Assay for uric acid level in rat striatum by a reagentless biosensor based on functionalized multi-wall carbon nanotubes with tin oxide

A novel reagentless amperometric uric acid biosensor based on functionalized multi-wall carbon nanotubes (MWCNTs) with tin oxide (SnO2) nanoparticles has been developed. This was successfully applied to assay uric acid levels from an in vivo microdialysis sampling. Compared with unfunctionalized or traditional carboxylic acid (-COOH)-functionalized MWCNTs, the MWCNTs-SnO2 electrode exhibited higher electrocatalytic oxidation to uric acid. Here, MWCNTs-SnO2 may act as an efficient promoter, and the system exhibited a linear dependence on the uric acid concentration over the range from 1.0 x 10(-7) to 5.0 x 10(-4) mol L-1. In addition, there was little ascorbic acid interference. The high sensitivity of the MWCNTs-SnO2 modified enzyme electrode enabled the monitoring of trace levels of uric acid in dialysate samples in rat striatum.