zone patterned paper for passive (diffusion mode), and a single-zone patterned paper for pumped mode of HS gas. The change in color intensity was quantitatively analyzed of Ag NPRs-coated paper after KCl treatment depending on the concentration of HS gas, from yellow to purplish brown.