Uricase biosensor based on a screen-printed electrode modified with Prussian blue for detection of uric acid in human blood serum

Uric acid (UA), the end-product of purine metabolism, is a very important biological molecule in body fluids. High levels of UA in blood are markers of several diseases such as gout, hyperuricemia and Lesch-Nyan syndrome. In this paper an uricase biosensor, based on a screen-printed electrode modified with Prussian blue, coupled with a portable instrumentation, was assembled showing a working range of 0.03-0.3 mM and a detection limit of 0.01 mM. This biosensor was employed for the analysis of 85 blood serum samples, whose UA levels were independently determined by our University Hospital, using a routine colorimetric method. Results of both methods were in agreement, showing a correlation coefficient equal to 0.981 and Bland-Altman analysis, used to assess the quality of the regression, confirmed that the two methods are comparable. Moreover, a diagnostic test evaluation, performed by constructing the ROC curve, was carried out in order to identify the cut-off of our method and its clinical sensitivity and specificity. In conclusion, the developed electrochemical biosensor could be considered an useful tool suitable for UA analysis in human blood serum, performed outside the classical diagnostic laboratory. (C) 2012 Elsevier B.V. All rights reserved.