Background
A biosensor can be defined as a device incorporating a biological sensing element (e.g., an enzyme) that is intimately connected to a transducer (e.g., an electrode). This emerging technology crosses many traditional academic boundaries and is a powerful analytical tool with biomedical, industrial and environmental applications.

Amperometric biosensors use enzyme technology to target specific analytes. These biosensors have a wide range of applications:

• Clinical diagnosis and biomedicine
• Phamaceutical and drug analysis
• Industrial effluent control
• Food and drink production and analysis

But what makes them more desirable than other analytical techniques?

1. Specificity
2. Speed
3. Simplicity
   

So how do 1st generation amperometric biosensors work? They use an immobilised enzyme to "regognise" the target molecule. The enzyme interacts with the target releasing H₂O₂ as a byproduct. This electroactive byproduct is oxidised and the electrode surface to produce a current which is directly proportional to the concentration of target analyte present. Click here to see a short movie.

Research
Research in our laboratory, among others, has shown recently that oxidase enzymes (EOx), such as glucose oxidase (GOx) and glutamate oxidase (GluOx), can be immobilised successfully onto platinum microelectrodes by trapping these macromolecular catalysts during electrosynthesis of poly-phenylenediamine (PPD) on the electrode surface.

We are also concerned with the fabrication of permselective polymer coatings such as poly-orthophenylenediamine (PoPD), poly-phenol, poly-aniline through electropolymerisation.

These sensors can be used for in-vivo glutamate and glucose monitoring.