A MAGNETIC pill that can be interrogated by radio could one day tell doctors
how acidic your stomach contents are. This would be a boon for people with
ulcers, who currently have to endure having a tube stuck down their throat so
their stomach pH can be measured.
Developed by researchers at the University of Kentucky, the 鈥減ill鈥� consists
of a tiny piece of magnetic tape coated with a polymer. The coating expands and
contracts in response to small changes in pH, distorting the magnetic
tape.
When stimulated by an external magnetic field, the magnetic tape emits radio
waves at frequencies that depend on its shape, revealing what the pH
is, says team leader Craig Grimes. Sensor readings can be taken from more than a
metre away, he says.
Advertisement
Different ceramic coatings will let them measure other factors such as
viscosity, pressure or humidity. Another of the numerous applications the team
is working towards, which they will soon describe in the journal Sensors and
Actuators A, is to monitor oil viscosity in cars鈥攖elling when the oil
needs changing.