Uricase Based Enzymatic Biosensor for Non-invasive Detection of Uric Acid by Entrapment in PVA-SbQ Polymer Matrix

In this work, an electrochemical approach using uricase (UOx) as an enzyme to detect uric acid (UA) for wound monitoring has been reported. UOx was entrapped in poly (vinyl alcohol) N-methyl-4(4'-formylstyryl) pyridinium methosulfate acetal (PVA-SbQ), a cationic polymer matrix. The polymer-enzyme ratio for immobilization was calculated as 53.2g cm(-2):0.25Ucm(-2). UA was detected both optically as well as electrochemically. A redox electron shuttle, ferrocene carboxylic acid (FCA) was used to facilitate electron transfer. Entrapped UOx provided improved response to UA detection compared to physisorbed UOx. Sensor response was linear in the physiologically relevant ranges between 12 and 100M. The entrapped UOx biosensor was stable for 48h and maintained 90% activity until 5days. This entrapped biosensor was used for UA measurements in biofluids of sweat and wounds. The sensor demonstrated a recovery of approximate to 102-107%. These results show that entrapment of UA in such a polymer matrix is a preferred approach for UA measurements under physiological conditions.