A novel disposable amperometric biosensor based on trienzyme electrode for the determination of total creatine kinase

A disposable biosensor was fabricated for the rapid detection of the activity of creatine kinase (CK: adenosine-5-triphosphate-creatine phosphotransferase, EC 2.7.3.2) at a low potential of −100 mV versus an integrated Ag|AgCl reference electrode. Platinum black nano-particles were deposited on the working and counter electrode of the biosensor, and then a highly active redox polymer containing Os(II/III) was modified on the working electrode. A trienzyme complex (containing horseradish peroxidase, glycerophosphate oxidase and glycerol kinase) was finally immobilized on the biosensor. The modified biosensor had excellent electrochemical characteristics for the rapid measurement of CK. The responses to CK in serum were linear over the clinically relevant range (10.01–2748.05 U/L) with a sensitivity of 7 nA/UL−1 cm−2, the correlation coefficient was 0.985 and the relative standard deviation was 4.1% for eight tests of 832.55 U/L CK serum with a response time of 3 min for each test. The integrated three-electrode system biosensor has a promise for application to rapid point-of-care for athletes and patients.