An amperomertic uric acid biosensor based on immobilization of uricase onto polyaniline-multiwalled carbon nanotube composite film.

A highly sensitive, amperometric uric acid biosensor possessing unique physical, electro-conductive properties of carbon nanotubes is described for determination of uric acid level in serum. A uric acid biosensor was constructed after immobilization of uricase onto a polyaniline/CNT matrix by carbonamide linkage. The scanning electron micrographs confirmed the immobilization of globular enzyme onto the electroploymerized polyaniline/CNT composite. Employment of carbon nanotubes composite in the present electrode leads to a very quick response time of 8 sec with the minimum detection limit of 5 microM along with an increase in shelf-life of electrode system to >180 days with slight loss of enzyme activity. Efficiency of the present amperometric uric acid biosensor was validated by quantitative estimation of uric acid level in biological serum of healthy individuals and the persons suffering from hyperuricemia and gout.