title: Amperometric biosensor for the determination of creatine.
abstract: An amperometric biosensor for the determination of creatine was developed. The carbon rod electrode surface was coated with sarcosine oxidase (SOX) and creatine amidinohydrolase by cross-linking under glutaraldehyde vapour. The SOX from Arthrobacter sp. 1-1 N was purified and previously used for creation of a creatine biosensor. The natural SOX electron acceptor, oxygen, was replaced by an [Fe(CN)(6)](3-) /[ Fe(CN)(6)](4-) redox mediating system, which allowed amperometric detection of an analytical signal at +400-mV potential. The response time of the biosensor was less than 1 min. The biosensor showed a linear dependence of the signal vs. creatine concentration at physiological creatine concentration levels. The optimal pH in 0.1 M tris(hydroxymethyl)aminomethane (Tris)-HCl buffer was found to be at pH 8.0. The half-life of the biosensor was 8 days in 0.1 M Tris-HCl buffer (pH 8.0) at 20 degrees C. Principal scheme of consecutively followed catalytic reactions used to design a biosensor for the determination of creatine.
authors.affiliation: Centre of Nanotechnology and Material Science, Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, 2006 Vilnius, Lithuania. arunas@imi.lt
authors.forename: A
authors.initials: A
authors.lastname: Ramanavicius
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003401:Creatine / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015203:Reproducibility of Results; D050879:Sarcosine Oxidase / Q000737:chemistry*; D012680:Sensitivity and Specificity; D014512:Ureohydrolases / Q000737:chemistry*
chemical_list: D050879:Sarcosine Oxidase; D014512:Ureohydrolases; C019944:creatinase; D003401:Creatine