title: Immobilization of glucose oxidase into a nanoporous TiO₂ film layered on metallophthalocyanine modified vertically-aligned carbon nanotubes for efficient direct electron transfer.
abstract: Glucose oxidase (GOD) was adsorbed into a nanoporous TiO₂ film layered on the surface of an iron phthalocyanine (FePc) vertically-aligned carbon nanotube (CNT) modified electrode. A Nafion film was then dropcast on the electrode's surface to improve operational and storage stabilities of the GOD-based electrode. Scanning electron microscopy (SEM) micrographs revealed the formation of FePc and nanoporous TiO₂ nanoparticles along the sidewall and the tip of CNTs. Cyclic voltammograms of the GOD electrode in neutral PBS exhibited a pair of well-defined redox peaks, attesting the direct electron transfer of GOD (FAD/FADH₂) with the underlying electrode. The potential of glucose electro-oxidation under nitrogen was ∼+0.12 V with an oxidation current density of 65.3 μA cm(-2) at +0.77 V. Voltammetric and amperometric responses were virtually unaffected by oxygen, illustrating an efficient and fast direct electron transfer. The modification of the CNT surface with FePc resulted in a biosensor with remarkable detection sensitivity with an oxygen-independent bioelectrocatalysis. In deaerated PBS, the biosensor displayed average response time of 12 s, linearity from 50 μM to 4 mM, and a detection limit of 30 μM (S/N=3) for glucose.
authors.affiliation: Department of Bioengineering, Zhengzhou University, 100# Science Avenue, Zhengzhou 450001, PR China. hfcui@zzu.edu.cn
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Cui
authors.forename: Kuan
authors.initials: K
authors.lastname: Zhang
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Zhang
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Sun
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Wei-De
authors.initials: WD
authors.lastname: Zhang
authors.forename: John H T
authors.initials: JH
authors.lastname: Luong
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D015374:Biosensing Techniques / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005296:Ferrous Compounds / Q000737:chemistry; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry* / Q000378:metabolism; D007211:Indoles / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity; D012680:Sensitivity and Specificity; D014025:Titanium / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005296:Ferrous Compounds; D007211:Indoles; D037742:Nanotubes, Carbon; C493990:iron phthalocyanine; C009495:titanium dioxide; D014025:Titanium; D005949:Glucose Oxidase; D005947:Glucose