Bansi Malhotra and colleagues have developed a novel sol-gel-derived nanostructured cerium oxide film on a gold electrode. The device can detect as little as 50 mg of glucose per decilitre of solution and has a long shelf-life of 12 weeks.

Malhotra's team made its cerium oxide films by dip coating the material onto a gold-coated glass plate. The films were dried in air at room temperature and then heat treated at 300 °C for about 3 hours. Next, the researchers spread a layer of glucose oxidase onto the cerium oxide film via a physical adsorption technique and then used the device to detect glucose in solution.

Real-time testing
"Our bioelectrode has many advantages over conventional devices, such as low cost, biocompatibility, non-toxicity, high stability and low detection limit," Malhotra told "The device might be used for real-time testing of glucose in serum and blood samples."

As well as being a good glucose sensor, the electrode could be used to estimate mycotoxicants (such as ochratoxin and aflatoxin) in food samples if it were functionalized with the appropriate antibodies. It might also be used to make DNA, urea and cholesterol biosensors, says Malhotra.

The team now plans to adapt the device so that it can measure glucose in vivo. This would be a big step forward for people with diabetes because they currently measure the amount of glucose in their blood by testing small blood samples, which makes real-time monitoring of blood sugar impossible.

The work was published in Applied Physics Letters.