Detection of Urea in Human Blood using Graphene-Based Amperometric Biosensor

Urea being an essential clinical analyte, its early and easy detection would be helpful in preventing various diseases. In this study, a graphene-based screen-printed enzymatic biosensor was fabricated for the blood urea detection by amperometric method. The electrode surface was modified with urease and glutamate dehydrogenase (Urs-GLDH) enzymes for sensitive and selective detection of urea with a wide detection range. The diffusion coefficient and the electron transfer rate constant of the screen-printed graphene electrode (SPGE) was found to be 8.53 × 10 −7 cm 2 s −1 and 7.58 × 10 −5 cm s −1 , respectively. The proposed graphene-based enzymatic urea biosensor can detect urea ranging from 2.5 to 30 mM with a sensitivity of 10.59 μ A·mM −1 ·cm −2 . The reliability of this enzymatic biosensor was confirmed by measuring urea in human blood and the results showed excellent agreement with the clinical testing method. Hence, the graphene-based biosensor described herein could provide rapid, sensitive, and selective detection of urea with low-cost and simple fabrication. In conclusion, this urea detection approach could be a promising method for developing feasible low-cost clinical diagnostic systems.