A flow-based enzyme-free biosensor fabricated using track-etched membrane electrodes: Selective and sensitive detection of uric acid

A flow-based, enzyme-free biosensor for the selective and sensitive determination of uric acid was developed using track-etched membrane electrodes (TEMEs). The proposed sensor system comprises a pre-reactor electrode to decompose interfering species, such as L-ascorbic acid, and a detector electrode to detect uric acid. TEMEs were prepared by sputter deposition of gold on a track-etched membrane filter. Acetylene black (AB) was introduced as an electrode catalyst by simple filtration with the TEME, and the sensitivity for uric acid using the AB-decorated Au-TEME was much greater than that with bare Au-TEME. The insertion of the 2-aminoethanethiol-modified Au-TEMEs as pre-reactor electrodes upstream of the AB-decorated detector electrode eliminated the interference caused by the co-existence of L-ascorbic acid because the interfering species were electrolyzed at the pre-reactor electrode prior to detection of uric acid. The proposed sensor system was incorporated into a flow-injection analysis system to evaluate the sensor performance. The detection limit of uric acid was 0.6 mu M. A recovery test by standard addition to human urine samples also showed satisfactory results.

Automated summary

A flow-based, enzyme-free biosensor for selective and sensitive determination of uric acid was developed using track-etched membrane electrodes. The sensor system consisted of a pre-reactor electrode for decomposing interfering species and a detector electrode for uric acid detection. The sensor system showed improved sensitivity with the introduction of acetylene black as an electrode catalyst. The system also successfully eliminated interference from co-existing L-ascorbic acid using 2-aminoethanethiol-modified Au-TEMEs as pre-reactor electrodes.