Development of uric acid and oxalic acid sensors using a bio-thermochip

Novel uric acid and oxalic acid sensors have been developed by immobilizing uricase and oxalate oxidase to form bio-thermochips. Uric acid is determined in the range 16 mM and oxalic acid in the range 0.2-0.8 mM. To measure the kidney calculus indices (uric acid and oxalic acid) simultaneously, the feasibility of integrating the two sensors has been examined. The pH dependence of the oxalic acid sensor, the effect of uric acid on the oxalic acid sensor and the effect of oxalic acid on the uric acid sensor ate examined. Although the optimum pH for oxalate oxidase is 5, the response of the oxalic acid sensor in pH 8 buffer is high enough for the determination of oxalic acid. Uric acid and oxalic acid do not interfere with the determination of each other's concentration using the oxalic acid and uric acid sensors. Therefore, construction of a multi-functional bio-thermochip system for the determination of kidney calculus indices, uric acid and oxalic acid, should be made possible by integrating the two bio-thermochips.