Sarcosine oxidase composite screen-printed electrode for sarcosine determination in biological samples

Tânia S C R Rebelo, Carlos M. Pereira, M. Goreti F Sales, João Paulo da Costa de Noronha, João Costa-Rodrigues, Fernando Silva, Maria H. Fernandes

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

As the prostate cancer (PCa) progresses, sarcosine levels increase both in tumor cells and urine samples, suggesting that this metabolite measurements can help in the creation of non-invasive diagnostic methods for this disease. In this work, a biosensor device was developed for the quanti fi cation of sarcosine via electrochemical detection of H 2 O 2 (at 0.6 V) generated from the catalyzed oxidation of sarcosine. The detection was carried out after the modi fi cation of carbon screen printed electrodes (SPEs) by immobilization of sarcosine oxidase (SOX) on the electrode surface. The strategies used herein included the activation of the carbon fi lms by an electrochemical step and the formation of an NHS/EDAC layer to bond the enzyme to the electrode, the use of metallic or semiconductor nanoparticles layer previously or during the enzyme immobilization. In order to improve the sensor stability and selectivity a polymeric layer with extra enzyme content was further added. The proposed methodology for the detection of sarcosine allowed obtaining a limit of detection (LOD) of 16 nM, using a linear concentration range between 10 and 100 nM. The biosensor was successfully applied to the analysis of sarcosine in urine samples.
Original languageEnglish
Pages (from-to)26-32
JournalAnalytica Chimica Acta
Volume850
DOIs
Publication statusPublished - 19 Nov 2014

Keywords

  • Electrochemical biosensor
  • Sarcosine
  • Sarcosine oxidase
  • Screen-printed electrodes
  • Urine

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