title: Co-immobilization of glucose oxidase and xylose dehydrogenase displayed whole cell on multiwalled carbon nanotube nanocomposite films modified electrode for simultaneous voltammetric detection of D-glucose and D-xylose.
abstract: In this paper, we first report the construction of Nafion/glucose oxidase (GOD)/xylose dehydrogenase displayed bacteria (XDH-bacteria)/multiwalled carbon nanotubes (MWNTs) modified electrode for simultaneous voltammetric determination of D-glucose and D-xylose. The optimal conditions for the immobilized enzymes were established. Both enzymes retained their good stability and activities. In the mixture solution of D-glucose and D-xylose containing coenzyme NAD⁺ (the oxidized form of nicotinamide adenine dinucleotide), the Nafion/GOD/XDH-bacteria/MWNTs modified electrode exhibited quasi-reversible oxidation-reduction peak at -0.5 V (vs. saturated calomel electrode, SCE) originating from the catalytic oxidation of D-glucose, and oxidation peak at +0.55 V(vs. SCE) responding to the oxidation of NADH (the reduced form of nicotinamide adenine dinucleotide) by the carbon nanotubes, where NADH is the resultant product of coenzyme NAD⁺ involved in the catalysis of D-xylose by XDH-displayed bacteria. For the proposed biosensor, cathodic peak current at -0.5 V was linear with the concentration of D-glucose within the range of 0.25-6 mM with a low detection limit of 0.1 mM D-glucose (S/N=3), and the anodic peak current at +0.55 V was linear with the concentration of d-xylose in the range of 0.25∼4 mM with a low detection limit of 0.1 mM D-xylose (S/N=3). Further, D-xylose and D-glucose did not interfere with each other. 300-fold excess saccharides including D-maltose, D-galactose, D-mannose, D-sucrose, D-fructose, D-cellobiose, and 60-fold excess L-arabinose, and common interfering substances (100-fold excess ascorbic acid, dopamine, uric acid) as well as 300-fold excess D-xylitol did not affect the detection of D-glucose and D-xylose (both 1 mM). Therefore, the proposed biosensor is stable, specific, reproducible, simple, rapid and cost-effective, which holds great potential in real applications.
authors.affiliation: College of Environment and Safety Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Liang
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Jianguo
authors.initials: J
authors.lastname: Shi
authors.forename: Marco
authors.initials: M
authors.lastname: Mascini
authors.forename: Qiaolin
authors.initials: Q
authors.lastname: Lang
authors.forename: Aihua
authors.initials: A
authors.lastname: Liu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D050542:D-Xylulose Reductase / Q000737:chemistry*; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000737:chemistry; D005947:Glucose / Q000302:isolation & purification*; D005949:Glucose Oxidase / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry; D010084:Oxidation-Reduction; D014994:Xylose / Q000302:isolation & purification*
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D014994:Xylose; D050542:D-Xylulose Reductase; D005949:Glucose Oxidase; D005947:Glucose