BIOSENSORS
Measuring sweat in real time
As soon as certain ions come in contact with this sensor, their current flow changes.
Flexible organic, electrochemical transistors calculate the concentration of ions when the current flow changes. | Photo: zVg
This innovative biosensor sticks to your skin like a plaster. It continuously measures the concentration of sodium, potassium and hydrogen ions in your sweat, which means it can warn you when you’re getting dehydrated.
At the heart of this thin, flexible sensor are so-called organic electrochemical transistors. These comprise conductive polymers and electrodes of silver nanoparticles. When they come into contact with ions, the current flow in the transistor changes, which enables the concentration of the ions to be measured. These components are just a few square millimetres in size, and a research team led by Danick Briand at EPFL has now printed an array of them onto a film, using an inkjet printer. They then cover them with membranes that only allow a specific kind of ion through.
Briand would like his system to be able to register other substances – such as cortisol – as this would enable it to improve the monitoring of our state of health yet further.
