title: Direct electrochemistry and reagentless biosensing of glucose oxidase immobilized on chitosan wrapped single-walled carbon nanotubes.
abstract: Single-walled carbon nanotubes (SWCNTs) selectively wrapped by a water-soluble, environmentally friendly, biocompatible polymer chitosan (CHI) were employed for the construction of a bioelectrochemical platform for the direct electron transfer (DET) of glucose oxidase (GOD) and biosensing purposes. Scanning electron microscopy and Raman spectroscopy were used to investigate the properties of the SWCNT-CHI film. The results show that the preferentially wrapped small-diameter SWCNTs are dispersed within the CHI film and exist on the surface of the electrode as small bundles. The DET between GOD and the electrode surface was observed with a formal potential of about ca. -460 mV vs. SCE in phosphate buffer solution. The heterogeneous electron transfer rate constant and the surface coverage of GOD are estimated to be 3.0 s(-1) and 1.3 x 10(-10)mol/cm(2), respectively. The experimental results demonstrate that the immobilized GOD retains its catalytic activity towards the oxidation of glucose. Such a GOD/SWCNT-CHI film-based biosensor not only exhibits a rapid response time, a wide linear rang and a low detection limits at a detection potential of -400 mV but also shows the effective anti-interference capability. Significantly improved analytical capabilities of the GOD/SWCNT-CHI/GC electrode could be ascribed to the unique properties of the individual SWCNTs and to the biocompatibility of CHI.
authors.affiliation: The Key Lab of Analytical Chemistry for Life Science, MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Hong-Yuan
authors.initials: HY
authors.lastname: Chen
mesh_terms: D001672:Biocompatible Materials; D015374:Biosensing Techniques / Q000379:methods*; D002384:Catalysis; D048271:Chitosan; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase; D037742:Nanotubes, Carbon
chemical_list: D001672:Biocompatible Materials; D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D048271:Chitosan; D005949:Glucose Oxidase; D005947:Glucose