Paper Based Low-Cost and Portable Ultrasensitive Electroanalytical Devicefor The Detection of Uric Acid in Human Urine

The electrochemical literature describes a plethora of devices for various applications. Design and development of such paper-based analytical device(PAD) for sensing applications is paramount of interest. In this work, a PAD was developed using common office-hold items like paper, pencil, crayons and scotch tape. On a paper, a three-electrode system was developed by simple drawing with pencils, and the accessible area was confined by creating a hydrophobic barrier using color crayons. The newly developed PAD can hold a low-dead volume of 25 mu L for the analysis and is sealed at the bottom using scotch tape. In our preliminary approach, uric acid (UA), a critical biomarker, was demonstrated as a model analyte for the application of the developed PAD as an electrochemical sensor. The sensor exhibited better analytical performance for UA sensing in a wide range (0.1-1 mM) with appreciable reproducibility, sensitivity (0.3x10(-3) A M-1) and selectivity over common interferents (ascorbic acid, urea and glucose). Furthermore, the developed electroanalytical approach was validated by testing the UA in non-invasive bio-sample (human urine). Such a cheap, portable, disposable, biocompatible, eco-friendly and fully-drawn PAD paves the way for the development of affordable 'lab on paper' devices for a wide range of bioanalytical applications.