title: Reagentless glucose biosensor based on direct electron transfer of glucose oxidase immobilized on colloidal gold modified carbon paste electrode.
abstract: The direct electrochemistry of glucose oxidase (GOD) adsorbed on a colloidal gold modified carbon paste electrode was investigated. The adsorbed GOD displayed a pair of redox peaks with a formal potential of -(449+/-1) mV in 0.1 M pH 5.0 phosphate buffer solution. The response showed a surface-controlled electrode process with an electron transfer rate constant of (38.9+/-5.3)/s determined in the scan rate range from 10 to 100 mV/s. GOD adsorbed on gold colloid nanoparticles maintained its bioactivity and stability. The immobilized GOD could electrocatalyze the reduction of dissolved oxygen and resulted in a great increase of the reduction peak current. Upon the addition of glucose, the reduction peak current decreased, which could be used for glucose detection with a high sensitivity (8.4 microA/mM), a linear range from 0.04 to 0.28 mM and a detection limit of 0.01 mM at a signal-to-noise ratio of 3sigma. The sensor could exclude the interference of commonly coexisted uric and ascorbic acid.
authors: Department of Chemistry, Institute of Analytical Science, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, China.
authors: Songqin
authors: S
authors: Liu
authors: Huangxian
authors: H
authors: Ju
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001786:Blood Glucose / Q000032:analysis*; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry; D003102:Colloids / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry; D019544:Equipment Failure Analysis; D005947:Glucose / Q000032:analysis* / Q000145:classification*; D005949:Glucose Oxidase / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007202:Indicators and Reagents; D009824:Ointments; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose; D020099:Coated Materials, Biocompatible; D003102:Colloids; D004800:Enzymes, Immobilized; D007202:Indicators and Reagents; D009824:Ointments; D006046:Gold; D006108:Graphite; D005949:Glucose Oxidase; D005947:Glucose