Abstract
Direct electrochemistry of a glucose oxidase (GOD)-graphene-chitosan nanocomposite was studied. The immobilized enzyme retains its bioactivity, exhibits a surface confined, reversible two-proton and two-electron transfer reaction, and has good stability, activity and a fast heterogeneous electron transfer rate with the rate constant (ks) of 2.83 s-1. A much higher enzyme loading (1.12 × 10-9 mol/cm2) is obtained as compared to the bare glass carbon surface. This GOD-graphene-chitosan nanocomposite film can be used for sensitive detection of glucose. The biosensor exhibits a wider linearity range from 0.08 mM to 12 mM glucose with a detection limit of 0.02 mM and much higher sensitivity (37.93 μA mM-1 cm-2) as compared with other nanostructured supports. The excellent performance of the biosensor is attributed to large surface-to-volume ratio and high conductivity of graphene, and good biocompatibility of chitosan, which enhances the enzyme absorption and promotes direct electron transfer between redox enzymes and the surface of electrodes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 901-905 |
| Number of pages | 5 |
| Journal | Biosensors and Bioelectronics |
| Volume | 25 |
| Issue number | 4 |
| DOIs | |
| State | Published - Dec 15 2009 |
All Science Journal Classification (ASJC) codes
- Biophysics
- Biotechnology
- Biomedical Engineering
- Electrochemistry
Keywords
- Chitosan
- Direct electron transfer
- Glucose oxidase
- Graphene