title: Iron oxide/carbon black (Fe2O3/CB) composite electrode for the detection of reduced nicotinamide cofactors using an amperometric method under a low overpotential.
abstract: An amperometric biosensor for the detection of the reduced nicotinamide cofactors NADH and NADPH was designed, based on the electrochemical oxidation of NAD(P)H with an iron oxide/carbon black composite (Fe(2)O(3)/CB) electrode. The electrode exhibited excellent performances in that it led to a substantial decrease in the overpotential of electrochemical NADH oxidation. Iron oxide plays a significant role as a catalyst for NADH oxidation and the reaction occurs at +0.00 V (vs. Ag/AgCl). The method of the sensor construction is very simple and the sensor performed well, giving high sensitivity, high stability, and a broad detection range. The sensitivity of this system is 2.54 microA mM(-1) and the limit of detection (S/N=3) is 10 microM. A linear range was observed between 10 microM and 1000 microM of NADH (R(2)=0.993), which is preferable to that of the previous studies. The Fe(2)O(3)/CB electrode also oxidizes NADPH under the same condition and can be applied as an NADPH sensor. Moreover, when the sensor system was integrated into a dehydrogenase-based sensor system, it also showed a good sensing performance.
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Yang Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Taeho
authors.initials: T
authors.lastname: Kim
authors.forename: Ji Heon
authors.initials: JH
authors.lastname: Ryu
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Yoo
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003067:Coenzymes / Q000032:analysis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005290:Ferric Compounds / Q000737:chemistry*; D009243:NAD / Q000032:analysis* / Q000737:chemistry; D009249:NADP / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053260:Soot / Q000737:chemistry*
chemical_list: D003067:Coenzymes; D005290:Ferric Compounds; D053260:Soot; D009243:NAD; C000499:ferric oxide; D009249:NADP