An amperometric biosensor for the assay of sarcosine based on the cross coupled chemical and electrochemical reactions with practical applications.

Abstract In the progresses of prostate cancer (PCa), sarcosine levels increase not only in cells but also in urine samples, suggesting that the measurement of sarcosine in urine can benefit in the creation of non-invasive diagnostic methods for PCa. In this work, a biosensor has been developed for the quantification of sarcosine via the cross coupled chemical and electrochemical reactions with a limit of detection (LOD) of 0.4 nM (S/N = 3). The biosensor has been successfully applied to the analysis of sarcosine in urine samples, which has a great potential application in noninvasive clinical diagnosis of PCa. Graphical abstract An amperometric biosensor has been developed for the quantification of sarcosine via the detection of H 2 O 2 generated from the catalyzed oxidation of sarcosine by sarcosine oxidase (SOX) in the urine. In order to improve the sensitivity of the biosensor, the PAA are immobilized on the electrode surface. PAA is a polymer that would act as a reducing agent on the gold electrode surface and improve the sensitivity of the biosensor through the cross coupled chemical and electrochemical reactions with a limit of detection (LOD) of 0.4 nM (S/N = 3). Unlabelled Image Highlights • A simple and sensitive biosensor for the detection of sarcosine has been developed. • The cross coupled chemical and electrochemical reactions are used for signal amplification skillfully. • Sarcosine has been detected effectively in complex biological samples. • This method may have potential applications in noninvasive clinical diagnosis of PCa. [ABSTRACT FROM AUTHOR]